{"headers": [], "text": "'''Agriculture''' is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of [[sedentism|sedentary]] [[human civilization]], whereby farming of [[domestication|domesticated]] species created food [[economic surplus|surpluses]] that enabled people to live in cities. The [[history of agriculture]] began thousands of years ago. After gathering wild grains beginning at least 105,000 years ago, nascent farmers began to plant them around 11,500 years ago. Pigs, sheep, and cattle were domesticated over 10,000 years ago. Plants were independently cultivated in at least 11 regions of the world. [[Industrial agriculture]] based on large-scale [[monoculture]] in the twentieth century came to dominate agricultural output, though about 2 billion people still depended on [[subsistence agriculture]]. Modern [[agronomy]], [[plant breeding]], [[agrochemical]] such as [[pesticide]] and [[fertilizer]], and technological developments have sharply increased [[crop]] yields, while causing [[Environmental impact of agriculture|widespread ecological and environmental damage]]. [[Selective breeding]] and modern practices in [[animal husbandry]] have similarly increased the output of meat, but have raised concerns about [[animal welfare]] and environmental damage. Environmental issues include contributions to [[global warming]], depletion of [[aquifer]], [[deforestation]], [[antibiotic resistance]], and [[growth hormone]] in [[industrial meat production]]. Agriculture is also very sensitive to [[environmental degradation]], such as [[biodiversity loss]], [[desertification]], [[soil degradation]] and [[Climate change and agriculture|global warming]], which cause decrease in crop yield. [[Genetically modified organism]] are widely used, although some are banned in certain countries. The major agricultural products can be broadly grouped into foods, fibers, [[fuel]] and [[raw material]] (such as [[natural rubber|rubber]]). Food classes include cereals ([[grains]]), [[vegetable]], fruits, [[cooking oil|oils]], meat, milk, [[edible mushroom|fungi]] and [[eggs as food|eggs]]. Over one-third of the world's workers are employed in agriculture, second only to the [[service sector]], although in recent decades, the global trend of a decreasing number of agricultural workers continues, especially in developing countries where [[smallholding]] is being overtaken by industrial agriculture and mechanization. Creating global [[sustainable food system]] which provides [[food security]] with [[sustainable agriculture]] practices is an international policy priority articulated in [[Sustainable Development Goal 2|Sustainable Development Goal 2: \"Zero hunger\"]], adopted by the [[United Nations]] in 2015.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Etymology and scope"], "text": "The word ''agriculture'' is a late [[Middle English]] adaptation of Latin ''agricultūra'', from ''ager'', \"field\", and ''cultūra'', \"[[Tillage|cultivation]]\" or \"growing\". While agriculture usually refers to human activities, certain species of [[Attine ants|ant]], [[termite]] and [[ambrosia beetle|beetle]] have been cultivating crops for up to 60 million years. Agriculture is defined with varying scopes, in its broadest sense using natural resources to \"produce commodities which maintain life, including food, fiber, forest products, horticultural crops, and their related services\". Thus defined, it includes [[arable farming]], [[horticulture]], [[animal husbandry]] and [[forestry]], but horticulture and forestry are in practice often excluded.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["History", "Origins"], "text": "The development of agriculture enabled the human population to grow many times larger than could be sustained by [[hunter-gatherer|hunting and gathering]]. Agriculture began independently in different parts of the globe, and included a diverse range of [[taxa]], in at least 11 separate [[centers of origin|centres of origin]]. Wild grains were collected and eaten from at least 105,000 years ago. From around 11,500 years ago, the eight [[Neolithic founder crops]], [[emmer wheat|emmer]] and [[einkorn wheat]], hulled [[barley]], [[pea]], [[lentil]], [[Vicia ervilia|bitter vetch]], [[chick pea]] and [[flax]] were cultivated in the [[Levant]]. Rice was domesticated in China between 11,500 and 6,200 BC with the earliest known cultivation from 5,700 BC, followed by [[mung bean|mung]], [[soy]] and [[Azuki bean|azuki]] beans. Sheep were domesticated in [[Mesopotamia]] between 13,000 and 11,000 years ago. Cattle were domesticated from the wild [[aurochs]] in the areas of modern Turkey and Pakistan some 10,500 years ago. [[Domestic pig|Pig production]] emerged in Eurasia, including Europe, East Asia and Southwest Asia, where [[wild boar]] were first domesticated about 10,500 years ago. In the [[Andes]] of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, [[coca]], [[llama]], [[alpaca]], and [[guinea pig]]. [[Sugarcane]] and some [[List of root vegetables|root vegetables]] were domesticated in [[New Guinea]] around 9,000 years ago. [[Sorghum]] was domesticated in the [[Sahel]] region of Africa by 7,000 years ago. Cotton was domesticated in [[Peru]] by 5,600 years ago, and was independently domesticated in Eurasia. [[Agriculture in Mesoamerica|In Mesoamerica]], wild [[teosinte]] was bred into maize by 6,000 years ago. Scholars have offered multiple hypotheses to explain the historical origins of agriculture. Studies of the transition from [[hunter-gatherer]] to agricultural societies indicate an initial period of intensification and increasing [[sedentism]]; examples are the [[Natufian culture]] in the [[Levant]], and the Early Chinese Neolithic in China. Then, wild stands that had previously been harvested started to be planted, and gradually came to be domesticated.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["History", "Civilizations"], "text": "In Eurasia, the [[Sumer]] started to live in villages from about 8,000 BC, relying on the [[Tigris]] and [[Euphrates]] rivers and a canal system for irrigation. Ploughs appear in [[pictograph]] around 3,000 BC; seed-ploughs around 2,300 BC. Farmers grew wheat, barley, vegetables such as lentils and onions, and fruits including dates, grapes, and figs. [[Ancient Egyptian agriculture]] relied on the [[Nile River]] and its seasonal flooding. Farming started in the predynastic period at the end of the [[Paleolithic]], after 10,000 BC. Staple food crops were grains such as wheat and barley, alongside industrial crops such as [[flax]] and [[papyrus]]. In [[Agriculture in India|India]], wheat, barley and [[jujube]] were domesticated by 9,000 BC, soon followed by sheep and goats. Cattle, sheep and goats were domesticated in [[Mehrgarh]] culture by 8,000–6,000 BC. Cotton was cultivated by the 5th–4th millennium BC. Archeological evidence indicates an animal-drawn [[plough]] from 2,500 BC in the [[Indus Valley Civilisation]]. In [[Agriculture in China|China]], from the 5th century BC there was a nationwide [[granary]] system and widespread [[sericulture|silk farming]]. Water-powered grain mills were in use by the 1st century BC, followed by irrigation. By the late 2nd century, [[heavy plough]] had been developed with iron ploughshares and [[mouldboard]]. These spread westwards across Eurasia. Asian rice was domesticated 8,200–13,500 years ago – depending on the [[molecular clock]] estimate that is used – on the Pearl River in southern China with a single genetic origin from the wild rice ''[[Oryza rufipogon]]''. In [[Agriculture in ancient Greece|Greece]] and [[Roman agriculture|Rome]], the major cereals were wheat, emmer, and barley, alongside vegetables including peas, beans, and olives. Sheep and goats were kept mainly for dairy products. In the Americas, crops domesticated in Mesoamerica (apart from [[teosinte]]) include squash, beans, and [[Theobroma cacao|cacao]]. Cocoa was being domesticated by the Mayo Chinchipe of the upper Amazon around 3,000 BC.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["History", "Civilizations"], "text": "The [[domestic turkey|turkey]] was probably domesticated in Mexico or the American Southwest. The [[Aztec]] developed irrigation systems, formed [[Terrace (agriculture)|terraced]] hillsides, fertilized their soil, and developed [[chinampa]] or artificial islands. The [[Maya civilization|Mayas]] used extensive canal and raised field systems to farm swampland from 400 BC. [[Coca]] was domesticated in the Andes, as were the peanut, tomato, tobacco, and [[pineapple]]. Cotton was domesticated in [[Peru]] by 3,600 BC. Animals including [[llama]], [[alpaca]], and [[guinea pig]] were domesticated there. In [[History of agriculture in the United States|North America]], the indigenous people of the [[Eastern Agricultural Complex|East domesticated crops]] such as [[sunflower]], tobacco, squash and ''[[Chenopodium]]''. Wild foods including [[wild rice]] and [[maple sugar]] were harvested. The domesticated [[strawberry]] is a hybrid of a Chilean and a North American species, developed by breeding in Europe and North America. The [[Agriculture in the prehistoric Southwest|indigenous people of the Southwest]] and the [[Pacific Northwest]] practiced [[forest gardening]] and [[fire-stick farming]]. The [[Native American use of fire|natives controlled fire]] on a regional scale to create a low-intensity [[fire ecology]] that [[Sustainable agriculture|sustained a low-density agriculture]] in loose rotation; a sort of \"wild\" [[permaculture]]. A system of [[companion planting]] called [[Three Sisters (agriculture)|the Three Sisters]] was developed in North America. The three crops were [[winter squash]], maize, and climbing beans. [[Indigenous Australians]], long supposed to have been nomadic [[hunter-gatherers]], practised systematic burning, possibly to enhance natural productivity in fire-stick farming. The [[Gunditjmara]] and other groups developed eel farming and fish trapping systems from some 5,000 years ago. There is evidence of 'intensification' across the whole continent over that period. In two regions of Australia, the central west coast and eastern central, early farmers cultivated yams, native millet, and bush onions, possibly in permanent settlements.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["History", "Revolution"], "text": "In the Middle Ages, both [[Arab Agricultural Revolution|in the Islamic world]] and in Europe, agriculture transformed with improved techniques and the diffusion of crop plants, including the introduction of sugar, rice, cotton and fruit trees (such as the orange) to Europe by way of [[Al-Andalus]]. After 1492 the [[Columbian exchange]] brought New World crops such as maize, potatoes, tomatoes, [[sweet potato]] and [[manioc]] to Europe, and Old World crops such as wheat, barley, rice and [[turnip]], and livestock (including horses, cattle, sheep and goats) to the Americas. [[Irrigation]], [[crop rotation]], and [[fertilizers]] advanced from the 17th century with the [[British Agricultural Revolution]], allowing global population to rise significantly. Since 1900 agriculture in developed nations, and to a lesser extent in the developing world, has seen large rises in productivity as [[Mechanized farming|mechanization]] replaces human labor, and assisted by [[synthetic fertilizer]], pesticides, and [[selective breeding]]. The [[Haber-Bosch]] method allowed the synthesis of [[ammonium nitrate]] fertilizer on an industrial scale, greatly increasing [[crop yields]] and sustaining a further increase in global population. Modern agriculture has raised or encountered ecological, political, and economic issues including [[water pollution]], [[biofuel]], [[genetically modified organism]], [[tariff]] and [[Agricultural subsidy|farm subsidies]], leading to alternative approaches such as the [[organic movement]].", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Types"], "text": "[[Pastoralism]] involves managing domesticated animals. In [[nomadic pastoralism]], herds of livestock are moved from place to place in search of pasture, fodder, and water. This type of farming is practised in arid and semi-arid regions of [[Sahara]], Central Asia and some parts of India. In [[shifting cultivation]], a small area of forest is cleared by cutting and burning the trees. The cleared land is used for growing crops for a few years until the soil becomes too infertile, and the area is abandoned. Another patch of land is selected and the process is repeated. This type of farming is practiced mainly in areas with abundant rainfall where the forest regenerates quickly. This practice is used in Northeast India, Southeast Asia, and the Amazon Basin. [[Subsistence farming]] is practiced to satisfy family or local needs alone, with little left over for transport elsewhere. It is intensively practiced in Monsoon Asia and South-East Asia. An estimated 2.5 billion subsistence farmers worked in 2018, cultivating about 60% of the earth's [[arable land]]. [[Intensive farming]] is cultivation to maximise productivity, with a low fallow ratio and a high use of inputs (water, fertilizer, pesticide and automation). It is practiced mainly in developed countries.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Contemporary agriculture", "Status"], "text": "From the twentieth century, intensive agriculture increased productivity. It substituted synthetic fertilizers and pesticides for labor, but caused increased water pollution, and often involved farm subsidies. In recent years there has been a backlash against the [[environmental awareness|environmental effects]] of conventional agriculture, resulting in the [[organic farming|organic]], [[Regenerative agriculture|regenerative]], and [[sustainable agriculture]] movements. One of the major forces behind this movement has been the [[European Union]], which first certified [[organic food]] in 1991 and began reform of its [[Common Agricultural Policy]] (CAP) in 2005 to phase out commodity-linked farm subsidies, also known as [[Decoupling and re-coupling|decoupling]]. The growth of organic farming has renewed research in alternative technologies such as [[integrated pest management]], selective breeding, and [[controlled-environment agriculture]]. Recent mainstream technological developments include [[genetically modified food]]. Demand for non-food biofuel crops, development of former farm lands, rising transportation costs, [[Climate change and agriculture|climate change]], growing consumer demand in China and India, and [[population growth]], are threatening [[food security]] in many parts of the world. The [[International Fund for Agricultural Development]] posits that an increase in [[smallholding|smallholder agriculture]] may be part of the solution to concerns about [[food prices]] and overall food security, given the favorable experience of Vietnam. [[soil retrogression and degradation|Soil degradation]] and diseases such as [[stem rust]] are major concerns globally; approximately 40% of the world's agricultural land is seriously degraded. By 2015, the [[Agriculture in China|agricultural output of China]] was the largest in the world, followed by the European Union, India and the United States. Economists measure the [[total factor productivity]] of agriculture and by this measure agriculture in the United States is roughly 1.7 times more productive than it was in 1948.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Contemporary agriculture", "Workforce"], "text": "Following the [[three-sector theory]], the number of people employed in agriculture and other [[primary sector|primary]] activities (such as fishing) can be more than 80% in the least developed countries, and less than 2% in the most highly developed countries. Since the [[Industrial Revolution]], many countries have made the transition to developed economies, and the proportion of people working in agriculture has steadily fallen. During the 16th century in Europe, for example, between 55 and 75% of the population was engaged in agriculture; by the 19th century, this had dropped to between 35 and 65%. In the same countries today, the figure is less than 10%. At the start of the 21st century, some one billion people, or over 1/3 of the available work force, were employed in agriculture. It constitutes approximately 70% of the global employment of children, and in many countries employs the largest percentage of women of any industry. The service sector overtook the agricultural sector as the largest global employer in 2007.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Contemporary agriculture", "Safety"], "text": "Agriculture, specifically farming, remains a hazardous industry, and farmers worldwide remain at high risk of work-related injuries, lung disease, [[noise-induced hearing loss]], skin diseases, as well as certain cancers related to chemical use and prolonged sun exposure. On [[industrial agriculture|industrialized farms]], injuries frequently involve the use of [[agricultural machinery]], and a common cause of fatal agricultural injuries in developed countries is [[Rollover protection structure|tractor rollovers]]. Pesticides and other chemicals used in farming can be [[Health effects of pesticides|hazardous to worker health]], and workers exposed to pesticides may experience illness or have children with birth defects. As an industry in which families commonly share in work and live on the farm itself, entire families can be at risk for injuries, illness, and death. Ages 0–6 May be an especially vulnerable population in agriculture; common causes of fatal injuries among young farm workers include drowning, machinery and motor accidents, including with all-terrain vehicles. The [[International Labour Organization]] considers agriculture \"one of the most hazardous of all economic sectors\". It estimates that the annual work-related death toll among agricultural employees is at least 170,000, twice the average rate of other jobs. In addition, incidences of death, injury and illness related to agricultural activities often go unreported. The organization has developed the [[Safety and Health in Agriculture Convention, 2001]], which covers the range of risks in the agriculture occupation, the prevention of these risks and the role that individuals and organizations engaged in agriculture should play. In the United States, agriculture has been identified by the [[National Institute for Occupational Safety and Health]] as a priority industry sector in the [[National Occupational Research Agenda]] to identify and provide intervention strategies for occupational health and safety issues. In the European Union, the [[European Agency for Safety and Health at Work]] has issued guidelines on implementing health and safety directives in agriculture, livestock farming, horticulture, and forestry. The Agricultural Safety and Health Council of America (ASHCA) also holds a yearly summit to discuss safety.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Production", "Crop cultivation systems"], "text": "Cropping systems vary among farms depending on the available resources and constraints; geography and climate of the farm; government policy; economic, social and political pressures; and the philosophy and culture of the farmer. Shifting cultivation (or [[slash and burn]]) is a system in which forests are burnt, releasing nutrients to support cultivation of annual and then [[perennial plant|perennial]] crops for a period of several years. Then the plot is left fallow to regrow forest, and the farmer moves to a new plot, returning after many more years (10–20). This fallow period is shortened if population density grows, requiring the input of nutrients (fertilizer or [[manure]]) and some manual [[pest control]]. Annual cultivation is the next phase of intensity in which there is no fallow period. This requires even greater nutrient and pest control inputs. Further industrialization led to the use of [[monoculture]], when one [[cultivar]] is planted on a large acreage. Because of the low [[biodiversity]], nutrient use is uniform and pests tend to build up, necessitating the greater use of [[pesticide]] and fertilizers. [[Multiple cropping]], in which several crops are grown sequentially in one year, and [[intercropping]], when several crops are grown at the same time, are other kinds of annual cropping systems known as [[polyculture]]. In [[subtropics|subtropical]] and [[arid]] environments, the timing and extent of agriculture may be limited by rainfall, either not allowing multiple annual crops in a year, or requiring irrigation. In all of these environments perennial crops are grown (coffee, chocolate) and systems are practiced such as agroforestry. In [[Temperateness|temperate]] environments, where ecosystems were predominantly [[grassland]] or [[prairie]], highly productive annual farming is the dominant agricultural system. Important categories of food crops include cereals, legumes, forage, fruits and vegetables. [[Natural fiber]] include cotton, [[wool]], [[hemp]], silk and [[flax]]. Specific crops are cultivated in distinct [[growing region]] throughout the world. Production is listed in millions of metric tons, based on [[Food and Agriculture Organization|FAO]] estimates.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Production", "Livestock production systems"], "text": "Animal husbandry is the breeding and raising of animals for meat, milk, [[egg (food)|eggs]], or [[wool]], and for work and transport. [[Working animal]], including horses, [[mule]], [[ox]], [[water buffalo]], camels, llamas, alpacas, donkeys, and dogs, have for centuries been used to help cultivate fields, [[harvest]] crops, wrangle other animals, and transport farm products to buyers. Livestock production systems can be defined based on feed source, as grassland-based, mixed, and landless. , 30% of Earth's ice- and water-free area was used for producing livestock, with the sector employing approximately 1.3 billion people. Between the 1960s and the 2000s, there was a significant increase in livestock production, both by numbers and by carcass weight, especially among beef, pigs and chickens, the latter of which had production increased by almost a factor of 10. Non-meat animals, such as milk cows and egg-producing chickens, also showed significant production increases. Global cattle, sheep and goat populations are expected to continue to increase sharply through 2050. [[Aquaculture]] or fish farming, the production of fish for human consumption in confined operations, is one of the fastest growing sectors of food production, growing at an average of 9% a year between 1975 and 2007. During the second half of the 20th century, producers using selective breeding focused on creating livestock [[breed]] and [[crossbreed]] that increased production, while mostly disregarding the need to preserve [[genetic diversity]]. This trend has led to a significant decrease in genetic diversity and resources among livestock breeds, leading to a corresponding decrease in disease resistance and local adaptations previously found among traditional breeds. Grassland based livestock production relies upon plant material such as [[shrubland]], [[rangeland]], and [[managed intensive rotational grazing|pastures]] for feeding [[ruminant]] animals. Outside nutrient inputs may be used, however manure is returned directly to the grassland as a major nutrient source. This system is particularly important in areas where crop production is not feasible because of climate or soil, representing 30–40 million pastoralists. Mixed production systems use grassland, [[fodder]] crops and grain feed crops as feed for ruminant and monogastric (one stomach; mainly chickens and pigs) livestock. Manure is typically recycled in mixed systems as a fertilizer for crops. Landless systems rely upon feed from outside the farm, representing the de-linking of crop and livestock production found more prevalently in [[Organisation for Economic Co-operation and Development]] member countries. Synthetic fertilizers are more heavily relied upon for crop production and manure use becomes a challenge as well as a source for pollution. Industrialized countries use these operations to produce much of the global supplies of poultry and pork. Scientists estimate that 75% of the growth in livestock production between 2003 and 2030 will be in [[confined animal feeding operations]], sometimes called [[factory farming]]. Much of this growth is happening in developing countries in Asia, with much smaller amounts of growth in Africa. Some of the practices used in commercial livestock production, including the usage of [[growth hormone]], are controversial.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Production", "Production practices"], "text": "Tillage is the practice of breaking up the soil with tools such as the plow or [[harrow (tool)|harrow]] to prepare for planting, for nutrient incorporation, or for pest control. Tillage varies in intensity from conventional to [[no-till farming|no-till]]. It may improve productivity by warming the soil, incorporating fertilizer and controlling weeds, but also renders soil more prone to erosion, triggers the decomposition of organic matter releasing CO, and reduces the abundance and diversity of soil organisms. Pest control includes the management of weeds, insects, [[mite]], and diseases. Chemical (pesticides), biological ([[biocontrol]]), mechanical (tillage), and cultural practices are used. Cultural practices include crop rotation, [[culling]], [[cover crop]], intercropping, [[compost]], avoidance, and [[Disease resistance in fruit and vegetables|resistance]]. Integrated pest management attempts to use all of these methods to keep pest populations below the number which would cause economic loss, and recommends pesticides as a last resort. [[Nutrient management]] includes both the source of nutrient inputs for crop and livestock production, and the method of use of manure produced by livestock. Nutrient inputs can be chemical inorganic fertilizers, manure, [[green manure]], compost and minerals. Crop nutrient use may also be managed using cultural techniques such as crop rotation or a [[fallow]] period. Manure is used either by holding livestock where the feed crop is growing, such as in managed intensive rotational grazing, or [[Manure spreader|by spreading]] either dry or liquid formulations of manure on cropland or [[pasture]]. [[Water management]] is needed where rainfall is insufficient or variable, which occurs to some degree in most regions of the world. Some farmers use irrigation to supplement rainfall. In other areas such as the [[Great Plains]] in the U.S. and Canada, farmers use a fallow year to conserve soil moisture to use for growing a crop in the following year. Agriculture represents 70% of freshwater use worldwide. Production practices are an important cause of on-farm losses, these include inadequate harvesting time, climatic conditions, practices applied at harvest and handling, and challenges in marketing produce. Significant losses are caused by inadequate storage conditions as well as decisions made at earlier stages of the supply chain, which predispose products to a shorter shelf life. According to a report by the [[International Food Policy Research Institute]], agricultural technologies will have the greatest impact on food production if adopted in combination with each other; using a model that assessed how eleven technologies could impact agricultural productivity, food security and trade by 2050, the International Food Policy Research Institute found that the number of people at risk from hunger could be reduced by as much as 40% and food prices could be reduced by almost half. [[Payment for ecosystem services]] is a method of providing additional incentives to encourage farmers to conserve some aspects of the environment. Measures might include paying for reforestation upstream of a city, to improve the supply of fresh water.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Crop alteration and biotechnology", "Plant breeding"], "text": "Crop alteration has been practiced by humankind for thousands of years, since the beginning of civilization. Altering crops through breeding practices changes the genetic make-up of a plant to develop crops with more beneficial characteristics for humans, for example, larger fruits or seeds, drought-tolerance, or resistance to pests. Significant advances in plant breeding ensued after the work of geneticist [[Gregor Mendel]]. His work on [[dominant allele|dominant]] and [[recessive allele]], although initially largely ignored for almost 50 years, gave plant breeders a better understanding of genetics and breeding techniques. Crop breeding includes techniques such as plant selection with desirable traits, [[self-pollination]] and [[cross-pollination]], and molecular techniques that genetically modify the organism. Domestication of plants has, over the centuries increased yield, improved disease resistance and [[drought tolerance]], eased harvest and improved the taste and nutritional value of crop plants. Careful selection and breeding have had enormous effects on the characteristics of crop plants. Plant selection and breeding in the 1920s and 1930s improved pasture (grasses and clover) in New Zealand. Extensive X-ray and ultraviolet induced mutagenesis efforts (i.e. primitive genetic engineering) during the 1950s produced the modern commercial varieties of grains such as wheat, corn (maize) and barley. The [[Green Revolution]] popularized the use of conventional [[Hybrid (biology)|hybridization]] to sharply increase yield by creating \"high-yielding varieties\". For example, average yields of corn (maize) in the US have increased from around 2.5 tons per hectare (t/ha) (40 bushels per acre) in 1900 to about 9.4 t/ha (150 bushels per acre) in 2001. Similarly, worldwide average wheat yields have increased from less than 1 t/ha in 1900 to more than 2.5 t/ha in 1990. South American average wheat yields are around 2 t/ha, African under 1 t/ha, and Egypt and Arabia up to 3.5 to 4 t/ha with irrigation. In contrast, the average wheat yield in countries such as France is over 8 t/ha. Variations in yields are due mainly to variation in climate, genetics, and the level of intensive farming techniques (use of fertilizers, chemical pest control, growth control to avoid lodging).", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Crop alteration and biotechnology", "Genetic engineering"], "text": "Genetically modified organisms (GMO) are [[organism]] whose [[Genetics|genetic]] material has been altered by genetic engineering techniques generally known as [[recombinant DNA technology]]. Genetic engineering has expanded the genes available to breeders to use in creating desired germlines for new crops. Increased durability, nutritional content, insect and virus resistance and herbicide tolerance are a few of the attributes bred into crops through genetic engineering. For some, GMO crops cause [[food safety]] and [[food labeling regulations|food labeling]] concerns. Numerous countries have placed restrictions on the production, import or use of GMO foods and crops. Currently a global treaty, the [[Biosafety Protocol]], regulates the trade of GMOs. There is ongoing discussion regarding the labeling of foods made from GMOs, and while the EU currently requires all GMO foods to be labeled, the US does not. Herbicide-resistant seed has a gene implanted into its genome that allows the plants to tolerate exposure to herbicides, including [[glyphosate]]. These seeds allow the farmer to grow a crop that can be sprayed with herbicides to control weeds without harming the resistant crop. Herbicide-tolerant crops are used by farmers worldwide. With the increasing use of herbicide-tolerant crops, comes an increase in the use of glyphosate-based herbicide sprays. In some areas glyphosate resistant weeds have developed, causing farmers to switch to other herbicides. Some studies also link widespread glyphosate usage to iron deficiencies in some crops, which is both a crop production and a nutritional quality concern, with potential economic and health implications. Other GMO crops used by growers include insect-resistant crops, which have a gene from the soil bacterium ''[[Bacillus thuringiensis]]'' (Bt), which produces a toxin specific to insects. These crops resist damage by insects. Some believe that similar or better pest-resistance traits can be acquired through traditional breeding practices, and resistance to various pests can be gained through hybridization or cross-pollination with wild species. In some cases, wild species are the primary source of resistance traits; some tomato cultivars that have gained resistance to at least 19 diseases did so through crossing with wild populations of tomatoes.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Effects and costs"], "text": "Agriculture imposes multiple external costs upon society through effects such as pesticide damage to nature (especially herbicides and insecticides), nutrient runoff, excessive water usage, and loss of natural environment. A 2000 assessment of agriculture in the UK determined total external costs for 1996 of £2,343 million, or £208 per hectare. A 2005 analysis of these costs in the US concluded that cropland imposes approximately $5 to $16 billion ($30 to $96 per hectare), while livestock production imposes $714 million. Both studies, which focused solely on the fiscal impacts, concluded that more should be done to internalize external costs. Neither included subsidies in their analysis, but they noted that subsidies also influence the cost of agriculture to society. Agriculture seeks to increase yield and to reduce costs. Yield increases with inputs such as fertilisers and removal of pathogens, predators, and competitors (such as weeds). Costs decrease with increasing scale of farm units, such as making fields larger; this means removing [[hedge]], ditches and other areas of habitat. Pesticides kill insects, plants and fungi. These and other measures have cut biodiversity to very low levels on intensively farmed land. In 2010, the [[International Resource Panel]] of the [[United Nations Environment Programme]] assessed the environmental impacts of consumption and production. It found that agriculture and food consumption are two of the most important drivers of environmental pressures, particularly habitat change, climate change, water use and toxic emissions. Agriculture is the main source of toxins released into the environment, including insecticides, especially those used on cotton. The 2011 UNEP Green Economy report states that \"[a]agricultural operations, excluding land use changes, produce approximately 13 per cent of anthropogenic global GHG emissions. This includes GHGs emitted by the use of inorganic fertilizers agro-chemical pesticides and herbicides; (GHG emissions resulting from production of these inputs are included in industrial emissions); and fossil fuel-energy inputs. \"On average we find that the total amount of fresh residues from agricultural and forestry production for second- generation biofuel production amounts to 3.8 billion tonnes per year between 2011 and 2050 (with an average annual growth rate of 11 per cent throughout the period analysed, accounting for higher growth during early years, 48 per cent for 2011–2020 and an average 2 per cent annual expansion after 2020).\" According to FAO’s The State of Food and Agriculture 2019, food production, and in particular food loss and waste, may generate significant negative environmental impacts. It is forecast that a growing population and rising incomes will lead to an increase in demand for agricultural products, exerting even more pressure on the world’s natural resources. This emphasizes the urgency of reducing food loss and waste since it will always improve resource use efficiency and lower GHG emissions per unit of food consumed because more food reaches the consumer for a given level of resources used.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Livestock issues"], "text": "A senior UN official, Henning Steinfeld, said that \"Livestock are one of the most significant contributors to today's most serious environmental problems\". Livestock production occupies 70% of all land used for agriculture, or 30% of the land surface of the planet. It is one of the largest sources of [[greenhouse gas]], responsible for 18% of the world's [[greenhouse gas emissions]] as measured in CO equivalents. By comparison, all transportation emits 13.5% of the CO. It produces 65% of human-related [[nitrous oxide]] (which has 296 times the global warming potential of CO) and 37% of all human-induced [[methane]] (which is 23 times as warming as CO.) It also generates 64% of the [[ammonia]] emission. Livestock expansion is cited as a key factor driving [[deforestation]]; in the Amazon basin 70% of [[Deforestation of the Amazon Rainforest|previously forested area]] is now occupied by pastures and the remainder used for feedcrops. Through deforestation and [[land degradation]], livestock is also driving reductions in biodiversity. Furthermore, the UNEP states that \"[[methane emissions]] from global livestock are projected to increase by 60 per cent by 2030 under current practices and consumption patterns.\"", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Land and water issues"], "text": "Land transformation, the use of land to yield goods and services, is the most substantial way humans alter the Earth's ecosystems, and is considered the driving force in the [[Biodiversity loss|loss of biodiversity]]. Estimates of the amount of land transformed by humans vary from 39 to 50%. Land degradation, the long-term decline in ecosystem function and productivity, is estimated to be occurring on 24% of land worldwide, with cropland overrepresented. The UN-FAO report cites land management as the driving factor behind degradation and reports that 1.5 billion people rely upon the degrading land. Degradation can be deforestation, [[desertification]], [[soil erosion]], mineral depletion, or chemical degradation ([[soil acidification|acidification]] and [[Soil salinity|salinization]]). Agriculture lead to rise in [[Zoonotic disease]] like the [[Coronavirus disease 2019]], by degrading natural buffers between humans and animals, reducing biodiversity and creating big groups of genetically similar animals. [[Eutrophication]], excessive nutrients in [[aquatic ecosystem]] resulting in [[algal bloom]] and [[anoxic waters|anoxia]], leads to [[fish kill]], loss of biodiversity, and renders water unfit for drinking and other industrial uses. Excessive fertilization and manure application to cropland, as well as high livestock stocking densities cause nutrient (mainly [[nitrogen]] and [[phosphorus]]) [[surface runoff|runoff]] and [[leaching (agriculture)|leaching]] from agricultural land. These nutrients are major [[nonpoint source pollution|nonpoint pollutants]] contributing to [[eutrophication]] of aquatic ecosystems and pollution of groundwater, with harmful effects on human populations. Fertilisers also reduce terrestrial biodiversity by increasing competition for light, favouring those species that are able to benefit from the added nutrients. Agriculture accounts for 70 percent of withdrawals of freshwater resources. Agriculture is a major draw on water from [[aquifer]], and currently draws from those underground water sources at an unsustainable rate. It is long known that aquifers in areas as diverse as northern China, the [[Ganges|Upper Ganges]] and the western US are being depleted, and new research extends these problems to aquifers in Iran, Mexico and Saudi Arabia. Increasing pressure is being placed on water resources by industry and urban areas, meaning that [[water scarcity]] is increasing and agriculture is facing the challenge of producing more food for the world's growing population with reduced water resources. [[Farm water|Agricultural water]] usage can also cause major environmental problems, including the destruction of natural wetlands, the spread of water-borne diseases, and land degradation through salinization and waterlogging, when irrigation is performed incorrectly.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Pesticides"], "text": "Pesticide use has increased since 1950 to 2.5million short tons annually worldwide, yet crop loss from pests has remained relatively constant. The World Health Organization estimated in 1992 that three million pesticide poisonings occur annually, causing 220,000 deaths. Pesticides select for [[pesticide resistance]] in the pest population, leading to a condition termed the \"pesticide treadmill\" in which pest resistance warrants the development of a new pesticide. An alternative argument is that the way to \"save the environment\" and prevent famine is by using pesticides and intensive high yield farming, a view exemplified by a quote heading the Center for Global Food Issues website: 'Growing more per acre leaves more land for nature'. However, critics argue that a trade-off between the environment and a need for food is not inevitable, and that pesticides simply replace [[good agricultural practices|good agronomic practices]] such as crop rotation. The [[Push–pull agricultural pest management]] technique involves intercropping, using plant aromas to repel pests from crops (push) and to lure them to a place from which they can then be removed (pull).", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Climate change"], "text": "[[Climate change]] and agriculture are interrelated on a global scale. Global warming affects agriculture through changes in [[instrumental temperature record|average temperatures]], rainfall, and [[extreme weather|weather extremes]] (like storms and heat waves); changes in pests and diseases; changes in atmospheric [[carbon dioxide]] and ground-level [[ozone]] concentrations; changes in the nutritional quality of some foods; and changes in [[current sea level rise|sea level]]. Global warming is already affecting agriculture, with effects unevenly distributed across the world. Future climate change will probably negatively affect [[crop yield|crop production]] in [[low latitude]] countries, while effects in northern [[latitude]] may be positive or negative. Global warming will probably increase the risk of [[food insecurity]] for some vulnerable groups, such as the [[poverty|poor]]. Animal husbandry is also responsible for greenhouse gas production of and a percentage of the world's methane, and future land infertility, and the displacement of wildlife. Agriculture contributes to climate change by [[Human impact on the environment|anthropogenic]] emissions of greenhouse gases, and by the conversion of non-agricultural land such as forest for agricultural use. Agriculture, forestry and land-use change contributed around 20 to 25% to global annual emissions in 2010. A range of policies can reduce the risk of negative climate change impacts on agriculture, and greenhouse gas emissions from the agriculture sector.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Sustainability"], "text": "Current farming methods have resulted in over-stretched water resources, high levels of erosion and reduced soil fertility. There is not enough water to continue farming using current practices; therefore how critical water, land, and [[ecosystem]] resources are used to boost crop yields must be reconsidered. A solution would be to give value to ecosystems, recognizing environmental and livelihood tradeoffs, and balancing the rights of a variety of users and interests. Inequities that result when such measures are adopted would need to be addressed, such as the reallocation of water from poor to rich, the clearing of land to make way for more productive farmland, or the preservation of a wetland system that limits fishing rights. Technological advancements help provide farmers with tools and resources to make farming more sustainable. Technology permits innovations like [[conservation tillage]], a farming process which helps prevent land loss to erosion, reduces water pollution, and enhances [[carbon sequestration]]. Other potential practices include [[conservation agriculture]], [[agroforestry]], improved [[Convertible husbandry|grazing]], avoided grassland conversion, and [[biochar]]. Current mono-crop farming practices in the United States preclude widespread adoption of sustainable practices, such as 2-3 crop rotations that incorporate grass or hay with annual crops, unless negative emission goals such as soil carbon sequestration become policy. According to a report by the International Food Policy Research Institute (IFPRI), agricultural technologies will have the greatest impact on food production if adopted in combination with each other; using a model that assessed how eleven technologies could impact agricultural productivity, food security and trade by 2050, IFPRI found that the number of people at risk from hunger could be reduced by as much as 40% and food prices could be reduced by almost half. The caloric demand of Earth's projected population, with current climate change predictions, can be satisfied by additional improvement of agricultural methods, expansion of agricultural areas, and a sustainability-oriented consumer mindset.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Environmental impact", "Energy dependence"], "text": "Since the 1940s, agricultural productivity has increased dramatically, due largely to the increased use of energy-intensive mechanization, fertilizers and pesticides. The vast majority of this energy input comes from [[fossil fuel]] sources. Between the 1960s and the 1980s, the Green Revolution transformed agriculture around the globe, with world grain production increasing significantly (between 70% and 390% for wheat and 60% to 150% for rice, depending on geographic area) as [[world population]] doubled. Heavy reliance on [[petrochemical]] has raised concerns that oil shortages could increase costs and reduce agricultural output. Industrialized agriculture depends on fossil fuels in two fundamental ways: direct consumption on the farm and manufacture of inputs used on the farm. Direct consumption includes the use of lubricants and fuels to operate farm vehicles and machinery. Indirect consumption includes the manufacture of fertilizers, pesticides, and farm machinery. In particular, the production of [[nitrogen fertilizer]] can account for over half of agricultural energy usage. Together, direct and indirect consumption by US farms accounts for about 2% of the nation's energy use. Direct and indirect energy consumption by U.S. farms peaked in 1979, and has since gradually declined. [[Food systems]] encompass not just agriculture but off-farm processing, packaging, transporting, marketing, consumption, and disposal of food and food-related items. Agriculture accounts for less than one-fifth of food system energy use in the US.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Disciplines", "Agricultural economics"], "text": "Agricultural economics is economics as it relates to the \"production, distribution and consumption of [agricultural] goods and services\". Combining agricultural production with general theories of marketing and business as a discipline of study began in the late 1800s, and grew significantly through the 20th century. Although the study of agricultural economics is relatively recent, major trends in agriculture have significantly affected national and international economies throughout history, ranging from [[tenant farmer]] and [[sharecropping]] in the post-[[American Civil War]] Southern United States to the European [[feudal]] system of [[manorialism]]. In the United States, and elsewhere, food costs attributed to [[food processing]], distribution, and [[agricultural marketing]], sometimes referred to as the [[Agricultural value chain|value chain]], have risen while the costs attributed to farming have declined. This is related to the greater efficiency of farming, combined with the increased level of [[value added|value addition]] (e.g. more highly processed products) provided by the supply chain. [[Market concentration]] has increased in the sector as well, and although the total effect of the increased market concentration is likely increased efficiency, the changes redistribute [[economic surplus]] from producers (farmers) and consumers, and may have negative implications for rural communities. National government policies can significantly change the economic marketplace for agricultural products, in the form of taxation, [[Subsidy|subsidies]], tariffs and other measures. Since at least the 1960s, a combination of trade restrictions, [[exchange rate policy|exchange rate policies]] and subsidies have affected farmers in both the developing and the developed world. In the 1980s, non-subsidized farmers in developing countries experienced adverse effects from national policies that created artificially low global prices for farm products. Between the mid-1980s and the early 2000s, several international agreements limited agricultural tariffs, subsidies and other trade restrictions. However, , there was still a significant amount of policy-driven distortion in global agricultural product prices. The three agricultural products with the greatest amount of trade distortion were sugar, milk and rice, mainly due to taxation. Among the [[oilseed]], sesame had the greatest amount of taxation, but overall, feed grains and oilseeds had much lower levels of taxation than livestock products. Since the 1980s, policy-driven distortions have seen a greater decrease among livestock products than crops during the worldwide reforms in agricultural policy. Despite this progress, certain crops, such as cotton, still see subsidies in developed countries artificially deflating global prices, causing hardship in developing countries with non-subsidized farmers. Unprocessed commodities such as corn, soybeans, and cattle are generally graded to indicate quality, affecting the price the producer receives. Commodities are generally reported by production quantities, such as volume, number or weight.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Disciplines", "Agricultural science"], "text": "[[Agricultural science]] is a broad multidisciplinary field of [[biology]] that encompasses the parts of exact, natural, economic and [[social science]] used in the practice and understanding of agriculture. It covers topics such as agronomy, plant breeding and genetics, [[plant pathology]], crop modelling, soil science, [[entomology]], production techniques and improvement, study of pests and their management, and study of adverse environmental effects such as soil degradation, [[waste management]], and [[bioremediation]]. The scientific study of agriculture began in the 18th century, when [[Johann Friedrich Mayer (agriculturist)|Johann Friedrich Mayer]] conducted experiments on the use of [[gypsum]] (hydrated [[calcium sulphate]]) as a fertilizer. Research became more systematic when in 1843, [[John Lawes]] and Henry Gilbert began a set of long-term agronomy field experiments at [[Rothamsted Research Station]] in England; some of them, such as the [[Park Grass Experiment]], are still running. In America, the [[Hatch Act of 1887]] provided funding for what it was the first to call \"agricultural science\", driven by farmers' interest in fertilizers. In agricultural entomology, the USDA began to research biological control in 1881; it instituted its first large program in 1905, searching Europe and Japan for natural enemies of the [[Lymantria dispar dispar|gypsy moth]] and [[brown-tail]] moth, establishing [[parasitoid]] (such as solitary wasps) and predators of both pests in the USA.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": ["Policy"], "text": "[[Agricultural policy]] is the set of government decisions and actions relating to domestic agriculture and imports of foreign agricultural products. Governments usually implement agricultural policies with the goal of achieving a specific outcome in the domestic agricultural product markets. Some overarching themes include risk management and adjustment (including policies related to climate change, food safety and natural disasters), [[economic stability]] (including policies related to taxes), natural resources and [[environmental sustainability]] (especially [[water resource management|water policy]]), research and development, and market access for domestic commodities (including relations with global organizations and agreements with other countries). Agricultural policy can also touch on [[food quality]], ensuring that the food supply is of a consistent and known quality, food security, ensuring that the food supply meets the population's needs, and [[Conservation biology|conservation]]. Policy programs can range from financial programs, such as subsidies, to encouraging producers to enroll in voluntary quality assurance programs. There are many influences on the creation of agricultural policy, including consumers, agribusiness, trade lobbies and other groups. [[Agribusiness]] interests hold a large amount of influence over policy making, in the form of [[lobbying]] and [[campaign contribution]]. Political action groups, including those interested in environmental issues and labor unions, also provide influence, as do lobbying organizations representing individual agricultural commodities. The [[Food and Agriculture Organization of the United Nations]] (FAO) leads international efforts to defeat hunger and provides a forum for the negotiation of global agricultural regulations and agreements. Dr. Samuel Jutzi, director of FAO's animal production and health division, states that lobbying by large corporations has stopped reforms that would improve human health and the environment. For example, proposals in 2010 for a voluntary code of conduct for the livestock industry that would have provided incentives for improving standards for health, and environmental regulations, such as the number of animals an area of land can support without long-term damage, were successfully defeated due to large food company pressure.", "id": "627", "title": "Agriculture", "categories": ["Agriculture", "Agronomy", "Food industry"], "seealso": ["Ecoagriculture", "Agroecology", "Remote sensing", "List of documentary films about agriculture", "Agricultural robot", "Building-integrated agriculture", "Corporate farming", "Vertical farming", "Vegetable farming", "Agricultural engineering", "Pharming (genetics)", "Hill farming", "Contract farming", "Agricultural aircraft", "Crofting", "Subsistence economy", "Aeroponics"]}
{"headers": [], "text": "'''Aldous Leonard Huxley''' (26 July 1894 – 22 November 1963) was an English writer and philosopher. He wrote nearly 50 books—both novels and non-fiction works—as well as wide-ranging essays, narratives, and poems. Born into the prominent [[Huxley family]], he graduated from [[Balliol College]], [[University of Oxford|Oxford]], with an undergraduate degree in English literature. Early in his career, he published short stories and poetry and edited the literary magazine ''[[Oxford Poetry]]'', before going on to publish travel writing, satire, and [[screenplays]]. He spent the latter part of his life in the United States, living in Los Angeles from 1937 until his death. By the end of his life, Huxley was widely acknowledged as one of the foremost intellectuals of his time. He was nominated for the [[Nobel Prize in Literature]] nine times and was elected Companion of Literature by the [[Royal Society of Literature]] in 1962. Huxley was a [[pacifist]]. He grew interested in philosophical [[mysticism]] and [[universalism]], addressing these subjects with works such as ''[[The Perennial Philosophy]]'' (1945)—which illustrates commonalities between [[Western esotericism|Western]] and [[Eastern philosophy|Eastern]] mysticism—and ''[[The Doors of Perception]]'' (1954)—which interprets his own [[psychedelic experience]] with [[mescaline]]. In his most famous novel ''[[Brave New World]]'' (1932) and his final novel ''[[Island (Huxley novel)|Island]]'' (1962), he presented his vision of [[dystopia]] and [[utopia]], respectively.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Early life"], "text": "Huxley was born in [[Godalming]], Surrey, England, in 1894. He was the third son of the writer and schoolmaster [[Leonard Huxley (writer)|Leonard Huxley]], who edited ''[[Cornhill Magazine]]'', and his first wife, Julia Arnold, who founded [[Prior's Field School]]. Julia was the niece of poet and critic [[Matthew Arnold]] and the sister of [[Mary Augusta Ward|Mrs. Humphry Ward]]. Julia named him Aldous after a character in one of her sister's novels. Aldous was the grandson of [[Thomas Henry Huxley]], the [[Zoology|zoologist]], agnostic, and controversialist (\"Darwin's Bulldog\"). His brother [[Julian Huxley]] and half-brother [[Andrew Huxley]] also became outstanding biologists. Aldous had another brother, Noel Trevenen Huxley (1889–1914), who took his own life after a period of [[Major depressive disorder|clinical depression]]. As a child, Huxley's nickname was \"Ogie\", short for \"Ogre\". He was described by his brother, Julian, as someone who frequently \"[contemplated] the strangeness of things\". According to his cousin and contemporary, Gervas Huxley, he had an early interest in drawing. Huxley's education began in his father's well-equipped botanical laboratory, after which he enrolled at Hillside School near [[Godalming]]. He was taught there by his own mother for several years until she became terminally ill. After Hillside he went on to [[Eton College]]. His mother died in 1908, when he was 14 (his [[Leonard Huxley (writer)|father]] later remarried). He contracted the eye disease [[Keratitis punctata]] in 1911; this \"left [him] practically blind for two to three years.\" This \"ended his early dreams of becoming a doctor.\" In October 1913, Huxley entered [[Balliol College, Oxford]], where he studied English literature. He volunteered for the [[British Army]] in January 1916, for the [[World War I|Great War]]; however, he was rejected on health grounds, being half-blind in one eye. His eyesight later partly recovered. He edited ''[[Oxford Poetry]]'' in 1916, and in June of that year graduated [[Bachelor of Arts|BA]] with [[British undergraduate degree classification#First Class Honours|first class honours]]. His brother Julian wrote: Following his years at Balliol, Huxley, being financially indebted to his father, decided to find employment. He taught French for a year at [[Eton College]], where Eric Blair (who was to take the pen name [[George Orwell]]) and [[Steven Runciman]] were among his pupils. He was mainly remembered as being an incompetent schoolmaster unable to keep order in class. Nevertheless, Blair and others spoke highly of his excellent command of language. Huxley also worked for a time during the 1920s at [[Tata Chemicals Europe|Brunner and Mond]], an advanced chemical plant in [[Billingham]] in County Durham, northeast England. According to the introduction to the latest edition of his science fiction novel ''[[Brave New World]]'' (1932), the experience he had there of \"an ordered universe in a world of planless incoherence\" was an important source for the novel.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Career"], "text": "Huxley completed his first (unpublished) novel at the age of 17 and began writing seriously in his early twenties, establishing himself as a successful writer and social satirist. His first published novels were social satires, ''[[Crome Yellow]]'' (1921), ''[[Antic Hay]]'' (1923), ''[[Those Barren Leaves]]'' (1925), and ''[[Point Counter Point]]'' (1928). ''[[Brave New World]]'' (1932) was his fifth novel and first dystopian work. In the 1920s he was also a contributor to ''[[Vanity Fair (American magazine 1913–1936)|Vanity Fair]]'' and [[Vogue (British magazine)|British ''Vogue'']] magazines.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Career", "Contact with the Bloomsbury Set"], "text": "During the First World War, Huxley spent much of his time at [[Garsington Manor]] near Oxford, home of [[Lady Ottoline Morrell]], working as a farm labourer. There he met several [[Bloomsbury Group]] figures, including [[Bertrand Russell]], [[Alfred North Whitehead]], and [[Clive Bell]]. Later, in ''Crome Yellow'' (1921) he caricatured the Garsington lifestyle. Jobs were very scarce, but in 1919 [[John Middleton Murry]] was reorganising the ''[[Athenaeum (British magazine)|Athenaeum]]'' and invited Huxley to join the staff. He accepted immediately, and quickly married the Belgian refugee Maria Nys, also at Garsington. They lived with their young son in Italy part of the time during the 1920s, where Huxley would visit his friend [[D. H. Lawrence]]. Following Lawrence's death in 1930, Huxley edited Lawrence's letters (1932). Works of this period included important novels on the dehumanising aspects of scientific progress, most famously ''[[Brave New World]]'', and on pacifist themes (for example, ''[[Eyeless in Gaza (novel)|Eyeless in Gaza]]''). In ''[[Brave New World]]'', set in a [[dystopia]] London, Huxley portrays a society operating on the principles of mass production and [[Classical conditioning|Pavlovian conditioning]]. Huxley was strongly influenced by [[F. Matthias Alexander]], and included him as a character in ''[[Eyeless in Gaza (novel)|Eyeless in Gaza]]''. Beginning in this period, Huxley began to write and edit non-fiction works on pacifist issues, including ''[[Ends and Means]]'', ''An Encyclopedia of Pacifism'', and ''Pacifism and Philosophy'', and was an active member of the [[Peace Pledge Union]].", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Career", "Life in the United States"], "text": "In 1937 Huxley moved to Hollywood with his wife Maria, son [[Matthew Huxley]], and friend [[Gerald Heard]]. He lived in the U.S., mainly in southern California, until his death, and also for a time in [[Taos, New Mexico]], where he wrote ''[[Ends and Means]]'' (published in 1937). The book contains tracts on war, religion, nationalism and ethics. Heard introduced Huxley to [[Vedanta]] ([[Upanishads|Upanishad-centered philosophy]]), meditation, and vegetarianism through the principle of [[ahimsa]]. In 1938, Huxley befriended [[Jiddu Krishnamurti]], whose teachings he greatly admired. Huxley and Krishnamurti entered into an enduring exchange (sometimes edging on debate) over many years, with Krishnamurti representing the more rarefied, detached, ivory-tower perspective and Huxley, with his pragmatic concerns, the more socially and historically informed position. Huxley provided an introduction to Krishnamurti's quintessential statement, ''[[The First and Last Freedom]]'' (1954). Huxley also became a Vedantist in the circle of [[Hindu]] [[Swami Prabhavananda]], and introduced [[Christopher Isherwood]] to this circle. Not long afterwards, Huxley wrote his book on widely held spiritual values and ideas, ''[[The Perennial Philosophy]]'', which discussed the teachings of renowned mystics of the world. Huxley's book affirmed a sensibility that insists there are realities beyond the generally accepted \"five senses\" and that there is genuine meaning for humans beyond both sensual satisfactions and sentimentalities. Huxley became a close friend of Remsen Bird, president of [[Occidental College]]. He spent much time at the college, which is in the [[Eagle Rock, Los Angeles|Eagle Rock]] neighbourhood of Los Angeles. The college appears as \"Tarzana College\" in his satirical novel ''[[After Many a Summer]]'' (1939). The novel won Huxley a British literary award, the 1939 [[James Tait Black Memorial Prize]] for fiction. Huxley also incorporated Bird into the novel. During this period, Huxley earned a substantial income as a Hollywood screenwriter; [[Christopher Isherwood]], in his autobiography ''My Guru and His Disciple'', states that Huxley earned more than $3,000 per week (approximately $50,000 in 2020 dollars) as a screenwriter, and that he used much of it to transport Jewish and left-wing writer and artist refugees from Hitler's Germany to the US. In March 1938, Huxley's friend [[Anita Loos]], a novelist and screenwriter, put him in touch with [[Metro-Goldwyn-Mayer]] (MGM), which hired him for ''[[Madame Curie (film)|Madame Curie]]'' which was originally to star [[Greta Garbo]] and be directed by [[George Cukor]]. (Eventually, the film was completed by MGM in 1943 with a different director and cast.) Huxley received screen credit for ''[[Pride and Prejudice (1940 film)|Pride and Prejudice]]'' (1940) and was paid for his work on a number of other films, including ''[[Jane Eyre (1943 film)|Jane Eyre]]'' (1944). He was commissioned by [[Walt Disney]] in 1945 to write a script based on ''[[Alice's Adventures in Wonderland]]'' and the biography of the story's author, [[Lewis Carroll]]. The script was not used, however. Huxley wrote an introduction to the posthumous publication of [[J. D. Unwin]]'s 1940 book ''Hopousia or The Sexual and Economic Foundations of a New Society''.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Career", "Life in the United States"], "text": "On 21 October 1949, Huxley wrote to George Orwell, author of ''[[Nineteen Eighty-Four]]'', congratulating him on \"how fine and how profoundly important the book is.\" In his letter to Orwell, he predicted: In 1953, Huxley and Maria applied for [[Citizenship in the United States|United States citizenship]] and presented themselves for examination. When Huxley refused to bear arms for the U.S. and would not state that his objections were based on religious ideals, the only excuse allowed under the [[McCarran Internal Security Act|McCarran Act]], the judge had to adjourn the proceedings. He withdrew his application. Nevertheless, he remained in the U.S. In 1959 Huxley turned down an offer of a [[Knight Bachelor]] by the [[Harold Macmillan#Prime Minister (1957–1963)|Macmillan government]] without putting forward a reason; his brother Julian had been knighted in 1958, while another brother Andrew would be knighted in 1974. In the fall semester of 1960, Huxley was invited by Professor [[Huston Smith]] to be the Carnegie Visiting Professor of Humanities at the [[Massachusetts Institute of Technology]] (MIT). As part of the MIT centennial program of events organised by the Department of Humanities, Huxley presented a series of lectures titled, \"What a Piece of Work is a Man\" which concerned history, language, and art.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Late-in-life perspectives"], "text": "Biographer Harold H. Watts wrote that Huxley's writings in the \"final and extended period of his life\" are \"the work of a man who is meditating on the central problems of many modern men.\" Huxley had deeply felt apprehensions about the future the developed world might make for itself. From these, he made some warnings in his writings and talks. In a 1958 televised interview conducted by journalist [[Mike Wallace]], Huxley outlined several major concerns: the difficulties and dangers of world overpopulation; the tendency towards distinctly hierarchical social organisation; the crucial importance of evaluating the use of technology in mass societies susceptible to persuasion; the tendency to promote modern politicians to a naive public as well-marketed commodities. In a December 1962 letter to brother Julian, summarizing a paper he had presented in Santa Barbara, he wrote, \"What I said was that if we didn't pretty quickly start thinking of human problems in ecological terms rather than in terms of power politics we should very soon be in a bad way.\" Huxley's engagement with Eastern wisdom traditions was entirely compatible with a strong appreciation of modern science. Biographer Milton Birnbaum wrote that Huxley \"ended by embracing both science and Eastern religion.\" In his last book, ''[[Literature and Science]]'', Huxley wrote that \"The ethical and philosophical implications of modern science are more Buddhist than Christian...\" In \"A Philosopher's Visionary Prediction,\" published one month before he died, Huxley endorsed training in [[general semantics]] and \"the nonverbal world of culturally uncontaminated consciousness,\" writing that \"We must learn how to be mentally silent, we must cultivate the art of pure receptivity... [T]he individual must learn to decondition himself, must be able to cut holes in the fence of verbalized symbols that hems him in.\"", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Association with Vedanta"], "text": "Beginning in 1939 and continuing until his death in 1963, Huxley had an extensive association with the [[Vedanta Society of Southern California]], founded and headed by [[Swami Prabhavananda]]. Together with Gerald Heard, Christopher Isherwood and other followers, he was initiated by the Swami and was taught meditation and spiritual practices. In 1944, Huxley wrote the introduction to the \"Bhagavad Gita: The Song of God\", translated by Swami Prabhavananda and Christopher Isherwood, which was published by the Vedanta Society of Southern California. From 1941 until 1960, Huxley contributed 48 articles to ''Vedanta and the West'', published by the society. He also served on the editorial board with Isherwood, Heard, and playwright [[John Van Druten]] from 1951 through 1962. Huxley also occasionally lectured at the Hollywood and Santa Barbara Vedanta temples. Two of those lectures have been released on CD: ''[[Knowledge and Understanding]]'' and ''[[Who Are We? (album)|Who Are We?]]'' from 1955. Nonetheless, Huxley's agnosticism, together with his speculative propensity, made it difficult for him to fully embrace any form of institutionalised religion.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Psychedelic drug use and mystical experiences"], "text": "In the spring of 1953, Huxley had his first experience with the [[psychedelic drug]] [[mescaline]]. Huxley had initiated a correspondence with Doctor [[Humphry Osmond]], a British psychiatrist then employed in a Canadian institution, and eventually asked him to supply a dose of mescaline; Osmond obliged and supervised Huxley's session in southern California. After the publication of ''[[The Doors of Perception]]'', in which he recounted this experience, Huxley and Swami Prabhavananda disagreed about the meaning and importance of the psychedelic drug experience, which may have caused the relationship to cool, but Huxley continued to write articles for the society's journal, lecture at the temple, and attend social functions. Huxley later had an [[The Doors of Perception#Later experience|experience on mescaline]] that he considered more profound than those detailed in ''The Doors of Perception''. Huxley wrote that \"The mystical experience is doubly valuable; it is valuable because it gives the experiencer a better understanding of himself and the world and because it may help him to lead a less self-centered and more creative life.\"", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Eyesight"], "text": "Differing accounts exist about the details of the quality of Huxley's eyesight at specific points in his life. Circa 1939, Huxley encountered the [[Bates method]], in which he was instructed by [[Margaret Darst Corbett]]. In 1940, Huxley relocated from Hollywood to a ''ranchito'' in the high desert hamlet of [[Llano, California]], in northern [[Los Angeles County]]. Huxley then said that his sight improved dramatically with the Bates Method and the extreme and pure natural lighting of the southwestern American desert. He reported that, for the first time in more than 25 years, he was able to read without glasses and without strain. He even tried driving a car along the dirt road beside the ranch. He wrote a book about his experiences with the Bates Method, ''[[The Art of Seeing]]'', which was published in 1942 (U.S.), 1943 (UK). The book contained some generally disputed theories, and its publication created a growing degree of popular controversy about Huxley's eyesight. It was, and is, widely believed that Huxley was nearly blind since [[#Aldous Huxley eye disease|the illness in his teens]], despite the partial recovery that had enabled him to study at Oxford. For example, some ten years after publication of ''The Art of Seeing'', in 1952, [[Bennett Cerf]] was present when Huxley spoke at a Hollywood banquet, wearing no glasses and apparently reading his paper from the lectern without difficulty: \"Then suddenly he faltered—and the disturbing truth became obvious. He wasn't reading his address at all. He had learned it by heart. To refresh his memory he brought the paper closer and closer to his eyes. When it was only an inch or so away he still couldn't read it, and had to fish for a magnifying glass in his pocket to make the typing visible to him. It was an agonising moment\". Brazilian author [[João Ubaldo Ribeiro]], who as a young journalist spent several evenings in the Huxleys' company in the late 1950s, wrote that Huxley had said to him, with a wry smile, \"I can hardly see at all. And I don't give a damn, really\".", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Eyesight"], "text": "On the other hand, Huxley's second wife, [[Laura Huxley|Laura Archera]], later emphasised in her biographical account, ''This Timeless Moment'': \"One of the great achievements of his life: that of having regained his sight\". After revealing a letter she wrote to the ''Los Angeles Times'' disclaiming the label of Huxley as a \"poor fellow who can hardly see\" by [[Walter C. Alvarez]], she tempered her statement with, \"Although I feel it was an injustice to treat Aldous as though he were blind, it is true there were many indications of his impaired vision. For instance, although Aldous did not wear glasses, he would quite often use a magnifying lens\". Laura Huxley proceeded to elaborate a few nuances of inconsistency peculiar to Huxley's vision. Her account, in this respect, agrees with the following sample of Huxley's own words from ''The Art of Seeing'': \"The most characteristic fact about the functioning of the total organism, or any part of the organism, is that it is not constant, but highly variable\". Nevertheless, the topic of Huxley's eyesight continues to endure similar, significant controversy. American [[popular science]] author [[Steven Johnson (author)|Steven Johnson]], in his book ''Mind Wide Open'', quotes Huxley about his difficulties with [[Encoding (memory)#Visual encoding|visual encoding]]: \"I am and, for as long as I can remember, I have always been a poor visualizer. Words, even the pregnant words of poets, [[Aphantasia|do not evoke pictures in my mind]]. No hypnagogic visions greet me on the verge of sleep. When I recall something, the memory does not present itself to me as a vividly seen event or object. By an effort of the will, I can evoke a not very vivid image of what happened yesterday afternoon ...\".", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Personal life"], "text": "Huxley married on 10 July 1919 Maria Nys (10 September 1899 – 12 February 1955), a Belgian epidemiologist from [[Bellem]], a village near [[Aalter]], he met at [[Garsington]], Oxfordshire, in 1919. They had one child, [[Matthew Huxley]] (19 April 1920 – 10 February 2005), who had a career as an author, anthropologist, and prominent [[epidemiology|epidemiologist]]. In 1955, Maria Huxley died of cancer. In 1956, Huxley married Laura Archera (1911–2007), also an author, as well as a violinist and psychotherapist. She wrote ''This Timeless Moment'', a biography of Huxley. She told the story of their marriage through Mary Ann Braubach's 2010 documentary, ''Huxley on Huxley''. Huxley was diagnosed with [[laryngeal cancer]] in 1960; in the years that followed, with his health deteriorating, he wrote the Utopian novel ''[[Island (Huxley novel)|Island]]'', and gave lectures on \"Human Potentialities\" both at the [[UCSF Medical Center]] and at the [[Esalen Institute]]. These lectures were fundamental to the beginning of the [[Human Potential Movement]]. Huxley was a close friend of [[Jiddu Krishnamurti]] and [[Rosalind Rajagopal]] and was involved in the creation of the Happy Valley School, now [[Besant Hill School]] of Happy Valley, in [[Ojai, California]]. The most substantial collection of Huxley's few remaining papers, following the destruction of most in a fire, is at the [[University of California, Los Angeles Library|Library of the University of California, Los Angeles]]. Some are also at the [[Stanford University Libraries]]. On 9 April 1962, Huxley was informed he was elected Companion of Literature by the [[Royal Society of Literature]], the senior literary organisation in Britain, and he accepted the title via letter on 28 April 1962. The correspondence between Huxley and the society is kept at the [[Cambridge University Library]]. The society invited Huxley to appear at a banquet and give a lecture at [[Somerset House]], London, in June 1963. Huxley wrote a draft of the speech he intended to give at the society; however, his deteriorating health meant he was not able to attend.", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Death"], "text": "On his deathbed, unable to speak owing to advanced laryngeal cancer, Huxley made a written request to his wife Laura for \"[[Lysergic acid diethylamide|LSD]], 100 [[Microgram|µg]], [[Intramuscular injection|intramuscular]].\" According to her account of his death in ''This Timeless Moment'', she obliged with an injection at 11:20 a.m. and a second dose an hour later; Huxley died aged 69, at 5:20 p.m. (Los Angeles time), on 22 November 1963. Media coverage of Huxley's death, along with that of fellow British author [[C. S. Lewis]], was overshadowed by the [[Assassination of John F. Kennedy|assassination of American President John F. Kennedy]] on the same day, less than seven hours before Huxley's death. In a 2009 article for ''[[New York (magazine)|New York]]'' magazine titled \"The Eclipsed Celebrity Death Club\", Christopher Bonanos wrote: This coincidence served as the basis for [[Peter Kreeft]]'s book ''[[Between Heaven and Hell (novel)|Between Heaven and Hell: A Dialog Somewhere Beyond Death with John F. Kennedy, C. S. Lewis, & Aldous Huxley]]'', which imagines a conversation among the three men taking place in Purgatory following their deaths. Huxley's memorial service took place in London in December 1963; it was led by his elder brother Julian. On 27 October 1971, his ashes were interred in the family grave at the Watts Cemetery, home of the [[Watts Mortuary Chapel]] in [[Compton, Guildford]], Surrey, England. Huxley had been a long-time friend of Russian composer [[Igor Stravinsky]], who dedicated his last orchestral composition to Huxley. Stravinsky began ''Variations'' in [[Santa Fe, New Mexico]], in July 1963, and completed the composition in Hollywood on 28 October 1964. It premiered in Chicago on 17 April 1965, by the Chicago Symphony Orchestra, conducted by [[Robert Craft]].", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Awards"], "text": "(-) 1939: [[James Tait Black Memorial Prize]] (-) 1959: [[American Academy of Arts and Letters]] Award of Merit . (-) 1962: Companion of Literature", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Film adaptations of Huxley's work"], "text": "(-) 1950: ''[[Prelude to Fame]]'' based upon ''Young Archimedes'' (-) 1968: ''[[Point Counter Point]]'' (-) 1971: ''[[The Devils (film)|The Devils]]'' (-) 1980: ''[[Brave New World (1980 film)|Brave New World]]'' (-) 1998: ''[[Brave New World (1998 film)|Brave New World]]'' (-) 2020: ''[[Brave New World (2020 TV series)|Brave New World]]''", "id": "628", "title": "Aldous Huxley", "categories": ["Aldous Huxley", "1894 births", "1963 deaths", "20th-century English novelists", "20th-century essayists", "Alumni of Balliol College, Oxford", "Anti-consumerists", "Bates method", "British agnostics", "British emigrants to the United States", "British essayists", "British male novelists", "British male poets", "British male short story writers", "British pacifists", "British philosophers", "British satirists", "British science fiction writers", "British short story writers", "Burials in Surrey", "Consciousness researchers and theorists", "Deaths from cancer in California", "Deaths from laryngeal cancer", "Duke University faculty", "English agnostics", "English essayists", "English expatriates in the United States", "English male novelists", "English male poets", "English male short story writers", "English pacifists", "English people of Cornish descent", "English philosophers", "English satirists", "English science fiction writers", "English short story writers", "English travel writers", "Futurologists", "Human Potential Movement", "Huxley family", "James Tait Black Memorial Prize recipients", "Male essayists", "Moral philosophers", "Mystics", "Neo-Vedanta", "People educated at Eton College", "People from Godalming", "Perennial philosophy", "Philosophers of culture", "Philosophers of ethics and morality", "Philosophers of literature", "Philosophers of mind", "Philosophers of technology", "Psychedelic drug advocates", "Writers from Los Angeles", "Writers from Taos, New Mexico", "20th-century English philosophers"], "seealso": ["List of peace activists"]}
{"headers": ["Places", "Africa"], "text": "(-) [[Ada Foah]] or Ada, Ghana, a town (-) [[Ada (Ghana parliament constituency)]] (-) [[Ada, Delta]], a town in Isoko region, Delta State, Nigeria (-) [[Ada, Osun]], a town in Osun State, Nigeria", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Places", "Asia"], "text": "(-) [[Adeh, Urmia]], also known as Ada, a village in West Azerbaijan Province (-) [[Ada, Karaman]], a village in Karaman Province, Turkey", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Places", "Europe"], "text": "(-) [[Ada, Croatia]], a village (-) [[Ada, Serbia]], a town and municipality (-) [[Ada Ciganlija]] or Ada, a river island artificially turned into a peninsula in Belgrade, Serbia", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Places", "North America", "United States"], "text": "(-) [[Ada, Alabama]], an unincorporated community (-) [[Ada County, Idaho]] (-) [[Ada, Kansas]], an unincorporated community (-) [[Ada Township, Michigan]] (-) [[Ada, Minnesota]], a city (-) [[Ada Township, Dickey County, North Dakota]] (-) [[Ada, Ohio]], a village (-) [[Ada, Oklahoma]], a city (-) [[Ada, Oregon]], an unincorporated community (-) [[Ada Township, Perkins County, South Dakota]] (-) [[Ada, West Virginia]], an unincorporated community (-) [[Ada, Wisconsin]], an unincorporated community", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Film and television"], "text": "(-) [[Ada TV]], a television channel in the Turkish Republic of Northern Cyprus (-) [[Ada (1961 film)|''Ada'' (1961 film)]], a 1961 film by Daniel Mann (-) [[Ada (2019 film)|''Ada'' (2019 film)]], a short biopic about Ada Lovelace (-) ''[[Ada... A Way of Life]]'', a 2008 Bollywood musical by Tanvir Ahmed (-) [[Ada (dog actor)]], a dog that played Colin on the sitcom ''Spaced'' (-) Ada, one of the main characters in 1991 movie [[Armour of God II: Operation Condor#Cast|Armour of God II: Operation Condor]]", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Biology"], "text": "(-) [[Ada (plant)|''Ada'' (plant)]], a genus of orchids (-) [[Adenosine deaminase]], an enzyme involved in purine metabolism (-) [[Ada (protein)]], an enzyme induced by treatment of bacterial cells", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Computer science"], "text": "(-) [[Ada (programming language)]], programming language based on Pascal (-) [[Ada (computer virus)]]", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Air travel"], "text": "(-) [[Ada Air]], a regional airline based in Tirana, Albania (-) [[Ada International Airport]] or Saipan International Airport, Saipan Island, Northern Mariana Islands (-) [[Aerolínea de Antioquia]], a Colombian airline (-) [[Airline Deregulation Act]], a 1978 US bill removing governmental control from commercial aviation", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Schools"], "text": "(-) [[Ada, the National College for Digital Skills]], a further education college in Tottenham Hale, London (-) [[Ada High School (Ohio)]], Ada, Ohio (-) [[Ada High School (Oklahoma)]], Ada, Oklahoma", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["People"], "text": "(-) [[Ada (name)]], a feminine given name and a surname, including a list of people and fictional characters (-) [[Ada Lovelace]] (1815–1852), computer scientist sometimes regarded as the first computer programmer", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": ["Other uses"], "text": "(-) [[List of tropical storms named Ada]] (-) [[Ada (food)]], a traditional Kerala delicacy (-) Ada, the currency of the [[Cardano (cryptocurrency platform)|Cardano cryptocurrency platform]] (-) [[Ada Bridge]], Belgrade, Serbia (-) , a cargo vessel built for the London and South Western Railway (-) [[Ada (ship)|''Ada'' (ship)]], a wooden ketch, wrecked near Newcastle, New South Wales, Australia (-) ''[[Ada or Ardor: A Family Chronicle]]'', novel by Vladimir Nabokov (-) [[Dangme language]], spoken in Ghana (ISO 639-2 and 639-3 code \"ada\") (-) [[Ada Health]] GmbH, a symptom checker app", "id": "630", "title": "Ada", "categories": [], "seealso": ["Adha (disambiguation)", "Ada'a", "Ade (disambiguation)", "ADA (disambiguation)", "Adah (disambiguation)", "Ada regulon", "USS ''Little Ada'' (1864)"]}
{"headers": [], "text": "'''[[Aberdeen]]''' is a city in Scotland, United Kingdom. '''Aberdeen''' may also refer to:", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "Africa"], "text": "(-) [[Aberdeen, Sierra Leone]] (-) [[Aberdeen, Eastern Cape]], South Africa", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "Asia", "Hong Kong"], "text": "(-) [[Aberdeen, Hong Kong]], an area and town on southwest Hong Kong Island (-) [[Aberdeen Channel]], a channel between Ap Lei Chau (Aberdeen Island) and Nam Long Shan on the Hong Kong Island in Hong Kong (-) [[Aberdeen floating village]], at Aberdeen Harbour, containing approximately 600 junks, which house an estimated 6,000 people (-) Aberdeen Harbour, a harbour between [[Aberdeen, Hong Kong]] and Ap Lei Chau (Aberdeen Island) (-) [[Aberdeen Tunnel]], a tunnel in Hong Kong Island (-) [[Ap Lei Chau]] or Aberdeen Island, an island of Hong Kong (-) [[Aberdeen (constituency)]], a constituency of Southern District Council", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "Asia", "India"], "text": "(-) Aberdeen Bazaar, a shopping centre in [[Port Blair]], South Andaman Island", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "Australia"], "text": "(-) [[Aberdeen, New South Wales]] (-) [[Aberdeen, South Australia]], one of the early townships that merged in 1940 to create the town of Burra (-) [[Aberdeen, Tasmania]], a suburb of the [[City of Devonport]]", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "Europe"], "text": "(-) [[Aberdeen (Parliament of Scotland constituency)]] (-) [[Aberdeen (UK Parliament constituency)]] 1832-1885 (-) [[Aberdeen Burghs (UK Parliament constituency)]] 1801-1832 (-) [[Aberdeen Central (Scottish Parliament constituency)]] (-) [[Aberdeen Central (UK Parliament constituency)]] (-) [[Aberdeen Donside (Scottish Parliament constituency)]] (-) [[County of Aberdeen]], a historic county of Scotland whose county town was Aberdeen (-) [[Old Aberdeen]], a part of the city of Aberdeen in Scotland", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "North America", "Canada"], "text": "(-) Aberdeen, community in the township of [[Champlain, Ontario|Champlain]], Prescott and Russell County, Ontario (-) [[Aberdeen, Abbotsford]], a neighbourhood in the City of Abbotsford, British Columbia (-) [[Aberdeen Centre]], a shopping mall in Richmond, British Columbia (-) [[Aberdeen, Grey County, Ontario]] (-) [[Aberdeen, Kamloops]], an area in the City of Kamloops, British Columbia (-) [[Aberdeen Lake (Nunavut)]], a lake in Kivalliq Region, Nunavut, Canada (-) [[Aberdeen, Nova Scotia]], part of the Municipality of Inverness County, Nova Scotia (-) [[Aberdeen Parish, New Brunswick]] (-) [[Rural Municipality of Aberdeen No. 373]], Saskatchewan (-) [[Aberdeen, Saskatchewan]] (-) Aberdeen Bay, a bay between southern [[Baffin Island]] and north-eastern Hector Island in the Nunavut territory (-) Aberdeen Township, Quebec, until 1960 part of Sheen-Esher-Aberdeen-et-Malakoff, now part of [[Rapides-des-Joachims, Quebec]] (-) [[Aberdeen River]], a tributary of rivière aux Castors Noirs in Mauricie, Québec (-) [[New Aberdeen, Nova Scotia]]", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Places", "North America", "United States"], "text": "(-) [[Aberdeen, Arkansas]] (-) [[Aberdeen, Florida]] (-) [[Aberdeen, Georgia]] (-) [[Aberdeen, Idaho]] (-) [[Aberdeen, Ohio County, Indiana]] (-) [[Aberdeen, Porter County, Indiana]] (-) [[Aberdeen, Kentucky]] (-) [[Aberdeen, Maryland]]  [[Aberdeen Proving Ground]], a United States Army facility located near Aberdeen, Maryland (-) Aberdeen, Massachusetts, a neighborhood of [[Brighton, Boston]] (-) [[Aberdeen, Mississippi]]  [[Aberdeen Lake (Mississippi)]], a lake in northeast Mississippi on the Tennessee-Tombigbee Waterway, close to Aberdeen, Mississippi (-) [[Aberdeen Township, New Jersey]] (-) [[Aberdeen, North Carolina]]  [[Aberdeen Historic District (Aberdeen, North Carolina)]] (-) [[Aberdeen, Ohio]] (-) [[Aberdeen, South Dakota]]  [[Aberdeen Historic District (Aberdeen, South Dakota)]] (-) [[Aberdeen, Texas]] (-) [[Aberdeen (Disputanta, Virginia)]] (-) [[Aberdeen Gardens (Hampton, Virginia)]] (-) [[Aberdeen, Washington]]  [[Aberdeen Gardens, Washington]] (-) [[Aberdeen, West Virginia]]", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Education"], "text": "(-) [[Aberdeen Business School]] (-) [[Aberdeen College]], formerly one of the largest further education colleges in Scotland, merged with Banff & Buchan College to form North East Scotland College (-) [[Aberdeen Grammar School]], Aberdeen, Scotland (-) [[Aberdeen Hall]], a university-preparatory school in Kelowna, British Columbia, Canada (-) [[Aberdeen High School (disambiguation)]] (-) [[King's College, Aberdeen]] (-) [[University of Aberdeen]], a public research university in the city of Aberdeen", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Entertainment"], "text": "(-) [[Aberdeen (2000 film)|''Aberdeen'' (2000 film)]], a 2000 Norwegian-British film directed by Hans Petter Moland, starring Stellan Skarsgård and Lena Headey (-) [[Aberdeen (2014 film)|''Aberdeen'' (2014 film)]], a 2014 Hong Kong film starring Louis Koo (-) [[Aberdeen (band)]], an American rock band (-) [[Aberdeen (song)]], a song by Cage The Elephant (-) [[Aberdeen City (band)]], Boston based indie/alternative rock band", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Other transportation"], "text": "(-) [[Aberdeen Airport (disambiguation)]] (-) [[Aberdeen Lock and Dam]], one of four lock and dam structures on the Tennessee-Tombigbee Waterway", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Rail"], "text": "(-) [[Aberdeen, Carolina and Western Railway]], a short-line railroad operating in North Carolina (-) [[Aberdeen and Rockfish Railroad]], a short-line railroad operating in North Carolina (-) [[Aberdeen Corporation Tramways]] (-) [[Aberdeen Line (disambiguation)]] (-) [[Aberdeen station (disambiguation)]] (-) [[Dundee and Perth and Aberdeen Junction Railway]], a later name of the Dundee and Perth Railway", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Shipping"], "text": "(-) [[Aberdeen Line]], a British shipping company founded in 1825 (-) , one of several ships by that name (-) , a sloop of the British Royal Navy that served between 1936 and 1948 (-) , a merchant ship operated during the latter stages of World War II, later commissioned as the USS ''Altair''", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": ["Sports"], "text": "(-) Aberdeen [[Dad Vail Regatta]], the largest regular intercollegiate rowing event in the United States, named after its sponsor, Aberdeen Asset Management (-) [[Aberdeen F.C. (disambiguation)]] (-) [[Aberdeen GSFP RFC]], an amateur rugby union club based in Aberdeen (-) [[Aberdeen IronBirds]], a minor league baseball team affiliated with the Baltimore Orioles (-) [[Aberdeen L.F.C.]], a women's football team affiliated with Aberdeen F.C.", "id": "632", "title": "Aberdeen (disambiguation)", "categories": [], "seealso": ["Battle of Aberdeen (disambiguation)", "Diocese of Aberdeen and Orkney", "Etymology of Aberdeen", "Aberdeen Central (disambiguation)", "Marquess of Aberdeen and Temair", "Aberdeen Hospital (disambiguation)", "Aberdeen Act", "Aberdeen Gardens (disambiguation)", "Aberdeen Historic District (disambiguation)", "Aberdeen Angus"]}
{"headers": [], "text": "'''Algae''' (; singular '''alga''' ) is an informal term for a large and diverse group of [[photosynthesis|photosynthetic]] [[eukaryotic]] [[organism]]. It is a [[polyphyletic]] grouping that includes species from multiple distinct [[clade]]. Included organisms range from [[unicellular organism|unicellular]] [[microalgae]], such as ''[[Chlorella]],'' [[Prototheca]] and the [[diatom]], to [[multicellular]] forms, such as the [[Macrocystis pyrifera|giant kelp]], a large [[brown algae|brown alga]] which may grow up to in length. Most are aquatic and [[autotrophic]] and lack many of the distinct cell and tissue types, such as [[stoma]], [[xylem]] and [[phloem]], which are found in [[embryophyte|land plants]]. The largest and most complex marine algae are called [[seaweed]], while the most complex freshwater forms are the [[Charophyta]], a [[phylum|division]] of green algae which includes, for example, ''[[Spirogyra]]'' and [[stonewort]]. No definition of algae is generally accepted. One definition is that algae \"have [[chlorophyll]] as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells\". Likewise, the colorless [[Prototheca]] under [[Chlorophyta]] are all devoid of any chlorophyll. Although [[cyanobacteria]] are often referred to as \"blue-green algae\", most authorities exclude all [[prokaryotes]] from the definition of algae. Algae constitute a [[polyphyletic]] group since they do not include a common ancestor, and although their [[plastid]] seem to have a single origin, from cyanobacteria, they were acquired in different ways. [[Green algae]] are examples of algae that have primary [[chloroplast]] derived from [[endosymbiotic theory|endosymbiotic]] cyanobacteria. [[Diatom]] and brown algae are examples of algae with secondary chloroplasts derived from an [[Endosymbiotic theory#Secondary endosymbiosis|endosymbiotic]] [[red alga]]. Algae exhibit a wide range of reproductive strategies, from simple [[asexual reproduction|asexual]] cell division to complex forms of [[sexual reproduction]]. Algae lack the various structures that characterize land plants, such as the phyllids (leaf-like structures) of [[bryophyte]], [[rhizoid]] in [[nonvascular plants]], and the [[root]], [[leaf|leaves]], and other [[Organ (anatomy)|organs]] found in [[tracheophyte]] ([[vascular plants]]). Most are [[phototroph]], although some are [[mixotroph]], deriving energy both from photosynthesis and uptake of organic carbon either by [[osmotrophy]], [[Myzocytosis|myzotrophy]], or [[phagocytosis|phagotrophy]]. Some unicellular species of [[green algae]], many [[golden algae]], [[euglenid]], [[dinoflagellate]], and other algae have become [[heterotroph]] (also called colorless or apochlorotic algae), sometimes parasitic, relying entirely on external energy sources and have limited or no photosynthetic apparatus. Some other heterotrophic organisms, such as the [[apicomplexans]], are also derived from cells whose ancestors possessed plastids, but are not traditionally considered as algae. Algae have photosynthetic machinery ultimately derived from [[cyanobacteria]] that produce [[oxygen]] as a by-product of photosynthesis, unlike other photosynthetic bacteria such as [[Purple sulfur bacteria|purple]] and [[green sulfur bacteria]]. Fossilized filamentous algae from the [[Vindhya]] basin have been dated back to 1.6 to 1.7 billion years ago.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": [], "text": "Because of the wide range of types of algae, they have increasing different industrial and traditional applications in human society. Traditional [[seaweed farming]] practices have existed for thousands of years and have strong traditions in East Asia food cultures. More modern [[algaculture]] applications extend the [[Edible seaweed|food traditions]] for other applications include cattle feed, using algae for [[bioremediation]] or pollution control, transforming sunlight into [[algae fuel]] or other chemicals used in industrial processes, and in medical and scientific applications. A 2020 review, found that these applications of algae could play an important role in [[carbon sequestration]] in order to [[Climate change mitigation|mitigate climate change]] while providing valuable value-add products for global economies.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Etymology and study"], "text": "The singular is the Latin word for 'seaweed' and retains that meaning in English. The [[etymology]] is obscure. Although some speculate that it is related to Latin , 'be cold', no reason is known to associate seaweed with temperature. A more likely source is , 'binding, entwining'. The [[Ancient Greek]] word for 'seaweed' was (), which could mean either the seaweed (probably red algae) or a red dye derived from it. The Latinization, , meant primarily the cosmetic rouge. The etymology is uncertain, but a strong candidate has long been some word related to the Biblical (), 'paint' (if not that word itself), a cosmetic eye-shadow used by the ancient Egyptians and other inhabitants of the eastern Mediterranean. It could be any color: black, red, green, or blue. Accordingly, the modern study of marine and freshwater algae is called either [[phycology]] or algology, depending on whether the Greek or Latin root is used. The name ''fucus'' appears in a number of [[Taxon|taxa]].", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Classifications"], "text": "The committee on the International Code of Botanical Nomenclature has recommended certain suffixes for use in the classification of algae. These are '''-phyta''' for division, ''-phyceae'' for class, ''-phycideae'' for subclass, ''-ales'' for order, ''-inales'' for suborder, ''-aceae'' for family, ''-oidease'' for subfamily, a Greek-based name for genus, and a Latin-based name for species.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Classifications", "Algal characteristics basic to primary classification"], "text": "The primary classification of algae is based on certain morphological features. The chief among these are (a) pigment constitution of the cell, (b) chemical nature of stored food materials, (c) kind, number, point of insertion and relative length of the flagella on the motile cell, (d) chemical composition of cell wall and (e) presence or absence of a definitely organized nucleus in the cell or any other significant details of cell structure.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Classifications", "History of classification of algae"], "text": "Although [[Carolus Linnaeus]] (1754) included algae along with lichens in his 25th class Cryptogamia, he did not elaborate further on the classification of algae. [[Jean Pierre Étienne Vaucher]] (1803) was perhaps the first to propose a system of classification of algae, and he recognized three groups, Conferves, Ulves, and Tremelles. While [[Johann Heinrich Friedrich Link]] (1820) classified algae on the basis of the colour of the pigment and structure, [[William Henry Harvey]] (1836) proposed a system of classification on the basis of the habitat and the pigment. [[J. G. Agardh]] (1849–1898) divided algae into six orders: Diatomaceae, Nostochineae, Confervoideae, Ulvaceae, Floriadeae and Fucoideae. Around 1880, algae along with fungi were grouped under Thallophyta, a division created by Eichler (1836). Encouraged by this, [[Adolf Engler]] and [[Karl Anton Eugen Prantl|Karl A. E. Prantl]] (1912) proposed a revised scheme of classification of algae and included fungi in algae as they were of opinion that fungi have been derived from algae. The scheme proposed by Engler and Prantl is summarised as follows: (1) Schizophyta (2) Phytosarcodina (3) Flagellata (4) Dinoflagellata (5) Bacillariophyta (6) Conjugatae (7) Chlorophyceae (8) Charophyta (9) Phaeophyceae (10) Rhodophyceae (11) Eumycetes (Fungi)  The algae contain [[chloroplast]] that are similar in structure to cyanobacteria. Chloroplasts contain circular [[DNA]] like that in cyanobacteria and are interpreted as representing reduced endosymbiotic cyanobacteria. However, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events. The table below describes the composition of the three major groups of algae. Their lineage relationships are shown in the figure in the upper right. Many of these groups contain some members that are no longer photosynthetic. Some retain plastids, but not chloroplasts, while others have lost plastids entirely. [[Phylogeny]] based on [[plastid]] not nucleocytoplasmic genealogy: [[Carl Linnaeus|Linnaeus]], in ''[[Species Plantarum]]'' (1753), the starting point for modern [[botanical nomenclature]], recognized 14 genera of algae, of which only four are currently considered among algae. In ''[[10th edition of Systema Naturae|Systema Naturae]]'', Linnaeus described the genera ''[[Volvox]]'' and ''[[Corallina]]'', and a species of ''[[Acetabularia]]'' (as ''[[Madrepora]]''), among the animals. In 1768, [[Samuel Gottlieb Gmelin]] (1744–1774) published the ''Historia Fucorum'', the first work dedicated to marine algae and the first book on [[marine biology]] to use the then new binomial nomenclature of Linnaeus. It included elaborate illustrations of seaweed and marine algae on folded leaves. [[William Henry Harvey|W. H. Harvey]] (1811–1866) and [[Lamouroux]] (1813) were the first to divide macroscopic algae into four divisions based on their pigmentation. This is the first use of a biochemical criterion in plant systematics. Harvey's four divisions are: red algae (Rhodospermae), brown algae (Melanospermae), green algae (Chlorospermae), and Diatomaceae. At this time, microscopic algae were discovered and reported by a different group of workers (e.g., [[Otto Friedrich Müller|O. F. Müller]] and [[Christian Gottfried Ehrenberg|Ehrenberg]]) studying the [[Infusoria]] (microscopic organisms). Unlike [[macroalgae]], which were clearly viewed as plants, [[microalgae]] were frequently considered animals because they are often motile. Even the nonmotile (coccoid) microalgae were sometimes merely seen as stages of the lifecycle of plants, macroalgae, or animals.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Classifications", "History of classification of algae"], "text": "Although used as a taxonomic category in some pre-Darwinian classifications, e.g., Linnaeus (1753), de Jussieu (1789), Horaninow (1843), Agassiz (1859), Wilson & Cassin (1864), in further classifications, the \"algae\" are seen as an artificial, polyphyletic group. Throughout the 20th century, most classifications treated the following groups as divisions or classes of algae: [[cyanophyte]], [[rhodophyte]], [[chrysophyte]], [[xanthophyte]], [[diatom|bacillariophytes]], [[phaeophyte]], [[Dinoflagellate#history|pyrrhophytes]] ([[Cryptomonad|cryptophytes]] and [[dinophyte]]), [[euglenophyte]], and [[chlorophyte]]. Later, many new groups were discovered (e.g., [[Bolidophyceae]]), and others were splintered from older groups: [[charophyte]] and [[glaucophyte]] (from chlorophytes), many [[heterokontophyte]] (e.g., [[Synurophyceae|synurophytes]] from chrysophytes, or [[eustigmatophyte]] from xanthophytes), [[haptophyte]] (from chrysophytes), and [[chlorarachniophyte]] (from xanthophytes). With the abandonment of plant-animal dichotomous classification, most groups of algae (sometimes all) were included in [[Protist]], later also abandoned in favour of [[Eukaryota]]. However, as a legacy of the older plant life scheme, some groups that were also treated as [[protozoa]] in the past still have duplicated classifications (see [[ambiregnal protist]]). Some parasitic algae (e.g., the green algae ''[[Prototheca]]'' and ''[[Helicosporidium]]'', parasites of metazoans, or ''[[Cephaleuros]]'', parasites of plants) were originally classified as [[fungi]], [[sporozoan]], or [[protist]] of ''[[incertae sedis]]'', while others (e.g., the green algae ''[[Phyllosiphon]]'' and ''[[Rhodochytrium]]'', parasites of plants, or the red algae ''[[Pterocladiophila]]'' and ''[[Gelidiocolax mammillatus]]'', parasites of other red algae, or the dinoflagellates ''[[Oodinium]]'', parasites of fish) had their relationship with algae conjectured early. In other cases, some groups were originally characterized as parasitic algae (e.g., ''[[Chlorochytrium]]''), but later were seen as [[endophytic]] algae. Some filamentous bacteria (e.g., ''[[Beggiatoa]]'') were originally seen as algae. Furthermore, groups like the [[apicomplexan]] are also parasites derived from ancestors that possessed plastids, but are not included in any group traditionally seen as algae.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Relationship to land plants"], "text": "The first land plants probably evolved from shallow freshwater charophyte algae much like ''[[Chara (alga)|Chara]]'' almost 500 million years ago. These probably had an isomorphic [[alternation of generations]] and were probably filamentous. Fossils of isolated land plant spores suggest land plants may have been around as long as 475 million years ago.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Morphology"], "text": "A range of algal [[Morphology (biology)|morphologies]] is exhibited, and [[Convergent evolution|convergence]] of features in unrelated groups is common. The only groups to exhibit three-dimensional multicellular [[Thallus|thalli]] are the [[Red algae|reds]] and [[Brown algae|browns]], and some [[Chlorophyta|chlorophytes]]. Apical growth is constrained to subsets of these groups: the [[Florideophyceae|florideophyte]] reds, various browns, and the charophytes. The form of charophytes is quite different from those of reds and browns, because they have distinct nodes, separated by internode 'stems'; whorls of branches reminiscent of the [[horsetail]] occur at the nodes. [[Conceptacle]] are another [[polyphyletic]] trait; they appear in the [[coralline algae]] and the [[Hildenbrandiales]], as well as the browns. Most of the simpler algae are [[unicellular]] [[flagellate]] or [[amoeboid]], but colonial and nonmotile forms have developed independently among several of the groups. Some of the more common organizational levels, more than one of which may occur in the [[biological life cycle|lifecycle]] of a species, are (-) [[Colony (biology)|Colonial]]: small, regular groups of motile cells (-) Capsoid: individual non-motile cells embedded in [[mucilage]] (-) Coccoid: individual non-motile cells with cell walls (-) Palmelloid: nonmotile cells embedded in mucilage (-) Filamentous: a string of nonmotile cells connected together, sometimes branching (-) Parenchymatous: cells forming a thallus with partial differentiation of tissues In three lines, even higher levels of organization have been reached, with full tissue differentiation. These are the brown algae,—some of which may reach 50 m in length ([[kelp]])—the red algae, and the green algae. The most complex forms are found among the charophyte algae (see [[Charales]] and [[Charophyta]]), in a lineage that eventually led to the higher land plants. The innovation that defines these nonalgal plants is the presence of female reproductive organs with protective cell layers that protect the zygote and developing embryo. Hence, the land plants are referred to as the [[Embryophyte]].", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Morphology", "Turfs"], "text": "The term algal turf is commonly used but poorly defined. Algal turfs are thick, carpet-like beds of seaweed that retain sediment and compete with foundation species like [[coral reef|corals]] and [[kelp forest#kelp|kelps]], and they are usually less than 15 cm tall. Such a turf may consist of one or more species, and will generally cover an area in the order of a square metre or more. Some common characteristics are listed: (-) Algae that form aggregations that have been described as turfs include diatoms, cyanobacteria, chlorophytes, phaeophytes and rhodophytes. Turfs are often composed of numerous species at a wide range of spatial scales, but monospecific turfs are frequently reported. (-) Turfs can be morphologically highly variable over geographic scales and even within species on local scales and can be difficult to identify in terms of the constituent species. (-) Turfs have been defined as short algae, but this has been used to describe height ranges from less than 0.5 cm to more than 10 cm. In some regions, the descriptions approached heights which might be described as canopies (20 to 30 cm).", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Physiology"], "text": "Many algae, particularly members of the [[Characeae]] species, have served as model experimental organisms to understand the mechanisms of the water permeability of membranes, [[osmoregulation]], [[turgor regulation]], [[salt tolerance]], [[cytoplasmic streaming]], and the generation of [[action potentials]]. [[Phytohormone]] are found not only in higher plants, but in algae, too.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Symbiotic algae"], "text": "Some species of algae form [[symbiosis|symbiotic relationships]] with other organisms. In these symbioses, the algae supply photosynthates (organic substances) to the host organism providing protection to the algal cells. The host organism derives some or all of its energy requirements from the algae. Examples are:", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Symbiotic algae", "Lichens"], "text": "[[Lichen]] are defined by the [[International Association for Lichenology]] to be \"an association of a fungus and a photosynthetic [[symbiont]] resulting in a stable vegetative body having a specific structure\". The fungi, or mycobionts, are mainly from the [[Ascomycota]] with a few from the [[Basidiomycota]]. In nature they do not occur separate from lichens. It is unknown when they began to associate. One mycobiont associates with the same phycobiont species, rarely two, from the green algae, except that alternatively, the mycobiont may associate with a species of cyanobacteria (hence \"photobiont\" is the more accurate term). A photobiont may be associated with many different mycobionts or may live independently; accordingly, lichens are named and classified as fungal species. The association is termed a morphogenesis because the lichen has a form and capabilities not possessed by the symbiont species alone (they can be experimentally isolated). The photobiont possibly triggers otherwise latent genes in the mycobiont. [[Trentepohlia (alga)|Trentepohlia]] is an example of a common green alga genus worldwide that can grow on its own or be lichenised. Lichen thus share some of the habitat and often similar appearance with specialized species of algae (''[[aerophyte]]'') growing on exposed surfaces such as tree trunks and rocks and sometimes discoloring them.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Symbiotic algae", "Coral reefs"], "text": " [[Coral reef]] are accumulated from the [[calcareous]] [[exoskeleton]] of [[marine invertebrate]] of the order [[Scleractinia]] (stony [[coral]]). These [[Animal#Food and energy sourcing|animals]] [[Metabolism|metabolize]] [[Sugar#Chemistry|sugar]] and oxygen to obtain energy for their cell-building processes, including [[secretion]] of the exoskeleton, with water and [[carbon dioxide]] as byproducts. Dinoflagellates (algal protists) are often [[endosymbiont]] in the cells of the coral-forming marine invertebrates, where they accelerate host-cell metabolism by generating sugar and oxygen immediately available through photosynthesis using incident light and the carbon dioxide produced by the host. Reef-building stony corals ([[hermatypic coral]]) require endosymbiotic algae from the genus ''[[Symbiodinium]]'' to be in a healthy condition. The loss of ''Symbiodinium'' from the host is known as [[coral bleaching]], a condition which leads to the deterioration of a reef.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Symbiotic algae", "Sea sponges"], "text": "[[Endosymbiont]] green algae live close to the surface of some sponges, for example, breadcrumb sponges (''[[Halichondria panicea]]''). The alga is thus protected from predators; the sponge is provided with oxygen and sugars which can account for 50 to 80% of sponge growth in some species.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Lifecycle"], "text": "[[Rhodophyta]], [[Chlorophyta]], and [[Heterokontophyta]], the three main algal [[phylum|divisions]], have lifecycles which show considerable variation and complexity. In general, an asexual phase exists where the seaweed's cells are [[diploid]], a sexual phase where the cells are [[haploid]], followed by fusion of the male and female [[gamete]]. Asexual reproduction permits efficient population increases, but less variation is possible. Commonly, in sexual reproduction of unicellular and colonial algae, two specialized, sexually compatible, haploid gametes make physical contact and fuse to form a [[zygote]]. To ensure a successful mating, the development and release of gametes is highly synchronized and regulated; pheromones may play a key role in these processes. Sexual reproduction allows for more variation and provides the benefit of efficient recombinational repair of DNA damages during [[meiosis]], a key stage of the sexual cycle. However, sexual reproduction is more costly than asexual reproduction. Meiosis has been shown to occur in many different species of algae.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Numbers"], "text": "The ''Algal Collection of the US National Herbarium'' (located in the [[National Museum of Natural History]]) consists of approximately 320,500 dried specimens, which, although not exhaustive (no exhaustive collection exists), gives an idea of the order of magnitude of the number of algal species (that number remains unknown). Estimates vary widely. For example, according to one standard textbook, in the [[British Isles]] the ''UK Biodiversity Steering Group Report'' estimated there to be 20,000 algal species in the UK. Another checklist reports only about 5,000 species. Regarding the difference of about 15,000 species, the text concludes: \"It will require many detailed field surveys before it is possible to provide a reliable estimate of the total number of species ...\" Regional and group estimates have been made, as well: (-) 5,000–5,500 species of red algae worldwide (-) \"some 1,300 in Australian Seas\" (-) 400 seaweed species for the western coastline of South Africa, and 212 species from the coast of KwaZulu-Natal. Some of these are duplicates, as the range extends across both coasts, and the total recorded is probably about 500 species. Most of these are listed in [[List of seaweeds of South Africa (disambiguation)|List of seaweeds of South Africa]]. These exclude [[phytoplankton]] and crustose corallines. (-) 669 marine species from California (US) (-) 642 in the check-list of Britain and Ireland and so on, but lacking any scientific basis or reliable sources, these numbers have no more credibility than the British ones mentioned above. Most estimates also omit microscopic algae, such as phytoplankton. The most recent estimate suggests 72,500 algal species worldwide.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Distribution"], "text": "The distribution of algal species has been fairly well studied since the founding of [[phytogeography]] in the mid-19th century. Algae spread mainly by the dispersal of [[spore]] analogously to the dispersal of [[Plantae]] by [[seeds]] and [[spores]]. This dispersal can be accomplished by air, water, or other organisms. Due to this, spores can be found in a variety of environments: fresh and marine waters, air, soil, and in or on other organisms. Whether a spore is to grow into an organism depends on the combination of the species and the environmental conditions where the spore lands. The spores of freshwater algae are dispersed mainly by running water and wind, as well as by living carriers. However, not all bodies of water can carry all species of algae, as the chemical composition of certain water bodies limits the algae that can survive within them. Marine spores are often spread by ocean currents. Ocean water presents many vastly different habitats based on temperature and nutrient availability, resulting in phytogeographic zones, regions, and provinces. To some degree, the distribution of algae is subject to floristic discontinuities caused by geographical features, such as [[Antarctica]], long distances of ocean or general land masses. It is, therefore, possible to identify species occurring by locality, such as \"[[Pacific]] algae\" or \"[[North Sea]] algae\". When they occur out of their localities, hypothesizing a transport mechanism is usually possible, such as the hulls of ships. For example, ''[[Ulva reticulata]]'' and ''[[U. fasciata]]'' travelled from the mainland to [[Hawaii]] in this manner. Mapping is possible for select species only: \"there are many valid examples of confined distribution patterns.\" For example, ''[[Clathromorphum]]'' is an arctic genus and is not mapped far south of there. However, scientists regard the overall data as insufficient due to the \"difficulties of undertaking such studies.\"", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Ecology"], "text": "Algae are prominent in bodies of water, common in terrestrial environments, and are found in unusual environments, such as on [[Snow algae|snow]] and [[Ice algae|ice]]. Seaweeds grow mostly in shallow marine waters, under deep; however, some such as ''[[Navicula]] pennata'' have been recorded to a depth of . A type of algae, ''Ancylonema nordenskioeldii'', was found in [[Greenland]] in areas known as the 'Dark Zone', which caused an increase in the rate of melting ice sheet. Same algae was found in the [[Italian Alps]], after pink ice appeared on parts of the Presena glacier. The various sorts of algae play significant roles in aquatic ecology. Microscopic forms that live suspended in the water column ([[phytoplankton]]) provide the food base for most marine [[food chain]]. In very high densities ([[algal bloom]]), these algae may discolor the water and outcompete, poison, or [[asphyxiate]] other life forms. Algae can be used as [[indicator organism]] to monitor pollution in various aquatic systems. In many cases, algal metabolism is sensitive to various pollutants. Due to this, the species composition of algal populations may shift in the presence of chemical pollutants. To detect these changes, algae can be sampled from the environment and maintained in laboratories with relative ease. On the basis of their habitat, algae can be categorized as: [[Aquatic plant|aquatic]] ([[planktonic]], [[benthic]], [[Marine biology|marine]], [[freshwater]], [[lentic]], [[lotic]]), [[Terrestrial plant|terrestrial]], [[Aerobiology|aerial]] (subaerial), [[lithophytic]], [[halophytic]] (or [[euryhaline]]), [[psammon]], [[thermophilic]], [[Psychrophile|cryophilic]], [[epibiont]] ([[epiphytic]], [[epizoic]]), [[endosymbiont]] ([[endophytic]], endozoic), [[parasitic]], [[calcareous|calcifilic]] or [[lichen]] (phycobiont).", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Cultural associations"], "text": "In [[classical Chinese]], the word is used both for \"algae\" and (in the modest tradition of the [[scholar-official|imperial scholars]]) for \"literary talent\". The third island in [[Kunming Lake]] beside the [[Summer Palace]] in Beijing is known as the Zaojian Tang Dao, which thus simultaneously means \"Island of the Algae-Viewing Hall\" and \"Island of the Hall for Reflecting on Literary Talent\".", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Agar"], "text": "[[Agar]], a [[gelatin]] substance derived from red algae, has a number of commercial uses. It is a good medium on which to grow bacteria and fungi, as most microorganisms cannot digest agar.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Alginates"], "text": "[[Alginic acid]], or alginate, is extracted from [[brown algae]]. Its uses range from gelling agents in food, to medical dressings. Alginic acid also has been used in the field of [[biotechnology]] as a [[Biocompatibility|biocompatible medium]] for cell encapsulation and cell immobilization. [[Molecular cuisine]] is also a user of the substance for its gelling properties, by which it becomes a delivery vehicle for flavours. Between 100,000 and 170,000 wet tons of ''[[Macrocystis]]'' are harvested annually in [[New Mexico]] for [[Alginic acid|alginate]] extraction and [[abalone]] feed.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Energy source"], "text": "To be competitive and independent from fluctuating support from (local) policy on the long run, biofuels should equal or beat the cost level of fossil fuels. Here, algae-based fuels hold great promise, directly related to the potential to produce more biomass per unit area in a year than any other form of biomass. The break-even point for algae-based biofuels is estimated to occur by 2025.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Fertilizer"], "text": "For centuries, seaweed has been used as a fertilizer; [[George Owen of Henllys]] writing in the 16th century referring to drift weed in [[South Wales]]: Today, algae are used by humans in many ways; for example, as [[fertilizer]], [[soil conditioner]], and livestock feed. Aquatic and microscopic species are cultured in clear tanks or ponds and are either harvested or used to treat effluents pumped through the ponds. [[Algaculture]] on a large scale is an important type of [[aquaculture]] in some places. [[Maerl]] is commonly used as a soil conditioner.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Nutrition"], "text": "Naturally growing seaweeds are an important source of food, especially in Asia, leading some to label them as [[superfood]]. They provide many vitamins including: A, [[Thiamine|B]], [[Riboflavin|B]], [[Vitamin B6|B]], [[niacin]], and [[Vitamin C|C]], and are rich in [[iodine]], [[potassium]], iron, [[magnesium]], and [[calcium]]. In addition, commercially cultivated microalgae, including both algae and cyanobacteria, are marketed as nutritional supplements, such as [[Spirulina (dietary supplement)|spirulina]], ''[[Chlorella]]'' and the vitamin-C supplement from ''[[Dunaliella]]'', high in [[beta-carotene]]. Algae are national foods of many nations: China consumes more than 70 species, including ''[[fat choy (vegetable)|fat choy]]'', a cyanobacterium considered a vegetable; Japan, over 20 species such as ''[[nori]]'' and ''[[aonori]]''; Ireland, [[dulse]]; [[Chile]], [[cochayuyo]]. [[laver (seaweed)|Laver]] is used to make laver bread in [[Wales]], where it is known as ; in [[Korea]], . It is also used along the west coast of North America from California to [[British Columbia]], in Hawaii and by the [[Māori people|Māori]] of [[New Zealand]]. [[Sea lettuce]] and [[Alaria esculenta|badderlocks]] are salad ingredients in [[Scotland]], Ireland, [[Greenland]], and [[Iceland]]. Algae is being considered a potential solution for world hunger problem. Two popular forms of algae are used in cuisine: (-) ''[[Chlorella]]'': This form of alga is found in freshwater and contains [[photosynthetic]] pigments in its [[chloroplast]]. It is high in [[iron]], [[zinc]], [[magnesium]], [[vitamin B2]] and [[Omega-3 Fatty acids]]. Furthermore, it contains all nine of the essential [[amino acids]] the body does not produce on its own (-) ''[[Spirulina (genus)|Spirulina]]'': Known otherwise as a cyanobacterium (a [[prokaryote]], incorrectly referred to as a \"blue-green alga\"), contains 10% more [[protein]] than ''Chlorella'' as well as more [[thiamine]] and [[copper]]. The oils from some algae have high levels of [[unsaturated fatty acid]]. For example, ''[[Parietochloris incisa]]'' is very high in [[arachidonic acid]], where it reaches up to 47% of the triglyceride pool. Some varieties of algae favored by [[vegetarianism]] and [[veganism]] contain the long-chain, essential [[omega-3 fatty acid]], [[docosahexaenoic acid]] (DHA) and [[eicosapentaenoic acid]] (EPA). Fish oil contains the omega-3 fatty acids, but the original source is algae (microalgae in particular), which are eaten by marine life such as [[copepod]] and are passed up the food chain. Algae have emerged in recent years as a popular source of omega-3 fatty acids for vegetarians who cannot get long-chain EPA and DHA from other vegetarian sources such as [[flaxseed oil]], which only contains the short-chain [[alpha-linolenic acid]] (ALA).", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Pollution control"], "text": "(-) Sewage can be treated with algae, reducing the use of large amounts of toxic chemicals that would otherwise be needed. (-) Algae can be used to capture fertilizers in runoff from farms. When subsequently harvested, the enriched algae can be used as fertilizer. (-) Aquaria and ponds can be filtered using algae, which absorb nutrients from the water in a device called an [[algae scrubber]], also known as an algae turf scrubber. [[Agricultural Research Service]] scientists found that 60–90% of nitrogen runoff and 70–100% of phosphorus runoff can be captured from [[manure effluents]] using a horizontal algae scrubber, also called an [[algal turf scrubber]] (ATS). Scientists developed the ATS, which consists of shallow, 100-foot raceways of nylon netting where algae colonies can form, and studied its efficacy for three years. They found that algae can readily be used to reduce the nutrient runoff from agricultural fields and increase the quality of water flowing into rivers, streams, and oceans. Researchers collected and dried the nutrient-rich algae from the ATS and studied its potential as an organic fertilizer. They found that cucumber and corn seedlings grew just as well using ATS organic fertilizer as they did with commercial fertilizers. Algae scrubbers, using bubbling upflow or vertical waterfall versions, are now also being used to filter aquaria and ponds.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Polymers"], "text": "Various polymers can be created from algae, which can be especially useful in the creation of bioplastics. These include hybrid plastics, cellulose-based plastics, poly-lactic acid, and bio-polyethylene. Several companies have begun to produce algae polymers commercially, including for use in flip-flops and in surf boards.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Bioremediation"], "text": "The alga ''[[Stichococcus bacillaris]]'' has been seen to colonize silicone resins used at archaeological sites; [[Biodegradation|biodegrading]] the synthetic substance.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Pigments"], "text": "The natural [[pigment]] ([[carotenoid]] and [[chlorophyll]]) produced by algae can be used as alternatives to chemical [[dye]] and coloring agents. The presence of some individual algal pigments, together with specific pigment concentration ratios, are taxon-specific: analysis of their concentrations with various analytical methods, particularly [[high-performance liquid chromatography]], can therefore offer deep insight into the taxonomic composition and relative abundance of natural algae populations in sea water samples.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": ["Uses", "Stabilizing substances"], "text": "Carrageenan, from the red alga ''Chondrus crispus'', is used as a stabilizer in milk products.", "id": "633", "title": "Algae", "categories": ["Algae", "Endosymbiotic events", "Polyphyletic groups"], "seealso": ["AlgaeBase", "Toxoid", "Plant", "Marimo", "Photobioreactor", "Eutrophication", "Microphyte", "Microbiofuels", "Phycotechnology", "Iron fertilization", "AlgaePARC"]}
{"headers": [], "text": "'''Analysis of variance''' ('''ANOVA''') is a collection of [[statistical model]] and their associated estimation procedures (such as the \"variation\" among and between groups) used to analyze the differences among means. ANOVA was developed by the [[statistician]] [[Ronald Fisher]]. ANOVA is based on the [[law of total variance]], where the observed [[variance]] in a particular variable is partitioned into components attributable to different sources of variation. In its simplest form, ANOVA provides a [[statistical test]] of whether two or more population [[mean]] are equal, and therefore generalizes the [[Student's t-test#Independent two-sample t-test|''t''-test]] beyond two means.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["History"], "text": "While the analysis of variance reached fruition in the 20th century, antecedents extend centuries into the past according to Stigler. These include hypothesis testing, the partitioning of sums of squares, experimental techniques and the additive model. [[Pierre-Simon Laplace|Laplace]] was performing hypothesis testing in the 1770s. Around 1800, Laplace and [[Carl Friedrich Gauss|Gauss]] developed the least-squares method for combining observations, which improved upon methods then used in astronomy and geodesy. It also initiated much study of the contributions to sums of squares. Laplace knew how to estimate a variance from a residual (rather than a total) sum of squares. By 1827, Laplace was using [[least squares]] methods to address ANOVA problems regarding measurements of atmospheric tides. Before 1800, astronomers had isolated observational errors resulting from reaction times (the \"[[personal equation]]\") and had developed methods of reducing the errors. The experimental methods used in the study of the personal equation were later accepted by the emerging field of psychology which developed strong (full factorial) experimental methods to which randomization and blinding were soon added. An eloquent non-mathematical explanation of the additive effects model was available in 1885. [[Ronald Fisher]] introduced the term [[variance]] and proposed its formal analysis in a 1918 article ''[[The Correlation Between Relatives on the Supposition of Mendelian Inheritance]]''. His first application of the analysis of variance was published in 1921. Analysis of variance became widely known after being included in Fisher's 1925 book ''[[Statistical Methods for Research Workers]]''. Randomization models were developed by several researchers. The first was published in Polish by [[Jerzy Neyman]] in 1923.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Example"], "text": "The analysis of variance can be used to describe otherwise complex relations among variables. A dog show provides an example. A dog show is not a random sampling of the breed: it is typically limited to dogs that are adult, pure-bred, and exemplary. A histogram of dog weights from a show might plausibly be rather complex, like the yellow-orange distribution shown in the illustrations. Suppose we wanted to predict the weight of a dog based on a certain set of characteristics of each dog. One way to do that is to ''explain'' the distribution of weights by dividing the dog population into groups based on those characteristics. A successful grouping will split dogs such that (a) each group has a low variance of dog weights (meaning the group is relatively homogeneous) and (b) the mean of each group is distinct (if two groups have the same mean, then it isn't reasonable to conclude that the groups are, in fact, separate in any meaningful way). In the illustrations to the right, groups are identified as ''X'', ''X'', etc. In the first illustration, the dogs are divided according to the product (interaction) of two binary groupings: young vs old, and short-haired vs long-haired (e.g., group 1 is young, short-haired dogs, group 2 is young, long-haired dogs, etc.). Since the distributions of dog weight within each of the groups (shown in blue) has a relatively large variance, and since the means are very similar across groups, grouping dogs by these characteristics does not produce an effective way to explain the variation in dog weights: knowing which group a dog is in doesn't allow us to predict its weight much better than simply knowing the dog is in a dog show. Thus, this grouping fails to explain the variation in the overall distribution (yellow-orange). An attempt to explain the weight distribution by grouping dogs as ''pet vs working breed'' and ''less athletic vs more athletic'' would probably be somewhat more successful (fair fit). The heaviest show dogs are likely to be big, strong, working breeds, while breeds kept as pets tend to be smaller and thus lighter. As shown by the second illustration, the distributions have variances that are considerably smaller than in the first case, and the means are more distinguishable. However, the significant overlap of distributions, for example, means that we cannot distinguish ''X'' and ''X'' reliably. Grouping dogs according to a coin flip might produce distributions that look similar. An attempt to explain weight by breed is likely to produce a very good fit. All Chihuahuas are light and all St Bernards are heavy. The difference in weights between Setters and Pointers does not justify separate breeds. The analysis of variance provides the formal tools to justify these intuitive judgments. A common use of the method is the analysis of experimental data or the development of models. The method has some advantages over correlation: not all of the data must be numeric and one result of the method is a judgment in the confidence in an explanatory relationship.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Background and terminology"], "text": "ANOVA is a form of [[statistical hypothesis testing]] heavily used in the analysis of experimental data. A test result (calculated from the [[null hypothesis]] and the sample) is called statistically significant if it is deemed unlikely to have occurred by chance, ''assuming the truth of the null hypothesis''. A statistically significant result, when a probability ([[p-value|''p''-value]]) is less than a pre-specified threshold (significance level), justifies the rejection of the [[null hypothesis]], but only if the a priori probability of the null hypothesis is not high. In the typical application of ANOVA, the null hypothesis is that all groups are random samples from the same population. For example, when studying the effect of different treatments on similar samples of patients, the null hypothesis would be that all treatments have the same effect (perhaps none). Rejecting the null hypothesis is taken to mean that the differences in observed effects between treatment groups are unlikely to be due to random chance. By construction, hypothesis testing limits the rate of [[Type I errors]] (false positives) to a significance level. Experimenters also wish to limit [[Type II errors]] (false negatives). The rate of Type II errors depends largely on sample size (the rate is larger for smaller samples), significance level (when the standard of proof is high, the chances of overlooking a discovery are also high) and [[effect size]] (a smaller effect size is more prone to Type II error). The terminology of ANOVA is largely from the statistical [[design of experiments]]. The experimenter adjusts factors and measures responses in an attempt to determine an effect. Factors are assigned to experimental units by a combination of randomization and [[Randomized block design|blocking]] to ensure the validity of the results. [[Blind experiment|Blinding]] keeps the weighing impartial. Responses show a variability that is partially the result of the effect and is partially random error. ANOVA is the synthesis of several ideas and it is used for multiple purposes. As a consequence, it is difficult to define concisely or precisely. \"Classical\" ANOVA for balanced data does three things at once: ANOVA \"has long enjoyed the status of being the most used (some would say abused) statistical technique in psychological research.\" ANOVA is difficult to teach, particularly for complex experiments, with [[Restricted randomization|split-plot designs]] being notorious. In some cases the proper application of the method is best determined by problem pattern recognition followed by the consultation of a classic authoritative test.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Classes of models"], "text": "There are three classes of models used in the analysis of variance, and these are outlined here.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Classes of models", "Fixed-effects models"], "text": "The fixed-effects model (class I) of analysis of variance applies to situations in which the experimenter applies one or more treatments to the subjects of the experiment to see whether the [[response variable]] values change. This allows the experimenter to estimate the ranges of response variable values that the treatment would generate in the population as a whole.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Classes of models", "Random-effects models"], "text": "Random-effects model (class II) is used when the treatments are not fixed. This occurs when the various factor levels are sampled from a larger population. Because the levels themselves are [[random variable]], some assumptions and the method of contrasting the treatments (a multi-variable generalization of simple differences) differ from the fixed-effects model.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Classes of models", "Mixed-effects models"], "text": "A mixed-effects model (class III) contains experimental factors of both fixed and random-effects types, with appropriately different interpretations and analysis for the two types. Example: Teaching experiments could be performed by a college or university department to find a good introductory textbook, with each text considered a treatment. The fixed-effects model would compare a list of candidate texts. The random-effects model would determine whether important differences exist among a list of randomly selected texts. The mixed-effects model would compare the (fixed) incumbent texts to randomly selected alternatives. Defining fixed and random effects has proven elusive, with competing definitions arguably leading toward a linguistic quagmire.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions"], "text": "The analysis of variance has been studied from several approaches, the most common of which uses a [[linear model]] that relates the response to the treatments and blocks. Note that the model is linear in parameters but may be nonlinear across factor levels. Interpretation is easy when data is balanced across factors but much deeper understanding is needed for unbalanced data.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions", "Textbook analysis using a normal distribution"], "text": "The analysis of variance can be presented in terms of a [[linear model]], which makes the following assumptions about the [[probability distribution]] of the responses: (-) [[Statistical independence|Independence]] of observations – this is an assumption of the model that simplifies the statistical analysis. (-) [[normal distribution|Normality]] – the distributions of the [[Residual (statistics)|residuals]] are [[Normal distribution|normal]]. (-) Equality (or \"homogeneity\") of variances, called [[homoscedasticity]] — the variance of data in groups should be the same. The separate assumptions of the textbook model imply that the [[errors and residuals in statistics|errors]] are independently, identically, and normally distributed for fixed effects models, that is, that the errors (formula_1) are independent and formula_2", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions", "Randomization-based analysis"], "text": "In a [[Randomized controlled trial|randomized controlled experiment]], the treatments are randomly assigned to experimental units, following the experimental protocol. This randomization is objective and declared before the experiment is carried out. The objective random-assignment is used to test the significance of the null hypothesis, following the ideas of [[Charles Sanders Peirce|C. S. Peirce]] and [[Ronald Fisher]]. This design-based analysis was discussed and developed by [[Francis J. Anscombe]] at [[Rothamsted Experimental Station]] and by [[Oscar Kempthorne]] at [[Iowa State University]]. Kempthorne and his students make an assumption of ''unit treatment additivity'', which is discussed in the books of Kempthorne and [[David R. Cox]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions", "Randomization-based analysis", "Unit-treatment additivity"], "text": "In its simplest form, the assumption of unit-treatment additivity states that the observed response formula_3 from experimental unit formula_4 when receiving treatment formula_5 can be written as the sum of the unit's response formula_6 and the treatment-effect formula_7, that is   formula_8 The assumption of unit-treatment additivity implies that, for every treatment formula_5, the formula_5th treatment has exactly the same effect formula_11 on every experiment unit. The assumption of unit treatment additivity usually cannot be directly [[falsificationism|falsified]], according to Cox and Kempthorne. However, many ''consequences'' of treatment-unit additivity can be falsified. For a randomized experiment, the assumption of unit-treatment additivity ''implies'' that the variance is constant for all treatments. Therefore, by [[contraposition]], a necessary condition for unit-treatment additivity is that the variance is constant. The use of unit treatment additivity and randomization is similar to the design-based inference that is standard in finite-population [[survey sampling]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions", "Randomization-based analysis", "Derived linear model"], "text": "Kempthorne uses the randomization-distribution and the assumption of ''unit treatment additivity'' to produce a ''derived linear model'', very similar to the textbook model discussed previously. The test statistics of this derived linear model are closely approximated by the test statistics of an appropriate normal linear model, according to approximation theorems and simulation studies. However, there are differences. For example, the randomization-based analysis results in a small but (strictly) negative correlation between the observations. In the randomization-based analysis, there is ''no assumption'' of a ''normal'' distribution and certainly ''no assumption'' of ''independence''. On the contrary, ''the observations are dependent''! The randomization-based analysis has the disadvantage that its exposition involves tedious algebra and extensive time. Since the randomization-based analysis is complicated and is closely approximated by the approach using a normal linear model, most teachers emphasize the normal linear model approach. Few statisticians object to model-based analysis of balanced randomized experiments.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions", "Randomization-based analysis", "Statistical models for observational data"], "text": "However, when applied to data from non-randomized experiments or [[observational study|observational studies]], model-based analysis lacks the warrant of randomization. For observational data, the derivation of confidence intervals must use ''subjective'' models, as emphasized by [[Ronald Fisher]] and his followers. In practice, the estimates of treatment-effects from observational studies generally are often inconsistent. In practice, \"statistical models\" and observational data are useful for suggesting hypotheses that should be treated very cautiously by the public.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Assumptions", "Summary of assumptions"], "text": "The normal-model based ANOVA analysis assumes the independence, normality and homogeneity of variances of the residuals. The randomization-based analysis assumes only the homogeneity of the variances of the residuals (as a consequence of unit-treatment additivity) and uses the randomization procedure of the experiment. Both these analyses require [[homoscedasticity]], as an assumption for the normal-model analysis and as a consequence of randomization and additivity for the randomization-based analysis. However, studies of processes that change variances rather than means (called dispersion effects) have been successfully conducted using ANOVA. There are ''no'' necessary assumptions for ANOVA in its full generality, but the ''F''-test used for ANOVA hypothesis testing has assumptions and practical limitations which are of continuing interest. Problems which do not satisfy the assumptions of ANOVA can often be transformed to satisfy the assumptions. The property of unit-treatment additivity is not invariant under a \"change of scale\", so statisticians often use transformations to achieve unit-treatment additivity. If the response variable is expected to follow a parametric family of probability distributions, then the statistician may specify (in the protocol for the experiment or observational study) that the responses be transformed to stabilize the variance. Also, a statistician may specify that logarithmic transforms be applied to the responses, which are believed to follow a multiplicative model. According to Cauchy's [[functional equation]] theorem, the [[logarithm]] is the only continuous transformation that transforms real multiplication to addition.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Characteristics"], "text": "ANOVA is used in the analysis of comparative experiments, those in which only the difference in outcomes is of interest. The statistical significance of the experiment is determined by a ratio of two variances. This ratio is independent of several possible alterations to the experimental observations: Adding a constant to all observations does not alter significance. Multiplying all observations by a constant does not alter significance. So ANOVA statistical significance result is independent of constant bias and scaling errors as well as the units used in expressing observations. In the era of mechanical calculation it was common to subtract a constant from all observations (when equivalent to dropping leading digits) to simplify data entry. This is an example of data [[Coding (social sciences)|coding]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Logic"], "text": "The calculations of ANOVA can be characterized as computing a number of means and variances, dividing two variances and comparing the ratio to a handbook value to determine statistical significance. Calculating a treatment effect is then trivial: \"the effect of any treatment is estimated by taking the difference between the mean of the observations which receive the treatment and the general mean\".", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Logic", "Partitioning of the sum of squares"], "text": "ANOVA uses traditional standardized terminology. The definitional equation of sample variance is formula_12, where the divisor is called the degrees of freedom (DF), the summation is called the sum of squares (SS), the result is called the mean square (MS) and the squared terms are deviations from the sample mean. ANOVA estimates 3 sample variances: a total variance based on all the observation deviations from the grand mean, an error variance based on all the observation deviations from their appropriate treatment means, and a treatment variance. The treatment variance is based on the deviations of treatment means from the grand mean, the result being multiplied by the number of observations in each treatment to account for the difference between the variance of observations and the variance of means. The fundamental technique is a partitioning of the total [[sum of squares (statistics)|sum of squares]] ''SS'' into components related to the effects used in the model. For example, the model for a simplified ANOVA with one type of treatment at different levels. formula_13 The number of [[Degrees of freedom (statistics)|degrees of freedom]] ''DF'' can be partitioned in a similar way: one of these components (that for error) specifies a [[chi-squared distribution]] which describes the associated sum of squares, while the same is true for \"treatments\" if there is no treatment effect. formula_14 See also [[Lack-of-fit sum of squares]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Logic", "The ''F''-test"], "text": "The [[F-test|''F''-test]] is used for comparing the factors of the total deviation. For example, in one-way, or single-factor ANOVA, statistical significance is tested for by comparing the F test statistic formula_15 formula_16 where ''MS'' is mean square, formula_17 = number of treatments and formula_18 = total number of cases to the [[F-distribution|''F''-distribution]] with formula_19, formula_20 degrees of freedom. Using the ''F''-distribution is a natural candidate because the test statistic is the ratio of two scaled sums of squares each of which follows a scaled [[chi-squared distribution]]. The expected value of F is formula_21 (where formula_22 is the treatment sample size) which is 1 for no treatment effect. As values of F increase above 1, the evidence is increasingly inconsistent with the null hypothesis. Two apparent experimental methods of increasing F are increasing the sample size and reducing the error variance by tight experimental controls. There are two methods of concluding the ANOVA hypothesis test, both of which produce the same result: (-) The textbook method is to compare the observed value of F with the critical value of F determined from tables. The critical value of F is a function of the degrees of freedom of the numerator and the denominator and the significance level (α). If F ≥ F, the null hypothesis is rejected. (-) The computer method calculates the probability (p-value) of a value of F greater than or equal to the observed value. The null hypothesis is rejected if this probability is less than or equal to the significance level (α). The ANOVA ''F''-test is known to be nearly optimal in the sense of minimizing false negative errors for a fixed rate of false positive errors (i.e. maximizing power for a fixed significance level). For example, to test the hypothesis that various medical treatments have exactly the same effect, the [[F-test|''F''-test]]'s ''p''-values closely approximate the [[permutation test]]'s [[p-value]]: The approximation is particularly close when the design is balanced. Such [[permutation test]] characterize [[uniformly most powerful test|tests with maximum power]] against all [[alternative hypothesis|alternative hypotheses]], as observed by Rosenbaum. The ANOVA ''F''-test (of the null-hypothesis that all treatments have exactly the same effect) is recommended as a practical test, because of its robustness against many alternative distributions.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Logic", "Extended logic"], "text": "ANOVA consists of separable parts; partitioning sources of variance and hypothesis testing can be used individually. ANOVA is used to support other statistical tools. Regression is first used to fit more complex models to data, then ANOVA is used to compare models with the objective of selecting simple(r) models that adequately describe the data. \"Such models could be fit without any reference to ANOVA, but ANOVA tools could then be used to make some sense of the fitted models, and to test hypotheses about batches of coefficients.\" \"[W]e think of the analysis of variance as a way of understanding and structuring multilevel models—not as an alternative to regression but as a tool for summarizing complex high-dimensional inferences ...\"", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["For a single factor"], "text": "The simplest experiment suitable for ANOVA analysis is the completely randomized experiment with a single factor. More complex experiments with a single factor involve constraints on randomization and include completely randomized blocks and Latin squares (and variants: Graeco-Latin squares, etc.). The more complex experiments share many of the complexities of multiple factors. A relatively complete discussion of the analysis (models, data summaries, ANOVA table) of the completely randomized experiment is [[One-way analysis of variance|available]]. For a single factor, there are some alternatives of one-way analysis of variance; namely, Welch's heteroscedastic F test, Welch's heteroscedastic F test with trimmed means and Winsorized variances, Brown-Forsythe test, AlexanderGovern test, James second order test and Kruskal-Wallis test, available in onewaytests [[R package]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["For multiple factors"], "text": "ANOVA generalizes to the study of the effects of multiple factors. When the experiment includes observations at all combinations of levels of each factor, it is termed [[Factorial experiment|factorial]]. Factorial experiments are more efficient than a series of single factor experiments and the efficiency grows as the number of factors increases. Consequently, factorial designs are heavily used. The use of ANOVA to study the effects of multiple factors has a complication. In a 3-way ANOVA with factors x, y and z, the ANOVA model includes terms for the main effects (x, y, z) and terms for [[Interaction (statistics)|interactions]] (xy, xz, yz, xyz). All terms require hypothesis tests. The proliferation of interaction terms increases the risk that some hypothesis test will produce a false positive by chance. Fortunately, experience says that high order interactions are rare. The ability to detect interactions is a major advantage of multiple factor ANOVA. Testing one factor at a time hides interactions, but produces apparently inconsistent experimental results. Caution is advised when encountering interactions; Test interaction terms first and expand the analysis beyond ANOVA if interactions are found. Texts vary in their recommendations regarding the continuation of the ANOVA procedure after encountering an interaction. Interactions complicate the interpretation of experimental data. Neither the calculations of significance nor the estimated treatment effects can be taken at face value. \"A significant interaction will often mask the significance of main effects.\" Graphical methods are recommended to enhance understanding. Regression is often useful. A lengthy discussion of interactions is available in Cox (1958). Some interactions can be removed (by transformations) while others cannot. A variety of techniques are used with multiple factor ANOVA to reduce expense. One technique used in factorial designs is to minimize replication (possibly no replication with support of [[Tukey's test of additivity|analytical trickery]]) and to combine groups when effects are found to be statistically (or practically) insignificant. An experiment with many insignificant factors may collapse into one with a few factors supported by many replications.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Associated analysis"], "text": "Some analysis is required in support of the ''design'' of the experiment while other analysis is performed after changes in the factors are formally found to produce statistically significant changes in the responses. Because experimentation is iterative, the results of one experiment alter plans for following experiments.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Associated analysis", "Preparatory analysis", "The number of experimental units"], "text": "In the design of an experiment, the number of experimental units is planned to satisfy the goals of the experiment. Experimentation is often sequential. Early experiments are often designed to provide mean-unbiased estimates of treatment effects and of experimental error. Later experiments are often designed to test a hypothesis that a treatment effect has an important magnitude; in this case, the number of experimental units is chosen so that the experiment is within budget and has adequate power, among other goals. Reporting sample size analysis is generally required in psychology. \"Provide information on sample size and the process that led to sample size decisions.\" The analysis, which is written in the experimental protocol before the experiment is conducted, is examined in grant applications and administrative review boards. Besides the power analysis, there are less formal methods for selecting the number of experimental units. These include graphical methods based on limiting the probability of false negative errors, graphical methods based on an expected variation increase (above the residuals) and methods based on achieving a desired confidence interval.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Associated analysis", "Preparatory analysis", "Power analysis"], "text": "[[Statistical power|Power analysis]] is often applied in the context of ANOVA in order to assess the probability of successfully rejecting the null hypothesis if we assume a certain ANOVA design, effect size in the population, sample size and significance level. Power analysis can assist in study design by determining what sample size would be required in order to have a reasonable chance of rejecting the null hypothesis when the alternative hypothesis is true.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Associated analysis", "Preparatory analysis", "Effect size"], "text": "Several standardized measures of effect have been proposed for ANOVA to summarize the strength of the association between a predictor(s) and the dependent variable or the overall standardized difference of the complete model. Standardized effect-size estimates facilitate comparison of findings across studies and disciplines. However, while standardized effect sizes are commonly used in much of the professional literature, a non-standardized measure of effect size that has immediately \"meaningful\" units may be preferable for reporting purposes.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Associated analysis", "Preparatory analysis", "Model confirmation"], "text": "Sometimes tests are conducted to determine whether the assumptions of ANOVA appear to be violated. Residuals are examined or analyzed to confirm [[homoscedasticity]] and gross normality. Residuals should have the appearance of (zero mean normal distribution) noise when plotted as a function of anything including time and modeled data values. Trends hint at interactions among factors or among observations.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Associated analysis", "Preparatory analysis", "Follow-up tests"], "text": "A statistically significant effect in ANOVA is often followed by additional tests. This can be done in order to assess which groups are different from which other groups or to test various other focused hypotheses. Follow-up tests are often distinguished in terms of whether they are \"planned\" ([[A priori and a posteriori|a priori]]) or [[Post-hoc analysis|\"post hoc]].\" Planned tests are determined before looking at the data, and post hoc tests are conceived only after looking at the data (though the term \"post hoc\" is inconsistently used). The follow-up tests may be \"simple\" pairwise comparisons of individual group means or may be \"compound\" comparisons (e.g., comparing the mean pooling across groups A, B and C to the mean of group D). Comparisons can also look at tests of trend, such as linear and quadratic relationships, when the independent variable involves ordered levels. Often the follow-up tests incorporate a method of adjusting for the [[multiple comparisons problem]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Study designs"], "text": "There are several types of ANOVA. Many statisticians base ANOVA on the [[experimental design|design of the experiment]], especially on the protocol that specifies the [[random assignment]] of treatments to subjects; the protocol's description of the assignment mechanism should include a specification of the structure of the treatments and of any [[blocking (statistics)|blocking]]. It is also common to apply ANOVA to observational data using an appropriate statistical model. Some popular designs use the following types of ANOVA: (-) [[One-way ANOVA]] is used to test for differences among two or more [[statistical independence|independent]] groups (means), e.g. different levels of urea application in a crop, or different levels of antibiotic action on several different bacterial species, or different levels of effect of some medicine on groups of patients. However, should these groups not be independent, and there is an order in the groups (such as mild, moderate and severe disease), or in the dose of a drug (such as 5 mg/mL, 10 mg/mL, 20 mg/mL) given to the same group of patients, then a [[linear trend estimation]] should be used. Typically, however, the one-way ANOVA is used to test for differences among at least three groups, since the two-group case can be covered by a [[t-test]]. When there are only two means to compare, the [[t-test]] and the ANOVA [[F-test|''F''-test]] are equivalent; the relation between ANOVA and ''t'' is given by ''F'' = ''t''. (-) [[Factorial experiment|Factorial]] ANOVA is used when there is more than one factor. (-) [[Repeated measures]] ANOVA is used when the same subjects are used for each factor (e.g., in a [[longitudinal study]]). (-) [[Multivariate analysis of variance]] (MANOVA) is used when there is more than one [[dependent variable|response variable]].", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Cautions"], "text": "Balanced experiments (those with an equal sample size for each treatment) are relatively easy to interpret; Unbalanced experiments offer more complexity. For single-factor (one-way) ANOVA, the adjustment for unbalanced data is easy, but the unbalanced analysis lacks both robustness and power. For more complex designs the lack of balance leads to further complications. \"The orthogonality property of main effects and interactions present in balanced data does not carry over to the unbalanced case. This means that the usual analysis of variance techniques do not apply. Consequently, the analysis of unbalanced factorials is much more difficult than that for balanced designs.\" In the general case, \"The analysis of variance can also be applied to unbalanced data, but then the sums of squares, mean squares, and ''F''-ratios will depend on the order in which the sources of variation are considered.\" The simplest techniques for handling unbalanced data restore balance by either throwing out data or by synthesizing missing data. More complex techniques use regression. ANOVA is (in part) a test of statistical significance. The American Psychological Association (and many other organisations) holds the view that simply reporting statistical significance is insufficient and that reporting confidence bounds is preferred.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Generalizations"], "text": "ANOVA is considered to be a special case of [[linear regression]] which in turn is a special case of the [[general linear model]]. All consider the observations to be the sum of a model (fit) and a residual (error) to be minimized. The [[Kruskal–Wallis test]] and the [[Friedman test]] are [[nonparametric]] tests, which do not rely on an assumption of normality.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Generalizations", "Connection to linear regression"], "text": "Below we make clear the connection between multi-way ANOVA and linear regression. Linearly re-order the data so that formula_23 observation is associated with a response formula_24 and factors formula_25 where formula_26 denotes the different factors and formula_27 is the total number of factors. In one-way ANOVA formula_28 and in two-way ANOVA formula_29. Furthermore, we assume the formula_30 factor has formula_31 levels, namely formula_32. Now, we can [[one-hot]] encode the factors into the formula_33 dimensional vector formula_34. The one-hot encoding function formula_35 is defined such that the formula_36 entry of formula_37 is formula_38 The vector formula_34 is the concatenation of all of the above vectors for all formula_40. Thus, formula_41. In order to obtain a fully general formula_27-way interaction ANOVA we must also concatenate every additional interaction term in the vector formula_34 and then add an intercept term. Let that vector be formula_44. With this notation in place, we now have the exact connection with linear regression. We simply regress response formula_24 against the vector formula_44. However, there is a concern about [[identifiability]]. In order to overcome such issues we assume that the sum of the parameters within each set of interactions is equal to zero. From here, one can use ''F''-statistics or other methods to determine the relevance of the individual factors.", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": ["Generalizations", "Connection to linear regression", "Example"], "text": "We can consider the 2-way interaction example where we assume that the first factor has 2 levels and the second factor has 3 levels. Define formula_47 if formula_48 and formula_49 if formula_50, i.e. formula_51 is the one-hot encoding of the first factor and formula_40 is the one-hot encoding of the second factor. With that, formula_53 where the last term is an intercept term. For a more concrete example suppose that formula_54 Then, formula_55", "id": "634", "title": "Analysis of variance", "categories": ["Analysis of variance", "Design of experiments", "Statistical tests", "Parametric statistics"], "seealso": ["Permutational analysis of variance", "Multivariate analysis of covariance", "Two-way analysis of variance", "Analysis of covariance", "Linear trend estimation", "Analysis of rhythmic variance", "Repeated measures ANOVA", "Expected mean squares", "ANOVA on ranks", "ANOVA-simultaneous component analysis", "WP:SEEALSO", "Multivariate analysis of variance", "One-way analysis of variance", "Explained variation", "Variance decomposition", "Mixed-design analysis of variance", "Analysis of molecular variance"]}
{"headers": [], "text": "[[Image:Methane-2D-stereo.svg|right|thumb|Chemical structure of [[methane]], the simplest alkane]] In [[organic chemistry]], an '''alkane''', or '''paraffin''' (a historical [[trivial name]] that also has [[Paraffin (disambiguation)|other meanings]]), is an [[Open-chain compound|acyclic]] [[Saturated and unsaturated compounds|saturated]] [[hydrocarbon]]. In other words, an alkane consists of [[hydrogen]] and [[carbon]] atoms arranged in a [[Tree (graph theory)|tree]] structure in which all the [[carbon–carbon bond]] are [[Single bond|single]]. Alkanes have the general chemical formula CH. The alkanes range in complexity from the simplest case of [[methane]] (CH), where ''n'' = 1 (sometimes called the parent molecule), to arbitrarily large and complex molecules, like [[Higher alkanes#Nonatetracontane to tetrapentacontane|pentacontane]] (CH) or 6-ethyl-2-methyl-5-(1-methylethyl) octane, an [[isomer]] of [[tetradecane]] (CH). The [[International Union of Pure and Applied Chemistry]] (IUPAC) defines alkanes as \"acyclic branched or unbranched hydrocarbons having the general formula , and therefore consisting entirely of hydrogen atoms and saturated carbon atoms\". However, some sources use the term to denote ''any'' saturated hydrocarbon, including those that are either monocyclic (i.e. the [[cycloalkane]]) or polycyclic, despite their having a distinct general formula (i.e. cycloalkanes are CH). In an alkane, each carbon atom is [[Orbital hybridisation|sp-hybridized]] with 4 [[sigma bond]] (either C–C or [[Carbon–hydrogen bond|C–H]]), and each hydrogen atom is joined to one of the carbon atoms (in a C–H bond). The longest series of linked carbon atoms in a molecule is known as its [[Skeletal formula|carbon skeleton]] or carbon backbone. The number of carbon atoms may be considered as the size of the alkane. One group of the [[higher alkanes]] are [[wax]], solids at [[Standard conditions for temperature and pressure|standard ambient temperature and pressure]] (SATP), for which the number of carbon atoms in the carbon backbone is greater than about 17. With their repeated –CH units, the alkanes constitute a [[homologous series]] of organic compounds in which the members differ in [[molecular mass]] by multiples of 14.03 [[Dalton (unit)|u]] (the total mass of each such [[Methylene bridge|methylene-bridge]] unit, which comprises a single carbon atom of mass 12.01 u and two hydrogen atoms of mass ~1.01 u each). Methane is produced by [[Methanogen|methanogenic bacteria]] and some long-chain alkanes function as pheromones in certain animal species or as protective waxes in plants and fungi. Nevertheless, most alkanes do not have much [[biological activity]]. They can be viewed as molecular trees upon which can be hung the more active/reactive [[functional group]] of biological molecules. The alkanes have two main commercial sources: [[petroleum]] (crude oil) and [[natural gas]]. An [[alkyl]] group is an alkane-based molecular fragment that bears one open valence for bonding. They are generally abbreviated with the symbol for any organyl group, R, although Alk is sometimes used to specifically symbolize an alkyl group (as opposed to an alkenyl group or aryl group).", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Structure and classification"], "text": "Ordinarily the C-C single bond distance is 1.53 Å. Saturated hydrocarbons can be linear, branched, or [[Cyclic compound|cyclic]]. The third group is sometimes called [[cycloalkane]]. Very complicated structures are possible by combining linear, branch, cyclic alkanes.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Isomerism"], "text": "[[Image:Saturated C4 hydrocarbons ball-and-stick.png|thumb|right| C alkanes and cycloalkanes (left to right): [[n-butane|''n''-butane]] and [[isobutane]] are the two CH isomers; [[cyclobutane]] and [[methylcyclopropane]] are the two CH alkane isomers. [[Bicyclobutane|Bicyclo[1.1.0]butane]] is the only CH alkane and has no alkane isomer; [[tetrahedrane]] (below) is the only CH alkane and so has no alkane isomer.]] Alkanes with more than three [[carbon]] atoms can be arranged in various ways, forming [[structural isomer]]. The simplest isomer of an alkane is the one in which the carbon atoms are arranged in a single chain with no branches. This isomer is sometimes called the ''n''-isomer (''n'' for \"normal\", although it is not necessarily the most common). However the chain of carbon atoms may also be branched at one or more points. The number of possible isomers increases rapidly with the number of carbon atoms. For example, for acyclic alkanes: (-) C: [[methane]] only (-) C: [[ethane]] only (-) C: [[propane]] only (-) C: 2 isomers: [[butane]] and [[isobutane]] (-) C: 3 isomers: [[pentane]], [[isopentane]], and [[neopentane]] (-) C: 5 isomers: [[hexane]], [[2-Methylpentane|2-methylpentane]], [[3-Methylpentane|3-methylpentane]], [[2,2-Dimethylbutane|2,2-dimethylbutane]], and [[2,3-Dimethylbutane|2,3-dimethylbutane]] (-) C: 9 isomers: [[heptane]], [[methylhexane]] (2 isomers), [[dimethylpentane]] (4 isomers), [[3-Ethylpentane|3-ethylpentane]], [[2,2,3-trimethylbutane]] (-) C: 355 isomers (-) C: 27,711,253,769 isomers (-) C: 22,158,734,535,770,411,074,184 isomers, many of which are not stable. Branched alkanes can be [[chirality (chemistry)|chiral]]. For example, [[3-methylhexane]] and its higher [[Homology (chemistry)|homologues]] are chiral due to their [[stereogenic center]] at carbon atom number 3. The above list only includes differences of connectivity, not stereochemistry. In addition to the alkane isomers, the chain of carbon atoms may form one or more rings. Such compounds are called [[cycloalkane]], and are also excluded from the above list because changing the number of rings changes the [[molecular formula]]. [[Cyclobutane]] and [[methylcyclopropane]] are isomers of each other, but are not isomers of butane.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Nomenclature"], "text": "The [[IUPAC nomenclature of organic chemistry#Alkanes|IUPAC nomenclature]] (systematic way of naming compounds) for alkanes is based on identifying hydrocarbon chains. Unbranched, saturated hydrocarbon chains are named systematically with a Greek numerical prefix denoting the number of carbons and the suffix \"-ane\". In 1866, [[August Wilhelm von Hofmann]] suggested systematizing nomenclature by using the whole sequence of vowels a, e, i, o and u to create suffixes -ane, -ene, -ine (or -yne), -one, -une, for the [[hydrocarbons]] CH, CH, CH, CH, CH. Now, the first three name hydrocarbons with single, double and triple bonds; \"-one\" represents a [[ketone]]; \"-ol\" represents an alcohol or OH group; \"-oxy-\" means an [[ether]] and refers to oxygen between two carbons, so that methoxymethane is the IUPAC name for [[dimethyl ether]]. It is difficult or impossible to find compounds with more than one [[International Union of Pure and Applied Chemistry|IUPAC]] name. This is because shorter chains attached to longer chains are prefixes and the convention includes brackets. Numbers in the name, referring to which carbon a group is attached to, should be as low as possible so that 1- is implied and usually omitted from names of organic compounds with only one side-group. Symmetric compounds will have two ways of arriving at the same name.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Nomenclature", "Linear alkanes"], "text": "Straight-chain alkanes are sometimes indicated by the prefix \"n-\" or \"''n''-\"(for \"normal\") where a non-linear [[isomer]] exists. Although this is not strictly necessary, the usage is still common in cases where there is an important difference in properties between the straight-chain and branched-chain isomers, e.g., \"[[butane|''n''-butane]]\" rather than simply \"butane\" to distinguish it from [[isobutane]]. Alternative names for this group are: '''linear paraffins''' or '''''n''-paraffins'''. The first six members of the series (in terms of number of carbon atoms) are named as follows: (-) [[methane]]: CH – one carbon and 4 hydrogen (-) [[ethane]] : CH – two carbon and 6 hydrogen (-) [[propane]]: CH – three carbon and 8 hydrogen (-) [[butane]] : CH – four carbon and 10 hydrogen (-) [[pentane]]: CH – five carbon and 12 hydrogen (-) [[hexane]] : CH – six carbon and 14 hydrogen The first four names were [[back-formation|derived]] from [[methanol]], [[diethyl ether|ether]], [[propionic acid]] and [[butyric acid]]. Alkanes with five or more carbon atoms are named by adding the [[Affix|suffix]] '''-ane''' to the appropriate [[IUPAC numerical multiplier|numerical multiplier]] prefix with [[elision]] of any terminal vowel (''-a'' or ''-o'') from the basic numerical term. Hence, [[pentane]], CH; [[hexane]], CH; [[heptane]], CH; [[octane]], CH; etc. The [[numeral prefix]] is generally Greek, however alkanes with a carbon atom count ending in nine, for example [[nonane]], use the [[Latin language|Latin]] prefix '''non-'''. For a more complete list, see [[list of straight-chain alkanes]].", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Nomenclature", "Branched alkanes"], "text": "[[Image:Isopentane-numbered-3D-balls.png|thumb|right|[[Ball-and-stick model]] of [[isopentane]] (common name) or 2-methylbutane (IUPAC systematic name)]] Simple branched alkanes often have a common name using a prefix to distinguish them from linear alkanes, for example [[pentane|''n''-pentane]], [[isopentane]], and [[neopentane]]. IUPAC naming conventions can be used to produce a systematic name. The key steps in the naming of more complicated branched alkanes are as follows: (-) Identify the longest continuous chain of carbon atoms (-) Name this longest root chain using standard naming rules (-) Name each side chain by changing the suffix of the name of the alkane from \"-ane\" to \"-yl\" (-) Number the longest continuous chain in order to give the lowest possible numbers for the side-chains (-) Number and name the side chains before the name of the root chain (-) If there are multiple side chains of the same type, use prefixes such as \"di-\" and \"tri-\" to indicate it as such, and number each one. (-) Add side chain names in alphabetical (disregarding \"di-\" etc. prefixes) order in front of the name of the root chain ", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Nomenclature", "Saturated cyclic hydrocarbons"], "text": "Though technically distinct from the alkanes, this class of hydrocarbons is referred to by some as the \"cyclic alkanes.\" As their description implies, they contain one or more rings. Simple cycloalkanes have a prefix \"cyclo-\" to distinguish them from alkanes. Cycloalkanes are named as per their acyclic counterparts with respect to the number of carbon atoms in their backbones, e.g., [[cyclopentane]] (CH) is a cycloalkane with 5 carbon atoms just like [[pentane]] (CH), but they are joined up in a five-membered ring. In a similar manner, [[propane]] and [[cyclopropane]], [[butane]] and [[cyclobutane]], etc. Substituted cycloalkanes are named similarly to substituted alkanes – the cycloalkane ring is stated, and the substituents are according to their position on the ring, with the numbering decided by the [[Cahn–Ingold–Prelog priority rules]].", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Nomenclature", "Trivial/common names"], "text": "The trivial (non-[[IUPAC nomenclature|systematic]]) name for alkanes is 'paraffins'. Together, alkanes are known as the 'paraffin series'. Trivial names for compounds are usually historical artifacts. They were coined before the development of systematic names, and have been retained due to familiar usage in industry. Cycloalkanes are also called naphthenes. It is almost certain that the term 'paraffin' stems from the [[petrochemical industry]]. Branched-chain alkanes are called '''isoparaffins'''. The use of the term \"paraffin\" is a general term and often does not distinguish between pure compounds and mixtures of [[isomer]], i.e., compounds of the same [[chemical formula]], e.g., [[pentane]] and [[isopentane]]. (-) In IUPAC The following trivial names are retained in the IUPAC system: (-) [[isobutane]] for 2-methylpropane (-) [[isopentane]] for 2-methylbutane (-) [[neopentane]] for 2,2-dimethylpropane. (-) Non-IUPAC Some non-IUPAC trivial names are occasionally used: (-) cetane, for [[hexadecane]] (-) cerane, for [[hexacosane]]", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties"], "text": "All alkanes are colorless. Alkanes with the lowest molecular weights are gasses, those of intermediate molecular weight are liquids, and the heaviest are waxy solids.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Boiling point"], "text": "[[Image:AlkaneBoilingMeltingPoint.png|right|thumb|400px|Melting (blue) and boiling (orange) points of the first 16 ''n''-alkanes in °C.]] Alkanes experience intermolecular [[van der Waals force]]. Stronger intermolecular van der Waals forces give rise to greater boiling points of alkanes. There are two determinants for the strength of the van der Waals forces: (-) the number of electrons surrounding the [[molecule]], which increases with the alkane's molecular weight (-) the surface area of the molecule Under [[standard conditions]], from CH to CH alkanes are gaseous; from CH to CH they are liquids; and after CH they are solids. As the boiling point of alkanes is primarily determined by weight, it should not be a surprise that the boiling point has almost a linear relationship with the size ([[molecular weight]]) of the molecule. As a rule of thumb, the boiling point rises 20–30 °C for each carbon added to the chain; this rule applies to other homologous series. A straight-chain alkane will have a boiling point higher than a branched-chain alkane due to the greater surface area in contact, thus the greater van der Waals forces, between adjacent molecules. For example, compare [[isobutane]] (2-methylpropane) and [[n-butane]] (butane), which boil at −12 and 0 °C, and 2,2-dimethylbutane and 2,3-dimethylbutane which boil at 50 and 58 °C, respectively. For the latter case, two molecules 2,3-dimethylbutane can \"lock\" into each other better than the cross-shaped 2,2-dimethylbutane, hence the greater van der Waals forces. On the other hand, cycloalkanes tend to have higher boiling points than their linear counterparts due to the locked conformations of the molecules, which give a plane of intermolecular contact.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Melting points"], "text": "The [[melting point]] of the alkanes follow a similar trend to [[boiling points]] for the same reason as outlined above. That is, (all other things being equal) the larger the molecule the higher the melting point. There is one significant difference between boiling points and melting points. Solids have more rigid and fixed structure than liquids. This rigid structure requires energy to break down. Thus the better put together solid structures will require more energy to break apart. For alkanes, this can be seen from the graph above (i.e., the blue line). The odd-numbered alkanes have a lower trend in melting points than even numbered alkanes. This is because even numbered alkanes pack well in the solid phase, forming a well-organized structure, which requires more energy to break apart. The odd-numbered alkanes pack less well and so the \"looser\" organized solid packing structure requires less energy to break apart. For a visualization of the crystal structures see. The melting points of branched-chain alkanes can be either higher or lower than those of the corresponding straight-chain alkanes, again depending on the ability of the alkane in question to pack well in the solid phase: This is particularly true for [[isoalkanes]] (2-methyl isomers), which often have melting points higher than those of the linear analogues.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Conductivity and solubility"], "text": "Alkanes do not conduct electricity in any way, nor are they substantially [[Relative static permittivity|polarized]] by an [[electric field]]. For this reason, they do not form [[hydrogen bond]] and are insoluble in polar solvents such as water. Since the hydrogen bonds between individual water molecules are aligned away from an alkane molecule, the coexistence of an alkane and water leads to an increase in molecular order (a reduction in [[entropy]]). As there is no significant bonding between water molecules and alkane molecules, the [[second law of thermodynamics]] suggests that this reduction in entropy should be minimized by minimizing the contact between alkane and water: Alkanes are said to be [[Hydrophobe|hydrophobic]] as they repel water. Their solubility in nonpolar solvents is relatively high, a property that is called [[lipophilicity]]. Alkanes are, for example, miscible in all proportions among themselves. The density of the alkanes usually increases with the number of carbon atoms but remains less than that of water. Hence, alkanes form the upper layer in an alkane–water mixture.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Molecular geometry"], "text": "[[Image:Ch4 hybridization.svg|thumb|right|sp-hybridization in [[methane]].]] The molecular structure of the alkanes directly affects their physical and chemical characteristics. It is derived from the [[electron configuration]] of [[carbon]], which has four [[valence electron]]. The carbon atoms in alkanes are always sp-hybridized, that is to say that the valence electrons are said to be in four equivalent orbitals derived from the combination of the 2s orbital and the three 2p orbitals. These orbitals, which have identical energies, are arranged spatially in the form of a [[tetrahedron]], the angle of cos(−) ≈ 109.47° between them.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Bond lengths and bond angles"], "text": "An alkane has only C–H and C–C single bonds. The former result from the overlap of an sp orbital of carbon with the 1s orbital of a hydrogen; the latter by the overlap of two sp orbitals on adjacent carbon atoms. The [[bond length]] amount to 1.09 × 10 m for a C–H bond and 1.54 × 10 m for a C–C bond. [[Image:Ch4-structure.png|thumb|right|The tetrahedral structure of methane.]] The spatial arrangement of the bonds is similar to that of the four sp orbitals—they are tetrahedrally arranged, with an angle of 109.47° between them. Structural formulae that represent the bonds as being at right angles to one another, while both common and useful, do not correspond with the reality.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Conformation"], "text": "The structural formula and the [[bond angle]] are not usually sufficient to completely describe the geometry of a molecule. There is a further [[degrees of freedom (physics and chemistry)|degree of freedom]] for each carbon–carbon bond: the [[torsion angle]] between the atoms or groups bound to the atoms at each end of the bond. The spatial arrangement described by the torsion angles of the molecule is known as its [[conformational isomerism|conformation]]. [[Image:Newman projection ethane.png|thumb|right|200px|Newman projections of the two conformations of ethane: eclipsed on the left, staggered on the right.]] [[Image:Ethane-rotamers-3D-balls.png|thumb|right|200px|[[Ball-and-stick model]]s of the two rotamers of ethane]] [[Ethane]] forms the simplest case for studying the conformation of alkanes, as there is only one C–C bond. If one looks down the axis of the C–C bond, one will see the so-called [[Newman projection]]. The hydrogen atoms on both the front and rear carbon atoms have an angle of 120° between them, resulting from the projection of the base of the tetrahedron onto a flat plane. However, the torsion angle between a given hydrogen atom attached to the front carbon and a given hydrogen atom attached to the rear carbon can vary freely between 0° and 360°. This is a consequence of the free rotation about a carbon–carbon single bond. Despite this apparent freedom, only two limiting conformations are important: [[eclipsed]] conformation and [[staggered conformation]]. The two conformations differ in energy: the staggered conformation is 12.6 kJ/mol lower in energy (more stable) than the eclipsed conformation (the least stable). This difference in energy between the two conformations, known as the [[torsion energy]], is low compared to the thermal energy of an ethane molecule at ambient temperature. There is constant rotation about the C–C bond. The time taken for an ethane molecule to pass from one staggered conformation to the next, equivalent to the rotation of one CH group by 120° relative to the other, is of the order of 10 seconds. The case of [[higher alkanes]] is more complex but based on similar principles, with the antiperiplanar conformation always being the most favored around each carbon–carbon bond. For this reason, alkanes are usually shown in a zigzag arrangement in diagrams or in models. The actual structure will always differ somewhat from these idealized forms, as the differences in energy between the conformations are small compared to the thermal energy of the molecules: Alkane molecules have no fixed structural form, whatever the models may suggest.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Spectroscopic properties"], "text": "Virtually all organic compounds contain carbon–carbon, and carbon–hydrogen bonds, and so show some of the features of alkanes in their spectra. Alkanes are notable for having no other groups, and therefore for the ''absence'' of other characteristic spectroscopic features of a functional group like [[Alcohol (chemistry)|–OH]], [[Aldehyde|–CHO]], [[Carboxylic acid|–COOH]] etc.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Spectroscopic properties", "Infrared spectroscopy"], "text": "The carbon–hydrogen stretching mode gives a strong absorption between 2850 and 2960 [[Wavenumber|cm]], while the carbon–carbon stretching mode absorbs between 800 and 1300 cm. The carbon–hydrogen bending modes depend on the nature of the group: methyl groups show bands at 1450 cm and 1375 cm, while methylene groups show bands at 1465 cm and 1450 cm. Carbon chains with more than four carbon atoms show a weak absorption at around 725 cm.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Spectroscopic properties", "NMR spectroscopy"], "text": "The proton resonances of alkanes are usually found at [[chemical shift|''δ'']] = 0.5–1.5. The carbon-13 resonances depend on the number of hydrogen atoms attached to the carbon: ''δ'' = 8–30 (primary, methyl, –CH), 15–55 (secondary, methylene, –CH–), 20–60 (tertiary, methyne, C–H) and quaternary. The carbon-13 resonance of quaternary carbon atoms is characteristically weak, due to the lack of [[nuclear Overhauser effect]] and the long [[relaxation time]], and can be missed in weak samples, or samples that have not been run for a sufficiently long time.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Physical properties", "Spectroscopic properties", "Mass spectrometry"], "text": "Alkanes have a high [[ionization energy]], and the molecular ion is usually weak. The fragmentation pattern can be difficult to interpret, but, in the case of branched chain alkanes, the carbon chain is preferentially cleaved at tertiary or quaternary carbons due to the relative stability of the resulting [[free radical]]. The fragment resulting from the loss of a single methyl group (''M'' − 15) is often absent, and other fragments are often spaced by intervals of fourteen mass units, corresponding to sequential loss of CH groups.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Chemical properties"], "text": "Alkanes are only weakly reactive with most chemical compounds. The [[acid dissociation constant]] (p''K'') values of all alkanes are estimated to range from 50 to 70, depending on the extrapolation method, hence they are extremely weak acids that are practically inert to bases (see: [[carbon acid]]). They are also extremely weak bases, undergoing no observable protonation in pure sulfuric acid (''H'' ~ –12), although [[superacid]] that are at least millions of times stronger have been known to protonate them to give hypercoordinate alkanium ions (see: [[Methanium|methanium ion]]). Similarly, they only show reactivity with the strongest of electrophilic reagents (e.g., [[dioxirane]] and salts containing the [[Tetrafluoroammonium|NF cation]]). By virtue of their strongly C–H bonds (~100 kcal/mol) and C–C bonds (~90 kcal/mol, but usually less sterically accessible), they are also relatively unreactive toward free radicals, although many electron-deficient radicals will react with alkanes in the absence of other electron-rich bonds (see below). This inertness is the source of the term ''paraffins'' (with the meaning here of \"lacking affinity\"). In [[crude oil]] the alkane molecules have remained chemically unchanged for millions of years. [[Free radical]], molecules with unpaired electrons, play a large role in most reactions of alkanes, such as cracking and reformation where long-chain alkanes are converted into shorter-chain alkanes and straight-chain alkanes into branched-chain isomers. Moreover, redox reactions of alkanes involving free radical intermediates, in particular with oxygen and the halogens, are possible as the carbon atoms are in a strongly reduced state; in the case of methane, carbon is in its lowest possible oxidation state (−4). Reaction with oxygen (''if'' present in sufficient quantity to satisfy the reaction [[stoichiometry]]) leads to combustion without any smoke, producing [[carbon dioxide]] and water. [[Free radical halogenation]] reactions occur with halogens, leading to the production of [[haloalkanes]]. In addition, alkanes have been shown to interact with, and bind to, certain transition metal complexes in [[carbon-hydrogen bond activation|C–H bond activation]] reactions. In highly branched alkanes, the bond angle may differ significantly from the optimal value (109.5°) to accommodate bulky groups. Such distortions introduce a tension in the molecule, known as [[steric hindrance]] or strain. Strain substantially increases reactivity. However, in general and perhaps surprisingly, when branching is not extensive enough to make highly disfavorable 1,2- and 1,3-alkyl–alkyl steric interactions (worth ~3.1 kcal/mol and ~3.7 kcal/mol in the case of the eclipsing conformations of butane and pentane, respectively) unavoidable, the branched alkanes are actually more thermodynamically stable than their linear (or less branched) isomers. For example, the highly branched 2,2,3,3-tetramethylbutane is about 1.9 kcal/mol more stable than its linear isomer, ''n''-octane. Due to the subtlety of this effect, the exact reasons for this rule have been vigorously debated in the chemical literature and is yet unsettled. Several explanations, including stabilization of branched alkanes by electron correlation, destabilization of linear alkanes by steric repulsion, stabilization by neutral hyperconjugation, and/or electrostatic effects have been advanced as possibilities. The controversy is related to the question of whether the traditional explanation of hyperconjugation is the primary factor governing the stability of alkyl radicals.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Chemical properties", "Reactions with oxygen (combustion reaction)"], "text": "All alkanes react with [[oxygen]] in a [[combustion]] reaction, although they become increasingly difficult to ignite as the number of carbon atoms increases. The general equation for complete combustion is: CH + (''n'' + ) O → (''n'' + 1) HO + ''n'' CO or CH + () O → (''n'' + 1) HO + ''n'' CO In the absence of sufficient oxygen, [[carbon monoxide]] or even [[soot]] can be formed, as shown below: CH + (''n'' + ) [[oxygen|O]] → (''n'' + 1) HO + ''n'' [[carbon monoxide|CO]] CH + (''n'' + ) [[oxygen|O]] → (''n'' + 1) HO + ''n'' [[carbon|C]] For example, [[methane]]: 2 CH + 3 O → 4 HO + 2 CO CH + O → 2 HO + C See the [[Standard enthalpy change of formation (data table)#Alkanes|alkane heat of formation table]] for detailed data. The [[standard enthalpy change of combustion]], Δ''H'', for alkanes increases by about 650 kJ/mol per CH group. Branched-chain alkanes have lower values of Δ''H'' than straight-chain alkanes of the same number of carbon atoms, and so can be seen to be somewhat more stable.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Chemical properties", "Reactions with halogens"], "text": "Alkanes react with [[halogen]] in a so-called ''free radical halogenation'' reaction. The hydrogen atoms of the alkane are progressively replaced by halogen atoms. [[Free radical]] are the reactive species that participate in the reaction, which usually leads to a mixture of products. The reaction is highly [[exothermic reaction|exothermic]], and can lead to an explosion. These reactions are an important industrial route to halogenated hydrocarbons. There are three steps: (-) '''Initiation''' the halogen radicals form by [[homolysis (chemistry)|homolysis]]. Usually, energy in the form of heat or light is required. (-) '''Chain reaction''' or '''Propagation''' then takes place—the halogen radical abstracts a hydrogen from the alkane to give an alkyl radical. This reacts further. (-) '''Chain termination''' where the radicals recombine. Experiments have shown that all halogenation produces a mixture of all possible isomers, indicating that all hydrogen atoms are susceptible to reaction. The mixture produced, however, is not a statistical mixture: Secondary and tertiary hydrogen atoms are preferentially replaced due to the greater stability of secondary and tertiary free-radicals. An example can be seen in the monobromination of propane: [[Image:Monobromination of propane.png|500px|center|Monobromination of [[propane]]]]", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Chemical properties", "Cracking"], "text": "Cracking breaks larger molecules into smaller ones. This can be done with a thermal or catalytic method. The thermal cracking process follows a [[homolysis (chemistry)|homolytic]] mechanism with formation of [[free-radical]]. The catalytic cracking process involves the presence of [[acid]] [[catalyst]] (usually solid acids such as [[silica-alumina]] and [[zeolite]]), which promote a [[heterolytic cleavage|heterolytic]] (asymmetric) breakage of bonds yielding pairs of ions of opposite charges, usually a [[carbocation]] and the very unstable [[hydride]] [[anion]]. Carbon-localized free radicals and cations are both highly unstable and undergo processes of chain rearrangement, C–C scission in position [[beta scission|beta]] (i.e., cracking) and [[Intramolecular reaction|intra-]] and [[intermolecular]] hydrogen transfer or [[hydride]] transfer. In both types of processes, the corresponding [[reactive intermediate]] (radicals, ions) are permanently regenerated, and thus they proceed by a self-propagating chain mechanism. The chain of reactions is eventually terminated by radical or ion recombination.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Chemical properties", "Isomerization and reformation"], "text": "Dragan and his colleague were the first to report about isomerization in alkanes. Isomerization and reformation are processes in which straight-chain alkanes are heated in the presence of a [[platinum]] catalyst. In isomerization, the alkanes become branched-chain isomers. In other words, it does not lose any carbons or hydrogens, keeping the same molecular weight. In reformation, the alkanes become [[cycloalkane]] or [[aromatic hydrocarbon]], giving off hydrogen as a by-product. Both of these processes raise the [[octane number]] of the substance. Butane is the most common alkane that is put under the process of isomerization, as it makes many branched alkanes with high octane numbers.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Chemical properties", "Other reactions"], "text": "Alkanes will react with [[steam]] in the presence of a [[nickel]] [[catalyst]] to give [[hydrogen]]. Alkanes can be [[Chlorosulfonation|chlorosulfonated]] and [[nitration|nitrated]], although both reactions require special conditions. The [[fermentation (biochemistry)|fermentation]] of alkanes to [[carboxylic acid]] is of some technical importance. In the [[Reed reaction]], [[sulfur dioxide]], [[chlorine]] and [[photochemistry|light]] convert hydrocarbons to [[Sulfonic acid|sulfonyl chlorides]]. [[Nucleophilic abstraction|Nucleophilic Abstraction]] can be used to separate an alkane from a metal. Alkyl groups can be transferred from one compound to another by [[transmetalation]] reactions. A mixture of [[antimony pentafluoride]] (SbF) and [[fluorosulfonic acid]] (HSOF), called [[magic acid]], can protonate alkanes.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Occurrence", "Occurrence of alkanes in the Universe"], "text": "[[Image:Jupiter.jpg|thumb|right|[[Methane]] and [[ethane]] make up a tiny proportion of [[Jupiter]]'s atmosphere]] [[Image:Oil well.jpg|thumb|right|Extraction of oil, which contains many distinct [[hydrocarbon]]s including alkanes]] Alkanes form a small portion of the [[Celestial body atmosphere|atmospheres]] of the outer gas planets such as [[Jupiter]] (0.1% methane, 2 [[parts per million|ppm]] ethane), [[Saturn]] (0.2% methane, 5 ppm ethane), [[Uranus]] (1.99% methane, 2.5 ppm ethane) and [[Neptune]] (1.5% methane, 1.5 ppm ethane). [[Titan (moon)|Titan]] (1.6% methane), a satellite of Saturn, was examined by the [[Huygens (spacecraft)|''Huygens'' probe]], which indicated that Titan's atmosphere periodically rains liquid methane onto the moon's surface. Also on Titan the Cassini mission has imaged seasonal methane/ethane lakes near the polar regions of Titan. [[Methane]] and [[ethane]] have also been detected in the tail of the comet [[Hyakutake]]. Chemical analysis showed that the abundances of ethane and methane were roughly equal, which is thought to imply that its ices formed in interstellar space, away from the Sun, which would have evaporated these volatile molecules. Alkanes have also been detected in [[meteorite]] such as [[carbonaceous chondrite]].", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Occurrence", "Occurrence of alkanes on Earth"], "text": "Traces of methane gas (about 0.0002% or 1745 ppb) occur in the Earth's atmosphere, produced primarily by [[methanogenesis|methanogenic]] microorganisms, such as [[Archaea]] in the gut of ruminants. The most important commercial sources for alkanes are natural gas and [[Petroleum|oil]]. Natural gas contains primarily methane and ethane, with some [[propane]] and [[butane]]: oil is a mixture of liquid alkanes and other [[hydrocarbons]]. These hydrocarbons were formed when marine animals and plants (zooplankton and phytoplankton) died and sank to the bottom of ancient seas and were covered with sediments in an [[wikt:anoxic|anoxic]] environment and converted over many millions of years at high temperatures and high pressure to their current form. Natural gas resulted thereby for example from the following reaction: CHO → 3 CH + 3 CO These hydrocarbon deposits, collected in porous rocks trapped beneath impermeable cap rocks, comprise commercial [[oil fields]]. They have formed over millions of years and once exhausted cannot be readily replaced. The depletion of these hydrocarbons reserves is the basis for what is known as the [[energy crisis]]. Methane is also present in what is called [[biogas]], produced by animals and decaying matter, which is a possible [[renewable energy source]]. Alkanes have a low solubility in water, so the content in the oceans is negligible; however, at high pressures and low temperatures (such as at the bottom of the oceans), methane can co-crystallize with water to form a solid [[methane clathrate]] (methane hydrate). Although this cannot be commercially exploited at the present time, the amount of combustible energy of the known methane clathrate fields exceeds the energy content of all the natural gas and oil deposits put together. Methane extracted from methane clathrate is, therefore, a candidate for future fuels.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Occurrence", "Biological occurrence"], "text": "Acyclic alkanes occur in nature in various ways. (-) Bacteria and archaea [[Image:Rotbuntes Rind.jpg|thumb|right|[[Methanogen]]ic [[archaea]] in the gut of this cow are responsible for some of the [[methane]] in Earth's atmosphere.]] Certain types of bacteria can metabolize alkanes: they prefer even-numbered carbon chains as they are easier to degrade than odd-numbered chains. On the other hand, certain [[archaea]], the [[methanogen]], produce large quantities of [[methane]] by the metabolism of [[carbon dioxide]] or other [[oxidation|oxidized]] organic compounds. The energy is released by the oxidation of [[hydrogen]]: CO + 4 H → CH + 2 HO Methanogens are also the producers of [[marsh gas]] in [[wetlands]]. The methane output of [[cattle]] and other [[herbivore]], which can release 30 to 50 gallons per day, and of [[termite]], is also due to methanogens. They also produce this simplest of all alkanes in the [[intestine]] of humans. Methanogenic archaea are, hence, at the end of the [[carbon cycle]], with carbon being released back into the atmosphere after having been fixed by [[photosynthesis]]. It is probable that our current deposits of natural gas were formed in a similar way. (-) Fungi and plants Alkanes also play a role, if a minor role, in the biology of the three [[eukaryote|eukaryotic]] groups of organisms: [[Fungus|fungi]], plants and animals. Some specialized yeasts, e.g., ''Candida tropicale'', ''[[Pichia]]'' sp., ''[[Rhodotorula]]'' sp., can use alkanes as a source of carbon or energy. The fungus ''[[Amorphotheca resinae]]'' prefers the longer-chain alkanes in [[aviation fuel]], and can cause serious problems for aircraft in tropical regions. In plants, the solid long-chain alkanes are found in the [[plant cuticle]] and [[epicuticular wax]] of many species, but are only rarely major constituents. They protect the plant against water loss, prevent the [[Leaching (agriculture)|leaching]] of important minerals by the rain, and protect against bacteria, fungi, and harmful insects. The carbon chains in plant alkanes are usually odd-numbered, between 27 and 33 carbon atoms in length and are made by the plants by [[decarboxylation]] of even-numbered [[fatty acid]]. The exact composition of the layer of wax is not only species-dependent but changes also with the season and such environmental factors as lighting conditions, temperature or humidity. More volatile short-chain alkanes are also produced by and found in plant tissues. The [[Jeffrey pine]] is noted for producing exceptionally high levels of ''n''-[[heptane]] in its resin, for which reason its distillate was designated as the zero point for one [[octane rating]]. Floral scents have also long been known to contain volatile alkane components, and ''n''-[[nonane]] is a significant component in the scent of some [[rose]]. Emission of gaseous and volatile alkanes such as [[ethane]], [[pentane]], and [[hexane]] by plants has also been documented at low levels, though they are not generally considered to be a major component of biogenic air pollution.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Occurrence", "Biological occurrence"], "text": "Edible vegetable oils also typically contain small fractions of biogenic alkanes with a wide spectrum of carbon numbers, mainly 8 to 35, usually peaking in the low to upper 20s, with concentrations up to dozens of milligrams per kilogram (parts per million by weight) and sometimes over a hundred for the total alkane fraction. (-) Animals Alkanes are found in animal products, although they are less important than unsaturated hydrocarbons. One example is the shark liver oil, which is approximately 14% [[pristane]] (2,6,10,14-tetramethylpentadecane, CH). They are important as [[pheromone]], chemical messenger materials, on which insects depend for communication. In some species, e.g. the support beetle ''[[Xylotrechus colonus]]'', [[pentacosane]] (CH), 3-methylpentaicosane (CH) and 9-methylpentaicosane (CH) are transferred by body contact. With others like the [[tsetse fly]] ''Glossina morsitans morsitans'', the pheromone contains the four alkanes 2-methylheptadecane (CH), 17,21-dimethylheptatriacontane (CH), 15,19-dimethylheptatriacontane (CH) and 15,19,23-trimethylheptatriacontane (CH), and acts by smell over longer distances. [[waggle dance|Waggle-dancing]] [[honey bee]] produce and release two alkanes, tricosane and pentacosane.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Occurrence", "Ecological relations"], "text": "[[Image:Ophrys sphegodes flower.jpg|thumb|right|Early spider orchid (''[[Ophrys sphegodes]]'')]] One example, in which both plant and animal alkanes play a role, is the ecological relationship between the [[sand bee]] (''[[Andrena nigroaenea]]'') and the [[early spider orchid]] (''[[Ophrys sphegodes]]''); the latter is dependent for [[pollination]] on the former. Sand bees use pheromones in order to identify a mate; in the case of ''A. nigroaenea'', the females emit a mixture of [[tricosane]] (CH), [[pentacosane]] (CH) and [[heptacosane]] (CH) in the ratio 3:3:1, and males are attracted by specifically this odor. The orchid takes advantage of this mating arrangement to get the male bee to collect and disseminate its pollen; parts of its flower not only resemble the appearance of sand bees but also produce large quantities of the three alkanes in the same ratio as female sand bees. As a result, numerous males are lured to the blooms and attempt to copulate with their imaginary partner: although this endeavor is not crowned with success for the bee, it allows the orchid to transfer its pollen, which will be dispersed after the departure of the frustrated male to other blooms.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Production", "Petroleum refining"], "text": "[[Image:ShellMartinez-refi.jpg|thumb|right|An [[oil refinery]] at [[Martinez, California]].]] As stated earlier, the most important source of alkanes is natural gas and [[crude oil]]. Alkanes are separated in an [[oil refinery]] by [[fractional distillation]] and processed into many products.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Production", "Fischer–Tropsch"], "text": "The [[Fischer–Tropsch process]] is a method to synthesize liquid hydrocarbons, including alkanes, from [[carbon monoxide]] and hydrogen. This method is used to produce substitutes for [[petroleum distillate]].", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Production", "Laboratory preparation"], "text": "There is usually little need for alkanes to be synthesized in the laboratory, since they are usually commercially available. Also, alkanes are generally unreactive chemically or biologically, and do not undergo [[functional group interconversion]] cleanly. When alkanes are produced in the laboratory, it is often a side-product of a reaction. For example, the use of [[N-Butyllithium|''n''-butyllithium]] as a strong [[base (chemistry)|base]] gives the conjugate acid, ''n''-butane as a side-product:  CHLi + HO → CH + [[lithium hydroxide|LiOH]] However, at times it may be desirable to make a section of a molecule into an alkane-like functionality ([[alkyl]] group) using the above or similar methods. For example, an [[ethyl group]] is an alkyl group; when this is attached to a [[Hydroxyl|hydroxy]] group, it gives [[ethanol]], which is not an alkane. To do so, the best-known methods are [[hydrogenation]] of [[alkene]]: RCH=CH + H → RCHCH(R = [[alkyl]]) Alkanes or alkyl groups can also be prepared directly from [[alkyl halide]] in the [[Corey–House synthesis|Corey–House–Posner–Whitesides reaction]]. The [[Barton–McCombie deoxygenation]] removes hydroxyl groups from alcohols e.g. [[Image:Barton-McCombie Deoxygenation Scheme.svg|600px|[[Barton–McCombie deoxygenation]] scheme]] and the [[Clemmensen reduction]] removes carbonyl groups from aldehydes and ketones to form alkanes or alkyl-substituted compounds e.g.: [[Image:Clemmensen Reduction Scheme.png|250px|[[Clemmensen Reduction]]]]", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds"], "text": "Alkanes can be prepared from a variety of organic compounds.These include alkenes, alkynes, haloalkanes, alcohols, aldehydes and ketones and carboxylic acids.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From alkenes and alkynes"], "text": "When alkenes and alkynes are subjected to hydrogenation reaction by treating them with hydrogen in the presence of palladium or platinum or nickel catalyst, they produce alkanes. In this reaction powdered catalyst is preferred to increase the surface area so that adsorption of hydrogen on the catalyst increases. In this reaction the hydrogen gets attached on the catalyst to form a hydrogen-catalyst bond which leads to weakening of H-H bond, thereby leading to the addition of hydrogen on alkenes and alkynes. The reaction is exothermic because the product alkane is stable as it has more sigma bonds than the reactant alkenes and alkynes due to conversion of pi bond to sigma bonds.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Wurtz reaction"], "text": "When haloalkane is treated with sodium in dry ether, alkane with double the number of carbon atoms is obtained. This reaction proceeds through free radical intermediate and has possibility of alkene formation in case of tertiary haloalkanes and vicinal dihalides.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Corey-House-Synthesis"], "text": "When haloalkane is treated with dialkyl lithium cuprite, which is otherwise known as Gilman's reagent, any higher alkane is obtained.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Reaction with metal hydride"], "text": "When haloalkanes are treated with metal hydride, e.g., sodium hydride and lithium aluminium hydride.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Frankland reaction"], "text": "When haloalkane is treated with zinc in ester, alkane is obtained.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Fittig reaction"], "text": "When aryl halide is treated with sodium in dry ether, it forms biphenyl.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Ullmann biaryl synthesis"], "text": "When aryl halide is treated with copper, it forms biphenyl.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Preparation of alkanes from other organic compounds", "From haloalkanes", "Wurtz-Fittig reaction"], "text": "When aryl halide is treated with haloalkane, we get alkyl benzene.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Applications"], "text": "The applications of alkanes depend on the number of carbon atoms. The first four alkanes are used mainly for heating and cooking purposes, and in some countries for electricity generation. [[Methane]] and [[ethane]] are the main components of natural gas; they are normally stored as gases under pressure. It is, however, easier to transport them as liquids: This requires both compression and cooling of the gas. [[Propane]] and [[butane]] are gases at atmospheric pressure that can be liquefied at fairly low pressures and are commonly known as [[liquified petroleum gas]] (LPG). Propane is used in propane gas burners and as a fuel for road vehicles, butane in space heaters and disposable cigarette lighters. Both are used as propellants in [[aerosol spray]]. From [[pentane]] to [[octane]] the alkanes are highly volatile liquids. They are used as fuels in [[internal combustion engine]], as they vaporize easily on entry into the combustion chamber without forming droplets, which would impair the uniformity of the combustion. Branched-chain alkanes are preferred as they are much less prone to premature ignition, which causes [[Engine knocking|knocking]], than their straight-chain homologues. This propensity to premature ignition is measured by the [[octane rating]] of the fuel, where [[2,2,4-Trimethylpentane|2,2,4-trimethylpentane]] (''isooctane'') has an arbitrary value of 100, and [[heptane]] has a value of zero. Apart from their use as fuels, the middle alkanes are also good [[solvent]] for nonpolar substances. Alkanes from [[nonane]] to, for instance, [[hexadecane]] (an alkane with sixteen carbon atoms) are liquids of higher [[viscosity]], less and less suitable for use in gasoline. They form instead the major part of [[Diesel fuel|diesel]] and [[aviation fuel]]. Diesel fuels are characterized by their [[cetane number]], cetane being an old name for hexadecane. However, the higher melting points of these alkanes can cause problems at low temperatures and in polar regions, where the fuel becomes too thick to flow correctly. Alkanes from hexadecane upwards form the most important components of [[fuel oil]] and [[lubricating oil]]. In the latter function, they work at the same time as anti-corrosive agents, as their hydrophobic nature means that water cannot reach the metal surface. Many solid alkanes find use as [[paraffin wax]], for example, in [[candle]]. This should not be confused however with true [[wax]], which consists primarily of [[ester]]. Alkanes with a chain length of approximately 35 or more carbon atoms are found in [[bitumen]], used, for example, in road surfacing. However, the higher alkanes have little value and are usually split into lower alkanes by [[Cracking (chemistry)|cracking]]. Some synthetic [[polymer]] such as [[polyethylene]] and [[polypropylene]] are alkanes with chains containing hundreds or thousands of carbon atoms. These materials are used in innumerable applications, and billions of kilograms of these materials are made and used each year.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Environmental transformations"], "text": "Alkanes are chemically very inert apolar molecules which are not very reactive as organic compounds. This inertness yields serious ecological issues if they are released into the environment. Due to their lack of functional groups and low water solubility, alkanes show poor bioavailability for microorganisms. There are, however, some microorganisms possessing the metabolic capacity to utilize ''n''-alkanes as both carbon and energy sources. Some bacterial species are highly specialised in degrading alkanes; these are referred to as hydrocarbonoclastic bacteria.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": ["Hazards"], "text": "Methane is flammable, explosive and dangerous to inhale; because it is a colorless, odorless gas, special caution must be taken around methane. Ethane is also extremely flammable, explosive, and dangerous to inhale. Both of them may cause suffocation. Propane, too, is flammable and explosive, and may cause drowsiness or unconsciousness if inhaled. Butane presents the same hazards as propane. Alkanes also pose a threat to the environment. Branched alkanes have a lower biodegradability than unbranched alkanes. Methane is considered to be the greenhouse gas that is most dangerous to the environment, although the amount of methane in the atmosphere is relatively low.", "id": "639", "title": "Alkane", "categories": ["Alkanes", "Hydrocarbons"], "seealso": ["Higher alkanes", "Alkyne", "Alkene", "Cycloalkane"]}
{"headers": [], "text": "'''United States appellate procedure''' involves the rules and regulations for filing [[appeal]] in [[state court (United States)|state courts]] and [[United States federal courts|federal courts]]. The nature of an appeal can vary greatly depending on the type of case and the rules of the court in the [[jurisdiction]] where the case was prosecuted. There are many types of [[standard of review]] for appeals, such as ''[[Trial de novo|de novo]]'' and [[abuse of discretion]]. However, most appeals begin when a party files a [[petition for review]] to a higher court for the purpose of overturning the lower court's decision. An [[appellate court]] is a [[court]] that hears cases on appeal from another court. Depending on the particular legal rules that apply to each circumstance, a party to a [[court case]] who is unhappy with the result might be able to challenge that result in an appellate court on specific grounds. These grounds typically could include errors of law, [[fact]], procedure or due process. In different jurisdictions, appellate courts are also called appeals courts, courts of appeals, superior courts, or supreme courts. The specific procedures for appealing, including even whether there is a right of appeal from a particular type of decision, can vary greatly from state to state. The right to file an appeal can also vary from state to state; for example, the [[New Jersey Constitution]] vests judicial power in a Supreme Court, a Superior Court, and other courts of limited jurisdiction, with an appellate court being part of the Superior Court.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Access to appellant status"], "text": "A party who files an appeal is called an \"appellant\", \"plaintiff in error\", \"petitioner\" or \"pursuer\", and a party on the other side is called an \"appellee\". A \"cross-appeal\" is an appeal brought by the respondent. For example, suppose at trial the judge found for the plaintiff and ordered the defendant to pay $50,000. If the defendant files an appeal arguing that he should not have to pay any money, then the plaintiff might file a cross-appeal arguing that the defendant should have to pay $200,000 instead of $50,000. The appellant is the party who, having lost part or all their [[lawsuit|claim]] in a [[lower court]] decision, is appealing to a higher court to have their case reconsidered. This is usually done on the basis that the lower court judge erred in the application of law, but it may also be possible to appeal on the basis of court misconduct, or that a finding of fact was entirely unreasonable to make on the evidence. The appellant in the new case can be either the [[plaintiff]] (or claimant), [[defendant]], third-party [[intervenor]], or respondent (appellee) from the lower case, depending on who was the losing party. The winning party from the lower court, however, is now the respondent. In unusual cases the appellant can be the victor in the court below, but still appeal. An appellee is the party to an appeal in which the lower court [[judgment (law)|judgment]] was in its favor. The appellee is required to respond to the [[petition]], [[oral argument]], and [[legal brief]] of the appellant. In general, the appellee takes the procedural posture that the lower court's decision should be affirmed.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Ability to appeal"], "text": "An appeal \"as of right\" is one that is guaranteed by statute or some underlying constitutional or legal principle. The appellate court cannot refuse to listen to the appeal. An appeal \"by leave\" or \"permission\" requires the appellant to obtain leave to appeal; in such a situation either or both of the lower court and the court may have the discretion to grant or refuse the appellant's demand to appeal the lower court's decision. In the [[United States Supreme Court|Supreme Court]], review in most cases is available only if the Court exercises its discretion and grants a writ of certiorari. In [[tort]], [[equity (law)|equity]], or other civil matters either party to a previous case may file an appeal. In criminal matters, however, the state or prosecution generally has no appeal \"as of right\". And due to the [[double jeopardy]] principle, the state or prosecution may never appeal a jury or bench verdict of acquittal. But in some jurisdictions, the state or prosecution may appeal \"as of right\" from a trial court's dismissal of an indictment in whole or in part or from a trial court's granting of a defendant's suppression motion. Likewise, in some jurisdictions, the state or prosecution may appeal an issue of law \"by leave\" from the trial court or the appellate court. The ability of the prosecution to appeal a decision in favor of a defendant varies significantly internationally. All parties must present grounds to appeal, or it will not be heard. By convention in some law reports, the appellant is named first. This can mean that where it is the defendant who appeals, the name of the case in the law reports reverses (in some cases twice) as the appeals work their way up the court hierarchy. This is not always true, however. In the [[United States federal courts|federal courts]], the parties' names always stay in the same order as the lower court when an appeal is taken to the [[United States Courts of Appeals|circuit courts of appeals]], and are re-ordered only if the appeal reaches the [[United States Supreme Court|Supreme Court]].", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Direct or collateral: Appealing criminal convictions"], "text": "Many jurisdictions recognize two types of appeals, particularly in the criminal context. The first is the traditional \"direct\" appeal in which the appellant files an appeal with the next higher court of review. The second is the collateral appeal or post-conviction petition, in which the petitioner-appellant files the appeal in a court of first instance—usually the court that tried the case. The key distinguishing factor between direct and collateral appeals is that the former occurs in state courts, and the latter in federal courts. Relief in post-conviction is rare and is most often found in [[capital punishment|capital]] or violent [[felony]] cases. The typical scenario involves an incarcerated defendant locating [[DNA]] evidence demonstrating the defendant's actual innocence.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Direct or collateral: Appealing criminal convictions", "Appellate review"], "text": "\"Appellate review\" is the general term for the process by which courts with appellate [[jurisdiction]] take jurisdiction of matters decided by lower courts. It is distinguished from [[Judicial review (theory)|judicial review]], which refers to the court's overriding constitutional or statutory right to determine if a legislative act or administrative decision is defective for jurisdictional or other reasons (which may vary by jurisdiction). In most jurisdictions the normal and preferred way of seeking appellate review is by filing an appeal of the final [[Legal judgment|judgment]]. Generally, an appeal of the judgment will also allow appeal of all other orders or rulings made by the trial court in the course of the case. This is because such orders cannot be appealed \"as of right\". However, certain critical interlocutory [[court order]], such as the denial of a request for an interim [[injunction]], or an order holding a person in [[contempt of court]], can be appealed immediately although the case may otherwise not have been fully disposed of. There are two distinct forms of appellate review, \"direct\" and \"collateral\". For example, a criminal defendant may be convicted in state court, and lose on \"direct appeal\" to higher state appellate courts, and if unsuccessful, mount a \"collateral\" action such as filing for a writ of [[habeas corpus]] in the [[United States federal courts|federal courts]]. Generally speaking, \"[d]irect appeal statutes afford defendants the opportunity to challenge the merits of a judgment and allege errors of law or fact. ... [Collateral review], on the other hand, provide[s] an independent and civil inquiry into the validity of a conviction and sentence, and as such are generally limited to challenges to constitutional, jurisdictional, or other fundamental violations that occurred at trial.\" \"Graham v. Borgen\", 483 F 3d. 475 (7th Cir. 2007) (no. 04–4103) (slip op. at 7) (citation omitted). In Anglo-American [[common law]] courts, appellate review of lower court decisions may also be obtained by filing a petition for review by [[prerogative writ]] in certain cases. There is no corresponding right to a writ in any pure or continental [[civil law (legal system)|civil law]] legal systems, though some mixed systems such as [[Civil Code of Quebec|Quebec]] recognize these prerogative writs.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Direct or collateral: Appealing criminal convictions", "Appellate review", "Direct appeal"], "text": "After exhausting the first appeal as of right, defendants usually petition the highest state court to review the decision. This appeal is known as a direct appeal. The highest state court, generally known as the Supreme Court, exercises discretion over whether it will review the case. On direct appeal, a prisoner challenges the grounds of the conviction based on an error that occurred at trial or some other stage in the adjudicative process.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Direct or collateral: Appealing criminal convictions", "Appellate review", "Direct appeal", "Preservation issues"], "text": "An appellant's claim(s) must usually be preserved at trial. This means that the defendant had to object to the error when it occurred in the trial. Because constitutional claims are of great magnitude, appellate courts might be more lenient to review the claim even if it was not preserved. For example, Connecticut applies the following standard to review unpreserved claims: 1.the record is adequate to review the alleged claim of error; 2. the claim is of constitutional magnitude alleging the violation of a fundamental right; 3. the alleged constitutional violation clearly exists and clearly deprived the defendant of a fair trial; 4. if subject to harmless error analysis, the state has failed to demonstrate harmlessness of the alleged constitutional violation beyond a reasonable doubt.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Direct or collateral: Appealing criminal convictions", "Appellate review", "State post-conviction relief: collateral appeal"], "text": "All States have a post-conviction relief process. Similar to federal post-conviction relief, an appellant can petition the court to correct alleged fundamental errors that were not corrected on direct review. Typical claims might include [[ineffective assistance of counsel]] and actual innocence based on new evidence. These proceedings are normally separate from the direct appeal, however some states allow for collateral relief to be sought on direct appeal. After direct appeal, the conviction is considered final. An appeal from the post conviction court proceeds just as a direct appeal. That is, it goes to the intermediate appellate court, followed by the highest court. If the petition is granted the appellant could be released from incarceration, the sentence could be modified, or a new trial could be ordered.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Notice of appeal"], "text": "A \"notice of appeal\" is a form or document that in many cases is required to begin an appeal. The form is completed by the appellant or by the appellant's legal representative. The nature of this form can vary greatly from country to country and from court to court within a country. The specific rules of the legal system will dictate exactly how the appeal is officially begun. For example, the appellant might have to file the notice of appeal with the appellate court, or with the court from which the appeal is taken, or both. Some courts have samples of a notice of appeal on the court's own web site. In New Jersey, for example, the Administrative Office of the Court has promulgated a form of notice of appeal for use by appellants, though using this exact form is not mandatory and the failure to use it is not a jurisdictional defect provided that all pertinent information is set forth in whatever form of notice of appeal is used. The deadline for beginning an appeal can often be very short: traditionally, it is measured in days, not months. This can vary from country to country, as well as within a country, depending on the specific rules in force. In the U.S. federal court system, criminal defendants must file a notice of appeal within 10 days of the entry of either the judgment or the order being appealed, or the right to appeal is forfeited.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Appellate procedure"], "text": "Generally speaking the appellate court examines the record of [[evidence (law)|evidence]] presented in the trial court and the law that the lower court applied and decides whether that decision was legally sound or not. The appellate court will typically be deferential to the lower court's findings of fact (such as whether a defendant committed a particular act), unless clearly erroneous, and so will focus on the court's application of the law to those facts (such as whether the act found by the court to have occurred fits a legal definition at issue). If the appellate court finds no defect, it \"affirms\" the judgment. If the appellate court does find a legal defect in the decision \"below\" (i.e., in the lower court), it may \"modify\" the ruling to correct the defect, or it may nullify (\"reverse\" or \"vacate\") the whole decision or any part of it. It may, in addition, send the case back (\"remand\" or \"remit\") to the lower court for further proceedings to remedy the defect. In some cases, an appellate court may review a lower court decision \"de novo\" (or completely), challenging even the lower court's findings of fact. This might be the proper standard of review, for example, if the lower court resolved the case by granting a pre-trial [[motion to dismiss]] or motion for [[summary judgment]] which is usually based only upon written submissions to the trial court and not on any trial testimony. Another situation is where appeal is by way of \"re-hearing\". Certain jurisdictions permit certain appeals to cause the trial to be heard afresh in the appellate court. Sometimes, the appellate court finds a defect in the procedure the parties used in filing the appeal and dismisses the appeal without considering its merits, which has the same effect as affirming the judgment below. (This would happen, for example, if the appellant waited too long, under the appellate court's rules, to file the appeal.) Generally, there is no [[Jury trial|trial]] in an appellate court, only consideration of the record of the evidence presented to the trial court and all the pre-trial and trial court proceedings are reviewed—unless the appeal is by way of re-hearing, new evidence will usually only be considered on appeal in \"very\" rare instances, for example if that material evidence was unavailable to a party for some very significant reason such as [[prosecutorial misconduct]]. In some systems, an appellate court will only consider the written decision of the lower court, together with any written evidence that was before that court and is relevant to the appeal. In other systems, the appellate court will normally consider the record of the lower court. In those cases the record will first be certified by the lower court.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Appellate procedure"], "text": "The appellant has the opportunity to present arguments for the granting of the appeal and the appellee (or respondent) can present arguments against it. Arguments of the parties to the appeal are presented through their appellate lawyers, if represented, or \"[[pro se]]\" if the party has not engaged legal representation. Those arguments are presented in written [[brief (law)|briefs]] and sometimes in [[oral argument]] to the court at a [[hearing (law)|hearing]]. At such hearings each party is allowed a brief presentation at which the appellate judges ask questions based on their review of the record below and the submitted briefs. In an [[adversarial system]], appellate courts do not have the power to review lower court decisions unless a party appeals it. Therefore, if a lower court has ruled in an improper manner, or against [[Precedent|legal precedent]], that judgment will stand if not appealed – even if it might have been overturned on appeal. The United States legal system generally recognizes two types of appeals: a trial \"de novo\" or an appeal on the record. A [[trial de novo]] is usually available for review of informal proceedings conducted by some minor judicial tribunals in proceedings that do not provide all the procedural attributes of a formal judicial [[trial (law)|trial]]. If unchallenged, these decisions have the power to settle more minor legal disputes once and for all. If a party is dissatisfied with the finding of such a tribunal, one generally has the power to request a trial \"de novo\" by a [[court of record]]. In such a proceeding, all issues and [[evidence (law)|evidence]] may be developed newly, as though never heard before, and one is not restricted to the evidence heard in the lower proceeding. Sometimes, however, the decision of the lower proceeding is itself admissible as evidence, thus helping to curb frivolous appeals. In some cases, an application for \"trial de novo\" effectively erases the prior trial as if it had never taken place. The Supreme Court of Virginia has stated that '\"This Court has repeatedly held that the effect of an appeal to circuit court is to \"annul the judgment of the inferior tribunal as completely as if there had been no previous trial.\"' The only exception to this is that if a defendant appeals a conviction for a crime having multiple levels of offenses, where they are convicted on a lesser offense, the appeal is of the lesser offense; the conviction represents an acquittal of the more serious offenses. \"[A] trial on the same charges in the circuit court does not violate double jeopardy principles, . . . subject only to the limitation that conviction in [the] district court for an offense lesser included in the one charged constitutes an acquittal of the greater offense, permitting trial de novo in the circuit court only for the lesser-included offense.\"", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Appellate procedure"], "text": "In an appeal on the record from a decision in a judicial proceeding, both appellant and respondent are bound to base their arguments wholly on the proceedings and body of evidence as they were presented in the lower tribunal. Each seeks to prove to the higher court that the result they desired was the just result. [[Precedent]] and [[case law]] figure prominently in the arguments. In order for the appeal to succeed, the appellant must prove that the lower court committed [[reversible error]], that is, an impermissible action by the court acted to cause a result that was unjust, and which would not have resulted had the court acted properly. Some examples of reversible error would be erroneously instructing the jury on the law applicable to the case, permitting seriously [[improper argument]] by an attorney, admitting or excluding evidence improperly, acting outside the court's jurisdiction, injecting bias into the proceeding or appearing to do so, juror misconduct, etc. The failure to formally object at the time, to what one views as improper action in the lower court, may result in the affirmance of the lower court's judgment on the grounds that one did not \"preserve the issue for appeal\" by objecting. In cases where a judge rather than a jury decided issues of fact, an appellate court will apply an \"abuse of discretion\" standard of review. Under this standard, the appellate court gives deference to the lower court's view of the evidence, and reverses its decision only if it were a clear abuse of discretion. This is usually defined as a decision outside the bounds of reasonableness. On the other hand, the appellate court normally gives less deference to a lower court's decision on issues of law, and may reverse if it finds that the lower court applied the wrong legal standard. In some cases, an appellant may successfully argue that the law under which the lower decision was rendered was [[Constitutionality|unconstitutional]] or otherwise invalid, or may convince the higher court to order a new trial on the basis that evidence earlier sought was concealed or only recently discovered. In the case of new evidence, there must be a high probability that its presence or absence would have made a material difference in the trial. Another issue suitable for appeal in criminal cases is effective assistance of counsel. If a defendant has been convicted and can prove that his lawyer did not adequately handle his case and that there is a reasonable probability that the result of the trial would have been different had the lawyer given competent representation, he is entitled to a new trial. A lawyer traditionally starts an oral argument to any appellate court with the words \"May it please the court.\"", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Appellate procedure"], "text": "After an appeal is heard, the \"mandate\" is a formal notice of a decision by a court of appeal; this notice is transmitted to the trial court and, when filed by the [[Court clerk|clerk]] of the trial court, constitutes the final judgment on the case, unless the appeal court has directed further proceedings in the trial court. The mandate is distinguished from the appeal court's [[court opinion|opinion]], which sets out the legal reasoning for its decision. In some jurisdictions the mandate is known as the \"remittitur\".", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": ["Results"], "text": "The result of an appeal can be: Affirmed: Where the reviewing court basically agrees with the result of the lower courts' ruling(s). Reversed: Where the reviewing court basically disagrees with the result of the lower courts' ruling(s), and overturns their decision. Vacated: Where the reviewing court overturns the lower courts' ruling(s) as invalid, without necessarily disagreeing with it/them, e.g. because the case was decided on the basis of a legal principle that no longer applies. Remanded: Where the reviewing court sends the case back to the lower court. There can be multiple outcomes, so that the reviewing court can affirm some rulings, reverse others and remand the case all at the same time. Remand is not required where there is nothing left to do in the case. \"Generally speaking, an appellate court's judgment provides 'the final directive of the appeals courts as to the matter appealed, setting out with specificity the court's determination that the action appealed from should be affirmed, reversed, remanded or modified'\". Some reviewing courts who have discretionary review may send a case back without comment other than ''review improvidently granted''. In other words, after looking at the case, they chose not to say anything. The result for the case of ''review improvidently granted'' is effectively the same as affirmed, but without that extra higher court stamp of approval.", "id": "640", "title": "Appellate procedure in the United States", "categories": ["United States appellate procedure", "Legal procedure", "United States procedural law"], "seealso": ["Criminal procedure", "Interlocutory appeal", "Writ of mandamus", "Court of Appeals", "List of wrongful convictions in the United States", "Pursuer", "List of legal topics", "Petition for stay", "Defendant", "Appellee", "Writ of habeas corpus", "Appellate court", "Supreme Court of the United States", "Civil procedure", "Plaintiff", "En banc", "Writ of Certiorari", "Courts-martial in the United States", "Reversible error"]}
{"headers": [], "text": "In law, an '''answer''' was originally a solemn assertion in opposition to someone or something, and thus generally any counter-statement or [[defense (legal)|defense]], a reply to a [[question]] or response, or [[objection (law)|objection]], or a correct solution of a problem. In the [[common law]], an '''answer''' is the first [[pleading]] by a [[defendant]], usually filed and served upon the [[plaintiff]] within a certain strict time limit after a civil [[complaint]] or criminal [[Information (formal criminal charge)|information]] or [[indictment]] has been served upon the defendant. It may have been preceded by an ''optional'' \"pre-answer\" [[motion to dismiss]] or [[demurrer]]; if such a motion is unsuccessful, the defendant ''must'' file an answer to the complaint or risk an adverse [[default judgment]]. In a criminal case, there is usually an arraignment or some other kind of appearance before the defendant comes to court. The pleading in the criminal case, which is entered on the record in open court, is usually either [[guilt (law)|guilt]] or not guilty. Generally speaking in private, civil cases there is no plea entered of guilt or innocence. There is only a judgment that grants money damages or some other kind of [[equitable remedy]] such as [[restitution]] or a permanent [[injunction]]. Criminal cases may lead to [[Fine (penalty)|fine]] or other [[punishment]], such as [[imprisonment]]. The famous Latin ''Responsa Prudentium'' (\"answers of the learned ones\") were the accumulated views of many successive generations of Roman [[lawyer]], a body of legal opinion which gradually became authoritative. During debates of a contentious nature, deflection, colloquially known as 'changing the topic', has been widely observed, and is often seen as a failure to answer a question.", "id": "642", "title": "Answer (law)", "categories": ["Common law", "Legal documents"], "seealso": []}
{"headers": [], "text": "An '''appellate court''', commonly called an '''''appeals court''''', '''''court of appeals''''' ([[American English]]), '''''appeal court''''', '''''court of appeal''''' ([[British English]]), '''''court of second instance''''' or '''''second instance court''''', is any [[court of law]] that is empowered to hear an [[appeal]] of a [[trial court]] or other lower [[tribunal]]. In most [[jurisdiction]], the court system is divided into at least three levels: the trial court, which initially hears cases and reviews evidence and testimony to determine the facts of the case; at least one intermediate appellate court; and a [[supreme court]] (or court of last resort) which primarily reviews the decisions of the intermediate courts. A jurisdiction's supreme court is that jurisdiction's highest appellate court. Appellate courts nationwide can operate under varying rules. The authority of appellate courts to review the decisions of lower courts varies widely from one jurisdiction to another. In some areas, the appellate court has limited powers of review. Generally, an appellate court's judgment provides the final directive of the appeals courts as to the matter appealed, setting out with specificity the court's determination that the action appealed from should be affirmed, reversed, remanded or modified.", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Bifurcation of civil and criminal appeals"], "text": "While many appellate courts have jurisdiction over all cases decided by lower courts, some systems have appellate courts divided by the type of jurisdiction they exercise. Some jurisdictions have specialized appellate courts, such as the [[Texas Court of Criminal Appeals]], which only hears appeals raised in criminal cases, and the [[United States Court of Appeals for the Federal Circuit|U.S. Court of Appeals for the Federal Circuit]], which has general jurisdiction but derives most of its caseload from patent cases, on one hand, and appeals from the [[Court of Federal Claims]] on the other. In the United States, Alabama, Tennessee, and Oklahoma also have separate courts of criminal appeals. Texas and Oklahoma have the final determination of criminal cases vested in their respective courts of criminal appeals, while Alabama and Tennessee allow decisions of its court of criminal appeals to be finally appealed to the state supreme court.", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Bifurcation of civil and criminal appeals", "Courts of criminal appeals"], "text": "'''Court of Criminal Appeals''' include: (-) Civilian (-) [[Court of Criminal Appeal (England and Wales)]], abolished 1966 (-) [[Court of Criminal Appeal (Ireland)]], abolished 2014 (-) U.S. States: (-) [[Alabama Court of Criminal Appeals]] (-) [[Oklahoma Court of Criminal Appeals]] (-) [[Tennessee Court of Criminal Appeals]] (-) [[Texas Court of Criminal Appeals]] (-) Military (-) [[United States Army Court of Criminal Appeals]] (-) [[Navy-Marine Corps Court of Criminal Appeals]] (United States) (-) [[Coast Guard Court of Criminal Appeals]] (United States) (-) [[Air Force Court of Criminal Appeals]] (United States)", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Bifurcation of civil and criminal appeals", "Courts of civil appeals"], "text": "(-) [[Alabama Court of Civil Appeals]] (-) [[Oklahoma Court of Civil Appeals]]", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Appellate courts by country", "New Zealand"], "text": "The [[Court of Appeal of New Zealand]], located in [[Wellington]], is New Zealand's principal intermediate appellate court. In practice, most appeals are resolved at this intermediate appellate level, rather than in the [[Supreme Court of New Zealand|Supreme Court]].", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Appellate courts by country", "Sri Lanka"], "text": "The [[Court of Appeal of Sri Lanka]], located in [[Colombo]], is the second senior court in the [[Courts of Sri Lanka|Sri Lankan legal system]].", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Appellate courts by country", "United States"], "text": "In the United States, both state and [[United States courts of appeals|federal]] appellate courts are usually restricted to examining whether the lower court made the correct legal determinations, rather than hearing direct evidence and determining what the facts of the case were. Furthermore, U.S. appellate courts are usually restricted to hearing appeals based on matters that were originally brought up before the trial court. Hence, such an appellate court will not consider an appellant's argument if it is based on a theory that is raised for the first time in the appeal. In most U.S. states, and in U.S. federal courts, parties before the court are allowed one appeal as of right. This means that a party who is unsatisfied with the outcome of a trial may bring an [[appeal]] to contest that outcome. However, appeals may be costly, and the appellate court must find an error on the part of the court below that justifies upsetting the verdict. Therefore, only a small proportion of trial court decisions result in appeals. Some appellate courts, particularly supreme courts, have the power of [[discretionary review]], meaning that they can decide whether they will hear an appeal brought in a particular case.", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": ["Appellate courts by country", "United States", "Institutional titles"], "text": "Many U.S. jurisdictions title their appellate court a '''''court of appeal''''' or '''''court of appeals'''''. Historically, others have titled their appellate court a '''''court of errors''''' (or '''''court of errors and appeals'''''), on the premise that it was intended to correct errors made by lower courts. Examples of such courts include the [[New Jersey Court of Errors and Appeals]] (which existed from 1844 to 1947), the Connecticut Supreme Court of Errors (which has been renamed the [[Connecticut Supreme Court]]), the Kentucky Court of Errors (renamed the [[Kentucky Supreme Court]]), and the Mississippi High Court of Errors and Appeals (since renamed the [[Supreme Court of Mississippi]]). In some jurisdictions, a court able to hear appeals is known as an '''appellate division'''. The phrase \"court of appeals\" most often refers to intermediate appellate courts. However, the Maryland and New York systems are different. The [[Maryland Court of Appeals]] and the [[New York Court of Appeals]] are the highest appellate courts in those states. The [[New York Supreme Court]] is a trial court of general jurisdiction. Depending on the system, certain courts may serve as both trial courts and appellate courts, hearing appeals of decisions made by courts with more limited jurisdiction.", "id": "643", "title": "Appellate court", "categories": ["Courts by type", "Appellate courts"], "seealso": ["Court of cassation", "Court of Appeal (Hong Kong)", "Court of Criminal Appeal (disambiguation)", "High Court (Hong Kong)", "Court of Appeal (England and Wales)"]}
{"headers": [], "text": "'''Arraignment''' is a formal reading of a [[crime|criminal]] charging document in the presence of the [[defendant]], to inform them of the charges against them. In response to arraignment, the accused is expected to enter a [[plea]]. Acceptable pleas vary among jurisdictions, but they generally include \"guilty\", \"not guilty\", and the [[peremptory pleas]] (or pleas in bar) setting out reasons why a trial cannot proceed. Pleas of \"[[nolo contendere]]\" (no contest) and the \"[[Alford plea|''Alford'' plea]]\" are allowed in some circumstances.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Australia"], "text": "In Australia, arraignment is the first of eleven stages in a criminal trial, and involves the [[court clerk|clerk]] of the [[court]] reading out the [[indictment]]. The judge will testify during the indictment process.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Canada"], "text": "In every province in Canada except British Columbia, defendants are arraigned on the day of their trial. In British Columbia, arraignment takes place in one of the first few court appearances by the defendant or their lawyer. The defendant is asked whether he or she pleads guilty or not guilty to each charge.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["France"], "text": "In France, the general rule is that one cannot remain in police custody for more than 24 hours from the time of the arrest. However, police custody can last another 24 hours in specific circumstances, especially if the offence is punishable by at least one year's imprisonment, or if the investigation is deemed to require the extra time, and can last up to 96 hours in certain cases involving terrorism, drug trafficking or organised crime. The police needs to have the consent of the prosecutor (in the vast majority of cases, the prosecutor will consent).", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Germany"], "text": "In Germany, if one has been arrested and taken into custody by the police one must be brought before a judge as soon as possible and at the latest on the day after the arrest.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["New Zealand"], "text": "At the first appearance, the accused is read the charges and asked for a plea. The available pleas are, guilty, not guilty, and no plea. No plea allows the defendant to get legal advice on the plea, which must be made on the second appearance.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["South Africa"], "text": "In South Africa, arraignment is defined as the calling upon the accused to appear, the informing of the accused of the crime charged against him, the demanding of the accused whether he be guilty or not guilty, and the entering of his plea. His plea having been entered he is said to stand arraigned.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["United Kingdom"], "text": "In England, Wales, and [[Northern Ireland]], arraignment is the first of eleven stages in a criminal trial, and involves the [[court clerk|clerk]] of the [[court]] reading out the [[indictment]]. In England and Wales, the police cannot legally detain anyone for more than 24 hours without charging them unless an officer with the rank of superintendent (or above) authorises detention for a further 12 hours (36 hours total), or a judge (who will be a magistrate) authorises detention by the police before charge for up to a maximum of 96 hours, but for terrorism-related offences people can be held by the police for up to 28 days before charge. If they are not released after being charged, they should be brought before a court as soon as practicable.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["United States"], "text": "Under the United States [[Federal Rules of Criminal Procedure]], \"arraignment shall [...] [consist of an] open [...] reading [of] the [[indictment]] [...] to the defendant [...] and call[] on him to plead thereto. He/she shall be given a copy of the indictment [...] before he/she is called upon to plead.\" In federal courts, arraignment takes place in two stages. The first is called the initial arraignment and must take place within 48 hours of an individual's arrest, 72 hours if the individual was arrested on the weekend and not able to go before a judge until Monday. During this arraignment the defendant is informed of the pending legal charges and is informed of his or her right to retain counsel. The presiding judge also decides at what amount, if any, to set [[bail]]. During the second arraignment, a post-indictment arraignment (PIA), the defendant is allowed to enter a plea. In New York, most people arrested must be released if they are not arraigned within 24 hours. In California, arraignments must be conducted without unnecessary delay and, in any event, within 48 hours of arrest, excluding weekends and holidays.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Form of the arraignment"], "text": "The wording of the arraignment varies from jurisdiction to jurisdiction. However, it generally conforms with the following principles: (1) The accused person ([[defendant]]) is addressed by [[name]]; (2) The [[criminal charge|charge]] against the accused person is read, including the alleged date, time, and place of offense (and sometimes the names of the state's witnesses and the range of punishment for the charge(s)); and, (3) The accused person is asked formally how he or she [[plea]].", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Video arraignment"], "text": "'''Video arraignment''' is the act of conducting the arraignment process using some form of [[videoconferencing]] technology. Use of video arraignment system allows the [[court]] to conduct the requisite arraignment process without the need to transport the defendant to the [[courtroom]] by using an [[audio-visual]] link between the location where the defendant is being held and the courtroom. Use of the video arraignment process addresses the problems associated with having to transport defendants. The transportation of defendants requires time, puts additional demands on the public safety organizations to provide for the safety of the public, court personnel and for the security of the population held in detention. It also addresses the rising costs of transportation.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Guilty and not-guilty pleas"], "text": "If the defendant pleads guilty, an [[Preliminary hearing|evidentiary hearing]] usually follows. The court is not required to accept a guilty plea. During the hearing, the judge assesses the offense, the [[mitigating factor]], and the defendant's character, and passes [[Sentence (law)|sentence]]. If the defendant pleads [[not guilty (plea)|not guilty]], a date is set for a [[preliminary hearing]] or a [[trial]]. In the past, a defendant who refused to plead (or \"stood mute\") was subject to [[peine forte et dure]] ([[Law French]] for \"strong and hard punishment\"). Today in [[Common law|common-law]] jurisdictions, the court enters a plea of not guilty for a defendant who refuses to enter a plea. The rationale for this is the defendant's [[right to silence]].", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": ["Pre-trial release"], "text": "This is also often the stage at which arguments for or against pre-trial release and bail may be made, depending on the alleged crime and jurisdiction.", "id": "649", "title": "Arraignment", "categories": ["Legal terminology", "Prosecution", "United States criminal procedure", "Criminal law of the United Kingdom", "Australian criminal law"], "seealso": ["Desk appearance ticket"]}
{"headers": [], "text": "\"'''America the Beautiful'''\" is a [[Patriotism|patriotic]] American song. Its lyrics were written by [[Katharine Lee Bates]] and its music was composed by church organist and choirmaster [[Samuel A. Ward]] at [[Grace Church (Newark)|Grace Episcopal Church]] in Newark, New Jersey. The two never met. Bates originally wrote the words as a poem entitled \"'''Pikes Peak'''\" that was first published in the [[Fourth of July]] 1895 edition of the church periodical, ''The Congregationalist''. It was at that time that the poem was first entitled \"America\". Ward had initially composed the song's melody in 1882 to accompany lyrics to \"Materna\", basis of the hymn, \"[[O Mother dear, Jerusalem]]\", though the hymn was not first published until 1892. The combination of Ward's melody and Bates's poem was first entitled \"America the Beautiful\" in 1910. The song is one of the most popular of the many U.S. patriotic songs.", "id": "651", "title": "America the Beautiful", "categories": ["1895 songs", "American Christian hymns", "American patriotic songs", "Pikes Peak", "History of Colorado Springs, Colorado", "Songs based on poems", "Grammy Hall of Fame Award recipients"], "seealso": []}
{"headers": ["History"], "text": "In 1893, at the age of 33, Bates, an English professor at [[Wellesley College]], had taken a train trip to [[Colorado Springs, Colorado|Colorado Springs]], Colorado, to teach at [[Colorado College]]. Several of the sights on her trip inspired her, and they found their way into her poem, including the [[World's Columbian Exposition]] in [[Chicago]], the \"White City\" with its promise of the future contained within its gleaming white buildings; the wheat fields of America's heartland [[Kansas]], through which her train was riding on July 16; and the majestic view of the [[Great Plains]] from high atop [[Pikes Peak]]. On the pinnacle of that mountain, the words of the poem started to come to her, and she wrote them down upon returning to her hotel room at the original [[Antlers Hilton Hotel|Antlers Hotel]]. The poem was initially published two years later in ''The Congregationalist'' to commemorate [[Independence Day (United States)|the Fourth of July]]. It quickly caught the public's fancy. An amended version was published in 1904. The first known melody written for the song was sent in by [[Silas Pratt]] when the poem was published in ''The Congregationalist''. By 1900, at least 75 different melodies had been written. A [[hymn tune]] composed in 1882 by [[Samuel A. Ward]], the organist and choir director at [[Grace Church, Newark]], was generally considered the best music as early as 1910 and is still the popular tune today. Just as Bates had been inspired to write her poem, Ward, too, was inspired. The tune came to him while he was on a ferryboat trip from [[Coney Island]] back to his home in [[New York City]] after a leisurely summer day and he immediately wrote it down. He composed the tune for the old hymn \"O Mother Dear, Jerusalem\", retitling the work \"Materna\". Ward's music combined with Bates's poem were first published together in 1910 and titled \"America the Beautiful\". Ward died in 1903, not knowing the national stature his music would attain. Bates was more fortunate, since the song's popularity was well established by the time of her death in 1929. It is included in songbooks in many religious congregations in the United States.", "id": "651", "title": "America the Beautiful", "categories": ["1895 songs", "American Christian hymns", "American patriotic songs", "Pikes Peak", "History of Colorado Springs, Colorado", "Songs based on poems", "Grammy Hall of Fame Award recipients"], "seealso": []}
{"headers": ["History"], "text": "At various times in the more than one hundred years that have elapsed since the song was written, particularly during the [[John F. Kennedy]] administration, there have been efforts to give \"America the Beautiful\" legal status either as a national hymn or as a national anthem equal to, or in place of, \"[[The Star-Spangled Banner]]\", but so far this has not succeeded. Proponents prefer \"America the Beautiful\" for various reasons, saying it is easier to sing, more melodic, and more adaptable to new orchestrations while still remaining as easily recognizable as \"The Star-Spangled Banner\". Some prefer \"America the Beautiful\" over \"The Star-Spangled Banner\" due to the latter's war-oriented imagery; others prefer \"The Star-Spangled Banner\" for the same reason. While that national dichotomy has stymied any effort at changing the tradition of the national anthem, \"America the Beautiful\" continues to be held in high esteem by a large number of Americans, and was even being considered before 1931 as a candidate to become the national anthem of the United States.", "id": "651", "title": "America the Beautiful", "categories": ["1895 songs", "American Christian hymns", "American patriotic songs", "Pikes Peak", "History of Colorado Springs, Colorado", "Songs based on poems", "Grammy Hall of Fame Award recipients"], "seealso": []}
{"headers": ["Popular versions"], "text": "[[Bing Crosby]] included the song in a medley on his album ''[[101 Gang Songs]]'' (1961). [[Frank Sinatra]] recorded the song with [[Nelson Riddle]] during the sessions for ''[[The Concert Sinatra]]'' in February 1963, for a projected 45 single release. The 45 was not commercially issued however, but the song was later added as a bonus track to the enhanced 2012 CD release of ''[[The Concert Sinatra]]''. In 1976, while the United States celebrated its bicentennial, a soulful version popularized by [[Ray Charles]] peaked at number 98 on the US R&B chart. His version was traditionally played on New Year's Eve in [[Times Square]] following the ball drop. Three different renditions of the song have entered the [[Hot Country Songs]] charts. The first was by [[Charlie Rich]], which went to number 22 in 1976. A second, by [[Mickey Newbury]], peaked at number 82 in 1980. An [[all-star]] version of \"America the Beautiful\" performed by [[country music|country]] singers [[Trace Adkins]], [[Sherrié Austin]], [[Billy Dean]], [[Vince Gill]], [[Carolyn Dawn Johnson]], [[Toby Keith]], [[Brenda Lee]], [[Lonestar]], [[Lyle Lovett]], [[Lila McCann]], [[Lorrie Morgan]], [[Jamie O'Neal]], [[The Oak Ridge Boys]], [[Collin Raye]], [[Kenny Rogers]], [[Keith Urban]] and [[Phil Vassar]] reached number 58 in July 2001. The song re-entered the chart following the [[September 11 attacks]]. Popularity of the song increased greatly following the September 11 attacks; at some sporting events it was sung in addition to the traditional singing of the national anthem. During the first taping of the ''[[Late Show with David Letterman]]'' following the attacks, CBS newsman [[Dan Rather]] cried briefly as he quoted the fourth verse. For [[Super Bowl XLVIII]], [[The Coca-Cola Company]] aired a multilingual version of the song, sung in several different languages. The commercial received some criticism on social media sites, such as Twitter and Facebook, and from some conservatives, such as [[Glenn Beck]]. Despite the controversies, Coca-Cola later reused the Super Bowl ad during [[Super Bowl LI]], the opening ceremonies of the [[2014 Winter Olympics]] and [[2016 Summer Olympics]] and for patriotic holidays.", "id": "651", "title": "America the Beautiful", "categories": ["1895 songs", "American Christian hymns", "American patriotic songs", "Pikes Peak", "History of Colorado Springs, Colorado", "Songs based on poems", "Grammy Hall of Fame Award recipients"], "seealso": []}
{"headers": ["Idioms"], "text": "\"From sea to shining sea\", originally used in the charters of some of the English Colonies in North America, is an American [[idiom]] meaning \"from the [[Atlantic Ocean]] to the [[Pacific Ocean]]\" (or vice versa). Other songs that have used this phrase include the American patriotic song \"[[God Bless the U.S.A.]]\" and [[Schoolhouse Rock]]'s \"Elbow Room\". The phrase and the song are also the namesake of the [[Shining Sea Bikeway]], a [[bike path]] in Bates's hometown of [[Falmouth, Massachusetts]]. The phrase is similar to the Latin phrase \"''''\" (\"From sea to sea\"), which is the official motto of [[Canada]]. \"Purple mountain majesties\" refers to the shade of the [[Pikes Peak]] in [[Colorado Springs, Colorado]], which inspired Bates to write the poem. In 2003, [[Tori Amos]] appropriated the phrase \"for amber waves of grain\" to create a [[personification]] for her song \"Amber Waves\". Amos imagines Amber Waves as an exotic dancer, like the character of the same name portrayed by [[Julianne Moore]] in ''[[Boogie Nights]]''.", "id": "651", "title": "America the Beautiful", "categories": ["1895 songs", "American Christian hymns", "American patriotic songs", "Pikes Peak", "History of Colorado Springs, Colorado", "Songs based on poems", "Grammy Hall of Fame Award recipients"], "seealso": []}
{"headers": ["Books"], "text": "[[Lynn Sherr]]'s 2001 book ''America the Beautiful'' discusses the origins of the song and the backgrounds of its authors in depth. The book points out that the poem has [[Common meter|the same meter]] as that of \"[[Auld Lang Syne]]\"; the songs can be sung interchangeably. Additionally, Sherr discusses the evolution of the lyrics, for instance, changes to the original third verse written by Bates. Melinda M. Ponder, in her 2017 biography ''Katharine Lee Bates: From Sea to Shining Sea'', draws heavily on Bates's diaries and letters to trace the history of the poem and its place in American culture.", "id": "651", "title": "America the Beautiful", "categories": ["1895 songs", "American Christian hymns", "American patriotic songs", "Pikes Peak", "History of Colorado Springs, Colorado", "Songs based on poems", "Grammy Hall of Fame Award recipients"], "seealso": []}
{"headers": [], "text": "[[Image:Hoergeraet analog 050609.jpg|thumb|Hearing aid]] '''Assistive technology''' (AT) is a term for assistive, adaptive, and rehabilitative devices for [[Disability|people with disabilities]] or the elderly population. People with disabilities often have difficulty performing [[activities of daily living]] (ADLs) independently, or even with assistance. ADLs are self-care activities that include toileting, mobility (ambulation), eating, bathing, dressing, grooming, and personal device care. Assistive technology can ameliorate the effects of disabilities that limit the ability to perform ADLs. Assistive technology promotes greater independence by enabling people to perform tasks they were formerly unable to accomplish, or had great difficulty accomplishing, by providing enhancements to, or changing methods of interacting with, the [[technology]] needed to accomplish such tasks. For example, wheelchairs provide independent mobility for those who cannot walk, while [[assistive eating devices]] can enable people who cannot feed themselves to do so. Due to assistive technology, people with disability have an opportunity of a more positive and easygoing lifestyle, with an increase in \"social participation,\" \"security and control,\" and a greater chance to \"reduce institutional costs without significantly increasing household expenses.\"", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Adaptive Technology"], "text": "Adaptive technology and assistive technology are different. ''Assistive technology'' is something that is used to help disabled people, while ''adaptive technology'' covers items that are specifically designed for disabled people and would seldom be used by a non-disabled person. In other words, assistive technology is any object or system that helps people with disabilities, while adaptive technology is specifically designed for disabled people. Consequently, adaptive technology is a subset of assistive technology. Adaptive technology often refers specifically to electronic and information technology access.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Occupational Therapy"], "text": "[[Occupational therapy]] (OT) is a healthcare profession that specializes in maintaining or improving the quality of life for individuals that experience challenges when independently performing life's occupations. According to the ''Occupational Therapy Practice Framework: Domain and Process'' (3rd ed.; [[AOTA]], 2014), occupations include areas related to all basic and instrumental activities of daily living (ADLs), rest and sleep, education, work, play, leisure and social participation. [[Occupational therapists]] have the specialized skill of employing assistive technology (AT) in the improvement and maintenance of optimal, functional participation in occupations. The application of AT enables an individual to adapt aspects of the environment, that may otherwise be challenging, to the user in order to optimize functional participation in those occupations. As a result, occupational therapists may educate, recommend, and promote the use of AT to improve the quality of life for their clients.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Mobility impairments", "Wheelchairs"], "text": "Wheelchairs are devices that can be manually propelled or electrically propelled, and that include a seating system and are designed to be a substitute for the normal mobility that most people have. Wheelchairs and other mobility devices allow people to perform mobility-related [[activities of daily living]] which include feeding, toileting, dressing, grooming, and bathing. The devices come in a number of variations where they can be propelled either by hand or by motors where the occupant uses electrical controls to manage motors and seating control actuators through a [[joystick]], [[sip-and-puff]] control, [[head switches]] or other input devices. Often there are handles behind the seat for someone else to do the pushing or input devices for caregivers. Wheelchairs are used by people for whom [[walking]] is difficult or impossible due to illness, injury, or disability. People with both sitting and walking disability often need to use a wheelchair or walker. Newer advancements in wheelchair design enable wheelchairs to climb stairs, go off-road or propel using [[segway]] technology or additional add-ons like [[Handcycle|handbikes]] or [[Wheelchair power add-on|power assists]].", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Mobility impairments", "Transfer devices"], "text": "Patient transfer devices generally allow patients with impaired mobility to be moved by caregivers between beds, wheelchairs, commodes, toilets, chairs, stretchers, shower benches, automobiles, swimming pools, and other patient support systems (i.e., radiology, surgical, or examining tables). The most common devices are [[Patient lift]] (for vertical transfer), [[Transfer bench]], stretcher or convertible chairs (for lateral, supine transfer), sit-to-stand lifts (for moving patients from one seated position to another i.e., from wheelchairs to commodes), air bearing inflatable mattresses (for supine transfer i.e., transfer from a gurney to an operating room table), and sliding boards (usually used for transfer from a bed to a wheelchair). Highly dependent patients who cannot assist their caregiver in moving them often require a [[Patient lift]] (a floor or ceiling-suspended sling lift) which though invented in 1955 and in common use since the early 1960s is still considered the state-of-the-art transfer device by OSHA and the American Nursing Association.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Mobility impairments", "Walkers"], "text": "A [[walker (mobility)|walker]] or walking frame or Rollator is a tool for disabled people who need additional support to maintain balance or stability while walking. It consists of a frame that is about waist high, approximately twelve inches deep and slightly wider than the user. Walkers are also available in other sizes, such as for children, or for heavy people. Modern walkers are height-adjustable. The front two legs of the walker may or may not have wheels attached depending on the strength and abilities of the person using it. It is also common to see caster wheels or glides on the back legs of a walker with wheels on the front.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Mobility impairments", "Prosthesis"], "text": "A '''prosthesis''', '''prosthetic''', or '''prosthetic limb''' is a device that replaces a missing [[Human body|body]] part. It is part of the field of [[biomechatronics]], the science of using [[Mechanical system|mechanical]] devices with human [[muscle]], [[skeleton]], and [[nervous systems]] to assist or enhance motor control lost by [[Trauma (medicine)|trauma]], [[disease]], or [[Congenital disorder|defect]]. Prostheses are typically used to replace parts lost by injury (traumatic) or missing from birth ([[Birth defect|congenital]]) or to supplement defective body parts. Inside the body, [[artificial heart valve]] are in common use with [[artificial heart]] and [[artificial lung|lungs]] seeing less common use but under active technology development. Other medical devices and aids that can be considered prosthetics include [[hearing aids]], [[visual prosthesis|artificial eyes]], [[palatal obturator]], [[Adjustable gastric band|gastric bands]], and [[dentures]]. Prostheses are specifically ''not'' [[orthoses]], although given certain circumstances a prosthesis might end up performing some or all of the same functionary benefits as an orthosis. Prostheses are technically the complete finished item. For instance, a C-Leg knee alone is ''not'' a prosthesis, but only a prosthetic ''component''. The complete prosthesis would consist of the attachment system  to the residual limb — usually a \"socket\", and all the attachment hardware components all the way down to and including the terminal device. Keep this in mind as nomenclature is often interchanged. The terms \"prosthetic\" and \"orthotic\" are adjectives used to describe devices such as a prosthetic knee. The terms \"prosthetics\" and \"orthotics\" are used to describe the respective allied health fields. An Occupational Therapist's role in prosthetics include therapy, training and evaluations. Prosthetic training includes orientation to prosthetics components and terminology, donning and doffing, wearing schedule, and how to care for residual limb and the prosthesis.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Mobility impairments", "Exoskeletons"], "text": "A [[powered exoskeleton]] is a wearable mobile machine that is powered by a system of electric motors, pneumatics, levers, hydraulics, or a combination of technologies that allow for limb movement with increased strength and endurance. Its design aims to provide back support, sense the user's motion, and send a signal to motors which manage the gears. The exoskeleton supports the shoulder, waist and thigh, and assists movement for lifting and holding heavy items, while lowering back stress.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Mobility impairments", "Adaptive Seating and Positioning"], "text": "People with balance and motor function challenges often need specialized equipment to sit or stand safely and securely. This equipment is frequently specialized for specific settings such as in a classroom or nursing home.  Positioning is often important in seating arrangements to ensure that user's body pressure is distributed equally without inhibiting movement in a desired way. Positioning devices have been developed to aid in allowing people to [[Standing frame|stand]] and bear weight on their legs without risk of a fall.  These standers are generally grouped into two categories based on the position of the occupant.  Prone standers distribute the body weight to the front of the individual and usually have a tray in front of them.  This makes them good for users who are actively trying to carry out some task.  Supine standers distribute the body weight to the back and are good for cases where the user has more limited mobility or is recovering from injury.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments"], "text": "Many people with serious visual impairments live independently, using a wide range of tools and techniques. Examples of assistive technology for visually impairment include screen readers, screen magnifiers, Braille embossers, desktop video magnifiers, and voice recorders.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Screen readers"], "text": "Screen readers are used to help the visually impaired to easily access electronic information. These software programs run on a computer in order to convey the displayed information through voice ([[text-to-speech]]) or [[braille]] ([[refreshable braille display]]) in combination with magnification for low vision users in some cases. There are a variety of platforms and applications available for a variety of costs with differing feature sets. Some example of screen readers are Apple [[VoiceOver]], [[Google TalkBack]] and [[Microsoft Narrator]]. This software is provided free of charge on all Apple devices. Apple VoiceOver includes the option to magnify the screen, control the keyboard, and provide verbal descriptions to describe what is happening on the screen. There are thirty languages to select from. It also has the capacity to read aloud file content, as well as web pages, E-mail messages, and word processing files. As mentioned above, screen readers may rely on the assistance of text-to-speech tools. To use the text-to-speech tools, the documents must in an electronic form, that is uploaded as the digital format. However, people usually will use the hard copy documents scanned into the computer, which is cannot be recognized by the text-to-speech software. To solve this issue, people always use [[Optical character recognition|Optical Character Recognition technology]] accompanied with text-to-speech software.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Braille and braille embossers"], "text": "Braille is a system of raised dots formed into units called braille cells. A full braille cell is made up of six dots, with two parallel rows of three dots, but other combinations and quantities of dots represent other letters, numbers, punctuation marks, or words. People can then use their fingers to read the code of raised dots. A braille embosser is, simply put, a printer for braille. Instead of a standard printer adding ink onto a page, the braille embosser imprints the raised dots of braille onto a page. Some braille embossers combine both braille and ink so the documents can be read with either sight or touch.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Refreshable braille display"], "text": "A refreshable braille display or braille terminal is an electro-mechanical device for displaying braille characters, usually by means of round-tipped pins raised through holes in a flat surface. Computer users who cannot use a computer monitor use it to read a braille output version of the displayed text.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Desktop video magnifier"], "text": "Desktop video magnifiers are electronic devices that use a camera and a display screen to perform digital magnification of printed materials. They enlarge printed pages for those with low vision. A camera connects to a monitor that displays real-time images, and the user can control settings such as magnification, focus, contrast, underlining, highlighting, and other screen preferences. They come in a variety of sizes and styles; some are small and portable with handheld cameras, while others are much larger and mounted on a fixed stand.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Screen magnification software"], "text": "A screen magnifier is software that interfaces with a computer's graphical output to present enlarged screen content. It allows users to enlarge the texts and graphics on their computer screens for easier viewing. Similar to desktop video magnifiers, this technology assists people with low vision. After the user loads the software into their computer's memory, it serves as a kind of \"computer magnifying glass.\" Wherever the computer cursor moves, it enlarges the area around it. This allows greater computer accessibility for a wide range of visual abilities.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Large-print and tactile keyboards"], "text": "A large-print keyboard has large letters printed on the keys. On the keyboard shown, the round buttons at the top control software which can magnify the screen (zoom in), change the background color of the screen, or make the mouse cursor on the screen larger. The \"bump dots\" on the keys, installed in this case by the organization using the keyboards, help the user find the right keys in a tactile way.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Navigation Assistance"], "text": "[[GPS for the visually impaired|Assistive technology for navigation]] has exploded on the [[IEEE Xplore]] database since 2000, with over 7,500 engineering articles written on assistive technologies and visual impairment in the past 25 years, and over 1,300 articles on solving the problem of navigation for people who are blind or visually impaired. As well, over 600 articles on augmented reality and visual impairment have appeared in the engineering literature since 2000. Most of these articles were published within the past 5 years, and the number of articles in this area is increasing every year. GPS, accelerometers, gyroscopes, and cameras can pinpoint the exact location of the user and provide information on what's in the immediate vicinity, and assistance in getting to a destination.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Visual impairments", "Wearable Technology"], "text": "Wearable technology are smart electronic devices that can be worn on the body as an implant or an accessory. New technologies are exploring how the visually impaired can receive visual information through wearable devices. Some wearable devices for visual impairment include: (1) [[OrCam device]] (2) [[eSight]] (3) [[Brainport]] NightWare (Prescription-only) Watch application for PTSD FDA approved : Zachary Zdroik An application for Apple watches that will \"vibrate\" to wake an individual up from a nightmare. The watch monitors your heart rate and vibrates enough to wake an individual up from a deep sleep, but not entirely awake. It will disrupt the nightmare but still allow the individual to sleep.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Personal emergency response systems"], "text": "[[Personal emergency response systems]] (PERS), or [[Telecare]] (UK term), are a particular sort of assistive technology that use electronic sensors connected to an alarm system to help caregivers manage risk and help vulnerable people stay independent at home longer. An example would be the systems being put in place for senior people such as fall detectors, thermometers (for [[hypothermia]] risk), flooding and unlit gas sensors (for people with mild [[dementia]]). Notably, these alerts can be customized to the particular person's risks. When the alert is triggered, a message is sent to a caregiver or contact center who can respond appropriately.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Accessibility software"], "text": "In human–computer interaction, computer accessibility (also known as accessible computing) refers to the accessibility of a computer system to all people, regardless of disability or severity of impairment, examples include [[web accessibility]] guidelines. Another approach is for the user to present a token to the computer terminal, such as a smart card, that has configuration information to adjust the computer speed, text size, etc. to their particular needs. This is useful where users want to access public computer based terminals in Libraries, ATM, Information kiosks etc. The concept is encompassed by the CEN EN 1332-4 Identification Card Systems – Man-Machine Interface. This development of this standard has been supported in Europe by [[SNAPI]] and has been successfully incorporated into the [[Lasseo]] specifications, but with limited success due to the lack of interest from public computer terminal suppliers.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Hearing impairments"], "text": "People in the d/Deaf and hard of hearing community have a more difficult time receiving auditory information as compared to hearing individuals. These individuals often rely on visual and tactile mediums for receiving and communicating information. The use of assistive technology and devices provides this community with various solutions to auditory communication needs by providing higher sound (for those who are hard of hearing), tactile feedback, visual cues and improved technology access. Individuals who are deaf or hard of hearing utilize a variety of assistive technologies that provide them with different access to information in numerous environments. Most devices either provide amplified sound or alternate ways to access information through vision and/or vibration. These technologies can be grouped into three general categories: [[Assistive Technology for Deaf and Hard of Hearing#Hearing Technology|Hearing Technology]], alerting devices, and [[Assistive Technology for Deaf and Hard of Hearing#Communication Support|communication support]].", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Hearing impairments", "Hearing aids"], "text": "A hearing aid or deaf aid is an electro-acoustic device which is designed to amplify sound for the wearer, usually with the aim of making speech more intelligible, and to correct impaired hearing as measured by audiometry. This type of assistive technology helps people with hearing loss participate more fully in their hearing communities by allowing them to hear more clearly. They amplify any and all sound waves through use of a microphone, amplifier, and speaker. There is a wide variety of hearing aids available, including digital, in-the-ear, in-the-canal, behind-the-ear, and on-the-body aids.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Hearing impairments", "Assistive listening devices"], "text": "Assistive listening devices include FM, infrared, and loop assistive listening devices. This type of technology allows people with hearing difficulties to focus on a speaker or subject by getting rid of extra background noises and distractions, making places like auditoriums, classrooms, and meetings much easier to participate in. The assistive listening device usually uses a microphone to capture an audio source near to its origin and broadcast it wirelessly over an FM (Frequency Modulation) transmission, IR (Infra Red) transmission, IL (Induction Loop) transmission, or other transmission methods. The person who is listening may use an FM/IR/IL Receiver to tune into the signal and listen at his/her preferred volume.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Hearing impairments", "Amplified telephone equipment"], "text": "This type of assistive technology allows users to amplify the volume and clarity of their phone calls so that they can easily partake in this medium of communication. There are also options to adjust the frequency and tone of a call to suit their individual hearing needs. Additionally, there is a wide variety of amplified telephones to choose from, with different degrees of amplification. For example, a phone with 26 to 40 decibel is generally sufficient for mild hearing loss, while a phone with 71 to 90 decibel is better for more severe hearing loss.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Augmentative and alternative communication"], "text": "Augmentative and alternative communication (AAC) is an umbrella term that encompasses methods of communication for those with impairments or restrictions on the production or comprehension of spoken or written language. AAC systems are extremely diverse and depend on the capabilities of the user. They may be as basic as pictures on a board that are used to request food, drink, or other care; or they can be advanced [[speech generating device]], based on speech synthesis, that are capable of storing hundreds of phrases and words.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Cognitive impairments"], "text": "Assistive Technology for Cognition (ATC) is the use of technology (usually high tech) to augment and assist cognitive processes such as attention, memory, self-regulation, navigation, [[emotion recognition]] and management, planning, and sequencing activity. Systematic reviews of the field have found that the number of ATC are growing rapidly, but have focused on memory and planning, that there is emerging evidence for efficacy, that a lot of scope exists to develop new ATC. Examples of ATC include: [[NeuroPage]] which prompts users about meetings, [[Wakamaru]], which provides companionship and reminds users to take medicine and calls for help if something is wrong, and telephone Reassurance systems.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Cognitive impairments", "Memory aids"], "text": "Memory aids are any type of assistive technology that helps a user learn and remember certain information. Many memory aids are used for cognitive impairments such as reading, writing, or organizational difficulties. For example, a [[Digital pen|Smartpen]] records handwritten notes by creating both a digital copy and an audio recording of the text. Users simply tap certain parts of their notes, the pen saves it, and reads it back to them. From there, the user can also download their notes onto a computer for increased accessibility. Digital voice recorders are also used to record \"in the moment\" information for fast and easy recall at a later time.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Cognitive impairments", "Educational software"], "text": "Educational software is software that assists people with reading, learning, comprehension, and organizational difficulties. Any accommodation software such as text readers, notetakers, text enlargers, organization tools, [[word prediction]], and talking word processors falls under the category of educational software.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Eating Impairments"], "text": "Adaptive eating devices include items commonly used by the general population like spoons and forks and plates. However they become assistive technology when they are modified to accommodate the needs of people who have difficulty using standard cutlery due to a disabling condition. Common modifications include increasing the size of the utensil handle to make it easier to grasp. Plates and bowls may have a guard on the edge that stops food being pushed off of the dish when it is being scooped. More sophisticated equipment for eating includes manual and powered feeding devices. These devices support those who have little or no hand and arm function and enable them to eat independently.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["In sports"], "text": "Assistive technology in sports is an area of technology design that is growing. Assistive technology is the array of new devices created to enable sports enthusiasts who have disabilities to play. Assistive technology may be used in [[adaptive sports]], where an existing sport is modified to enable players with a disability to participate; or, assistive technology may be used to invent completely new sports with athletes with disabilities exclusively in mind. An increasing number of people with disabilities are participating in sports, leading to the development of new assistive technology. Assistive technology devices can be simple, or \"low-technology\", or they may use highly advanced technology. \"Low-tech\" devices can include velcro gloves and adaptive bands and tubes. \"High-tech\" devices can include all-terrain wheelchairs and adaptive bicycles. Accordingly, assistive technology can be found in sports ranging from local community recreation to the elite [[Paralympic Games]]. More complex assistive technology devices have been developed over time, and as a result, sports for people with disabilities \"have changed from being a clinical therapeutic tool to an increasingly competition-oriented activity\".", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["In education"], "text": "In the United States there are two major pieces of legislation that govern the use of assistive technology within the school system. The first is Section 504 of the [[Rehabilitation Act of 1973]] and the second being the [[Individuals with Disabilities Education Act]] (IDEA) which was first enacted in 1975 under the name The Education for All Handicapped Children Act. In 2004, during the reauthorization period for IDEA, the National Instructional Material Access Center (NIMAC) was created which provided a repository of accessible text including publisher's textbooks to students with a qualifying disability. Files provided are in XML format and used as a starting platform for braille readers, screen readers, and other digital text software. IDEA defines assistive technology as follows: \"any item, piece of equipment, or product system, whether acquired commercially off the shelf, modified, or customized, that is used to increase, maintain, or improve functional capabilities of a child with a disability. (B) Exception.--The term does not include a medical device that is surgically implanted, or the replacement of such device.\" Assistive technology listed is a student’s IEP is not only recommended, it is required (Koch, 2017). These devices help students both with and without disabilities access the curriculum in a way they were previously unable to (Koch, 2017). Occupational therapists play an important role in educating students, parents and teachers about the assistive technology they may interact with (Koch, 2017). Assistive technology in this area is broken down into low, mid, and high tech categories. Low tech encompasses equipment that is often low cost and does not include batteries or requires charging. Examples include adapted paper and pencil grips for writing or masks and color overlays for reading. Mid tech supports used in the school setting include the use of handheld spelling dictionaries and portable word processors used to keyboard writing. High tech supports involve the use of tablet devices and computers with accompanying software. Software supports for writing include the use of auditory feedback while keyboarding, word prediction for spelling, and [[speech to text]]. Supports for reading include the use of text to speech (TTS) software and font modification via access to digital text. Limited supports are available for math instruction and mostly consist of grid based software to allow younger students to keyboard equations and auditory feedback of more complex equations using MathML and Daisy.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Computer accessibility"], "text": "One of the largest problems that affect disabled people is discomfort with prostheses. An experiment performed in Massachusetts utilized 20 people with various sensors attached to their arms. The subjects tried different arm exercises, and the sensors recorded their movements. All of the data helped engineers develop new engineering concepts for prosthetics. Assistive technology may attempt to improve the ergonomics of the devices themselves such as [[Dvorak Simplified Keyboard|Dvorak]] and other alternative keyboard layouts, which offer more ergonomic layouts of the keys. Assistive technology devices have been created to enable disabled people to use modern touch screen mobile computers such as the [[iPad]], [[iPhone]] and [[iPod touch]]. The Pererro is a plug and play adapter for [[iOS]] devices which uses the built in [[Apple VoiceOver]] feature in combination with a basic switch. This brings touch screen technology to those who were previously unable to use it. Apple, with the release of iOS 7 had introduced the ability to navigate apps using switch control. Switch access could be activated either through an external bluetooth connected switch, single touch of the screen, or use of right and left head turns using the device's camera. Additional accessibility features include the use of Assistive Touch which allows a user to access multi-touch gestures through pre-programmed onscreen buttons. For users with physical disabilities a large variety of switches are available and customizable to the user's needs varying in size, shape, or amount of pressure required for activation. [[Switch access]] may be placed near any area of the body which has consistent and reliable mobility and less subject to fatigue. Common sites include the hands, head, and feet. [[eye tracking|Eye gaze]] and head mouse systems can also be used as an alternative mouse navigation. A user may utilize single or multiple switch sites and the process often involves a scanning through items on a screen and activating the switch once the desired object is highlighted.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Home automation"], "text": "The form of [[home automation]] called [[assistive domotics]] focuses on making it possible for elderly and disabled people to live independently. Home automation is becoming a viable option for the elderly and disabled who would prefer to stay in their own homes rather than move to a healthcare facility. This field uses much of the same technology and equipment as home automation for security, entertainment, and energy conservation but tailors it towards elderly and disabled users. For example, automated prompts and reminders utilize motion sensors and pre-recorded audio messages; an automated prompt in the kitchen may remind the resident to turn off the oven, and one by the front door may remind the resident to lock the door.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": ["Impacts"], "text": "Overall, assistive technology aims to allow disabled people to \"participate more fully in all aspects of life (home, school, and community)\" and increases their opportunities for \"education, social interactions, and potential for meaningful employment\". It creates greater independence and control for disabled individuals. For example, in one study of 1,342 infants, toddlers and preschoolers, all with some kind of developmental, physical, sensory, or cognitive disability, the use of assistive technology created improvements in child development. These included improvements in \"cognitive, social, communication, literacy, motor, adaptive, and increases in engagement in learning activities\". Additionally, it has been found to lighten caregiver load. Both family and professional caregivers benefit from assistive technology. Through its use, the time that a family member or friend would need to care for a patient significantly decreases. However, studies show that care time for a professional caregiver increases when assistive technology is used. Nonetheless, their work load is significantly easier as the assistive technology frees them of having to perform certain tasks. There are several platforms that use machine learning to identify the appropriate assistive device to suggest to patients, making assistive devices more accessible.", "id": "653", "title": "Assistive technology", "categories": ["Assistive technology", "Educational technology", "Web accessibility"], "seealso": ["Durable medical equipment", "Assisted Living", "OATS", "Design for All (in ICT)", "Accessibility", "Occupational Therapy", "WP:SEEALSO", "Braille technology", "Augmentative and alternative communication", "Matching person and technology model", "Transgenerational design", "Universal access to education"]}
{"headers": [], "text": "The '''abacus''' (''plural'' '''abaci''' or '''abacuses'''), also called a '''counting frame''', is a calculating tool that has been in use since ancient times and is still in use today. It was used in the [[ancient Near East]], Europe, China, and Russia, centuries before the adoption of the written [[Eastern Arabic numerals|Arabic numeral system]]. The exact origin of the abacus is unknown. The abacus essentially consists of a number of rows of movable beads or other objects, which represent digits. One of two numbers is set up, and the beads are manipulated to implement an operation involving a second number (e.g., addition), or rarely a square or cubic root. In earliest use the rows of beads could be loose on a flat surface, or sliding in grooves. Later the beads were made to slide on rods of some sort built into a frame, allowing faster manipulation. Abacuses are still made, often as a [[bamboo]] frame with beads sliding on wires. In the ancient world, particularly before the introduction of [[positional notation]], abacuses were a practical calculating tool. There are distinctive modern implementations of the abacus. Some designs, like the bead frame consisting of beads divided into tens, are used mainly to teach [[arithmetic]], although they remain popular in the [[post-Soviet states]] as a tool. Other designs, such as the Japanese [[soroban]], have been used for practical calculations even involving numbers of several digits. For any particular abacus design, there are usually numerous different methods to perform calculations, which may include the four basic operations, and also [[square root|square]] and [[cube root]]. Some of these methods work with non-[[Natural number|natural]] numbers (numbers such as and ). Although today [[calculator]] and [[computer]] are usually used instead of abacuses, abacuses still remain in common use in some countries. Merchants, traders and clerks in some parts of Eastern Europe, Russia, China and Africa use abacuses, and they are still used to teach arithmetic to children. Some people who are unable to use a calculator because of visual impairment may use an abacus.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["Etymology"], "text": "The use of the word ''abacus'' dates from before 1387 AD, when a [[Middle English]] work borrowed the word from [[Latin]] to describe a sandboard abacus. The Latin word came from [[ancient Greek]] (''abax'') which means something without base, and improperly, any piece of rectangular board or plank. Alternatively, without reference to ancient texts on etymology, it has been suggested that it means \"a square tablet strewn with dust\", or \"drawing-board covered with dust (for the use of mathematics)\" (the exact shape of the Latin perhaps reflects the [[Genitive case|genitive form]] of the Greek word, ''abakos''). While the table strewn with dust definition is popular, some disagree, saying that it is not proven. Greek itself is probably a borrowing of a [[Northwest Semitic language]], perhaps [[Phoenician language|Phoenician]], and cognate with the [[Hebrew language|Hebrew]] word ''ʾābāq'' (), or “dust” (in post-Biblical sense meaning \"sand used as a writing surface\"). Both ''abacuses'' and ''abaci'' (soft or hard \"c\") are used as plurals. The user of an abacus is called an ''abacist''.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Mesopotamian"], "text": "The period 2700–2300 BC saw the first appearance of the [[Sumer]] abacus, a table of successive columns which delimited the successive orders of magnitude of their [[sexagesimal]] number system. Some scholars point to a character in [[Akkadian language|Babylonian cuneiform]] which may have been derived from a representation of the abacus. It is the belief of Old Babylonian scholars such as Carruccio that Old Babylonians \"may have used the abacus for the operations of addition and subtraction; however, this primitive device proved difficult to use for more complex calculations\".", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Egyptian"], "text": "The use of the abacus in [[Ancient Egypt]] is mentioned by the Greek historian [[Herodotus]], who writes that the Egyptians manipulated the pebbles from right to left, opposite in direction to the Greek left-to-right method. Archaeologists have found ancient disks of various sizes that are thought to have been used as counters. However, wall depictions of this instrument have not been discovered.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Persian"], "text": "During the [[Achaemenid Empire]], around 600 BC the Persians first began to use the abacus. Under the [[Parthian Empire|Parthian]], [[Sassanian]] and [[Iran]] empires, scholars concentrated on exchanging knowledge and inventions with the countries around them – [[India]], [[China]], and the [[Roman Empire]], when it is thought to have been exported to other countries.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Greek"], "text": "[[Image:Salaminische Tafel Salamis Tablet nach Wilhelm Kubitschek Numismatische Zeitschrift Bd 31 Wien 1899 p. 394 ff.jpg|thumb|upright|An early photograph of the Salamis Tablet, 1899. The original is marble and is held by the National Museum of Epigraphy, in Athens.]] The earliest archaeological evidence for the use of the Greek abacus dates to the 5th century BC. Also [[Demosthenes]] (384 BC–322 BC) talked of the need to use pebbles for calculations too difficult for your head. A play by [[Alexis (poet)|Alexis]] from the 4th century BC mentions an abacus and pebbles for accounting, and both [[Diogenes]] and [[Polybius]] mention men that sometimes stood for more and sometimes for less, like the pebbles on an abacus. The Greek abacus was a table of wood or marble, pre-set with small counters in wood or metal for mathematical calculations. This Greek abacus saw use in Achaemenid Persia, the Etruscan civilization, Ancient Rome and, until the French Revolution, the Western Christian world. A tablet found on the Greek island [[Salamis Island|Salamis]] in 1846 AD (the [[Salamis Tablet]]), dates back to 300 BC, making it the oldest counting board discovered so far. It is a slab of white marble long, wide, and thick, on which are 5 groups of markings. In the center of the tablet is a set of 5 parallel lines equally divided by a vertical line, capped with a semicircle at the intersection of the bottom-most horizontal line and the single vertical line. Below these lines is a wide space with a horizontal crack dividing it. Below this crack is another group of eleven parallel lines, again divided into two sections by a line perpendicular to them, but with the semicircle at the top of the intersection; the third, sixth and ninth of these lines are marked with a cross where they intersect with the vertical line. Also from this time frame the ''Darius Vase'' was unearthed in 1851. It was covered with pictures including a \"treasurer\" holding a wax tablet in one hand while manipulating counters on a table with the other.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Chinese"], "text": "The earliest known written documentation of the Chinese abacus dates to the 2nd century BC. The Chinese abacus, known as the ''[[suanpan]]'' (算盤/算盘, lit. \"calculating tray\"), is typically tall and comes in various widths depending on the operator. It usually has more than seven rods. There are two beads on each rod in the upper deck and five beads each in the bottom. The beads are usually rounded and made of a [[hardwood]]. The beads are counted by moving them up or down towards the beam; beads moved toward the beam are counted, while those moved away from it are not. One of the top beads is 5, while one of the bottom beads is 1. Each rod has a number under it, showing the place value.The ''suanpan'' can be reset to the starting position instantly by a quick movement along the horizontal axis to spin all the beads away from the horizontal beam at the center. The prototype of the Chinese abacus appeared during the [[Han Dynasty]], and the beads are oval. The [[Song Dynasty]] and earlier used the 1:4 type or four-beads abacus similar to the modern abacus including the shape of the beads commonly known as Japanese-style abacus. In the early [[Ming Dynasty]], the abacus began to appear in the form of 1:5 abacus. The upper deck had one bead and the bottom had five beads. In the late Ming Dynasty, the abacus styles appeared in the form of 2:5. The upper deck had two beads, and the bottom had five beads. Various calculation techniques were devised for ''Suanpan'' enabling efficient calculations. There are currently schools teaching students how to use it. In the long scroll ''[[Along the River During the Qingming Festival]]'' painted by [[Zhang Zeduan]] during the [[Song dynasty]] (960–1297), a ''suanpan'' is clearly visible beside an account book and doctor's prescriptions on the counter of an [[apothecary]]'s (Feibao). The similarity of the [[Roman abacus]] to the Chinese one suggests that one could have inspired the other, as there is some evidence of a trade relationship between the [[Roman Empire]] and China. However, no direct connection can be demonstrated, and the similarity of the abacuses may be coincidental, both ultimately arising from counting with five fingers per hand. Where the Roman model (like most modern Korean and [[#Japanese abacus|Japanese]]) has 4 plus 1 bead per decimal place, the standard ''suanpan'' has 5 plus 2. Incidentally, this allows use with a [[hexadecimal]] numeral system (or any [[Radix|base]] up to 18) which may have been used for traditional Chinese measures of weight. (Instead of running on wires as in the Chinese, Korean, and Japanese models, the beads of Roman model run in grooves, presumably making arithmetic calculations much slower.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Chinese"], "text": "Another possible source of the ''suanpan'' is Chinese [[counting rods]], which operated with a [[decimal|decimal system]] but lacked the concept of [[0 (number)|zero]] as a place holder. The zero was probably introduced to the Chinese in the [[Tang dynasty]] (618–907) when travel in the [[Indian Ocean]] and the [[Middle East]] would have provided direct contact with [[India]], allowing them to acquire the concept of zero and the [[decimal point]] from Indian merchants and mathematicians.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Roman"], "text": "The normal method of calculation in ancient Rome, as in Greece, was by moving counters on a smooth table. Originally pebbles (''calculi'') were used. Later, and in medieval Europe, [[jeton]] were manufactured. Marked lines indicated units, fives, tens etc. as in the [[Roman numeral]] system. This system of 'counter casting' continued into the late Roman empire and in medieval Europe, and persisted in limited use into the nineteenth century. Due to [[Pope Sylvester II]]'s reintroduction of the abacus with modifications, it became widely used in Europe once again during the 11th century This abacus used beads on wires, unlike the traditional Roman counting boards, which meant the abacus could be used much faster. Writing in the 1st century BC, Horace refers to the wax abacus, a board covered with a thin layer of black wax on which columns and figures were inscribed using a stylus. One example of archaeological evidence of the [[Roman abacus]], shown here in reconstruction, dates to the 1st century AD. It has eight long grooves containing up to five beads in each and eight shorter grooves having either one or no beads in each. The groove marked I indicates units, X tens, and so on up to millions. The beads in the shorter grooves denote fives –five units, five tens etc., essentially in a [[bi-quinary coded decimal]] system, related to the [[Roman numerals]]. The short grooves on the right may have been used for marking Roman \"ounces\" (i.e. fractions).", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Indian"], "text": "The ''[[Abhidharmakośabhāṣya]]'' of [[Vasubandhu]] (316-396), a Sanskrit work on Buddhist philosophy, says that the second-century CE philosopher [[Vasumitra]] said that \"placing a wick (Sanskrit ''vartikā'') on the number one (''ekāṅka'') means it is a one, while placing the wick on the number hundred means it is called a hundred, and on the number one thousand means it is a thousand\". It is unclear exactly what this arrangement may have been. Around the 5th century, Indian clerks were already finding new ways of recording the contents of the Abacus. Hindu texts used the term ''śūnya'' (zero) to indicate the empty column on the abacus.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Japanese"], "text": "In Japanese, the abacus is called ''[[soroban]]'' (, lit. \"Counting tray\"), imported from China in the 14th century. It was probably in use by the working class a century or more before the ruling class started, as the class structure did not allow for devices used by the lower class to be adopted or used by the ruling class. The 1/4 abacus, which removes the seldom used second and fifth bead became popular in the 1940s. Today's Japanese abacus is a 1:4 type, four-bead abacus was introduced from China in the Muromachi era. It adopts the form of the upper deck one bead and the bottom four beads. The top bead on the upper deck was equal to five and the bottom one is equal to one like the Chinese or Korean abacus, and the decimal number can be expressed, so the abacus is designed as one four abacus. The beads are always in the shape of a diamond. The quotient division is generally used instead of the division method; at the same time, in order to make the multiplication and division digits consistently use the division multiplication. Later, Japan had a 3:5 abacus called 天三算盤, which is now the Ize Rongji collection of Shansi Village in [[Yamagata, Yamagata|Yamagata]] City. There were also 2:5 type abacus. With the four-bead abacus spread, it is also common to use Japanese abacus around the world. There are also improved Japanese abacus in various places. One of the Japanese-made abacus made in China is an aluminum frame plastic bead abacus. The file is next to the four beads, and the \"clearing\" button, press the clearing button, immediately put the upper bead to the upper position, the lower bead is dialed to the lower position, immediately clearing, easy to use. The abacus is still manufactured in Japan today even with the proliferation, practicality, and affordability of pocket [[electronic calculator]]. The use of the soroban is still taught in Japanese [[primary school]] as part of [[mathematics]], primarily as an aid to faster mental calculation. Using visual imagery of a soroban, one can arrive at the answer in the same time as, or even faster than, is possible with a physical instrument.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Korean"], "text": "The Chinese abacus migrated from China to [[Korea]] around 1400 AD. Koreans call it ''jupan'' (주판), ''supan'' (수판) or ''jusan'' (주산). The four beads abacus( 1:4 ) was introduced to Korea Goryeo Dynasty from the China during Song Dynasty, later the five beads abacus (5:1) abacus was introduced to Korean from China during the Ming Dynasty.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Native American"], "text": "Some sources mention the use of an abacus called a ''nepohualtzintzin'' in ancient [[Aztec]] culture. This Mesoamerican abacus used a 5-digit base-20 system. The word Nepōhualtzintzin comes from [[Nahuatl]] and it is formed by the roots; ''Ne'' – personal -; ''pōhual'' or ''pōhualli'' – the account -; and ''tzintzin'' – small similar elements. Its complete meaning was taken as: counting with small similar elements by somebody. Its use was taught in the [[Calmecac]] to the ''temalpouhqueh'' , who were students dedicated to take the accounts of skies, from childhood. The Nepōhualtzintzin was divided in two main parts separated by a bar or intermediate cord. In the left part there were four beads, which in the first row have unitary values (1, 2, 3, and 4), and in the right side there are three beads with values of 5, 10, and 15 respectively. In order to know the value of the respective beads of the upper rows, it is enough to multiply by 20 (by each row), the value of the corresponding account in the first row. Altogether, there were 13 rows with 7 beads in each one, which made up 91 beads in each Nepōhualtzintzin. This was a basic number to understand, 7 times 13, a close relation conceived between natural phenomena, the underworld and the cycles of the heavens. One Nepōhualtzintzin (91) represented the number of days that a season of the year lasts, two Nepōhualtzitzin (182) is the number of days of the corn's cycle, from its sowing to its harvest, three Nepōhualtzintzin (273) is the number of days of a baby's gestation, and four Nepōhualtzintzin (364) completed a cycle and approximate a year (1 days short). When translated into modern computer arithmetic, the Nepōhualtzintzin amounted to the rank from 10 to the 18 in [[floating point]], which calculated stellar as well as infinitesimal amounts with absolute precision, meant that no round off was allowed. The rediscovery of the Nepōhualtzintzin was due to the Mexican engineer David Esparza Hidalgo, who in his wanderings throughout Mexico found diverse engravings and paintings of this instrument and reconstructed several of them made in gold, jade, encrustations of shell, etc. There have also been found very old Nepōhualtzintzin attributed to the [[Olmec]] culture, and even some bracelets of [[Maya peoples|Maya]] origin, as well as a diversity of forms and materials in other cultures. George I. Sanchez, \"Arithmetic in Maya\", Austin-Texas, 1961 found another base 5, base 4 abacus in the [[Yucatán Peninsula]] that also computed calendar data. This was a finger abacus, on one hand 0, 1, 2, 3, and 4 were used; and on the other hand 0, 1, 2 and 3 were used. Note the use of zero at the beginning and end of the two cycles. Sanchez worked with [[Sylvanus Morley]], a noted Mayanist.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Native American"], "text": "The [[quipu]] of the [[Inca]] was a system of colored knotted cords used to record numerical data, like advanced [[tally stick]] – but not used to perform calculations. Calculations were carried out using a [[yupana]] ([[Quechua languages|Quechua]] for \"counting tool\"; see figure) which was still in use after the conquest of Peru. The working principle of a yupana is unknown, but in 2001 an explanation of the mathematical basis of these instruments was proposed by Italian mathematician Nicolino De Pasquale. By comparing the form of several yupanas, researchers found that calculations were based using the [[Fibonacci sequence]] 1, 1, 2, 3, 5 and powers of 10, 20 and 40 as place values for the different fields in the instrument. Using the Fibonacci sequence would keep the number of grains within any one field at a minimum.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["History", "Russian"], "text": "The Russian abacus, the ''schoty'' (, plural from , counting), usually has a single slanted deck, with ten beads on each wire (except one wire, usually positioned near the user, with four beads for quarter-ruble fractions). Older models have another 4-bead wire for quarter-[[Russian ruble|kopek]], which were minted until 1916. The Russian abacus is often used vertically, with each wire from left to right like lines in a book. The wires are usually bowed to bulge upward in the center, to keep the beads pinned to either of the two sides. It is cleared when all the beads are moved to the right. During manipulation, beads are moved to the left. For easy viewing, the middle 2 beads on each wire (the 5th and 6th bead) usually are of a different color from the other eight beads. Likewise, the left bead of the thousands wire (and the million wire, if present) may have a different color. As a simple, cheap and reliable device, the Russian abacus was in use in all shops and markets throughout the [[Commonwealth of Independent States|former Soviet Union]], and the usage of it was taught in most schools until the 1990s. Even the 1874 invention of [[mechanical calculator]], [[Odhner Arithmometer|Odhner arithmometer]], had not replaced them in [[Russia]]; according to [[Yakov Perelman]], even in his times, some businessmen attempting to import such devices into the Russian Empire were known to give up and leave in despair after being shown the work of a skilled abacus operator. Likewise the mass production of Felix arithmometers since 1924 did not significantly reduce their use in the [[Soviet Union]]. The Russian abacus began to lose popularity only after the mass production of [[Pocket calculator|microcalculators]] had started in the Soviet Union in 1974. Today it is regarded as an archaism and replaced by the handheld calculator. The Russian abacus was brought to France around 1820 by the mathematician [[Jean-Victor Poncelet]], who served in [[Napoleon]]'s army and had been a prisoner of war in Russia. The abacus had fallen out of use in western Europe in the 16th century with the rise of decimal notation and [[algorism]] methods. To Poncelet's French contemporaries, it was something new. Poncelet used it, not for any applied purpose, but as a teaching and demonstration aid. The [[Turkic peoples|Turks]] and the [[Armenians|Armenian]] people also used abacuses similar to the Russian schoty. It was named a ''coulba'' by the Turks and a ''choreb'' by the Armenians.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["School abacus"], "text": "Around the world, abacuses have been used in pre-schools and elementary schools as an aid in teaching the [[numeral system]] and [[arithmetic]]. In Western countries, a bead frame similar to the Russian abacus but with straight wires and a vertical frame has been common (see image). It is still often seen as a plastic or wooden toy. The wire frame may be used either with positional notation like other abacuses (thus the 10-wire version may represent numbers up to 9,999,999,999), or each bead may represent one unit (so that e.g. 74 can be represented by shifting all beads on 7 wires and 4 beads on the 8th wire, so numbers up to 100 may be represented). In the bead frame shown, the gap between the 5th and 6th wire, corresponding to the color change between the 5th and the 6th bead on each wire, suggests the latter use. Teaching multiplication, e.g. 6 times 7 may be represented by shifting 7 beads on 6 wires. The red-and-white abacus is used in contemporary primary schools for a wide range of number-related lessons. The twenty bead version, referred to by its [[Dutch language|Dutch]] name ''rekenrek'' (\"calculating frame\"), is often used, sometimes on a string of beads, sometimes on a rigid framework.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["Speed"], "text": "Eminent physicist [[Richard Feynman]] was noted for expertise in mathematical calculations. He wrote about an encounter in Brazil with a Japanese abacus expert, who challenged him to speed contests between Feynman's pen and paper, and the abacus. The abacus was much faster for addition, somewhat faster for multiplication, but Feynman was faster at division. When the abacus was used for a really difficult challenge, cube roots, Feynman won easily, but by a fluke, as the number chosen at random was close to a number Feynman happened to know was an exact cube, allowing approximate methods to be used.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["Neurological analysis"], "text": "By learning how to calculate with abacus, one can improve one's mental calculation which becomes faster and more accurate in doing large number calculations. [[Mental abacus|Abacus-based mental calculation]] (AMC) was derived from the abacus which means doing calculation, including addition, subtraction, multiplication, and division, in mind with an imagined abacus. It is a high-level cognitive skill that runs through calculations with an effective algorithm. People doing long-term AMC training show higher numerical memory capacity and have more effectively connected neural pathways. They are able to retrieve memory to deal with complex processes to calculate. The processing of AMC involves both the [[Visuospatial function|visuospatial]] and visuomotor processing which generate the visual abacus and perform the movement of the imaginary bead. Since the only thing needed to be remembered is the final position of beads, it takes less memory and less computation time.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["Binary abacus"], "text": "The binary abacus is used to explain how computers manipulate numbers. The abacus shows how numbers, letters, and signs can be stored in a [[binary number|binary system]] on a computer, or via [[ASCII]]. The device consists of a series of beads on parallel wires arranged in three separate rows. The beads represent a switch on the computer in either an \"on\" or \"off\" position.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": ["Uses by blind people"], "text": "An adapted abacus, invented by Tim Cranmer, called a '''Cranmer abacus''' is still commonly used by individuals who are [[blindness|blind]]. A piece of soft fabric or rubber is placed behind the beads so that they do not move inadvertently. This keeps the beads in place while the users feel or manipulate them. The device is then used to perform the mathematical functions of [[multiplication]], [[division (mathematics)|division]], [[addition]], [[subtraction]], [[square root]], and [[cube root]]. Although blind students have benefited from talking calculators, the abacus is still very often taught to these students in early grades, both in public schools and state schools for the blind. Blind students also complete mathematical assignments using a braille-writer and [[Nemeth Braille|Nemeth code]] (a type of braille code for mathematics) but large multiplication and [[long division]] problems can be long and difficult. The abacus gives blind and visually impaired students a tool to compute mathematical problems that equals the speed and mathematical knowledge required by their sighted peers using pencil and paper. Many blind people find this number machine a very useful tool throughout life.", "id": "655", "title": "Abacus", "categories": ["Abacus", "Mathematical tools", "Chinese mathematics", "Egyptian mathematics", "Greek mathematics", "Indian mathematics", "Japanese mathematics", "Roman mathematics"], "seealso": ["Logical abacus", "Mental abacus", "Soroban", "Sand table", "Suanpan", "Chisanbop", "Chinese Zhusuan", "Slide rule", "Napier's bones"]}
{"headers": [], "text": "An '''acid''' is a [[molecule]] or [[ion]] capable of donating a [[proton]] (hydrogen ion H) (a [[Brønsted–Lowry acid–base theory|Brønsted–Lowry acid]]), or, alternatively, capable of forming a [[covalent bond]] with an [[electron pair]] (a [[Lewis acid]]). The first category of acids are the proton donors, or [[Brønsted–Lowry acid–base theory|Brønsted–Lowry acid]]. In the special case of [[aqueous solutions]], proton donors form the [[hydronium ion]] HO and are known as [[Acid–base reaction#Arrhenius theory|Arrhenius acids]]. [[Johannes Nicolaus Brønsted|Brønsted]] and [[Thomas Martin Lowry|Lowry]] generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H. Aqueous Arrhenius acids have characteristic properties which provide a practical description of an acid. Acids form [[aqueous solution]] with a sour taste, can turn blue [[litmus]] red, and react with [[Base (chemistry)|bases]] and certain metals (like [[calcium]]) to form [[Salt (chemistry)|salts]]. The word ''acid'' is derived from the [[Latin]] ''acidus/acēre'', meaning 'sour'. An aqueous solution of an acid has a [[pH]] less than 7 and is colloquially also referred to as \"acid\" (as in \"dissolved in acid\"), while the strict definition refers only to the [[solution|solute]]. A lower pH means a higher '''acidity''', and thus a higher concentration of [[Hydron (chemistry)|positive hydrogen ions]] in the [[solution]]. Chemicals or substances having the property of an acid are said to be '''acidic'''. Common aqueous acids include [[hydrochloric acid]] (a solution of [[hydrogen chloride]] which is found in [[gastric acid]] in the stomach and activates [[digestive enzymes]]), [[acetic acid]] (vinegar is a dilute aqueous solution of this liquid), [[sulfuric acid]] (used in [[car battery|car batteries]]), and [[citric acid]] (found in citrus fruits). As these examples show, acids (in the colloquial sense) can be solutions or pure substances, and can be derived from acids (in the strict sense) that are solids, liquids, or gases. [[Acid strength|Strong acid]] and some concentrated weak acids are [[corrosive substance|corrosive]], but there are exceptions such as [[carborane]] and [[boric acid]]. The second category of acids are [[Lewis acids and bases|Lewis acids]], which form a covalent bond with an electron pair. An example is [[boron trifluoride]] (BF), whose boron atom has a vacant [[atomic orbital|orbital]] which can form a covalent bond by sharing a lone pair of electrons on an atom in a base, for example the nitrogen atom in [[ammonia]] (NH). [[Gilbert N. Lewis|Lewis]] considered this as a generalization of the Brønsted definition, so that an acid is a chemical species that accepts electron pairs either directly ''or'' by releasing protons (H) into the solution, which then accept electron pairs. However, hydrogen chloride, acetic acid, and most other Brønsted–Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. Conversely, many Lewis acids are not Arrhenius or Brønsted–Lowry acids. In modern terminology, an ''acid'' is implicitly a Brønsted acid and not a Lewis acid, since chemists almost always refer to a Lewis acid explicitly as ''a Lewis acid''.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Definitions and concepts"], "text": "Modern definitions are concerned with the fundamental chemical reactions common to all acids. Most acids encountered in everyday life are [[aqueous solutions]], or can be dissolved in water, so the Arrhenius and Brønsted–Lowry definitions are the most relevant. The Brønsted–Lowry definition is the most widely used definition; unless otherwise specified, acid–base reactions are assumed to involve the transfer of a proton (H) from an acid to a base. Hydronium ions are acids according to all three definitions. Although alcohols and amines can be Brønsted–Lowry acids, they can also function as [[Lewis base]] due to the lone pairs of electrons on their oxygen and nitrogen atoms.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Definitions and concepts", "Arrhenius acids"], "text": "In 1884, [[Svante Arrhenius]] attributed the properties of acidity to [[hydrogen ion]] (H), later described as [[Proton#Hydrogen ion|protons]] or [[Hydron (chemistry)|hydron]]. An '''Arrhenius acid''' is a substance that, when added to water, increases the concentration of H ions in the water. Note that chemists often write H(''aq'') and refer to the [[hydrogen ion]] when describing acid–base reactions but the free hydrogen nucleus, a [[proton]], does not exist alone in water, it exists as the '''hydronium ion''' (HO) or other forms (HO, HO). Thus, an Arrhenius acid can also be described as a substance that increases the concentration of hydronium ions when added to water. Examples include molecular substances such as hydrogen chloride and acetic acid. An Arrhenius [[base (chemistry)|base]], on the other hand, is a substance which increases the concentration of [[hydroxide]] (OH) ions when dissolved in water. This decreases the concentration of hydronium because the ions react to form HO molecules: HO + OH ⇌ HO + HO Due to this equilibrium, any increase in the concentration of hydronium is accompanied by a decrease in the concentration of hydroxide. Thus, an Arrhenius acid could also be said to be one that decreases hydroxide concentration, while an Arrhenius base increases it. In an acidic solution, the concentration of hydronium ions is greater than 10 [[Mole (unit)|moles]] per liter. Since pH is defined as the negative logarithm of the concentration of hydronium ions, acidic solutions thus have a pH of less than 7.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Definitions and concepts", "Brønsted–Lowry acids"], "text": "While the Arrhenius concept is useful for describing many reactions, it is also quite limited in its scope. In 1923 chemists [[Johannes Nicolaus Brønsted]] and [[Thomas Martin Lowry]] independently recognized that acid–base reactions involve the transfer of a proton. A '''Brønsted–Lowry acid''' (or simply Brønsted acid) is a species that donates a proton to a Brønsted–Lowry base. Brønsted–Lowry acid–base theory has several advantages over Arrhenius theory. Consider the following reactions of [[acetic acid]] (CHCOOH), the [[organic acid]] that gives vinegar its characteristic taste:  + +  Both theories easily describe the first reaction: CHCOOH acts as an Arrhenius acid because it acts as a source of HO when dissolved in water, and it acts as a Brønsted acid by donating a proton to water. In the second example CHCOOH undergoes the same transformation, in this case donating a proton to ammonia (NH), but does not relate to the Arrhenius definition of an acid because the reaction does not produce hydronium. Nevertheless, CHCOOH is both an Arrhenius and a Brønsted–Lowry acid. Brønsted–Lowry theory can be used to describe reactions of [[molecule|molecular compounds]] in nonaqueous solution or the gas phase. [[Hydrogen chloride]] (HCl) and ammonia combine under several different conditions to form [[ammonium chloride]], NHCl. In aqueous solution HCl behaves as [[hydrochloric acid]] and exists as hydronium and chloride ions. The following reactions illustrate the limitations of Arrhenius's definition: (1) HO + Cl + NH → Cl + NH + HO (2) HCl + NH → NHCl (3) HCl + NH → NHCl  As with the acetic acid reactions, both definitions work for the first example, where water is the solvent and hydronium ion is formed by the HCl solute. The next two reactions do not involve the formation of ions but are still proton-transfer reactions. In the second reaction hydrogen chloride and ammonia (dissolved in [[benzene]]) react to form solid ammonium chloride in a benzene solvent and in the third gaseous HCl and NH combine to form the solid.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Definitions and concepts", "Lewis acids"], "text": "A third, only marginally related concept was proposed in 1923 by [[Gilbert N. Lewis]], which includes reactions with acid–base characteristics that do not involve a proton transfer. A '''Lewis acid''' is a species that accepts a pair of electrons from another species; in other words, it is an electron pair acceptor. Brønsted acid–base reactions are proton transfer reactions while Lewis acid–base reactions are electron pair transfers. Many Lewis acids are not Brønsted–Lowry acids. Contrast how the following reactions are described in terms of acid–base chemistry: In the first reaction a [[fluoride|fluoride ion]], F, gives up an [[lone pair|electron pair]] to [[boron trifluoride]] to form the product [[tetrafluoroborate]]. Fluoride \"loses\" a pair of [[valence electron]] because the electrons shared in the B—F bond are located in the region of space between the two atomic [[atomic nucleus|nuclei]] and are therefore more distant from the fluoride nucleus than they are in the lone fluoride ion. BF is a Lewis acid because it accepts the electron pair from fluoride. This reaction cannot be described in terms of Brønsted theory because there is no proton transfer. The second reaction can be described using either theory. A proton is transferred from an unspecified Brønsted acid to ammonia, a Brønsted base; alternatively, ammonia acts as a Lewis base and transfers a lone pair of electrons to form a bond with a hydrogen ion. The species that gains the electron pair is the Lewis acid; for example, the oxygen atom in HO gains a pair of electrons when one of the H—O bonds is broken and the electrons shared in the bond become localized on oxygen. Depending on the context, a Lewis acid may also be described as an [[Oxidizing agent|oxidizer]] or an [[electrophile]]. Organic Brønsted acids, such as acetic, citric, or oxalic acid, are not Lewis acids. They dissociate in water to produce a Lewis acid, H, but at the same time also yield an equal amount of a Lewis base (acetate, citrate, or oxalate, respectively, for the acids mentioned). This article deals mostly with Brønsted acids rather than Lewis acids.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Dissociation and equilibrium"], "text": "Reactions of acids are often generalized in the form HA H + A, where HA represents the acid and A is the [[conjugate acid|conjugate base]]. This reaction is referred to as '''protolysis'''. The protonated form (HA) of an acid is also sometimes referred to as the '''free acid'''. Acid–base conjugate pairs differ by one proton, and can be interconverted by the addition or removal of a proton ([[protonation]] and [[deprotonation]], respectively). Note that the acid can be the charged species and the conjugate base can be neutral in which case the generalized reaction scheme could be written as HA H + A. In solution there exists an [[chemical equilibrium|equilibrium]] between the acid and its conjugate base. The [[equilibrium constant]] ''K'' is an expression of the equilibrium concentrations of the molecules or the ions in solution. Brackets indicate concentration, such that [HO] means ''the concentration of HO''. The [[acid dissociation constant]] ''K'' is generally used in the context of acid–base reactions. The numerical value of ''K'' is equal to the product of the concentrations of the products divided by the concentration of the reactants, where the reactant is the acid (HA) and the products are the conjugate base and H. formula_1 The stronger of two acids will have a higher ''K'' than the weaker acid; the ratio of hydrogen ions to acid will be higher for the stronger acid as the stronger acid has a greater tendency to lose its proton. Because the range of possible values for ''K'' spans many orders of magnitude, a more manageable constant, p''K'' is more frequently used, where p''K'' = −log ''K''. Stronger acids have a smaller p''K'' than weaker acids. Experimentally determined p''K'' at 25 °C in aqueous solution are often quoted in textbooks and reference material.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Nomenclature"], "text": "Arrhenius acids are named according to their [[anion]]. In the classical naming system, the ionic suffix is dropped and replaced with a new suffix, according to the table following. The prefix \"hydro-\" is used when the acid is made up of just hydrogen and one other element. For example, HCl has [[chloride]] as its anion, so the hydro- prefix is used, and the -ide suffix makes the name take the form [[hydrochloric acid]]. ''Classical naming system:'' In the [[IUPAC]] naming system, \"aqueous\" is simply added to the name of the ionic compound. Thus, for hydrogen chloride, as an acid solution, the IUPAC name is aqueous hydrogen chloride.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Acid strength"], "text": "The strength of an acid refers to its ability or tendency to lose a proton. A strong acid is one that completely dissociates in water; in other words, one [[mole (unit)|mole]] of a strong acid HA dissolves in water yielding one mole of H and one mole of the conjugate base, A, and none of the protonated acid HA. In contrast, a weak acid only partially dissociates and at equilibrium both the acid and the conjugate base are in solution. Examples of [[strong acid]] are [[hydrochloric acid]] (HCl), [[hydroiodic acid]] (HI), [[hydrobromic acid]] (HBr), [[perchloric acid]] (HClO), [[nitric acid]] (HNO) and [[sulfuric acid]] (HSO). In water each of these essentially ionizes 100%. The stronger an acid is, the more easily it loses a proton, H. Two key factors that contribute to the ease of deprotonation are the [[chemical polarity|polarity]] of the H—A bond and the size of atom A, which determines the strength of the H—A bond. Acid strengths are also often discussed in terms of the stability of the conjugate base. Stronger acids have a larger [[acid dissociation constant]], ''K'' and a more negative p''K'' than weaker acids. Sulfonic acids, which are organic oxyacids, are a class of strong acids. A common example is [[toluenesulfonic acid]] (tosylic acid). Unlike sulfuric acid itself, sulfonic acids can be solids. In fact, [[polystyrene]] functionalized into polystyrene sulfonate is a solid strongly acidic plastic that is filterable. [[Superacid]] are acids stronger than 100% sulfuric acid. Examples of superacids are [[fluoroantimonic acid]], [[magic acid]] and [[perchloric acid]]. Superacids can permanently protonate water to give ionic, crystalline [[hydronium]] \"salts\". They can also quantitatively stabilize [[carbocation]]. While ''K'' measures the strength of an acid compound, the strength of an aqueous acid solution is measured by pH, which is an indication of the concentration of hydronium in the solution. The pH of a simple solution of an acid compound in water is determined by the dilution of the compound and the compound's ''K''.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Lewis acid strength in non-aqueous solutions"], "text": "[[Lewis acids]] have been classified in the [[ECW model]] and it has been shown that there is no one order of acid strengths. The relative acceptor strength of Lewis acids toward a series of bases, versus other Lewis acids, can be illustrated by [[ECW model|C-B plots]]. It has been shown that to define the order of Lewis acid strength at least two properties must be considered. For Pearson's qualitative [[HSAB theory]] the two properties are [[HSAB theory|hardness]] and strength while for Drago's quantitative [[ECW model]] the two properties are electrostatic and covalent.", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Chemical characteristics", "Monoprotic acids"], "text": "Monoprotic acids, also known as monobasic acids, are those acids that are able to donate one [[proton]] per molecule during the process of [[dissociation (chemistry)|dissociation]] (sometimes called ionization) as shown below (symbolized by HA): HA + HO HO + A         ''K'' Common examples of monoprotic acids in [[mineral acid]] include [[hydrochloric acid]] (HCl) and [[nitric acid]] (HNO). On the other hand, for [[organic acids]] the term mainly indicates the presence of one [[carboxylic acid]] group and sometimes these acids are known as monocarboxylic acid. Examples in [[organic acids]] include [[formic acid]] (HCOOH), [[acetic acid]] (CHCOOH) and [[benzoic acid]] (CHCOOH).", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": ["Chemical characteristics", "Polyprotic acids"], "text": "Polyprotic acids, also known as polybasic acids, are able to donate more than one proton per acid molecule, in contrast to monoprotic acids that only donate one proton per molecule. Specific types of polyprotic acids have more specific names, such as diprotic (or dibasic) acid (two potential protons to donate), and triprotic (or tribasic) acid (three potential protons to donate). A diprotic acid (here symbolized by HA) can undergo one or two dissociations depending on the pH. Each dissociation has its own dissociation constant, K and K.  The first dissociation constant is typically greater than the second; i.e., ''K'' > ''K''. For example, [[sulfuric acid]] (HSO) can donate one proton to form the [[bisulfate]] anion (HSO), for which ''K'' is very large; then it can donate a second proton to form the [[sulfate]] anion (SO), wherein the ''K'' is intermediate strength. The large ''K'' for the first dissociation makes sulfuric a strong acid. In a similar manner, the weak unstable [[carbonic acid]] can lose one proton to form [[bicarbonate]] anion and lose a second to form [[carbonate]] anion (CO). Both ''K'' values are small, but ''K'' > ''K'' . A triprotic acid (HA) can undergo one, two, or three dissociations and has three dissociation constants, where ''K'' > ''K'' > ''K''.  An [[inorganic]] example of a triprotic acid is orthophosphoric acid (HPO), usually just called [[phosphoric acid]]. All three protons can be successively lost to yield HPO, then HPO, and finally PO, the orthophosphate ion, usually just called [[phosphate]]. Even though the positions of the three protons on the original phosphoric acid molecule are equivalent, the successive ''K'' values differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged. An [[organic compound|organic]] example of a triprotic acid is [[citric acid]], which can successively lose three protons to finally form the [[citrate]] ion. Although the subsequent loss of each hydrogen ion is less favorable, all of the conjugate bases are present in solution. The fractional concentration, ''α'' (alpha), for each species can be calculated. For example, a generic diprotic acid will generate 3 species in solution: HA, HA, and A. The fractional concentrations can be calculated as below when given either the pH (which can be converted to the [H]) or the concentrations of the acid with all its conjugate bases: formula_2 A plot of these fractional concentrations against pH, for given ''K'' and ''K'', is known as a [[Bjerrum plot]]. A pattern is observed in the above equations and can be expanded to the general ''n'' -protic acid that has been deprotonated ''i'' -times: <math chem> \\alpha_{\\ce H_{n-i} A^{i-} }= ", "id": "656", "title": "Acid", "categories": ["Acids", "Acid–base chemistry"], "seealso": []}
{"headers": [], "text": "'''Asphalt''', also known as '''bitumen''' (, ), is a sticky, black, highly [[viscosity|viscous]] liquid or semi-solid form of [[petroleum]]. It may be found in natural deposits or may be a refined product, and is classed as a [[Pitch (resin)|pitch]]. Before the 20th century, the term '''asphaltum''' was also used. The word is derived from the [[Ancient Greek]] ἄσφαλτος ''ásphaltos''. The largest natural deposit of asphalt in the world, estimated to contain 10 million tons, is the [[Pitch Lake]] located in [[La Brea, Trinidad and Tobago|La Brea]] in southwest [[Trinidad]] ([[Antilles]] island located on the northeastern coast of [[Venezuela]]), within the [[Siparia Regional Corporation]]. The primary use (70%) of asphalt is in [[Road surface|road construction]], where it is used as the glue or binder mixed with [[construction aggregate|aggregate]] particles to create [[asphalt concrete]]. Its other main uses are for [[bituminous waterproofing]] products, including production of [[roofing felt]] and for sealing flat roofs. In material sciences and engineering, the terms \"asphalt\" and \"bitumen\" are often used interchangeably to mean both natural and manufactured forms of the substance, although there is regional variation as to which term is most common. Worldwide, geologists tend to favor the term \"bitumen\" for the naturally occurring material. For the manufactured material, which is a refined residue from the [[distillation]] process of selected crude oils, \"bitumen\" is the prevalent term in much of the world; however, in [[American English]], \"asphalt\" is more commonly used. To help avoid confusion, the phrases \"liquid asphalt\", \"asphalt binder\", or \"asphalt cement\" are used in the U.S. Colloquially, various forms of asphalt are sometimes referred to as \"tar\", as in the name of the [[La Brea Tar Pits]], although [[tar]] is a different material. Naturally occurring asphalt is sometimes specified by the term \"crude bitumen\". Its viscosity is similar to that of cold [[molasses]] while the material obtained from the [[fractional distillation]] of [[crude oil]] boiling at is sometimes referred to as \"refined bitumen\". The Canadian province of [[Alberta]] has most of the world's reserves of natural asphalt in the [[Athabasca oil sands]], which cover , an area larger than [[England]]. Asphalt properties change with temperature, which means that there is a specific range where viscosity permits adequate compaction by providing lubrication between particles during the compaction process. Low temperature prevents aggregate particles from moving, and the required density is not possible to achieve. Computer simulations of simplified model systems are able to reproduce some of asphalt's characteristic properties.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Terminology", "Etymology"], "text": "The word \"asphalt\" is derived from the late [[Middle English]], in turn from French ''asphalte'', based on [[Late Latin]] ''asphalton'', ''asphaltum'', which is the [[Latinisation (literature)|latinisation]] of the [[Ancient Greek|Greek]] (''ásphaltos'', ''ásphalton''), a word meaning \"asphalt/bitumen/[[Pitch (resin)|pitch]]\", which perhaps derives from , \"not, without\", i.e. the [[alpha privative]], and (''sphallein''), \"to cause to fall, baffle, (in passive) err, (in passive) be balked of\". The first use of asphalt by the ancients was in the nature of a cement for securing or joining together various objects, and it thus seems likely that the name itself was expressive of this application. Specifically, [[Herodotus]] mentioned that bitumen was brought to Babylon to build its gigantic fortification wall. From the Greek, the word passed into late Latin, and thence into French (''asphalte'') and English (\"asphaltum\" and \"asphalt\"). In French, the term ''asphalte'' is used for naturally occurring asphalt-soaked limestone deposits, and for specialised manufactured products with fewer voids or greater bitumen content than the \"asphaltic concrete\" used to pave roads. The expression \"bitumen\" originated in the [[Sanskrit]] words ''jatu'', meaning \"pitch\", and ''jatu-krit'', meaning \"pitch creating\" or \"pitch producing\" (referring to [[coniferous]] or resinous trees). The Latin equivalent is claimed by some to be originally ''gwitu-men'' (pertaining to pitch), and by others, ''pixtumens'' (exuding or bubbling pitch), which was subsequently shortened to ''bitumen'', thence passing via French into English. From the same root is derived the [[Anglo-Saxons|Anglo-Saxon]] word ''cwidu'' (mastix), the German word ''Kitt'' (cement or mastic) and the old Norse word ''kvada''.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Terminology", "Modern terminology"], "text": "In [[British English]], \"bitumen\" is used instead of \"asphalt\". The word \"asphalt\" is instead used to refer to [[asphalt concrete]], a mixture of [[construction aggregate]] and asphalt itself (also called \"tarmac\" in common parlance). Bitumen mixed with clay was usually called \"asphaltum\", but the term is less commonly used today. In [[Australian English]], the word \"asphalt\" is used to describe a mix of [[construction aggregate]]. \"Bitumen\" refers to the liquid derived from the heavy-residues from crude oil distillation. In [[American English]], \"asphalt\" is equivalent to the British \"bitumen\". However, \"asphalt\" is also commonly used as a shortened form of \"[[asphalt concrete]]\" (therefore equivalent to the British \"asphalt\" or \"tarmac\"). In [[Canadian English]], the word \"bitumen\" is used to refer to the vast Canadian deposits of extremely heavy [[crude oil]], while \"asphalt\" is used for the oil refinery product. Diluted bitumen (diluted with [[naphtha]] to make it flow in pipelines) is known as \"[[dilbit]]\" in the Canadian petroleum industry, while bitumen \"[[Upgrader|upgraded]]\" to [[synthetic crude]] oil is known as \"syncrude\", and syncrude blended with bitumen is called \"synbit\". \"Bitumen\" is still the preferred geological term for naturally occurring deposits of the solid or semi-solid form of petroleum. \"Bituminous rock\" is a form of [[sandstone]] impregnated with bitumen. The [[oil sands]] of [[Alberta, Canada]] are a similar material. Neither of the terms \"asphalt\" or \"bitumen\" should be confused with [[tar]] or [[coal tars]]. Tar is the thick liquid product of the dry distillation and [[pyrolysis]] of organic hydrocarbons primarily sourced from vegetation masses, whether fossilized as with coal, or freshly harvested. The majority of bitumen, on the other hand, was formed naturally when vast quantities of organic animal materials were deposited by water and buried hundreds of metres deep at the [[diagenesis|diagenetic]] point, where the disorganized fatty hydrocarbon molecules joined together in long chains in the absence of oxygen. Bitumen occurs as a solid or highly viscous liquid. It may even be mixed in with coal deposits. Bitumen, and coal using the [[Bergius process]], can be refined into petrols such as gasoline, and bitumen may be distilled into tar, not the other way around.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Composition", "Normal composition"], "text": "The components of asphalt include four main classes of compounds: (-) Naphthene aromatics ([[naphthalene]]), consisting of partially hydrogenated polycyclic aromatic compounds (-) Polar aromatics, consisting of high [[molecular weight]] [[phenols]] and [[carboxylic acid]] produced by partial oxidation of the material (-) [[Saturated hydrocarbons]]; the percentage of saturated compounds in asphalt correlates with its softening point (-) Asphaltenes, consisting of high molecular weight phenols and [[heterocyclic compound]] The naphthene aromatics and polar aromatics are typically the majority components. Most natural bitumens also contain [[organosulfur compound]], resulting in an overall sulfur content of up to 4%. [[Nickel]] and [[vanadium]] are found at <10 parts per million, as is typical of some petroleum. The substance is soluble in [[carbon disulfide]]. It is commonly modelled as a [[colloid]], with [[asphaltene]] as the dispersed phase and [[maltenes]] as the continuous phase. \"It is almost impossible to separate and identify all the different molecules of asphalt, because the number of molecules with different chemical structure is extremely large\". Asphalt may be confused with [[coal tar]], which is a visually similar black, thermoplastic material produced by the [[destructive distillation]] of [[coal]]. During the early and mid-20th century, when [[town gas]] was produced, coal tar was a readily available byproduct and extensively used as the binder for road aggregates. The addition of coal tar to [[macadam]] roads led to the word \"[[Tarmacadam|tarmac]]\", which is now used in common parlance to refer to road-making materials. However, since the 1970s, when natural gas succeeded town gas, asphalt has completely overtaken the use of coal tar in these applications. Other examples of this confusion include the [[La Brea Tar Pits]] and the Canadian [[oil sands]], both of which actually contain natural bitumen rather than tar. \"Pitch\" is another term sometimes informally used at times to refer to asphalt, as in [[Pitch Lake]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Composition", "Additives, mixtures and contaminants"], "text": "For economic and other reasons, asphalt is sometimes sold combined with other materials, often without being labeled as anything other than simply \"asphalt\". Of particular note is the use of [[Automotive oil recycling#REOB|re-refined engine oil bottoms – \"REOB\" or \"REOBs\"]] residue of [[Automotive oil recycling|recycled automotive engine oil]] collected from the bottoms of re-refining [[vacuum distillation]] towers, in the manufacture of asphalt. REOB contains various elements and compounds found in recycled engine oil: additives to the original oil and materials accumulating from its circulation in the engine (typically iron and copper). Some research has indicated a correlation between this adulteration of asphalt and poorer-performing pavement.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Occurrence"], "text": "The majority of asphalt used commercially is obtained from petroleum. Nonetheless, large amounts of asphalt occur in concentrated form in nature. Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic [[algae]] ([[diatom]]) and other once-living things. These remains were deposited in the mud on the bottom of the ocean or lake where the organisms lived. Under the heat (above 50 °C) and [[pressure]] of burial deep in the earth, the remains were transformed into materials such as bitumen, [[kerogen]], or petroleum. Natural deposits of bitumen include lakes such as the [[Pitch Lake]] in Trinidad and Tobago and [[Lake Bermudez]] in [[Venezuela]]. Natural [[petroleum seep|seeps]] occur in the [[La Brea Tar Pits]] and in the [[Dead Sea]]. Bitumen also occurs in unconsolidated sandstones known as \"oil sands\" in [[Alberta]], Canada, and the similar \"tar sands\" in [[Utah]], US. The Canadian province of [[Alberta]] has most of the world's reserves, in three huge deposits covering , an area larger than [[England]] or [[New York state]]. These bituminous sands contain of commercially established oil reserves, giving Canada the third largest [[oil reserves]] in the world. Although historically it was used without refining to pave roads, nearly all of the output is now used as [[raw material]] for [[Oil refinery|oil refineries]] in Canada and the United States. The world's largest deposit of natural bitumen, known as the [[Athabasca oil sands]], is located in the [[McMurray Formation]] of Northern Alberta. This formation is from the early [[Cretaceous]], and is composed of numerous [[lens (geology)|lenses]] of oil-bearing sand with up to 20% oil. Isotopic studies show the oil deposits to be about 110 million years old. Two smaller but still very large formations occur in the [[Peace River oil sands]] and the [[Cold Lake oil sands]], to the west and southeast of the Athabasca oil sands, respectively. Of the Alberta deposits, only parts of the Athabasca oil sands are shallow enough to be suitable for surface mining. The other 80% has to be produced by oil wells using [[enhanced oil recovery]] techniques like [[steam-assisted gravity drainage]]. Much smaller heavy oil or bitumen deposits also occur in the [[Uinta Basin]] in Utah, US. The [[Tar Sand Triangle]] deposit, for example, is roughly 6% bitumen. Bitumen may occur in [[hydrothermal vein]]. An example of this is within the [[Uinta Basin]] of [[Utah]], in the US, where there is a swarm of laterally and vertically extensive veins composed of a solid hydrocarbon termed [[Gilsonite]]. These veins formed by the polymerization and solidification of hydrocarbons that were mobilized from the deeper oil shales of the [[Green River Formation]] during burial and [[diagenesis]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Occurrence"], "text": "Bitumen is similar to the organic matter in carbonaceous [[meteorite]]. However, detailed studies have shown these materials to be distinct. The vast Alberta bitumen resources are considered to have started out as living material from marine plants and animals, mainly [[algae]], that died millions of years ago when an ancient ocean covered Alberta. They were covered by mud, buried deeply over time, and gently cooked into oil by geothermal heat at a temperature of . Due to pressure from the rising of the [[Rocky Mountains]] in southwestern Alberta, 80 to 55 million years ago, the oil was driven northeast hundreds of kilometres and trapped into underground sand deposits left behind by ancient river beds and ocean beaches, thus forming the oil sands.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "Ancient times"], "text": "The use of natural bitumen for [[waterproofing]], and as an [[adhesive]] dates at least to the fifth [[millennium]] BC, with a crop storage basket discovered in [[Mehrgarh]], of the [[Indus Valley Civilization]], lined with it. By the 3rd millennium BC refined rock asphalt was in use in the region, and was used to waterproof the [[Great Bath, Mohenjo-daro|Great Bath]] in Mohenjo-daro. In the ancient Middle East, the [[Sumer]] used natural bitumen deposits for [[mortar (masonry)|mortar]] between [[brick]] and stones, to cement parts of carvings, such as eyes, into place, for ship [[caulking]], and for waterproofing. The Greek historian [[Herodotus]] said hot bitumen was used as mortar in the walls of [[Babylon]]. The long [[Euphrates Tunnel]] beneath the river [[Euphrates]] at [[Babylon]] in the time of Queen [[Semiramis]] (c. 800 BC) was reportedly constructed of burnt bricks covered with bitumen as a waterproofing agent. Bitumen was used by [[ancient Egypt]] to [[Embalming|embalm]] mummies. The [[Persian language|Persian]] word for asphalt is ''moom'', which is related to the English word [[mummy]]. The Egyptians' primary source of bitumen was the [[Dead Sea]], which the [[Ancient Rome|Romans]] knew as ''Palus Asphaltites'' (Asphalt Lake). In approximately 40 AD, [[Dioscorides]] described the Dead Sea material as ''Judaicum bitumen'', and noted other places in the region where it could be found. The Sidon bitumen is thought to refer to material found at [[Hasbeya]] in Lebanon. [[Pliny the Elder|Pliny]] also refers to bitumen being found in [[Selenicë|Epirus]]. Bitumen was a valuable strategic resource. It was the object of the first known battle for a hydrocarbon deposit – between the [[Seleucid]] and the [[Nabateans]] in 312 BC. In the ancient Far East, natural bitumen was slowly boiled to get rid of the higher [[Fraction (chemistry)|fractions]], leaving a [[thermoplastic]] material of higher molecular weight that when layered on objects became quite hard upon cooling. This was used to cover objects that needed waterproofing, such as [[scabbard]] and other items. [[Statuettes]] of household [[deities]] were also cast with this type of material in [[Japan]], and probably also in [[China]]. In [[North America]], archaeological recovery has indicated that bitumen was sometimes used to adhere stone [[projectile point]] to wooden shafts. In Canada, aboriginal people used bitumen seeping out of the banks of the [[Athabasca River|Athabasca]] and other rivers to waterproof birch bark [[canoe]], and also heated it in smudge pots to ward off [[mosquito]] in the summer.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "Continental Europe"], "text": "In 1553, [[Pierre Belon]] described in his work ''[[Observations (Pierre Belon)|Observations]]'' that ''pissasphalto'', a mixture of [[Pitch (resin)|pitch]] and bitumen, was used in the [[Republic of Ragusa]] (now [[Dubrovnik]], [[Croatia]]) for tarring of ships. An 1838 edition of ''Mechanics Magazine'' cites an early use of asphalt in France. A pamphlet dated 1621, by \"a certain Monsieur d'Eyrinys, states that he had discovered the existence (of asphaltum) in large quantities in the vicinity of Neufchatel\", and that he proposed to use it in a variety of ways – \"principally in the construction of air-proof granaries, and in protecting, by means of the arches, the water-courses in the city of Paris from the intrusion of dirt and filth\", which at that time made the water unusable. \"He expatiates also on the excellence of this material for forming level and durable terraces\" in palaces, \"the notion of forming such terraces in the streets not one likely to cross the brain of a Parisian of that generation\". But the substance was generally neglected in France until the [[July Revolution|revolution of 1830]]. In the 1830s there was a surge of interest, and asphalt became widely used \"for pavements, flat roofs, and the lining of cisterns, and in England, some use of it had been made of it for similar purposes\". Its rise in Europe was \"a sudden phenomenon\", after natural deposits were found \"in France at Osbann ([[Bas-Rhin]]), the Parc ([[Ain]]) and the Puy-de-la-Poix ([[Puy-de-Dôme]])\", although it could also be made artificially. One of the earliest uses in France was the laying of about 24,000 square yards of Seyssel asphalt at the [[Place de la Concorde]] in 1835.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "United Kingdom"], "text": "Among the earlier uses of bitumen in the United Kingdom was for etching. William Salmon's ''Polygraphice'' (1673) provides a recipe for varnish used in etching, consisting of three ounces of virgin wax, two ounces of [[mastic (plant resin)|mastic]], and one ounce of asphaltum. By the fifth edition in 1685, he had included more asphaltum recipes from other sources. The first British patent for the use of asphalt was \"Cassell's patent asphalte or bitumen\" in 1834. Then on 25 November 1837, [[Captain R. T. Claridge|Richard Tappin Claridge]] patented the use of Seyssel asphalt (patent #7849), for use in asphalte pavement, having seen it employed in France and Belgium when visiting with [[Frederick Walter Simms]], who worked with him on the introduction of asphalt to Britain. Dr T. Lamb Phipson writes that his father, Samuel Ryland Phipson, a friend of Claridge, was also \"instrumental in introducing the asphalte pavement (in 1836)\". Claridge obtained a patent in Scotland on 27 March 1838, and obtained a patent in Ireland on 23 April 1838. In 1851, extensions for the 1837 patent and for both 1838 patents were sought by the trustees of a company previously formed by Claridge. ''Claridge's Patent Asphalte Company''formed in 1838 for the purpose of introducing to Britain \"Asphalte in its natural state from the mine at Pyrimont Seysell in France\",\"laid one of the first asphalt pavements in Whitehall\". Trials were made of the pavement in 1838 on the footway in Whitehall, the stable at Knightsbridge Barracks, \"and subsequently on the space at the bottom of the steps leading from Waterloo Place to St. James Park\". \"The formation in 1838 of Claridge's Patent Asphalte Company (with a distinguished list of aristocratic patrons, and [[Marc Isambard Brunel|Marc]] and [[Isambard Kingdom Brunel|Isambard Brunel]] as, respectively, a trustee and consulting engineer), gave an enormous impetus to the development of a British asphalt industry\". \"By the end of 1838, at least two other companies, Robinson's and the Bastenne company, were in production\", with asphalt being laid as paving at Brighton, Herne Bay, Canterbury, Kensington, the Strand, and a large floor area in Bunhill-row, while meantime Claridge's Whitehall paving \"continue(d) in good order\". The [[Bonnington Chemical Works]] manufactured asphalt using [[coal tar]] and by 1839 had installed it in [[Bonnington, Edinburgh|Bonnington]]. In 1838, there was a flurry of entrepreneurial activity involving asphalt, which had uses beyond paving. For example, asphalt could also be used for flooring, damp proofing in buildings, and for waterproofing of various types of pools and baths, both of which were also proliferating in the 19th century. On the London stockmarket, there were various claims as to the exclusivity of asphalt quality from France, Germany and England. And numerous patents were granted in France, with similar numbers of patent applications being denied in England due to their similarity to each other. In England, \"Claridge's was the type most used in the 1840s and 50s\".", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "United Kingdom"], "text": "In 1914, Claridge's Company entered into a joint venture to produce [[Macadam#Tar-bound macadam|tar-bound macadam]], with materials manufactured through a subsidiary company called Clarmac Roads Ltd. Two products resulted, namely ''Clarmac'', and ''Clarphalte'', with the former being manufactured by Clarmac Roads and the latter by Claridge's Patent Asphalte Co., although ''Clarmac'' was more widely used. However, the [[First World War]] ruined the Clarmac Company, which entered into liquidation in 1915. The failure of Clarmac Roads Ltd had a flow-on effect to Claridge's Company, which was itself compulsorily wound up, ceasing operations in 1917, having invested a substantial amount of funds into the new venture, both at the outset and in a subsequent attempt to save the Clarmac Company. Bitumen was thought in 19th century Britain to contain chemicals with medicinal properties. Extracts from bitumen were used to treat [[catarrh]] and some forms of [[asthma]] and as a remedy against worms, especially the [[tapeworm]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "United States"], "text": "The first use of bitumen in the New World was by indigenous peoples. On the west coast, as early as the 13th century, the [[Tongva people|Tongva]], [[Luiseño people|Luiseño]] and [[Chumash people|Chumash]] peoples collected the naturally occurring bitumen that seeped to the surface above underlying petroleum deposits. All three groups used the substance as an adhesive. It is found on many different artifacts of tools and ceremonial items. For example, it was used on [[rattle (percussion instrument)|rattle]] to adhere gourds or turtle shells to rattle handles. It was also used in decorations. Small round shell beads were often set in asphaltum to provide decorations. It was used as a sealant on baskets to make them watertight for carrying water, possibly poisoning those who drank the water. Asphalt was used also to seal the planks on ocean-going canoes. Asphalt was first used to pave streets in the 1870s. At first naturally occurring \"bituminous rock\" was used, such as at Ritchie Mines in Macfarlan in [[Ritchie County, West Virginia]] from 1852 to 1873. In 1876, asphalt-based paving was used to pave Pennsylvania Avenue in Washington DC, in time for the celebration of the national centennial. In the horse-drawn era, US streets were mostly unpaved and covered with dirt or gravel. Especially where mud or trenching often made streets difficult to pass, pavements were sometimes made of diverse materials including wooden planks, cobble stones or other stone blocks, or bricks. Unpaved roads produced uneven wear and hazards for pedestrians. In the late 19th century with the rise of the popular [[bicycle]], bicycle clubs were important in pushing for more general pavement of streets. Advocacy for pavement increased in the early 20th century with the rise of the [[automobile]]. Asphalt gradually became an ever more common method of paving. [[St. Charles Avenue]] in [[New Orleans]] was paved its whole length with asphalt by 1889.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "United States"], "text": "In 1900 Manhattan alone had 130,000 horses, pulling streetcars, wagons, and carriages, and leaving their waste behind. They were not fast, and pedestrians could dodge and scramble their way across the crowded streets. Small towns continued to rely on dirt and gravel, but larger cities wanted much better streets. They looked to wood or granite blocks by the 1850s. In 1890, a third of Chicago's 2000 miles of streets were paved, chiefly with wooden blocks, which gave better traction than mud. Brick surfacing was a good compromise, but even better was asphalt paving, which was easy to install and to cut through to get at sewers. With London and Paris serving as models, Washington laid 400,000 square yards of asphalt paving by 1882; it became the model for Buffalo, Philadelphia and elsewhere. By the end of the century, American cities boasted 30 million square yards of asphalt paving, well ahead of brick. The streets became faster and more dangerous so electric traffic lights were installed. Electric trolleys (at 12 miles per hour) became the main transportation service for middle class shoppers and office workers until they bought automobiles after 1945 and commuted from more distant suburbs in privacy and comfort on asphalt highways.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "Canada"], "text": "Canada has the world's largest deposit of natural bitumen in the [[Athabasca oil sands]], and Canadian [[First Nations]] along the [[Athabasca River]] had long used it to waterproof their canoes. In 1719, a [[Cree]] named Wa-Pa-Su brought a sample for trade to [[Henry Kelsey]] of the [[Hudson's Bay Company]], who was the first recorded European to see it. However, it wasn't until 1787 that fur trader and explorer [[Alexander Mackenzie (explorer)|Alexander MacKenzie]] saw the Athabasca oil sands and said, \"At about 24 miles from the fork (of the Athabasca and Clearwater Rivers) are some bituminous fountains into which a pole of 20 feet long may be inserted without the least resistance.\" The value of the deposit was obvious from the start, but the means of extracting the bitumen was not. The nearest town, [[Fort McMurray, Alberta]], was a small fur trading post, other markets were far away, and transportation costs were too high to ship the raw bituminous sand for paving. In 1915, Sidney Ells of the Federal Mines Branch experimented with separation techniques and used the product to pave 600 feet of road in [[Edmonton]], Alberta. Other roads in Alberta were paved with material extracted from oil sands, but it was generally not economic. During the 1920s [[Karl Clark (chemist)|Dr. Karl A. Clark]] of the [[Alberta Research Council]] patented a hot water oil separation process and entrepreneur Robert C. Fitzsimmons built the [[Bitumount]] oil separation plant, which between 1925 and 1958 produced up to per day of bitumen using Dr. Clark's method. Most of the bitumen was used for waterproofing roofs, but other uses included fuels, lubrication oils, printers ink, medicines, rust- and acid-proof paints, fireproof roofing, street paving, patent leather, and fence post preservatives. Eventually Fitzsimmons ran out of money and the plant was taken over by the Alberta government. Today the Bitumount plant is a [[Provincial historic sites of Alberta|Provincial Historic Site]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["History", "Photography and art"], "text": "Bitumen was used in early photographic technology. In 1826 or 1827, it was used by French scientist [[Joseph Nicéphore Niépce]] to make the [[View from the Window at Le Gras|oldest surviving photograph from nature]]. The bitumen was thinly coated onto a [[pewter]] plate which was then exposed in a camera. Exposure to light hardened the bitumen and made it insoluble, so that when it was subsequently rinsed with a solvent only the sufficiently light-struck areas remained. Many hours of exposure in the camera were required, making bitumen impractical for ordinary photography, but from the 1850s to the 1920s it was in common use as a [[photoresist]] in the production of printing plates for various photomechanical printing processes. Bitumen was the nemesis of many artists during the 19th century. Although widely used for a time, it ultimately proved unstable for use in oil painting, especially when mixed with the most common diluents, such as linseed oil, varnish and turpentine. Unless thoroughly diluted, bitumen never fully solidifies and will in time corrupt the other pigments with which it comes into contact. The use of bitumen as a glaze to set in shadow or mixed with other colors to render a darker tone resulted in the eventual deterioration of many paintings, for instance those of [[Eugène Delacroix|Delacroix]]. Perhaps the most famous example of the destructiveness of bitumen is [[Théodore Géricault]]'s [[Raft of the Medusa]] (1818–1819), where his use of bitumen caused the brilliant colors to degenerate into dark greens and blacks and the paint and canvas to buckle.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Global use"], "text": "The vast majority of refined asphalt is used in construction: primarily as a constituent of products used in paving and roofing applications. According to the requirements of the end use, asphalt is produced to specification. This is achieved either by refining or blending. It is estimated that the current world use of asphalt is approximately 102 million tonnes per year. Approximately 85% of all the asphalt produced is used as the [[Binder (material)|binder]] in asphalt concrete for roads. It is also used in other paved areas such as airport runways, car parks and footways. Typically, the production of asphalt concrete involves mixing fine and coarse [[Construction aggregate|aggregates]] such as [[sand]], [[gravel]] and crushed rock with asphalt, which acts as the binding agent. Other materials, such as recycled polymers (e.g., [[Natural rubber|rubber]] [[tire|tyres]]), may be added to the asphalt to modify its properties according to the application for which the asphalt is ultimately intended. A further 10% of global asphalt production is used in roofing applications, where its waterproofing qualities are invaluable. The remaining 5% of asphalt is used mainly for sealing and insulating purposes in a variety of building materials, such as pipe coatings, carpet tile backing and paint. Asphalt is applied in the construction and maintenance of many structures, systems, and components, such as the following: (-) Highways (-) Airport runways (-) Footways and pedestrian ways (-) Car parks (-) Racetracks (-) Tennis courts (-) Roofing (-) Damp proofing (-) Dams (-) Reservoir and pool linings (-) Soundproofing (-) Pipe coatings (-) Cable coatings (-) Paints (-) Building water proofing (-) Tile underlying waterproofing (-) Newspaper ink production (-) and many other applications", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Rolled asphalt concrete"], "text": "The largest use of asphalt is for making [[asphalt concrete]] for road surfaces; this accounts for approximately 85% of the asphalt consumed in the United States. There are about 4,000 asphalt concrete mixing plants in the US, and a similar number in Europe. Asphalt concrete pavement mixes are typically composed of 5% asphalt cement and 95% aggregates (stone, sand, and gravel). Due to its highly viscous nature, asphalt cement must be heated so it can be mixed with the aggregates at the asphalt mixing facility. The temperature required varies depending upon characteristics of the asphalt and the aggregates, but [[Warm-mix asphalt|warm-mix asphalt technologies]] allow producers to reduce the temperature required. The weight of an asphalt pavement depends upon the [[construction aggregate|aggregate]] type, the asphalt, and the air void content. An average example in the United States is about 112 pounds per square yard, per inch of pavement thickness. When maintenance is performed on asphalt pavements, such as [[Pavement milling|milling]] to remove a worn or damaged surface, the removed material can be returned to a facility for processing into new pavement mixtures. The asphalt in the removed material can be reactivated and put back to use in new pavement mixes. With some 95% of paved roads being constructed of or surfaced with asphalt, a substantial amount of asphalt pavement material is reclaimed each year. According to industry surveys conducted annually by the [[Federal Highway Administration]] and the National Asphalt Pavement Association, more than 99% of the asphalt removed each year from road surfaces during widening and resurfacing projects is reused as part of new pavements, roadbeds, shoulders and embankments or stockpiled for future use. Asphalt concrete paving is widely used in airports around the world. Due to the sturdiness and ability to be repaired quickly, it is widely used for [[runway]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Mastic asphalt"], "text": "[[Mastic asphalt]] is a type of asphalt that differs from dense graded asphalt ([[asphalt concrete]]) in that it has a higher asphalt ([[binder (material)|binder]]) content, usually around 7–10% of the whole aggregate mix, as opposed to rolled asphalt concrete, which has only around 5% asphalt. This thermoplastic substance is widely used in the building industry for waterproofing flat roofs and tanking underground. Mastic asphalt is heated to a temperature of and is spread in layers to form an impervious barrier about thick.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Asphalt emulsion"], "text": "A number of technologies allow asphalt to be applied at mild temperatures. The viscosity can be lowered by [[emulsion|emulsfying]] the asphalt by the addition of [[fatty amine]]. 2–25% is the content of these emulsifying agents. The cationic amines enhance the binding of the asphalt to the surface of the crushed rock. Asphalt emulsions are used in a wide variety of applications. [[Chipseal]] involves spraying the road surface with asphalt emulsion followed by a layer of crushed rock, gravel or crushed slag. Slurry seal is a mixture of asphalt emulsion and fine crushed aggregate that is spread on the surface of a road. Cold-mixed asphalt can also be made from asphalt emulsion to create pavements similar to hot-mixed asphalt, several inches in depth, and asphalt emulsions are also blended into recycled hot-mix asphalt to create low-cost pavements.Bitumen emulsion based techniques are known to be useful for all classes of roads, their use may also be possible in the following applications: 1. Asphalts for heavily trafficked roads(based on the use of polymer modified emulsions) 2.warm emulsion based mixtures, to improve both their maturation time and mechanical properties 3.half-warm technology, in which aggregates are heated up to 100 degree, producing mixtures with similar properties to those of hot asphalts 4.high performance surface dressing", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Synthetic crude oil"], "text": "Synthetic crude oil, also known as syncrude, is the output from a bitumen upgrader facility used in connection with oil sand production in Canada. Bituminous sands are mined using enormous (100-ton capacity) [[power shovel]] and loaded into even larger (400-ton capacity) [[dump trucks]] for movement to an upgrading facility. The process used to extract the bitumen from the sand is a hot water process originally developed by [[Karl Clark (chemist)|Dr. Karl Clark]] of the [[University of Alberta]] during the 1920s. After extraction from the sand, the bitumen is fed into a [[Upgrader|bitumen upgrader]] which converts it into a [[light crude oil]] equivalent. This synthetic substance is fluid enough to be transferred through conventional [[oil pipeline]] and can be fed into conventional oil refineries without any further treatment. By 2015 Canadian bitumen upgraders were producing over per day of synthetic crude oil, of which 75% was exported to oil refineries in the United States. In Alberta, five bitumen upgraders produce synthetic crude oil and a variety of other products: The [[Suncor Energy]] upgrader near [[Fort McMurray, Alberta]] produces synthetic crude oil plus diesel fuel; the [[Syncrude Canada]], [[Canadian Natural Resources]], and [[Nexen]] upgraders near Fort McMurray produce synthetic crude oil; and the Shell [[Scotford Upgrader]] near Edmonton produces synthetic crude oil plus an intermediate feedstock for the nearby Shell Oil Refinery. A sixth upgrader, under construction in 2015 near [[Redwater, Alberta]], will upgrade half of its crude bitumen directly to diesel fuel, with the remainder of the output being sold as feedstock to nearby oil refineries and petrochemical plants.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Non-upgraded crude bitumen"], "text": "Canadian bitumen does not differ substantially from oils such as Venezuelan extra-heavy and Mexican [[heavy crude oil|heavy oil]] in chemical composition, and the real difficulty is moving the extremely viscous bitumen through [[oil pipeline]] to the refinery. Many modern oil refineries are extremely sophisticated and can process non-upgraded bitumen directly into products such as gasoline, diesel fuel, and refined asphalt without any preprocessing. This is particularly common in areas such as the US [[Gulf coast]], where refineries were designed to process Venezuelan and Mexican oil, and in areas such as the US [[Midwest]] where refineries were rebuilt to process heavy oil as domestic light oil production declined. Given the choice, such heavy oil refineries usually prefer to buy bitumen rather than synthetic oil because the cost is lower, and in some cases because they prefer to produce more diesel fuel and less gasoline. By 2015 Canadian production and exports of non-upgraded bitumen exceeded that of synthetic crude oil at over per day, of which about 65% was exported to the United States. Because of the difficulty of moving crude bitumen through pipelines, non-upgraded bitumen is usually diluted with [[natural-gas condensate]] in a form called [[dilbit]] or with synthetic crude oil, called [[synbit]]. However, to meet international competition, much non-upgraded bitumen is now sold as a blend of multiple grades of bitumen, conventional crude oil, synthetic crude oil, and condensate in a standardized benchmark product such as [[Western Canadian Select]]. This sour, heavy crude oil blend is designed to have uniform refining characteristics to compete with internationally marketed heavy oils such as [[Petroleum industry in Mexico|Mexican Mayan]] or Arabian [[Dubai Crude]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Radioactive waste encapsulation matrix"], "text": "Asphalt was used starting in the 1960s as a [[hydrophobic]] matrix aiming to encapsulate radioactive waste such as medium-activity salts (mainly soluble [[sodium nitrate]] and [[sodium sulfate]]) produced by the reprocessing of [[spent nuclear fuel]] or radioactive [[sludge]] from sedimentation ponds. Bituminised radioactive waste containing highly [[radiotoxic]] [[ionizing radiation#Alpha particles|alpha-emitting]] [[Transuranium element|transuranic element]] from nuclear reprocessing plants have been produced at industrial scale in France, Belgium and Japan, but this type of waste conditioning has been abandoned because operational safety issues (risks of fire, as occurred in a bituminisation plant at Tokai Works in Japan) and long-term stability problems related to their [[Deep geological repository|geological disposal]] in deep rock formations. One of the main problems is the swelling of asphalt exposed to radiation and to water. Asphalt swelling is first induced by radiation because of the presence of [[hydrogen]] gas bubbles generated by alpha and gamma [[radiolysis]]. A second mechanism is the matrix swelling when the encapsulated [[hygroscopic]] salts exposed to water or moisture start to rehydrate and to dissolve. The high concentration of salt in the pore solution inside the bituminised matrix is then responsible for [[osmosis|osmotic]] effects inside the bituminised matrix. The water moves in the direction of the concentrated salts, the asphalt acting as a [[Semipermeable membrane|semi-permeable membrane]]. This also causes the matrix to swell. The swelling pressure due to osmotic effect under constant volume can be as high as 200 bar. If not properly managed, this high pressure can cause fractures in the near field of a disposal gallery of bituminised medium-level waste. When the bituminised matrix has been altered by swelling, encapsulated radionuclides are easily leached by the contact of ground water and released in the geosphere. The high [[ionic strength]] of the concentrated saline solution also favours the migration of radionuclides in clay host rocks. The presence of chemically reactive nitrate can also affect the [[redox]] conditions prevailing in the host rock by establishing oxidizing conditions, preventing the reduction of redox-sensitive radionuclides. Under their higher valences, radionuclides of elements such as [[selenium]], [[technetium]], [[uranium]], [[neptunium]] and [[plutonium]] have a higher solubility and are also often present in water as non-retarded [[anion]]. This makes the disposal of medium-level bituminised waste very challenging. Different types of asphalt have been used: blown bitumen (partly oxidized with air oxygen at high temperature after distillation, and harder) and direct distillation bitumen (softer). Blown bitumens like Mexphalte, with a high content of saturated hydrocarbons, are more easily biodegraded by microorganisms than direct distillation bitumen, with a low content of saturated hydrocarbons and a high content of aromatic hydrocarbons. Concrete encapsulation of radwaste is presently considered a safer alternative by the [[nuclear industry]] and the waste management organisations.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Modern use", "Other uses"], "text": "[[Asphalt shingle|Roofing shingle]] and [[Asphalt roll roofing|roll roofing]] account for most of the remaining asphalt consumption. Other uses include cattle sprays, fence-post treatments, and waterproofing for fabrics. Asphalt is used to make [[Japan black]], a [[lacquer]] known especially for its use on iron and steel, and it is also used in paint and marker inks by some exterior paint supply companies to increase the weather resistance and permanence of the paint or ink, and to make the color darker. Asphalt is also used to seal some alkaline batteries during the manufacturing process.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Production"], "text": "About 40,000,000 tons were produced in 1984. It is obtained as the \"heavy\" (i.e., difficult to distill) fraction. Material with a [[boiling point]] greater than around 500 °C is considered asphalt. Vacuum distillation separates it from the other components in crude oil (such as [[naphtha]], gasoline and [[Diesel fuel|diesel]]). The resulting material is typically further treated to extract small but valuable amounts of lubricants and to adjust the properties of the material to suit applications. In a [[de-asphalting unit]], the crude asphalt is treated with either [[propane]] or [[butane]] in a [[Supercritical fluid|supercritical]] phase to extract the lighter molecules, which are then separated. Further processing is possible by \"blowing\" the product: namely reacting it with [[oxygen]]. This step makes the product harder and more viscous. Asphalt is typically stored and transported at temperatures around . Sometimes [[diesel oil]] or [[kerosene]] are mixed in before shipping to retain liquidity; upon delivery, these lighter materials are separated out of the mixture. This mixture is often called \"bitumen feedstock\", or BFS. Some [[dump truck]] route the hot engine exhaust through pipes in the dump body to keep the material warm. The backs of tippers carrying asphalt, as well as some handling equipment, are also commonly sprayed with a releasing agent before filling to aid release. Diesel oil is no longer used as a [[release agent]] due to environmental concerns.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Production", "Oil sands"], "text": "Naturally occurring crude bitumen impregnated in sedimentary rock is the prime feed stock for petroleum production from \"[[oil sands]]\", currently under development in Alberta, Canada. Canada has most of the world's supply of natural bitumen, covering 140,000 square kilometres (an area larger than England), giving it the second-largest proven [[oil reserves]] in the world. The [[Athabasca oil sands]] are the largest bitumen deposit in Canada and the only one accessible to [[surface mining]], although recent technological breakthroughs have resulted in deeper deposits becoming producible by ''[[in-situ#Petroleum|in situ]]'' methods. Because of [[world oil market chronology from 2003|oil price increases after 2003]], producing bitumen became highly profitable, but as a result of the decline after 2014 it became uneconomic to build new plants again. By 2014, Canadian crude bitumen production averaged about per day and was projected to rise to per day by 2020. The total amount of crude bitumen in Alberta that could be extracted is estimated to be about , which at a rate of would last about 200 years.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Production", "Alternatives and bioasphalt"], "text": "Although uncompetitive economically, asphalt can be made from nonpetroleum-based renewable resources such as sugar, [[molasses]] and rice, corn and potato [[starch]]. Asphalt can also be made from waste material by [[fractional distillation]] of used [[motor oil]], which is sometimes otherwise disposed of by burning or dumping into landfills. Use of motor oil may cause premature cracking in colder climates, resulting in roads that need to be repaved more frequently. Nonpetroleum-based asphalt binders can be made light-colored. Lighter-colored roads absorb less heat from solar radiation, reducing their contribution to the [[urban heat island]] effect. Parking lots that use asphalt alternatives are called [[green parking lot]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Production", "Albanian deposits"], "text": "Selenizza is a naturally occurring solid hydrocarbon bitumen found in native deposits in [[Selenice]], in [[Albania]], the only European asphalt mine still in use. The bitumen is found in the form of veins, filling cracks in a more or less horizontal direction. The bitumen content varies from 83% to 92% (soluble in carbon disulphide), with a penetration value near to zero and a softening point (ring and ball) around 120 °C. The insoluble matter, consisting mainly of silica ore, ranges from 8% to 17%. Albanian bitumen extraction has a long history and was practiced in an organized way by the Romans. After centuries of silence, the first mentions of Albanian bitumen appeared only in 1868, when the Frenchman [[Henri Coquand|Coquand]] published the first geological description of the deposits of Albanian bitumen. In 1875, the exploitation rights were granted to the Ottoman government and in 1912, they were transferred to the Italian company Simsa. Since 1945, the mine was exploited by the Albanian government and from 2001 to date, the management passed to a French company, which organized the mining process for the manufacture of the natural bitumen on an industrial scale. Today the mine is predominantly exploited in an open pit quarry but several of the many underground mines (deep and extending over several km) still remain viable. Selenizza is produced primarily in granular form, after melting the bitumen pieces selected in the mine. Selenizza is mainly used as an additive in the road construction sector. It is mixed with traditional asphalt to improve both the viscoelastic properties and the resistance to ageing. It may be blended with the hot asphalt in tanks, but its granular form allows it to be fed in the mixer or in the recycling ring of normal asphalt plants. Other typical applications include the production of mastic asphalts for sidewalks, bridges, car-parks and urban roads as well as drilling fluid additives for the oil and gas industry. Selenizza is available in powder or in granular material of various particle sizes and is packaged in sacks or in thermal fusible polyethylene bags. A [[life-cycle assessment]] study of the natural selenizza compared with petroleum asphalt has shown that the environmental impact of the selenizza is about half the impact of the road asphalt produced in oil refineries in terms of [[Greenhouse gas emissions|carbon dioxide emission]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Recycling"], "text": "Asphalt is a commonly recycled material in the construction industry. The two most common recycled materials that contain asphalt are reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS). RAP is recycled at a greater rate than any other material in the United States, and typically contains approximately 5 – 6% asphalt binder. Asphalt shingles typically contain 20 – 40% asphalt binder. Asphalt naturally becomes stiffer over time due to oxidation, evaporation, exudation, and physical hardening. For this reason, recycled asphalt is typically combined with virgin asphalt, softening agents, and/or rejuvenating additives to restore its physical and chemical properties. For information on the processing and performance of RAP and RAS, see [[Asphalt concrete#Recycling|Asphalt Concrete]]. For information on the different types of RAS and associated health and safety concerns, see [[Asphalt shingle#Disposal%20and%20recycling|Asphalt Shingles]]. For information on in-place recycling methods used to restore pavements and roadways, see [[Road surface#Recycling|Road Surface]].", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Economics"], "text": "Although asphalt typically makes up only 4 to 5 percent (by weight) of the pavement mixture, as the pavement's binder, it is also the most expensive part of the cost of the road-paving material. During asphalt's early use in modern paving, oil refiners gave it away. However, asphalt is, today, a highly traded commodity. Its prices increased substantially in the early 21st Century. A U.S. government report states: \"In 2002, asphalt sold for approximately $160 per ton. By the end of 2006, the cost had doubled to approximately $320 per ton, and then it almost doubled again in 2012 to approximately $610 per ton.\" The report indicates that an \"average\" 1-mile (1.6-kilometer)-long, four-lane highway would include \"300 tons of asphalt,\" which, \"in 2002 would have cost around $48,000. By 2006 this would have increased to $96,000 and by 2012 to $183,000... an increase of about $135,000 for every mile of highway in just 10 years.\"", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": ["Health and safety"], "text": "People can be exposed to asphalt in the workplace by breathing in fumes or skin absorption. The [[National Institute for Occupational Safety and Health]] (NIOSH) has set a [[recommended exposure limit]] of 5 mg/m over a 15-minute period. Asphalt is basically an inert material that must be heated or diluted to a point where it becomes workable for the production of materials for paving, roofing, and other applications. In examining the potential health hazards associated with asphalt, the [[International Agency for Research on Cancer]] (IARC) determined that it is the application parameters, predominantly temperature, that affect occupational exposure and the potential bioavailable [[carcinogenic]] hazard/risk of the asphalt emissions. In particular, temperatures greater than 199 °C (390 °F), were shown to produce a greater exposure risk than when asphalt was heated to lower temperatures, such as those typically used in asphalt pavement mix production and placement. IARC has classified paving asphalt fumes as a [[List of IARC Group 2B carcinogens|Class 2B]] possible carcinogen, indicating inadequate evidence of carcinogenicity in humans. In 2020 scientists reported that asphalt currently is a significant and largely overlooked source of [[air pollution]] in urban areas, especially during hot and sunny periods. An asphalt-like substance found in the Himalayas and known as ''[[shilajit]]'' is sometimes used as an [[Ayurveda]] medicine, but is not in fact a tar, resin or asphalt.", "id": "657", "title": "Asphalt", "categories": ["Asphalt", "Amorphous solids", "Building materials", "Chemical mixtures", "IARC Group 2B carcinogens", "Pavements", "Petroleum products", "Road construction materials"], "seealso": ["Asphalt plant", "Bitumen-based fuel", "Blacktop", "Pitch drop experiment", "Road surface", "Tar", "Sealcoat", "Bioasphalt", "Stamped asphalt", "Cooper Research Technology", "Tarmac", "Bituminous rocks", "Asphaltene", "Pitch (resin)", "Oil sands", "Duxit", "Cariphalte", "Macadam"]}
{"headers": [], "text": "The '''American National Standards Institute''' ('''ANSI''' ) is a private [[non-profit organization]] that oversees the development of [[Standardization|voluntary consensus standards]] for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. ANSI accredits standards that are developed by representatives of other [[standards organization]], [[government agency|government agencies]], [[consumer organization|consumer groups]], companies, and others. These standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same way. ANSI also accredits organizations that carry out product or personnel certification in accordance with requirements defined in international standards. The organization's headquarters are in [[Washington, D.C.]] ANSI's operations office is located in [[New York City]]. The ANSI annual operating budget is funded by the sale of publications, membership dues and fees, accreditation services, fee-based programs, and international standards programs.", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["History"], "text": "ANSI was originally formed in 1918, when five engineering societies and three government agencies founded the '''American Engineering Standards Committee''' ('''AESC'''). In 1928, the AESC became the '''American Standards Association''' ('''ASA'''). In 1966, the ASA was reorganized and became '''United States of America Standards Institute''' ('''USASI'''). The present name was adopted in 1969. Prior to 1918, these five founding engineering societies: (-) [[American Institute of Electrical Engineers]] (AIEE, now [[IEEE]]) (-) [[American Society of Mechanical Engineers]] (ASME) (-) [[American Society of Civil Engineers]] (ASCE) (-) American Institute of Mining Engineers (AIME, now [[American Institute of Mining, Metallurgical, and Petroleum Engineers]]) (-) American Society for Testing and Materials (now [[ASTM International]]) had been members of the United Engineering Society (UES). At the behest of the AIEE, they invited the U.S. government Departments of War, Navy (combined in 1947 to become the [[United States Department of Defense|Department of Defense]] or DOD) and Commerce to join in founding a national standards organization. According to Adam Stanton, the first permanent secretary and head of staff in 1919, AESC started as an ambitious program and little else. Staff for the first year consisted of one executive, Clifford B. LePage, who was on loan from a founding member, ASME. An annual budget of $7,500 was provided by the founding bodies. In 1931, the organization (renamed ASA in 1928) became affiliated with the U.S. National Committee of the [[International Electrotechnical Commission]] ([[International Electrotechnical Commission|IEC]]), which had been formed in 1904 to develop electrical and electronics standards.", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["Members"], "text": "ANSI's members are government agencies, organizations, academic and international bodies, and individuals. In total, the Institute represents the interests of more than 270,000 companies and organizations and 30 million professionals worldwide.", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["Process"], "text": "Although ANSI itself does not develop standards, the Institute oversees the development and use of standards by accrediting the procedures of standards developing organizations. ANSI accreditation signifies that the procedures used by standards developing organizations meet the institute's requirements for openness, balance, consensus, and due process. ANSI also designates specific standards as American National Standards, or ANS, when the Institute determines that the standards were developed in an environment that is equitable, accessible and responsive to the requirements of various stakeholders. Voluntary consensus standards quicken the market acceptance of products while making clear how to improve the safety of those products for the protection of consumers. There are approximately 9,500 American National Standards that carry the ANSI designation. The American National Standards process involves: (-) consensus by a group that is open to representatives from all interested parties (-) broad-based public review and comment on draft standards (-) consideration of and response to comments (-) incorporation of submitted changes that meet the same consensus requirements into a draft standard (-) availability of an appeal by any participant alleging that these principles were not respected during the standards-development process.", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["International activities"], "text": "In addition to facilitating the formation of standards in the United States, ANSI promotes the use of U.S. standards internationally, advocates U.S. policy and technical positions in international and regional standards organizations, and encourages the adoption of international standards as national standards where appropriate. The institute is the official U.S. representative to the two major international standards organizations, the [[International Organization for Standardization]] (ISO), as a founding member, and the [[International Electrotechnical Commission]] (IEC), via the U.S. National Committee (USNC). ANSI participates in almost the entire technical program of both the ISO and the IEC, and administers many key committees and subgroups. In many instances, U.S. standards are taken forward to ISO and IEC, through ANSI or the USNC, where they are adopted in whole or in part as international standards. Adoption of ISO and IEC standards as American standards increased from 0.2% in 1986 to 15.5% in May 2012.", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["International activities", "Standards panels"], "text": "The Institute administers nine standards panels: (-) ANSI Homeland Defense and Security Standardization Collaborative (HDSSC) (-) [[American National Standards Institute Nanotechnology Panel|ANSI Nanotechnology Standards Panel (ANSI-NSP)]] (-) ID Theft Prevention and ID Management Standards Panel (IDSP) (-) ANSI Energy Efficiency Standardization Coordination Collaborative (EESCC) (-) Nuclear Energy Standards Coordination Collaborative (NESCC) (-) Electric Vehicles Standards Panel (EVSP) (-) ANSI-NAM Network on Chemical Regulation (-) ANSI Biofuels Standards Coordination Panel (-) Healthcare Information Technology Standards Panel (HITSP) Each of the panels works to identify, coordinate, and harmonize voluntary standards relevant to these areas. In 2009, ANSI and the [[National Institute of Standards and Technology]] (NIST) formed the Nuclear Energy Standards Coordination Collaborative (NESCC). NESCC is a joint initiative to identify and respond to the current need for standards in the nuclear industry.", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["International activities", "American national standards"], "text": "(-) The [[ASA film speed|ASA]] (as for American Standards Association) photographic exposure system, originally defined in ASA Z38.2.1 (since 1943) and ASA PH2.5 (since 1954), together with the [[DIN film speed|DIN system (DIN 4512 since 1934)]], became the basis for the [[ISO film speed|ISO]] system (since 1974), currently used worldwide ([[ISO 6]], [[ISO 2240]], [[ISO 5800]], [[ISO 12232]]). (-) A standard for the set of values used to represent characters in digital computers. The ANSI code standard extended the previously created [[ASCII]] seven bit code standard (ASA X3.4-1963), with additional codes for European alphabets (see also [[Extended Binary Coded Decimal Interchange Code]] or EBCDIC). In [[Microsoft Windows]], the phrase \"ANSI\" refers to the [[Windows code page|Windows ANSI code page]] (even though they are not ANSI standards). Most of these are fixed width, though some characters for [[ideographic language]] are variable width. Since these characters are based on a draft of the [[ISO-8859]] series, some of Microsoft's symbols are visually very similar to the ISO symbols, leading many to falsely assume that they are identical. (-) The first computer [[programming language]] standard was \"American Standard [[Fortran]]\" (informally known as \"FORTRAN 66\"), approved in March 1966 and published as ASA X3.9-1966. (-) The programming language [[COBOL]] had ANSI standards in 1968, 1974, and 1985. The COBOL 2002 standard was issued by [[International Organization for Standardization|ISO]]. (-) The original standard implementation of the [[C (computer language)|C]] programming language was standardized as ANSI X3.159-1989, becoming the well-known [[ANSI C]]. (-) The [[X3J13|X3J13 committee]] was created in 1986 to formalize the ongoing consolidation of [[Common Lisp]], culminating in 1994 with the publication of ANSI's first object-oriented programming standard. (-) A popular [[Unified Thread Standard]] for nuts and bolts is ANSI/ASME B1.1 which was defined in 1935, 1949, 1989, and 2003. (-) The ANSI-NSF International standards used for commercial kitchens, such as restaurants, cafeterias, delis, etc. (-) The ANSI/APSP (Association of Pool & Spa Professionals) standards used for pools, spas, hot tubs, barriers, and suction entrapment avoidance. (-) The ANSI/HI (Hydraulic Institute) standards used for pumps. (-) The ANSI for [[eye protection]] is Z87.1, which gives a specific impact resistance rating to the eyewear. This standard is commonly used for shop glasses, shooting glasses, and many other examples of protective eyewear. (-) The [[Paper size#ANSI paper sizes|ANSI paper sizes]] (ANSI/ASME Y14.1).", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": ["International activities", "Other initiatives"], "text": "(-) In 2008, ANSI, in partnership with Citation Technologies, created the first dynamic, online web library for [[ISO 14000]] standards. (-) On June 23, 2009, ANSI announced a product and services agreement with Citation Technologies to deliver all ISO Standards on a web-based platform. Through the ANSI-Citation partnership, 17,765 International Standards developed by more than 3,000 ISO technical bodies will be made available on the citation platform, arming subscribers with powerful search tools and collaboration, notification, and change-management functionality. (-) ANSI, in partnership with Citation Technologies, [[Association for the Advancement of Medical Instrumentation|AAMI]], [[ASTM]], and [[DIN]], created a single, centralized database for medical device standards on September 9, 2009.<ref name=\"Medical Device Standards Press Release 09/09/09\">Medical Device Standards Database Press Release 09/09/09</ref> (-) In early 2009, ANSI launched a new Certificate Accreditation Program (ANSI-CAP) to provide neutral, third-party attestation that a given certificate program meets the American National Standard ASTM E2659-09. (-) In 2009, ANSI began accepting applications for certification bodies seeking accreditation according to requirements defined under the Toy Safety Certification Program (TSCP) as the official third-party accreditor of TSCP's product certification bodies. (-) In 2006, ANSI launched www.StandardsPortal.org, an online resource for facilitating more open and efficient trade between international markets in the areas of standards, conformity assessment, and technical regulations. The site currently features content for China, India, and Korea, with additional countries and regions planned for future content. (-) ANSI design standards have also been incorporated into building codes encompassing several specific building sub-sets, such as the ANSI/SPRI ES-1, which pertains to \"Wind Design Standard for Edge Systems Used With Low Slope Roofing Systems\", for example.<ref name=\"The ANSI/SPRI ES-1 Standard Explained\"></ref>", "id": "659", "title": "American National Standards Institute", "categories": ["American National Standards Institute", "1918 establishments in the United States", "501(c)(3) organizations", "Charities based in Washington, D.C.", "ISO member bodies", "Organizations established in 1918", "Technical specifications"], "seealso": ["ANSI ASC X9", "Open standard", "ANSI ASC X12", "National Institute of Standards and Technology", "Institute of Nuclear Materials Management", "National Information Standards Organization", "Institute of Environmental Sciences and Technology", "ISO", "ANSI C", "Accredited Crane Operator Certification"]}
{"headers": [], "text": "In logic and philosophy, an '''[[argument]]''' is an attempt to persuade someone of something, or give evidence or reasons for accepting a particular conclusion. '''Argument''' may also refer to:", "id": "661", "title": "Argument (disambiguation)", "categories": [], "seealso": ["The Argument (disambiguation)"]}
{"headers": ["Mathematics and computer science"], "text": "(-) [[Argument (complex analysis)]], a function which returns the polar angle of a complex number (-) [[Command-line argument]], an item of information provided to a program when it is started (-) [[Parameter (computer programming)]], a piece of data provided as input to a subroutine (-) [[Argument principle]], a theorem in complex analysis (-) An [[argument of a function]], also known as an independent variable", "id": "661", "title": "Argument (disambiguation)", "categories": [], "seealso": ["The Argument (disambiguation)"]}
{"headers": ["Language and rhetoric"], "text": "(-) [[Argument (literature)]], a brief summary, often in prose, of a poem or section of a poem or other work (-) [[Argument (linguistics)]], a phrase that appears in a syntactic relationship with the verb in a clause (-) [[Oral argument in the United States]], a spoken presentation to a judge or appellate court by a lawyer (or parties when representing themselves) of the legal reasons why they should prevail (-) [[Closing argument]], in law, the concluding statement of each party's counsel reiterating the important arguments in a court case", "id": "661", "title": "Argument (disambiguation)", "categories": [], "seealso": ["The Argument (disambiguation)"]}
{"headers": ["Other uses"], "text": "(-) [[Musical argument]], a concept in the theory of musical form (-) [[Argument (ship)|''Argument'' (ship)]], an Australian sloop wrecked in 1809 (-) ''[[Das Argument]]'', a German academic journal (-) [[Argument Clinic]], a Monty Python sketch (-) A [[disagreement]] between two or more parties or the discussion of the disagreement (-) [[Argument (horse)]]", "id": "661", "title": "Argument (disambiguation)", "categories": [], "seealso": ["The Argument (disambiguation)"]}
{"headers": [], "text": "'''Apollo 11''' (July 16–24, 1969) was the [[Human spaceflight|spaceflight]] that first [[Moon landing|landed]] humans on the [[Moon]]. Commander [[Neil Armstrong]] and lunar module pilot [[Buzz Aldrin]] formed the American crew that landed the [[Apollo Lunar Module]] [[Lunar Module Eagle|''Eagle'']] on July 20, 1969, at 20:17 [[Coordinated Universal Time|UTC]] (14:17 [[Central Standard Time|CST]]). Armstrong became the first person to step onto the lunar surface six hours and 39 minutes later on July 21 at 02:56 UTC; Aldrin joined him 19 minutes later. They spent about two and a quarter hours together outside the [[spacecraft]], and collected of lunar material to bring back to [[Earth]]. Command module pilot [[Michael Collins (astronaut)|Michael Collins]] flew the [[Command Module Columbia|Command Module ''Columbia'']] alone in [[lunar orbit]] while they were on the Moon's surface. Armstrong and Aldrin spent 21 hours, 36 minutes on the lunar surface, at a site they had named [[Tranquility Base]] upon landing, before lifting off to rejoin ''Columbia'' in lunar orbit. Apollo 11 was launched by a [[Saturn V]] rocket from [[Kennedy Space Center]] on [[Merritt Island, Florida]], on July 16 at 13:32 UTC, and it was the fifth crewed mission of [[NASA]]'s [[Apollo program]]. The Apollo [[Apollo (spacecraft)|spacecraft]] had three parts: a [[Apollo command and service module#Command module (CM)|command module (CM)]] with a cabin for the three astronauts, the only part that returned to Earth; a [[Apollo service module|service module (SM)]], which supported the command module with propulsion, electrical power, oxygen, and water; and a [[Apollo Lunar Module|lunar module (LM)]] that had two stages—a descent stage for landing on the Moon and an ascent stage to place the astronauts back into lunar orbit. After being [[Trans-lunar injection|sent to the Moon]] by the Saturn V's third stage, the astronauts separated the spacecraft from it and traveled for three days until they entered lunar orbit. Armstrong and Aldrin then moved into [[Lunar Module Eagle|''Eagle'']] and landed in the [[Sea of Tranquility]] on July 20. The astronauts used ''Eagle''s ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisoned ''Eagle'' before they performed the maneuvers that propelled ''Columbia'' out of the last of its 30 lunar orbits onto a trajectory back to Earth. They returned to Earth and [[Splashdown|splashed down]] in the Pacific Ocean on July 24 after more than eight days in space. Armstrong's first step onto the lunar surface was broadcast on [[Live television|live TV]] to a worldwide audience. He described the event as \"one small step for [a] man, one giant leap for mankind.\" Apollo 11 effectively proved US victory in the [[Space Race]] to demonstrate spaceflight superiority, by fulfilling a national goal proposed in 1961 by [[President of the United States|President]] [[John F. Kennedy]], \"before this decade is out, of landing a man on the Moon and returning him safely to the Earth.\"", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Background"], "text": "In the late [[1950s]] and early [[1960s]], the United States was engaged in the [[Cold War]], a geopolitical rivalry with the [[Soviet Union]]. On October 4, 1957, the Soviet Union launched [[Sputnik 1]], the first [[Satellite|artificial satellite]]. This surprise success fired fears and imaginations around the world. It demonstrated that the Soviet Union had the capability to deliver nuclear weapons over intercontinental distances, and challenged American claims of military, economic and technological superiority. This precipitated the [[Sputnik crisis]], and triggered the [[Space Race]] to prove which superpower would achieve superior spaceflight capability. [[President of the United States|President]] [[Dwight D. Eisenhower]] responded to the Sputnik challenge by creating the [[National Aeronautics and Space Administration]] (NASA), and initiating [[Project Mercury]], which aimed to launch a man into [[Earth orbit]]. But on April 12, 1961, Soviet [[cosmonaut]] [[Yuri Gagarin]] became the first person in space, and the first to orbit the Earth. Nearly a month later, on May 5, 1961, [[Alan Shepard]] became the first American in space, completing a 15-minute suborbital journey. After being recovered from the Atlantic Ocean, he received a congratulatory telephone call from Eisenhower's successor, [[John F. Kennedy]]. Since the [[Soviet Union]] had higher lift capacity [[launch vehicle]], Kennedy chose, from among options presented by NASA, a challenge beyond the capacity of the existing generation of rocketry, so that the US and Soviet Union would be starting from a position of equality. A crewed mission to the Moon would serve this purpose. On May 25, 1961, Kennedy addressed the [[United States Congress]] on \"Urgent National Needs\" and declared: On September 12, 1962, Kennedy [[We choose to go to the Moon|delivered another speech]] before a crowd of about 40,000 people in the [[Rice Stadium (Rice University)|Rice University football stadium]] in [[Houston]], [[Texas]]. A widely quoted refrain from the middle portion of the speech reads as follows: In spite of that, the proposed program faced the opposition of many Americans and was dubbed a \"[[Boondoggle|moondoggle]]\" by [[Norbert Wiener]], a mathematician at the [[Massachusetts Institute of Technology]]. The effort to land a man on the Moon already had a name: [[Project Apollo]]. When Kennedy met with [[Nikita Khrushchev]], the [[Premier of the Soviet Union]] in June 1961, he proposed making the Moon landing a joint project, but Khrushchev did not take up the offer. Kennedy again proposed a joint expedition to the Moon in a speech to the [[United Nations General Assembly]] on September 20, 1963. The idea of a joint Moon mission was abandoned after Kennedy's death.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Background"], "text": "An early and crucial decision was choosing [[lunar orbit rendezvous]] over both [[direct ascent]] and [[Earth orbit rendezvous]]. A [[space rendezvous]] is an [[orbital maneuver]] in which two spacecraft navigate through space and meet up. In July 1962 NASA head [[James E. Webb|James Webb]] announced that lunar orbit rendezvous would be used and that the [[Apollo (spacecraft)|Apollo spacecraft]] would have three major parts: a command module (CM) with a cabin for the three astronauts, and the only part that returned to Earth; a service module (SM), which supported the command module with propulsion, electrical power, oxygen, and water; and a lunar module (LM) that had two stages—a descent stage for landing on the Moon, and an ascent stage to place the astronauts back into lunar orbit. This design meant the spacecraft could be launched by a single [[Saturn V]] rocket that was then under development. Technologies and techniques required for Apollo were developed by [[Project Gemini]]. The Apollo project was enabled by NASA's adoption of new advances in [[semiconductor]] [[electronic technology]], including [[metal-oxide-semiconductor field-effect transistor]] (MOSFETs) in the [[Interplanetary Monitoring Platform]] (IMP) and [[silicon]] [[integrated circuit]] (IC) chips in the [[Apollo Guidance Computer]] (AGC). Project Apollo was abruptly halted by the [[Apollo 1]] fire on January 27, 1967, in which astronauts [[Gus Grissom]], [[Ed White (astronaut)|Ed White]], and [[Roger B. Chaffee]] died, and the subsequent investigation. In October 1968, [[Apollo 7]] evaluated the command module in Earth orbit, and in December [[Apollo 8]] tested it in lunar orbit. In March 1969, [[Apollo 9]] put the lunar module through its paces in Earth orbit, and in May [[Apollo 10]] conducted a \"dress rehearsal\" in lunar orbit. By July 1969, all was in readiness for Apollo 11 to take the final step onto the Moon. The Soviet Union appeared to be winning the Space Race by beating the US to firsts, but its early lead was overtaken by the US [[Project Gemini|Gemini program]] and Soviet failure to develop the [[N1 (rocket)|N1 launcher]], which would have been comparable to the Saturn V. The Soviets tried to beat the US to return lunar material to the Earth by means of [[Uncrewed spacecraft|uncrewed probes]]. On July 13, three days before Apollo 11's launch, the Soviet Union launched [[Luna 15]], which reached lunar orbit before Apollo 11. During descent, a malfunction caused Luna 15 to crash in [[Mare Crisium]] about two hours before Armstrong and Aldrin took off from the Moon's surface to begin their voyage home. The [[Nuffield Radio Astronomy Laboratories]] radio telescope in England recorded transmissions from Luna 15 during its descent, and these were released in July 2009 for the 40th anniversary of Apollo 11.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Personnel", "Prime crew"], "text": "The initial crew assignment of Commander [[Neil Armstrong]], Command Module Pilot (CMP) [[Jim Lovell]], and Lunar Module Pilot (LMP) [[Buzz Aldrin]] on the backup crew for Apollo9 was officially announced on November 20, 1967. Lovell and Aldrin had previously flown together as the crew of [[Gemini 12]]. Due to design and manufacturing delays in the LM, Apollo8 and Apollo9 swapped prime and backup crews, and Armstrong's crew became the backup for Apollo8. Based on the normal crew rotation scheme, Armstrong was then expected to command Apollo 11. There would be one change. [[Michael Collins (astronaut)|Michael Collins]], the CMP on the Apollo8 crew, began experiencing trouble with his legs. Doctors diagnosed the problem as a bony growth between his fifth and sixth vertebrae, requiring surgery. Lovell took his place on the Apollo8 crew, and when Collins recovered he joined Armstrong's crew as CMP. In the meantime, [[Fred Haise]] filled in as backup LMP, and Aldrin as backup CMP for Apollo 8. Apollo 11 was the second American mission where all the crew members had prior spaceflight experience, the first being Apollo 10. The next was [[STS-26]] in 1988. [[Deke Slayton]] gave Armstrong the option to replace Aldrin with Lovell, since some thought Aldrin was difficult to work with. Armstrong had no issues working with Aldrin but thought it over for a day before declining. He thought Lovell deserved to command his own mission (eventually [[Apollo 13]]). The Apollo 11 prime crew had none of the close cheerful camaraderie characterized by that of [[Apollo 12]]. Instead, they forged an amiable working relationship. Armstrong in particular was notoriously aloof, but Collins, who considered himself a loner, confessed to rebuffing Aldrin's attempts to create a more personal relationship. Aldrin and Collins described the crew as \"amiable strangers\". Armstrong did not agree with the assessment, and said \"... all the crews I was on worked very well together.\"", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Personnel", "Backup crew"], "text": "The backup crew consisted of Lovell as Commander, [[William Anders]] as CMP, and Haise as LMP. Anders had flown with Lovell on Apollo8. In early 1969, he accepted a job with the [[National Space Council|National Aeronautics and Space Council]] effective August 1969, and announced he would retire as an astronaut at that time. [[Ken Mattingly]] was moved from the support crew into parallel training with Anders as backup CMP in case Apollo 11 was delayed past its intended July launch date, at which point Anders would be unavailable. By the normal crew rotation in place during Apollo, Lovell, Mattingly, and Haise were scheduled to fly on [[Apollo 14]] after backing up for Apollo 11. Later, Lovell's crew was forced to switch places with [[Alan Shepard]]'s tentative [[Apollo 13]] crew to give Shepard more training time.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Personnel", "Support crew"], "text": "During Projects Mercury and Gemini, each mission had a prime and a backup crew. For Apollo, a third crew of astronauts was added, known as the support crew. The support crew maintained the flight plan, checklists and mission ground rules, and ensured the prime and backup crews were apprised of changes. They developed procedures, especially those for emergency situations, so these were ready for when the prime and backup crews came to train in the simulators, allowing them to concentrate on practicing and mastering them. For Apollo 11, the support crew consisted of Ken Mattingly, [[Ronald Evans (astronaut)|Ronald Evans]] and [[William R. Pogue|Bill Pogue]].", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Personnel", "Capsule communicators"], "text": "The [[capsule communicator]] (CAPCOM) was an astronaut at the [[Christopher C. Kraft Jr. Mission Control Center|Mission Control Center]] in [[Houston, Texas]], who was the only person who communicated directly with the flight crew. For Apollo 11, the CAPCOMs were: [[Charles Duke]], Ronald Evans, [[Bruce McCandless II]], James Lovell, William Anders, Ken Mattingly, Fred Haise, [[Don L. Lind]], [[Owen K. Garriott]] and [[Harrison Schmitt]].", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Personnel", "Other key personnel"], "text": "Other key personnel who played important roles in the Apollo 11 mission include the following.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Preparations", "Insignia"], "text": "The Apollo 11 [[Mission patch|mission emblem]] was designed by Collins, who wanted a symbol for \"peaceful lunar landing by the United States\". At Lovell's suggestion, he chose the [[bald eagle]], the [[national bird]] of the United States, as the symbol. Tom Wilson, a simulator instructor, suggested an [[olive branch]] in its beak to represent their peaceful mission. Collins added a lunar background with the Earth in the distance. The sunlight in the image was coming from the wrong direction; the shadow should have been in the lower part of the Earth instead of the left. Aldrin, Armstrong and Collins decided the Eagle and the Moon would be in their natural colors, and decided on a blue and gold border. Armstrong was concerned that \"eleven\" would not be understood by non-English speakers, so they went with \"Apollo 11\", and they decided not to put their names on the patch, so it would \"be representative of ''everyone'' who had worked toward a lunar landing\". An illustrator at the [[Manned Spacecraft Center]] (MSC) did the artwork, which was then sent off to NASA officials for approval. The design was rejected. [[Bob Gilruth]], the director of the MSC felt the talons of the eagle looked \"too warlike\". After some discussion, the olive branch was moved to the talons. When the [[Eisenhower dollar|Eisenhower dollar coin]] was released in 1971, the patch design provided the eagle for its reverse side. The design was also used for the smaller [[Susan B. Anthony dollar]] unveiled in 1979.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Preparations", "Call signs"], "text": "After the crew of Apollo 10 named their spacecraft ''Charlie Brown'' and ''Snoopy'', assistant manager for public affairs [[Julian Scheer]] wrote to [[George M. Low]], the Manager of the Apollo Spacecraft Program Office at the MSC, to suggest the Apollo 11 crew be less flippant in naming their craft. The name ''Snowcone'' was used for the CM and ''Haystack'' was used for the LM in both internal and external communications during early mission planning. The LM was named ''[[Lunar Module Eagle|Eagle]]'' after the motif which was featured prominently on the mission insignia. At Scheer's suggestion, the CM was named ''[[Command module Columbia|Columbia]]'' after ''[[Columbiad#In fiction|Columbiad]]'', the giant cannon that launched a spacecraft (also from Florida) in [[Jules Verne]]'s 1865 novel ''[[From the Earth to the Moon]]''. It also referred to [[Columbia (name)|Columbia]], a historical name of the United States. In Collins' 1976 book, he said ''Columbia'' was in reference to [[Christopher Columbus]].", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Preparations", "Mementos"], "text": "The astronauts had [[personal preference kit]] (PPKs), small bags containing personal items of significance they wanted to take with them on the mission. Five PPKs were carried on Apollo 11: three (one for each astronaut) were stowed on ''Columbia'' before launch, and two on ''Eagle''. Neil Armstrong's LM PPK contained a piece of wood from the [[Wright brothers]]' 1903 ''[[Wright Flyer]]''s left propeller and a piece of fabric from its wing, along with a diamond-studded [[astronaut pin]] originally given to Slayton by the widows of the Apollo1 crew. This pin had been intended to be flown on that mission and given to Slayton afterwards, but following the disastrous launch pad fire and subsequent funerals, the widows gave the pin to Slayton. Armstrong took it with him on Apollo 11.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Preparations", "Site selection"], "text": "NASA's Apollo Site Selection Board announced five potential landing sites on February 8, 1968. These were the result of two years' worth of studies based on high-resolution photography of the lunar surface by the five uncrewed probes of the [[Lunar Orbiter program]] and information about surface conditions provided by the [[Surveyor program]]. The best Earth-bound telescopes could not resolve features with the resolution Project Apollo required. The landing site had to be close to the lunar equator to minimize the amount of propellant required, clear of obstacles to minimize maneuvering, and flat to simplify the task of the landing radar. Scientific value was not a consideration. Areas that appeared promising on photographs taken on Earth were often found to be totally unacceptable. The original requirement that the site be free of craters had to be relaxed, as no such site was found. Five sites were considered: Sites1 and2 were in the Sea of Tranquility (''[[Mare Tranquillitatis]]''); Site3 was in the Central Bay (''[[Sinus Medii]]''); and Sites4 and5 were in the Ocean of Storms (''[[Oceanus Procellarum]]''). The final site selection was based on seven criteria: (-) The site needed to be smooth, with relatively few craters; (-) with approach paths free of large hills, tall cliffs or deep craters that might confuse the landing radar and cause it to issue incorrect readings; (-) reachable with a minimum amount of propellant; (-) allowing for delays in the launch countdown; (-) providing the Apollo spacecraft with a free-return trajectory, one that would allow it to coast around the Moon and safely return to Earth without requiring any engine firings should a problem arise on the way to the Moon; (-) with good visibility during the landing approach, meaning the Sun would be between 7and 20 degrees behind the LM; and (-) a general slope of less than two degrees in the landing area. The requirement for the Sun angle was particularly restrictive, limiting the launch date to one day per month. A landing just after dawn was chosen to limit the temperature extremes the astronauts would experience. The Apollo Site Selection Board selected Site2, with Sites 3and5 as backups in the event of the launch being delayed. In May 1969, Apollo 10's lunar module flew to within of Site2, and reported it was acceptable.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Preparations", "First-step decision"], "text": "During the first press conference after the Apollo 11 crew was announced, the first question was, \"Which one of you gentlemen will be the first man to step onto the lunar surface?\" Slayton told the reporter it had not been decided, and Armstrong added that it was \"not based on individual desire\". One of the first versions of the egress checklist had the lunar module pilot exit the spacecraft before the commander, which matched what had been done on Gemini missions, where the commander had never performed the spacewalk. Reporters wrote in early 1969 that Aldrin would be the first man to walk on the Moon, and Associate Administrator [[George Mueller (NASA)|George Mueller]] told reporters he would be first as well. Aldrin heard that Armstrong would be the first because Armstrong was a civilian, which made Aldrin livid. Aldrin attempted to persuade other lunar module pilots he should be first, but they responded cynically about what they perceived as a lobbying campaign. Attempting to stem interdepartmental conflict, Slayton told Aldrin that Armstrong would be first since he was the commander. The decision was announced in a press conference on April 14, 1969. For decades, Aldrin believed the final decision was largely driven by the lunar module's hatch location. Because the astronauts had their spacesuits on and the spacecraft was so small, maneuvering to exit the spacecraft was difficult. The crew tried a simulation in which Aldrin left the spacecraft first, but he damaged the simulator while attempting to egress. While this was enough for mission planners to make their decision, Aldrin and Armstrong were left in the dark on the decision until late spring. Slayton told Armstrong the plan was to have him leave the spacecraft first, if he agreed. Armstrong said, \"Yes, that's the way to do it.\" The media accused Armstrong of exercising his commander's prerogative to exit the spacecraft first. [[Chris Kraft]] revealed in his 2001 autobiography that a meeting occurred between Gilruth, Slayton, Low, and himself to make sure Aldrin would not be the first to walk on the Moon. They argued that the first person to walk on the Moon should be like [[Charles Lindbergh]], a calm and quiet person. They made the decision to change the flight plan so the commander was the first to egress from the spacecraft.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Preparations", "Pre-launch"], "text": "The ascent stage of [[Lunar Module Eagle|LM-5 ''Eagle'']] arrived at the [[Kennedy Space Center]] on January 8, 1969, followed by the descent stage four days later, and [[Command module Columbia|CSM-107 ''Columbia'']] on January 23. There were several differences between ''Eagle'' and Apollo 10's LM-4 ''Snoopy''; ''Eagle'' had a VHF radio antenna to facilitate communication with the astronauts during their EVA on the lunar surface; a lighter ascent engine; more thermal protection on the landing gear; and a package of scientific experiments known as the [[Early Apollo Scientific Experiments Package]] (EASEP). The only change in the configuration of the command module was the removal of some insulation from the forward hatch. The CSM was mated on January 29, and moved from the [[Operations and Checkout Building]] to the [[Vehicle Assembly Building]] on April 14. The [[S-IVB]] third stage of Saturn V AS-506 had arrived on January 18, followed by the [[S-II]] second stage on February 6, [[S-IC]] first stage on February 20, and the [[Saturn V Instrument Unit]] on February 27. At 12:30 on May 20, the assembly departed the Vehicle Assembly Building atop the [[crawler-transporter]], bound for Launch Pad 39A, part of [[Launch Complex 39]], while Apollo 10 was still on its way to the Moon. A countdown test commenced on June 26, and concluded on July 2. The launch complex was floodlit on the night of July 15, when the crawler-transporter carried the [[service structure|mobile service structure]] back to its parking area. In the early hours of the morning, the fuel tanks of the S-II and S-IVB stages were filled with [[liquid hydrogen]]. Fueling was completed by three hours before launch. Launch operations were partly automated, with 43 programs written in the [[ATOLL (programming language)|ATOLL programming language]]. Slayton roused the crew shortly after 04:00, and they showered, shaved, and had the traditional pre-flight breakfast of steak and eggs with Slayton and the backup crew. They then donned their space suits and began breathing pure oxygen. At 06:30, they headed out to Launch Complex 39. Haise entered ''Columbia'' about three hours and ten minutes before launch time. Along with a technician, he helped Armstrong into the left-hand couch at 06:54. Five minutes later, Collins joined him, taking up his position on the right-hand couch. Finally, Aldrin entered, taking the center couch. Haise left around two hours and ten minutes before launch. The closeout crew sealed the hatch, and the cabin was purged and pressurized. The closeout crew then left the launch complex about an hour before launch time. The countdown became automated at three minutes and twenty seconds before launch time. Over 450 personnel were at the consoles in the [[firing room]].", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Launch and flight to lunar orbit"], "text": "An estimated one million spectators watched the launch of Apollo 11 from the highways and beaches in the vicinity of the launch site. Dignitaries included the [[Chief of Staff of the United States Army]], [[General (United States)|General]] [[William Westmoreland]], four [[Cabinet of the United States|cabinet members]], 19 [[Governor (United States)|state governors]], 40 [[Mayoralty in the United States|mayors]], 60 [[ambassador]] and 200 [[congressmen]]. [[Vice President of the United States|Vice President]] [[Spiro Agnew]] viewed the launch with former president [[Lyndon B. Johnson]] and his wife [[Lady Bird Johnson]]. Around 3,500 media representatives were present. About two-thirds were from the United States; the rest came from 55 other countries. The launch was televised live in 33 countries, with an estimated 25 million viewers in the United States alone. Millions more around the world listened to radio broadcasts. President [[Richard Nixon]] viewed the launch from his office in the [[White House]] with his NASA liaison officer, Apollo astronaut [[Frank Borman]]. Saturn V AS-506 launched Apollo 11 on July 16, 1969, at 13:32:00 [[UTC]] (9:32:00 [[Eastern Daylight Time|EDT]]). At 13.2 seconds into the flight, the launch vehicle began to [[Roll program|roll]] into its [[flight azimuth]] of 72.058°. Full shutdown of the first-stage engines occurred about 2minutes and 42 seconds into the mission, followed by separation of the S-IC and ignition of the S-II engines. The second stage engines then cut off and separated at about 9minutes and 8seconds, allowing the first ignition of the S-IVB engine a few seconds later. Apollo 11 entered a [[elliptic orbit|near-circular Earth orbit]] at an altitude of by , twelve minutes into its flight. After one and a half orbits, a second ignition of the S-IVB engine pushed the spacecraft onto its trajectory toward the Moon with the [[trans-lunar injection]] (TLI) burn at 16:22:13 UTC. About 30 minutes later, with Collins in the left seat and at the controls, the [[transposition, docking, and extraction]] maneuver was performed. This involved separating ''Columbia'' from the spent S-IVB stage, turning around, and docking with ''Eagle'' still attached to the stage. After the LM was extracted, the combined spacecraft headed for the Moon, while the rocket stage flew on a trajectory past the Moon. This was done to avoid the third stage colliding with the spacecraft, the Earth, or the Moon. A [[Gravity assist|slingshot effect]] from passing around the Moon threw it into an [[heliocentric orbit|orbit around the Sun]]. On July 19 at 17:21:50 UTC, Apollo 11 passed behind the Moon and fired its service propulsion engine to enter [[lunar orbit]]. In the thirty orbits that followed, the crew saw passing views of their landing site in the southern Sea of Tranquility about southwest of the crater [[Collins (crater)|Sabine D]]. The site was selected in part because it had been characterized as relatively flat and smooth by the automated [[Ranger 8]] and [[Surveyor 5]] landers and the Lunar Orbiter mapping spacecraft, and because it was unlikely to present major landing or EVA challenges. It lay about southeast of the Surveyor5 landing site, and southwest of Ranger8's crash site.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Lunar descent"], "text": "At 12:52:00 UTC on July 20, Aldrin and Armstrong entered [[Lunar Module Eagle|''Eagle'']], and began the final preparations for lunar descent. At 17:44:00 ''Eagle'' separated from ''Columbia''. Collins, alone aboard ''Columbia'', inspected ''Eagle'' as it pirouetted before him to ensure the craft was not damaged, and that the landing gear was correctly deployed. Armstrong exclaimed: \"The ''Eagle'' has wings!\" As the descent began, Armstrong and Aldrin found themselves passing landmarks on the surface two or three seconds early, and reported that they were \"long\"; they would land miles west of their target point. ''Eagle'' was traveling too fast. The problem could have been [[mass concentration (astronomy)|mascons]]—concentrations of high mass that could have altered the trajectory. Flight Director Gene Kranz speculated that it could have resulted from extra air pressure in the docking tunnel. Or it could have been the result of ''Eagle''s pirouette maneuver. Five minutes into the descent burn, and above the surface of the Moon, the [[Apollo Guidance Computer|LM guidance computer]] (LGC) distracted the crew with the first of several unexpected 1201 and 1202 program alarms. Inside Mission Control Center, computer engineer [[Jack Garman]] told [[Flight controller#GUIDO|Guidance Officer]] [[Steve Bales]] it was safe to continue the descent, and this was relayed to the crew. The program alarms indicated \"executive overflows\", meaning the guidance computer could not complete all its tasks in real-time and had to postpone some of them. [[Margaret Hamilton (scientist)|Margaret Hamilton]], the Director of Apollo Flight Computer Programming at the [[MIT]] [[Charles Stark Draper Laboratory]] later recalled: During the mission, the cause was diagnosed as the rendezvous radar switch being in the wrong position, causing the computer to process data from both the rendezvous and landing radars at the same time. Software engineer [[Don Eyles]] concluded in a 2005 Guidance and Control Conference paper that the problem was due to a hardware design bug previously seen during testing of the first uncrewed LM in [[Apollo 5]]. Having the rendezvous radar on (so it was warmed up in case of an emergency landing abort) should have been irrelevant to the computer, but an electrical phasing mismatch between two parts of the rendezvous radar system could cause the stationary antenna to appear to the computer as dithering back and forth between two positions, depending upon how the hardware randomly powered up. The extra spurious [[cycle stealing]], as the rendezvous radar updated an involuntary counter, caused the computer alarms.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Landing"], "text": "When Armstrong again looked outside, he saw that the computer's landing target was in a boulder-strewn area just north and east of a crater (later determined to be [[West (lunar crater)|West crater]]), so he took semi-automatic control. Armstrong considered landing short of the boulder field so they could collect geological samples from it, but could not since their horizontal velocity was too high. Throughout the descent, Aldrin called out navigation data to Armstrong, who was busy piloting ''Eagle''. Now above the surface, Armstrong knew their propellant supply was dwindling and was determined to land at the first possible landing site. Armstrong found a clear patch of ground and maneuvered the spacecraft towards it. As he got closer, now above the surface, he discovered his new landing site had a crater in it. He cleared the crater and found another patch of level ground. They were now from the surface, with only 90 seconds of propellant remaining. Lunar dust kicked up by the LM's engine began to impair his ability to determine the spacecraft's motion. Some large rocks jutted out of the dust cloud, and Armstrong focused on them during his descent so he could determine the spacecraft's speed. A light informed Aldrin that at least one of the probes hanging from ''Eagle'' footpads had touched the surface a few moments before the landing and he said: \"Contact light!\" Armstrong was supposed to immediately shut the engine down, as the engineers suspected the pressure caused by the engine's own exhaust reflecting off the lunar surface could make it explode, but he forgot. Three seconds later, ''Eagle'' landed and Armstrong shut the engine down. Aldrin immediately said \"Okay, engine stop. ACA—out of [[detent]].\" Armstrong acknowledged: \"Out of detent. Auto.\" Aldrin continued: \"Mode control—both auto. Descent engine command override off. Engine arm—off. 413 is in.\" ACA was the [[Attitude control|Attitude Control Assembly]]—the LM's control stick. Output went to the LGC to command the [[reaction control system]] (RCS) jets to fire. \"Out of Detent\" meant the stick had moved away from its centered position; it was spring-centered like the turn indicator in a car. LGC address 413 contained the variable that indicated the LM had landed. ''Eagle'' landed at 20:17:40 UTC on Sunday July 20 with of usable fuel remaining. Information available to the crew and mission controllers during the landing showed the LM had enough fuel for another 25 seconds of powered flight before an abort without touchdown would have become unsafe, but post-mission analysis showed that the real figure was probably closer to 50 seconds. Apollo 11 landed with less fuel than most subsequent missions, and the astronauts encountered a premature low fuel warning. This was later found to be the result of greater propellant 'slosh' than expected, uncovering a fuel sensor. On subsequent missions, extra anti-slosh baffles were added to the tanks to prevent this.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Landing"], "text": "Armstrong acknowledged Aldrin's completion of the post-landing checklist with \"Engine arm is off\", before responding to the CAPCOM, Charles Duke, with the words, \"Houston, [[Tranquility Base]] here. The ''[[Lunar Module Eagle|Eagle]]'' has landed.\" Armstrong's unrehearsed change of call sign from \"Eagle\" to \"Tranquility Base\" emphasized to listeners that landing was complete and successful. Duke mispronounced his reply as he expressed the relief at Mission Control: \"Roger, Twan—Tranquility, we copy you on the ground. You got a bunch of guys about to turn blue. We're breathing again. Thanks a lot.\" Two and a half hours after landing, before preparations began for the EVA, Aldrin radioed to Earth: He then took [[Eucharist|communion]] privately. At this time NASA was still fighting a lawsuit brought by atheist [[Madalyn Murray O'Hair]] (who had objected to the [[Apollo 8 Genesis reading|Apollo8 crew reading from the Book of Genesis]]) demanding that their astronauts refrain from broadcasting religious activities while in space. As such, Aldrin chose to refrain from directly mentioning taking communion on the Moon. Aldrin was an elder at the [[Webster, Texas|Webster]] [[Presbyterianism|Presbyterian Church]], and his communion kit was prepared by the pastor of the church, Dean Woodruff. Webster Presbyterian possesses the chalice used on the Moon and commemorates the event each year on the Sunday closest to July 20. The schedule for the mission called for the astronauts to follow the landing with a five-hour sleep period, but they chose to begin preparations for the EVA early, thinking they would be unable to sleep.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Lunar surface operations"], "text": "Preparations for [[Neil Armstrong]] and [[Buzz Aldrin]] to walk on the Moon began at 23:43. These took longer than expected; three and a half hours instead of two. During training on Earth, everything required had been neatly laid out in advance, but on the Moon the cabin contained a large number of other items as well, such as checklists, food packets, and tools. Six hours and thirty-nine minutes after landing Armstrong and Aldrin were ready to go outside, and ''Eagle'' was depressurized. ''Eagle''s hatch was opened at 02:39:33. Armstrong initially had some difficulties squeezing through the hatch with his [[primary life support system|portable life support system]] (PLSS). Some of the highest heart rates recorded from Apollo astronauts occurred during LM egress and ingress. At 02:51 Armstrong began his descent to the lunar surface. The remote control unit on his chest kept him from seeing his feet. Climbing down the nine-rung ladder, Armstrong pulled a D-ring to deploy the modular equipment stowage assembly (MESA) folded against ''Eagle'' side and activate the TV camera. Apollo 11 used [[slow-scan television]] (TV) incompatible with broadcast TV, so it was displayed on a special monitor, and a conventional TV camera viewed this monitor, significantly reducing the quality of the picture. The signal was received at [[Goldstone Deep Space Communications Complex|Goldstone]] in the United States, but with better fidelity by [[Honeysuckle Creek Tracking Station]] near [[Canberra]] in Australia. Minutes later the feed was switched to the more sensitive [[Parkes Observatory|Parkes radio telescope]] in Australia. Despite some technical and weather difficulties, ghostly black and white images of the first lunar EVA were received and broadcast to at least 600 million people on Earth. Copies of this video in broadcast format were saved and are widely available, but [[Apollo 11 missing tapes|recordings of the original slow scan source transmission from the lunar surface]] were likely destroyed during routine magnetic tape re-use at NASA. After describing the surface dust as \"very fine-grained\" and \"almost like a powder\", at 02:56:15, six and a half hours after landing, Armstrong stepped off ''Eagle'' footpad and declared: \"That's one small step for [a] man, one giant leap for mankind.\" Armstrong intended to say \"That's one small step for a man\", but the word \"a\" is not audible in the transmission, and thus was not initially reported by most observers of the live broadcast. When later asked about his quote, Armstrong said he believed he said \"for a man\", and subsequent printed versions of the quote included the \"a\" in square brackets. One explanation for the absence may be that his accent caused him to slur the words \"for a\" together; another is the intermittent nature of the audio and video links to Earth, partly because of storms near Parkes Observatory. A more recent digital analysis of the tape claims to reveal the \"a\" may have been spoken but obscured by static. Other analysis points to the claims of static and slurring as \"face-saving fabrication\", and that Armstrong himself later admitted to misspeaking the line.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Lunar surface operations"], "text": "About seven minutes after stepping onto the Moon's surface, Armstrong collected a contingency soil sample using a sample bag on a stick. He then folded the bag and tucked it into a pocket on his right thigh. This was to guarantee there would be some lunar soil brought back in case an emergency required the astronauts to abandon the EVA and return to the LM. Twelve minutes after the sample was collected, he removed the TV camera from the MESA and made a panoramic sweep, then mounted it on a tripod. The TV camera cable remained partly coiled and presented a tripping hazard throughout the EVA. Still photography was accomplished with a [[Hasselblad]] camera which could be operated hand held or mounted on Armstrong's [[Apollo/Skylab A7L|Apollo space suit]]. Aldrin joined Armstrong on the surface. He described the view with the simple phrase: \"Magnificent desolation.\" Armstrong said moving in the [[Gravitation of the Moon|lunar gravity]], one-sixth of Earth's, was \"even perhaps easier than the simulations ... It's absolutely no trouble to walk around.\" Aldrin joined him on the surface and tested methods for moving around, including two-footed kangaroo hops. The PLSS backpack created a tendency to tip backward, but neither astronaut had serious problems maintaining balance. Loping became the preferred method of movement. The astronauts reported that they needed to plan their movements six or seven steps ahead. The fine soil was quite slippery. Aldrin remarked that moving from sunlight into ''Eagle'' shadow produced no temperature change inside the suit, but the helmet was warmer in sunlight, so he felt cooler in shadow. The MESA failed to provide a stable work platform and was in shadow, slowing work somewhat. As they worked, the moonwalkers kicked up gray dust which soiled the outer part of their suits. The astronauts planted the [[Lunar Flag Assembly]] containing a [[flag of the United States]] on the lunar surface, in clear view of the TV camera. Aldrin remembered, \"Of all the jobs I had to do on the Moon the one I wanted to go the smoothest was the flag raising.\" But the astronauts struggled with the telescoping rod and could only jam the pole about into the hard lunar surface. Aldrin was afraid it might topple in front of TV viewers. But he gave \"a crisp West Point salute\". Before Aldrin could take a photo of Armstrong with the flag, President Richard Nixon spoke to them through a telephone-radio transmission which Nixon called \"the most historic phone call ever made from the White House.\" Nixon originally had a long speech prepared to read during the phone call, but Frank Borman, who was at the White House as a NASA liaison during Apollo 11, convinced Nixon to keep his words brief.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Lunar surface operations"], "text": "They deployed the [[Early Apollo Scientific Experiments Package|EASEP]], which included a passive seismic experiment package used to measure [[moonquake]] and a [[Retroreflector#On the Moon|retroreflector]] array used for the [[lunar laser ranging experiment]]. Then Armstrong walked from the LM to snap photos at the rim of [[Little West (lunar crater)|Little West Crater]] while Aldrin collected two [[core sample]]. He used the [[geologist's hammer]] to pound in the tubes—the only time the hammer was used on Apollo 11—but was unable to penetrate more than deep. The astronauts then collected rock samples using scoops and tongs on extension handles. Many of the surface activities took longer than expected, so they had to stop documenting sample collection halfway through the allotted 34 minutes. Aldrin shoveled of soil into the box of rocks in order to pack them in tightly. Two types of rocks were found in the geological samples: [[basalt]] and [[breccia]]. Three new minerals were discovered in the rock samples collected by the astronauts: [[armalcolite]], [[tranquillityite]], and [[pyroxferroite]]. Armalcolite was named after Armstrong, Aldrin, and Collins. All have subsequently been found on Earth. While on the surface, Armstrong uncovered a [[lunar plaque|plaque]] mounted on the LM ladder, bearing two drawings of Earth (of the Western and Eastern Hemispheres), an inscription, and signatures of the astronauts and President Nixon. The inscription read: At the behest of the [[Nixon administration]] to add a reference to God, NASA included the vague date as a reason to include A.D., which stands for [[Anno Domini]], \"in the year of our Lord\" (although it should have been placed before the year, not after). Mission Control used a coded phrase to warn Armstrong his metabolic rates were high, and that he should slow down. He was moving rapidly from task to task as time ran out. As metabolic rates remained generally lower than expected for both astronauts throughout the walk, Mission Control granted the astronauts a 15-minute extension. In a 2010 interview, Armstrong explained that NASA limited the first moonwalk's time and distance because there was no empirical proof of how much cooling water the astronauts' PLSS backpacks would consume to handle their body heat generation while working on the Moon.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Lunar ascent"], "text": "Aldrin entered ''Eagle'' first. With some difficulty the astronauts lifted film and two sample boxes containing of lunar surface material to the LM hatch using a flat cable pulley device called the Lunar Equipment Conveyor (LEC). This proved to be an inefficient tool, and later missions preferred to carry equipment and samples up to the LM by hand. Armstrong reminded Aldrin of a bag of memorial items in his sleeve pocket, and Aldrin tossed the bag down. Armstrong then jumped onto the ladder's third rung, and climbed into the LM. After transferring to LM [[life support]], the explorers lightened the ascent stage for the return to lunar orbit by tossing out their PLSS backpacks, lunar overshoes, an empty Hasselblad camera, and other equipment. The hatch was closed again at 05:11:13. They then pressurized the LM and settled down to sleep. Presidential speech writer [[William Safire]] had prepared an ''In Event of Moon Disaster'' announcement for Nixon to read in the event the Apollo 11 astronauts were stranded on the Moon. The remarks were in a memo from Safire to Nixon's [[White House Chief of Staff]] [[H. R. Haldeman]], in which Safire suggested a protocol the administration might follow in reaction to such a disaster. According to the plan, Mission Control would \"close down communications\" with the LM, and a clergyman would \"commend their souls to the deepest of the deep\" in a public ritual likened to [[burial at sea]]. The last line of the prepared text contained an allusion to [[Rupert Brooke]]'s First World War poem, \"[[The Soldier (poem)|The Soldier]]\". While moving inside the cabin, Aldrin accidentally damaged the [[circuit breaker]] that would arm the main engine for liftoff from the Moon. There was a concern this would prevent firing the engine, stranding them on the Moon. A [[Marker pen|felt-tip pen]] was sufficient to activate the switch. After more than hours on the lunar surface, in addition to the scientific instruments, the astronauts left behind: an [[Apollo 1]] mission patch in memory of astronauts [[Roger B. Chaffee|Roger Chaffee]], [[Gus Grissom]], and [[Ed White (astronaut)|Edward White]], who died when their command module caught fire during a test in January 1967; two memorial medals of Soviet cosmonauts [[Vladimir Komarov]] and [[Yuri Gagarin]], who died in 1967 and 1968 respectively; a memorial bag containing a gold replica of an olive branch as a traditional symbol of peace; and a silicon message disk carrying the [[Apollo 11 goodwill messages|goodwill statements]] by Presidents Eisenhower, Kennedy, Johnson, and Nixon along with messages from leaders of 73 countries around the world. The disk also carries a listing of the leadership of the US Congress, a listing of members of the four committees of the House and Senate responsible for the NASA legislation, and the names of NASA's past and then-current top management.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Lunar ascent"], "text": "After about seven hours of rest, the crew was awakened by Houston to prepare for the return flight. Two and a half hours later, at 17:54:00 UTC, they lifted off in ''Eagle'' ascent stage to rejoin Collins aboard ''Columbia'' in lunar orbit. Film taken from the LM ascent stage upon liftoff from the Moon reveals the American flag, planted some from the descent stage, whipping violently in the exhaust of the ascent stage engine. Aldrin looked up in time to witness the flag topple: \"The ascent stage of the LM separated ... I was concentrating on the computers, and Neil was studying the [[attitude indicator]], but I looked up long enough to see the flag fall over.\" Subsequent Apollo missions planted their flags farther from the LM.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "''Columbia'' in lunar orbit"], "text": "During his day flying solo around the Moon, Collins never felt lonely. Although it has been said \"not since [[Adam]] has any human known such solitude\", Collins felt very much a part of the mission. In his autobiography he wrote: \"this venture has been structured for three men, and I consider my third to be as necessary as either of the other two\". In the 48 minutes of each orbit when he was out of radio contact with the Earth while ''Columbia'' passed round the far side of the Moon, the feeling he reported was not fear or loneliness, but rather \"awareness, anticipation, satisfaction, confidence, almost exultation\". One of Collins' first tasks was to identify the lunar module on the ground. To give Collins an idea where to look, Mission Control radioed that they believed the lunar module landed about off target. Each time he passed over the suspected lunar landing site, he tried in vain to find the module. On his first orbits on the back side of the Moon, Collins performed maintenance activities such as dumping excess water produced by the [[fuel cell]] and preparing the cabin for Armstrong and Aldrin to return. Just before he reached the dark side on the third orbit, Mission Control informed Collins there was a problem with the temperature of the coolant. If it became too cold, parts of ''Columbia'' might freeze. Mission Control advised him to assume manual control and implement Environmental Control System Malfunction Procedure 17. Instead, Collins flicked the switch on the system from automatic to manual and back to automatic again, and carried on with normal housekeeping chores, while keeping an eye on the temperature. When ''Columbia'' came back around to the near side of the Moon again, he was able to report that the problem had been resolved. For the next couple of orbits, he described his time on the back side of the Moon as \"relaxing\". After Aldrin and Armstrong completed their EVA, Collins slept so he could be rested for the rendezvous. While the flight plan called for ''Eagle'' to meet up with ''Columbia'', Collins was prepared for a contingency in which he would fly ''Columbia'' down to meet ''Eagle''.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Return"], "text": "''Eagle'' rendezvoused with ''Columbia'' at 21:24 UTC on July 21, and the two docked at 21:35. ''Eagle''s ascent stage was jettisoned into lunar orbit at 23:41. Just before the [[Apollo 12]] flight, it was noted that ''Eagle'' was still likely to be orbiting the Moon. Later NASA reports mentioned that ''Eagle'' orbit had decayed, resulting in it impacting in an \"uncertain location\" on the lunar surface. On July 23, the last night before splashdown, the three astronauts made a television broadcast in which Collins commented: Aldrin added: Armstrong concluded: On the return to Earth, a bearing at the Guam tracking station failed, potentially preventing communication on the last segment of the Earth return. A regular repair was not possible in the available time but the station director, Charles Force, had his ten-year-old son Greg use his small hands to reach into the housing and pack it with grease. Greg was later thanked by Armstrong.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Splashdown and quarantine"], "text": "The [[aircraft carrier]] , under the command of [[Captain (United States O-6)|Captain]] [[Carl J. Seiberlich]], was selected as the primary recovery ship (PRS) for Apollo 11 on June 5, replacing its sister ship, the [[Landing platform helicopter|LPH]] , which had recovered Apollo 10 on May 26. ''Hornet'' was then at her home port of [[Long Beach, California]]. On reaching [[Pearl Harbor]] on July 5, ''Hornet'' [[Embarkation|embarked]] the [[Sikorsky SH-3 Sea King]] helicopters of [[HS-4]], a unit which specialized in recovery of Apollo spacecraft, specialized divers of [[Underwater Demolition Team|UDT]] Detachment Apollo, a 35-man NASA recovery team, and about 120 media representatives. To make room, most of ''Hornet''s air wing was left behind in Long Beach. Special recovery equipment was also loaded, including a [[Boilerplate (spaceflight)|boilerplate]] command module used for training. On July 12, with Apollo 11 still on the launch pad, ''Hornet'' departed Pearl Harbor for the recovery area in the central Pacific, in the vicinity of . A presidential party consisting of Nixon, Borman, [[United States Secretary of State|Secretary of State]] [[William P. Rogers]] and [[National Security Advisor (United States)|National Security Advisor]] [[Henry Kissinger]] flew to [[Johnston Atoll]] on [[Air Force One]], then to the [[command ship]] in [[Marine One]]. After a night on board, they would fly to ''Hornet'' in Marine One for a few hours of ceremonies. On arrival aboard ''Hornet'', the party was greeted by the [[United States Pacific Command|Commander-in-Chief, Pacific Command (CINCPAC)]], [[Admiral (United States)|Admiral]] [[John S. McCain Jr.]], and [[NASA Administrator]] [[Thomas O. Paine]], who flew to ''Hornet'' from [[Pago Pago]] in one of ''Hornet''s [[carrier onboard delivery]] aircraft. Weather satellites were not yet common, but US Air Force [[Captain (United States O-3)|Captain]] Hank Brandli had access to top-secret spy satellite images. He realized that a storm front was headed for the Apollo recovery area. Poor visibility which could make locating the capsule difficult, and strong upper-level winds which \"would have ripped their parachutes to shreds\" according to Brandli, posed a serious threat to the safety of the mission. Brandli alerted Navy Captain Willard S. Houston Jr., the commander of the [[Joint Typhoon Warning Center|Fleet Weather Center]] at Pearl Harbor, who had the required security clearance. On their recommendation, [[Rear Admiral (United States)|Rear Admiral]] [[Donald C. Davis]], commander of Manned Spaceflight Recovery Forces, Pacific, advised NASA to change the recovery area, each man risking their careers. A new location was selected northeast. This altered the flight plan. A different sequence of computer programs was used, one never before attempted. In a conventional entry, P64 was followed by P67. For a skip-out re-entry, P65 and P66 were employed to handle the exit and entry parts of the skip. In this case, because they were extending the re-entry but not actually skipping out, P66 was not invoked and instead, P65 led directly to P67. The crew were also warned they would not be in a full-lift (heads-down) attitude when they entered P67. The first program's acceleration subjected the astronauts to ; the second, to .", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Splashdown and quarantine"], "text": "Before dawn on July 24, ''Hornet'' launched four Sea King helicopters and three [[Grumman E-1 Tracer]]. Two of the E-1s were designated as \"air boss\" while the third acted as a communications relay aircraft. Two of the Sea Kings carried divers and recovery equipment. The third carried photographic equipment, and the fourth carried the decontamination swimmer and the flight surgeon. At 16:44 UTC (05:44 local time) ''Columbia''s [[drogue parachute]] were deployed. This was observed by the helicopters. Seven minutes later ''Columbia'' struck the water forcefully east of [[Wake Island]], south of Johnston Atoll, and from ''Hornet'', at . with seas and winds at from the east were reported under broken clouds at with visibility of at the recovery site. Reconnaissance aircraft flying to the original splashdown location reported the conditions Brandli and Houston had predicted. During [[splashdown]], ''Columbia'' landed upside down but was righted within ten minutes by flotation bags activated by the astronauts. A diver from the Navy helicopter hovering above attached a [[sea anchor]] to prevent it from drifting. More divers attached flotation collars to stabilize the module and positioned rafts for astronaut extraction. The divers then passed biological isolation garments (BIGs) to the astronauts, and assisted them into the life raft. The possibility of bringing back [[pathogen]] from the lunar surface was considered remote, but NASA took precautions at the recovery site. The astronauts were rubbed down with a [[sodium hypochlorite]] solution and ''Columbia'' wiped with [[Betadine]] to remove any lunar dust that might be present. The astronauts were winched on board the recovery helicopter. BIGs were worn until they reached isolation facilities on board ''Hornet''. The raft containing decontamination materials was intentionally sunk. After touchdown on ''Hornet'' at 17:53 UTC, the helicopter was lowered by the elevator into the hangar bay, where the astronauts walked the to the [[Mobile Quarantine Facility]] (MQF), where they would begin the Earth-based portion of their 21 days of quarantine. This practice would continue for two more Apollo missions, Apollo 12 and [[Apollo 14]], before the Moon was proven to be barren of life, and the quarantine process dropped. Nixon welcomed the astronauts back to Earth. He told them: \"[A]s a result of what you've done, the world has never been closer together before.\" After Nixon departed, ''Hornet'' was brought alongside the ''Columbia'', which was lifted aboard by the ship's crane, placed on a [[Dolly (trailer)|dolly]] and moved next to the MQF. It was then attached to the MQF with a flexible tunnel, allowing the lunar samples, film, data tapes and other items to be removed. ''Hornet'' returned to Pearl Harbor, where the MQF was loaded onto a [[Lockheed C-141 Starlifter]] and airlifted to the Manned Spacecraft Center. The astronauts arrived at the [[Lunar Receiving Laboratory]] at 10:00 UTC on July 28. ''Columbia'' was taken to [[Ford Island]] for deactivation, and its pyrotechnics made safe. It was then taken to [[Hickham Air Force Base]], from whence it was flown to Houston in a [[Douglas C-133 Cargomaster]], reaching the Lunar Receiving Laboratory on July 30.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Splashdown and quarantine"], "text": "In accordance with the [[Extra-Terrestrial Exposure Law]], a set of regulations promulgated by NASA on July 16 to codify its quarantine protocol, the astronauts continued in quarantine. After three weeks in confinement (first in the Apollo spacecraft, then in their trailer on ''Hornet'', and finally in the Lunar Receiving Laboratory), the astronauts were given a clean bill of health. On August 10, 1969, the Interagency Committee on Back Contamination met in Atlanta and lifted the quarantine on the astronauts, on those who had joined them in quarantine (NASA physician [[William Carpentier]] and MQF project engineer [[John Hirasaki]]), and on ''Columbia'' itself. Loose equipment from the spacecraft remained in isolation until the lunar samples were released for study.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Mission", "Celebrations"], "text": "On August 13, the three astronauts rode in [[ticker-tape parade]] in their honor in New York and Chicago, with an estimated six million attendees. On the same evening in Los Angeles there was an official [[state dinner]] to celebrate the flight, attended by members of Congress, 44 governors, [[Chief Justice of the United States]] [[Warren E. Burger]] and his predecessor, [[Earl Warren]], and ambassadors from 83 nations at the [[Century Plaza Hotel]]. Nixon and Agnew honored each astronaut with a presentation of the [[Presidential Medal of Freedom]]. The three astronauts spoke before a [[joint session of the United States Congress|joint session of Congress]] on September 16, 1969. They presented two US flags, one to the [[United States House of Representatives|House of Representatives]] and the other to the [[United States Senate|Senate]], that they had carried with them to the surface of the Moon. The [[flag of American Samoa]] on Apollo 11 is on display at the [[Jean P. Haydon Museum]] in Pago Pago, the capital of American Samoa. This celebration began a 38-day world tour that brought the astronauts to 22 foreign countries and included visits with the leaders of many countries. The crew toured from September 29 to November 5. Many nations honored the first human [[Moon landing]] with special features in magazines or by issuing Apollo 11 commemorative postage stamps or coins.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Cultural significance"], "text": "Humans walking on the Moon and returning safely to Earth accomplished Kennedy's goal set eight years earlier. In Mission Control during the Apollo 11 landing, Kennedy's speech flashed on the screen, followed by the words \"TASK ACCOMPLISHED, July 1969\". The success of Apollo 11 demonstrated the United States' technological superiority; and with the success of Apollo 11, America had won the [[Space Race]]. New phrases permeated into the English language. \"If they can send a man to the Moon, why can't they ...?\" became a common saying following Apollo 11. Armstrong's words on the lunar surface also spun off various parodies. While most people celebrated the accomplishment, disenfranchised Americans saw it as a symbol of the divide in America, evidenced by protesters outside of Kennedy Space Center the day before Apollo 11 launched. This is not to say they were not awed by it. [[Ralph Abernathy]], leading a protest march, was so captivated by the spectacle of the Apollo 11 launch that he forgot what he was going to say. Racial and financial inequalities frustrated citizens who wondered why money spent on the Apollo program was not spent taking care of humans on Earth. A poem by [[Gil Scott-Heron]] called \"[[Whitey on the Moon]]\" illustrated the [[racial inequality in the United States]] that was highlighted by the Space Race. The poem starts with: Twenty percent of the world's population watched humans walk on the Moon for the first time. While Apollo 11 sparked the interest of the world, the follow-on Apollo missions did not hold the interest of the nation. One possible explanation was the shift in complexity. Landing someone on the Moon was an easy goal to understand; lunar geology was too abstract for the average person. Another is that Kennedy's goal of landing humans on the Moon had already been accomplished. A well-defined objective helped Project Apollo accomplish its goal, but after it was completed it was hard to justify continuing the lunar missions. While most Americans were proud of their nation's achievements in space exploration, only once during the late 1960s did the [[Gallup Poll]] indicate that a majority of Americans favored \"doing more\" in space as opposed to \"doing less\". By 1973, 59 percent of those polled favored cutting spending on space exploration. The Space Race had been won, and Cold War tensions were easing as the US and Soviet Union entered the era of [[détente]]. This was also a time when [[inflation]] was rising, which put pressure on the government to reduce spending. What saved the space program was that it was one of the few government programs that had achieved something great. Drastic cuts, warned [[Caspar Weinberger]], the deputy director of the [[Office of Management and Budget]], might send a signal that \"our best years are behind us\".", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Cultural significance"], "text": "After the Apollo 11 mission, officials from the Soviet Union said landing humans on the Moon was dangerous and unnecessary. At the time the Soviet Union was attempting to retrieve lunar samples robotically. The Soviets publicly denied there was a race to the Moon, and indicated they were not making an attempt. [[Mstislav Keldysh]] said in July 1969, \"We are concentrating wholly on the creation of large satellite systems.\" It was revealed in 1989 that the Soviets had tried to send people to the Moon, but were unable due to technological difficulties. The public's reaction in the Soviet Union was mixed. The Soviet government limited the release of information about the lunar landing, which affected the reaction. A portion of the populace did not give it any attention, and another portion was angered by it. The Apollo 11 landing is referenced in the songs \"Armstrong, Aldrin and Collins\" by [[The Byrds]] on the 1969 album ''[[Ballad of Easy Rider (album)|Ballad of Easy Rider]]'' and \"Coon on the Moon\" by [[Howlin' Wolf]] on the 1973 album ''The Back Door Wolf''.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Spacecraft"], "text": "The [[Command Module Columbia|command module ''Columbia'']] went on a tour of the United States, visiting 49 state capitals, the [[Washington, D.C.|District of Columbia]], and [[Anchorage, Alaska]]. In 1971, it was transferred to the [[Smithsonian Institution]], and was displayed at the [[National Air and Space Museum]] (NASM) in Washington, DC. It was in the central ''Milestones of Flight'' exhibition hall in front of the Jefferson Drive entrance, sharing the main hall with other pioneering flight vehicles such as the ''[[Wright Flyer]]'', ''[[Spirit of St. Louis]]'', [[Bell X-1]], [[North American X-15]] and ''[[Friendship 7]]''. ''Columbia'' was moved in 2017 to the NASM Mary Baker Engen Restoration Hangar at the [[Steven F. Udvar-Hazy Center]] in Chantilly, Virginia, to be readied for a four-city tour titled ''Destination Moon: The Apollo 11 Mission''. This included [[Space Center Houston]] from October 14, 2017, to March 18, 2018, the [[Saint Louis Science Center]] from April 14 to September 3, 2018, the Senator John [[Heinz History Center]] in [[Pittsburgh]] from September 29, 2018, to February 18, 2019, and its last location at [[Museum of Flight]] in [[Seattle]] from March 16 to September 2, 2019. Continued renovations at the Smithsonian allowed time for an additional stop for the capsule, and it was moved to the [[Cincinnati Museum Center]]. The ribbon cutting ceremony was on September 29, 2019. For 40 years Armstrong's and Aldrin's space suits were displayed in the museum's ''Apollo to the Moon'' exhibit, until it permanently closed on December 3, 2018, to be replaced by a new gallery which was scheduled to open in 2022. A special display of Armstrong's suit was unveiled for the 50th anniversary of Apollo 11 in July 2019. The quarantine trailer, the flotation collar and the flotation bags are in the Smithsonian's [[Steven F. Udvar-Hazy Center]] annex near [[Washington Dulles International Airport]] in Chantilly, Virginia, where they are on display along with a test lunar module. The descent stage of the LM ''Eagle'' remains on the Moon. In 2009, the [[Lunar Reconnaissance Orbiter]] (LRO) imaged the various Apollo landing sites on the surface of the Moon, for the first time with sufficient resolution to see the descent stages of the lunar modules, scientific instruments, and foot trails made by the astronauts. The remains of the ascent stage lie at an unknown location on the lunar surface, after being abandoned and impacting the Moon. The location is uncertain because ''Eagle'' ascent stage was not tracked after it was jettisoned, and the lunar gravity field is sufficiently non-uniform to make the orbit of the spacecraft unpredictable after a short time.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Spacecraft"], "text": "In March 2012 a team of specialists financed by [[Amazon.com|Amazon]] founder [[Jeff Bezos]] located the [[Rocketdyne F-1|F-1 engines]] from the S-IC stage that launched Apollo 11 into space. They were found on the Atlantic seabed using advanced sonar scanning. His team brought parts of two of the five engines to the surface. In July 2013, a conservator discovered a serial number under the rust on one of the engines raised from the Atlantic, which NASA confirmed was from Apollo 11. The S-IVB third stage which performed Apollo 11's trans-lunar injection remains in a solar orbit near to that of Earth.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Moon rocks"], "text": "The main repository for the Apollo Moon rocks is the [[Lunar Sample Laboratory Facility]] at the Lyndon B. Johnson Space Center in [[Houston, Texas]]. For safekeeping, there is also a smaller collection stored at [[White Sands Test Facility]] near [[Las Cruces, New Mexico]]. Most of the rocks are stored in nitrogen to keep them free of moisture. They are handled only indirectly, using special tools. Over 100 research laboratories around the world conduct studies of the samples, and approximately 500 samples are prepared and sent to investigators every year. In November 1969, Nixon asked NASA to make up about 250 presentation [[Apollo 11 lunar sample display]] for 135 nations, the fifty states of the United States and its possessions, and the United Nations. Each display included Moon dust from Apollo 11. The rice-sized particles were four small pieces of Moon soil weighing about 50 mg and were enveloped in a clear acrylic button about as big as a [[Half dollar (United States coin)|United States half dollar coin]]. This acrylic button magnified the grains of lunar dust. The Apollo 11 lunar sample displays were given out as goodwill gifts by Nixon in 1970.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Experiment results"], "text": "The Passive Seismic Experiment ran until the command uplink failed on August 25, 1969. The downlink failed on December 14, 1969. , the [[Lunar Laser Ranging experiment]] remains operational.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Armstrong's camera"], "text": "Armstrong's Hasselblad camera was thought to be lost or left on the Moon surface.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "LM memorabilia"], "text": "In 2015, after Armstrong died in 2012, his widow contacted the [[National Air and Space Museum]] to inform them she had found a white cloth bag in one of Armstrong's closets. The bag contained various items, which should be left behind in lunar module, including 16mm Data Acquisition Camera that had been used to capture images of the first Moon landing. The camera is currently on display at the National Air and Space Museum.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Anniversary events", "40th anniversary"], "text": "On July 15, 2009, [[Life (magazine)|Life.com]] released a photo gallery of previously unpublished photos of the astronauts taken by ''Life'' photographer [[Ralph Morse]] prior to the Apollo 11 launch. From July 16 to 24, 2009, NASA streamed the original mission audio on its website in real time 40 years to the minute after the events occurred. It is in the process of restoring the video footage and has released a preview of key moments. In July 2010, air-to-ground voice recordings and film footage shot in Mission Control during the Apollo 11 powered descent and landing was re-synchronized and released for the first time. The [[John F. Kennedy Presidential Library and Museum]] set up an [[Adobe Flash]] website that rebroadcasts the transmissions of Apollo 11 from launch to landing on the Moon. On July 20, 2009, Armstrong, Aldrin, and Collins met with US President [[Barack Obama]] at the White House. \"We expect that there is, as we speak, another generation of kids out there who are looking up at the sky and are going to be the next Armstrong, Collins, and Aldrin\", Obama said. \"We want to make sure that NASA is going to be there for them when they want to take their journey.\" On August 7, 2009, an act of Congress awarded the three astronauts a [[Congressional Gold Medal]], the highest civilian award in the United States. The bill was sponsored by Florida Senator [[Bill Nelson (politician)|Bill Nelson]] and Florida Representative [[Alan Grayson]]. A group of British scientists interviewed as part of the anniversary events reflected on the significance of the Moon landing:", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Legacy", "Anniversary events", "50th anniversary"], "text": "On June 10, 2015, Congressman [[Bill Posey]] introduced resolution H.R. 2726 to the 114th session of the [[United States House of Representatives]] directing the [[United States Mint]] to design and sell commemorative coins in gold, silver and clad for the 50th anniversary of the Apollo 11 mission. On January 24, 2019, the Mint released the [[Apollo 11 Fiftieth Anniversary commemorative coins]] to the public on its website. A documentary film, ''[[Apollo 11 (2019 film)|Apollo 11]]'', with restored footage of the 1969 event, premiered in [[IMAX]] on March 1, 2019, and broadly in theaters on March 8. The Smithsonian Institute's [[National Air and Space Museum]] and [[NASA]] sponsored the \"Apollo 50 Festival\" on the [[National Mall]] in Washington DC. The three day (July 18 to 20, 2019) outdoor festival featured hands-on exhibits and activities, live performances, and speakers such as [[Adam Savage]] and NASA scientists. As part of the festival, a projection of the tall [[Saturn V]] rocket was displayed on the east face of the tall [[Washington Monument]] from July 16 through the 20th from 9:30pm until 11:30pm (EDT). The program also included a 17-minute show that combined full-motion video projected on the Washington Monument to recreate the assembly and launch of the [[Saturn V]] rocket. The projection was joined by a wide recreation of the [[Kennedy Space Center]] countdown clock and two large video screens showing archival footage to recreate the time leading up to the moon landing. There were three shows per night on July 19–20, with the last show on Saturday, delayed slightly so the portion where Armstrong first set foot on the Moon would happen exactly 50 years to the second after the actual event. On July 19, 2019, the [[Google Doodle]] paid tribute to the Apollo 11 Moon Landing, complete with a link to an animated [[YouTube]] video with voiceover by astronaut [[Michael Collins (astronaut)|Michael Collins]]. Aldrin, Collins, and Armstrong's sons were hosted by President [[Donald Trump]] in the Oval Office.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": ["Films and documentaries"], "text": "(-) ''[[Footprints on the Moon (1969 film)|Footprints on the Moon]]'', a 1969 documentary film by Bill Gibson and Barry Coe, about the Apollo 11 mission (-) ''[[Moonwalk One]]'', a 1971 documentary film by [[Theo Kamecke]] (-) ''Apollo 11: As it Happened'', a 1994 six-hour documentary on ABC News' coverage of the event (-) ''[[Apollo 11 (2019 film)|Apollo 11]]'', a 2019 documentary film by Todd Douglas Miller with restored footage of the 1969 event (-) ''[[Chasing the Moon (2019 film)|Chasing the Moon]]'', a July 2019 [[PBS]] three-night six-hour documentary, directed by [[Robert Stone (director)|Robert Stone]], examined the events leading up to the Apollo 11 mission. An accompanying book of the same name was also released. (-) ''8 Days: To the Moon and Back'', a [[PBS]] and [[BBC Studios]] 2019 documentary film by Anthony Philipson re-enacting major portions of the Apollo 11 mission using mission audio recordings, new studio footage, NASA and news archives, and computer-generated imagery.", "id": "662", "title": "Apollo 11", "categories": ["Apollo 11", "Buzz Aldrin", "Neil Armstrong", "Michael Collins (astronaut)", "Apollo program missions", "1969 on the Moon", "Soft landings on the Moon", "Spacecraft launched by Saturn rockets", "Articles containing video clips", "Crewed missions to the Moon"], "seealso": ["Moon landing conspiracy theories"]}
{"headers": [], "text": "'''Apollo 8''' (December 21–27, 1968) was the first crewed [[spacecraft]] to leave [[low Earth orbit]], and also the first [[human spaceflight]] to reach another [[astronomical object]], namely the [[Moon]], which the crew orbited without landing, and then departed safely back to [[Earth]]. These three [[astronaut]]—[[Frank Borman]], [[Jim Lovell|James Lovell]], and [[William Anders]]—were the first humans to witness and photograph an [[Earthrise]]. Apollo 8 launched on December 21, 1968, and was the second [[crewed spaceflight]] mission flown in the United States [[Apollo space program]] after [[Apollo 7|Apollo7]], which stayed in Earth orbit. Apollo8 was the third flight and the first crewed launch of the [[Saturn V]] rocket, and was the first human spaceflight from the [[Kennedy Space Center]], located adjacent to [[Cape Canaveral Space Force Station|Cape Kennedy Air Force Station]] in Florida. Originally planned as the second crewed [[Apollo Lunar Module]] and [[Apollo command and service module|command module]] test, to be flown in an elliptical [[medium Earth orbit]] in early 1969, the mission profile was changed in August 1968 to a more ambitious command-module-only lunar orbital flight to be flown in December, as the lunar module was not yet ready to make its first flight. Astronaut [[Jim McDivitt]]'s crew, who were training to fly the first lunar module flight in low Earth orbit, became the crew for the [[Apollo 9|Apollo9]] mission, and Borman's crew were moved to the Apollo8 mission. This left Borman's crew with two to three months' less training and preparation time than originally planned, and replaced the planned lunar module training with translunar navigation training. Apollo 8 took 68 hours (almost three days) to travel the distance to the Moon. The crew orbited the Moon ten times over the course of twenty hours, during which they made a Christmas Eve [[Apollo TV camera|television broadcast]] in which they [[Apollo 8 Genesis reading|read the first ten verses from]] the [[Book of Genesis]]. At the time, the broadcast was the most watched TV program ever. Apollo8's successful mission paved the way for [[Apollo 11|Apollo11]] to fulfill U.S. president [[John F. Kennedy]]'s goal of landing a man on the Moon before the end of the 1960s. The Apollo8 astronauts returned to Earth on December 27, 1968, when their spacecraft splashed down in the northern Pacific Ocean. The crew members were named [[Time (magazine)|''Time'' magazine]]'s [[Time Person of the Year|\"Men of the Year\"]] for 1968 upon their return.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Background"], "text": "In the late 1950s and early 1960s, the United States was engaged in the [[Cold War]], a geopolitical rivalry with the [[Soviet Union]]. On October 4, 1957, the Soviet Union launched [[Sputnik 1]], the first [[Satellite|artificial satellite]]. This unexpected success stoked fears and imaginations around the world. It not only demonstrated that the Soviet Union had the capability to deliver nuclear weapons over intercontinental distances, it challenged American claims of military, economic, and technological superiority. The launch precipitated the [[Sputnik crisis]] and triggered the [[Space Race]]. [[President of the United States|President]] [[John F. Kennedy]] believed that not only was it in the national interest of the United States to be superior to other nations, but that the perception of American power was at least as important as the actuality. It was therefore intolerable to him for the Soviet Union to be more advanced in the field of space exploration. He was determined that the United States should compete, and sought a challenge that maximized its chances of winning. The Soviet Union had heavier-lifting [[carrier rocket]], which meant Kennedy needed to choose a goal that was beyond the capacity of the existing generation of rocketry, one where the US and Soviet Union would be starting from a position of equality—something spectacular, even if it could not be justified on military, economic, or scientific grounds. After consulting with his experts and advisors, he chose such a project: to land a man on the Moon and return him to the Earth. This project already had a name: [[Project Apollo]]. An early and crucial decision was the adoption of [[lunar orbit rendezvous]], under which a specialized spacecraft would land on the lunar surface. The [[Apollo (spacecraft)|Apollo spacecraft]] therefore had three primary components: a [[Apollo command and service module#Command module (CM)|command module]] (CM) with a cabin for the three astronauts, and the only part that would return to Earth; a [[service module]] (SM) to provide the command module with propulsion, electrical power, oxygen, and water; and a two-stage [[lunar module]] (LM), which comprised a descent stage for landing on the Moon and an ascent stage to return the astronauts to lunar orbit. This configuration could be launched by the [[Saturn V]] rocket that was then under development.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Framework", "Prime crew"], "text": "The initial crew assignment of [[Frank Borman]] as Commander, [[Michael Collins (astronaut)|Michael Collins]] as Command Module Pilot (CMP) and [[William Anders]] as Lunar Module Pilot (LMP) for the third crewed Apollo flight was officially announced on November 20, 1967. Collins was replaced by [[Jim Lovell]] in July 1968, after suffering a [[intervertebral disc|cervical]] [[Spinal disc herniation|disc herniation]] that required surgery to repair. This crew was unique among pre-[[Space Shuttle]] era missions in that the commander was not the most experienced member of the crew: Lovell had flown twice before, on [[Gemini 7|Gemini VII]] and [[Gemini 12|Gemini XII]]. This would also be the first case of a commander of a previous mission (Lovell, Gemini XII) flying as a non-commander. This was also the first mission to reunite crewmates from a previous mission (Lovell and Borman, Gemini VII).", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Framework", "Backup crew"], "text": "The backup crew assignment of [[Neil Armstrong]] as Commander, Lovell as CMP, and [[Buzz Aldrin]] as LMP for the third crewed Apollo flight was officially announced at the same time as the prime crew. When Lovell was reassigned to the prime crew, Aldrin was moved to CMP, and [[Fred Haise]] was brought in as backup LMP. Armstrong would later command Apollo11, with Aldrin as LMP and Collins as CMP. Haise served on the backup crew of Apollo11 as LMP and flew on [[Apollo 13|Apollo13]] as LMP.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Framework", "Support personnel"], "text": "During Projects Mercury and Gemini, each mission had a prime and a backup crew. For Apollo, a third crew of astronauts was added, known as the support crew. The support crew maintained the flight plan, checklists, and mission ground rules, and ensured that the prime and backup crews were apprised of any changes. The support crew developed procedures in the simulators, especially those for emergency situations, so that the prime and backup crews could practice and master them in their simulator training. For Apollo8, the support crew consisted of [[Ken Mattingly]], [[Vance Brand]], and [[Gerald P. Carr|Gerald Carr]]. The [[capsule communicator]] (CAPCOM) was an astronaut at the [[Christopher C. Kraft Jr. Mission Control Center|Mission Control Center]] in [[Houston, Texas]], who was the only person who communicated directly with the flight crew. For Apollo8, the CAPCOMs were Michael Collins, Gerald Carr, Ken Mattingly, Neil Armstrong, Buzz Aldrin, Vance Brand, and Fred Haise. The mission control teams rotated in three shifts, each led by a flight director. The directors for Apollo8 were [[Clifford E. Charlesworth]] (Green team), [[Glynn Lunney]] (Black team), and [[Milton Windler]] (Maroon team).", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Framework", "Mission insignia and callsign"], "text": "The triangular shape of the insignia refers to the shape of the Apollo CM. It shows a red figure8 looping around the Earth and Moon to reflect both the mission number and the circumlunar nature of the mission. On the bottom of the8 are the names of the three astronauts. The initial design of the insignia was developed by Jim Lovell, who reportedly sketched it while riding in the back seat of a [[Northrop T-38 Talon|T-38]] flight from [[California]] to [[Houston]] shortly after learning of Apollo8's re-designation as a lunar-orbital mission. The crew wanted to name their spacecraft, but NASA did not allow it. The crew would have likely chosen ''Columbiad'', the name of the giant cannon that launches a space vehicle in [[Jules Verne]]'s 1865 novel ''[[From the Earth to the Moon]]''. The Apollo11 CM was named ''Columbia'' in part for that reason.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Preparations", "Mission schedule"], "text": "On September 20, 1967, NASA adopted a seven-step plan for Apollo missions, with the final step being a Moon landing. [[Apollo 4|Apollo4]] and [[Apollo 6|Apollo6]] were \"A\" missions, tests of the [[Saturn V|SaturnV]] launch vehicle using an uncrewed Block I production model of the command and service module (CSM) in Earth orbit. [[Apollo 5|Apollo5]] was a \"B\" mission, a test of the LM in Earth orbit. Apollo7, scheduled for October 1968, would be a \"C\" mission, a crewed Earth-orbit flight of the CSM. Further missions depended on the readiness of the LM. It had been decided as early as May 1967 that there would be at least four additional missions. Apollo8 was planned as the \"D\" mission, a test of the LM in a low Earth orbit in December 1968 by [[James McDivitt]], [[David Scott]], and [[Rusty Schweickart|Russell Schweickart]], while Borman's crew would fly the \"E\" mission, a more rigorous LM test in an elliptical medium Earth orbit as Apollo9, in early 1969. The \"F\" Mission would test the CSM and LM in lunar orbit, and the \"G\" mission would be the finale, the Moon landing. Production of the LM fell behind schedule, and when Apollo8's LM-3 arrived at the [[Kennedy Space Center]] (KSC) in June 1968, more than a hundred significant defects were discovered, leading [[Bob Gilruth]], the director of the [[Manned Spacecraft Center]] (MSC), and others to conclude that there was no prospect of LM-3 being ready to fly in 1968. Indeed, it was possible that delivery would slip to February or March 1969. Following the original seven-step plan would have meant delaying the \"D\" and subsequent missions, and endangering the program's goal of a lunar landing before the end of 1969. [[George Low]], the Manager of the Apollo Spacecraft Program Office, proposed a solution in August 1968 to keep the program on track despite the LM delay. Since the next CSM (designated as \"CSM-103\") would be ready three months before LM-3, a CSM-only mission could be flown in December 1968. Instead of repeating the \"C\" mission flight of Apollo7, this CSM could be sent all the way to the Moon, with the possibility of entering a lunar orbit and returning to Earth. The new mission would also allow NASA to test lunar landing procedures that would otherwise have had to wait until [[Apollo 10|Apollo10]], the scheduled \"F\" mission. This also meant that the medium Earth orbit \"E\" mission could be dispensed with. The net result was that only the \"D\" mission had to be delayed, and the plan for lunar landing in mid-1969 could remain on timeline.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Preparations", "Mission schedule"], "text": "On August 9, 1968, Low discussed the idea with Gilruth, Flight Director [[Chris Kraft]], and the Director of Flight Crew Operations, [[Donald Slayton]]. They then flew to the [[Marshall Space Flight Center]] (MSFC) in [[Huntsville, Alabama]], where they met with KSC Director [[Kurt Debus]], Apollo Program Director [[Samuel C. Phillips]], [[Rocco Petrone]], and [[Wernher von Braun]]. Kraft considered the proposal feasible from a flight control standpoint; Debus and Petrone agreed that the next Saturn V, AS-503, could be made ready by December 1; and von Braun was confident the [[pogo oscillation]] problems that had afflicted Apollo6 had been fixed. Almost every senior manager at NASA agreed with this new mission, citing confidence in both the hardware and the personnel, along with the potential for a circumlunar flight providing a significant morale boost. The only person who needed some convincing was [[James E. Webb]], the NASA administrator. Backed by the full support of his agency, Webb authorized the mission. Apollo8 was officially changed from a \"D\" mission to a \"C-Prime\" lunar-orbit mission. With the change in mission for Apollo 8, Slayton asked McDivitt if he still wanted to fly it. McDivitt turned it down; his crew had spent a great deal of time preparing to test the LM, and that was what he still wanted to do. Slayton then decided to swap the prime and backup crews of the Dand Emissions. This swap also meant a swap of spacecraft, requiring Borman's crew to use CSM-103, while McDivitt's crew would use CSM-104, since CM-104 could not be made ready by December. David Scott was not happy about giving up CM-103, the testing of which he had closely supervised, for CM-104, although the two were almost identical, and Anders was less than enthusiastic about being an LMP on a flight with no LM. Instead, in order that the spacecraft would have the correct weight and balance, Apollo8 would carry LM test article, a boilerplate model of LM-3. Added pressure on the Apollo program to make its 1969 landing goal was provided by the [[Soviet Union]]'s [[Zond 5|Zond5]] mission, which flew some living creatures, including [[Russian tortoise]], in a [[cislunar]] loop around the Moon and returned them to Earth on September 21. There was speculation within NASA and the press that they might be preparing to launch [[astronaut#Russian|cosmonauts]] on a similar [[Zond program#Circumlunar missions|circumlunar mission]] before the end of 1968. The Apollo 8 crew, now living in the crew quarters at Kennedy Space Center, received a visit from [[Charles Lindbergh]] and his wife, [[Anne Morrow Lindbergh]], the night before the launch. They talked about how, before his [[Spirit of St. Louis|1927 flight]], Lindbergh had used a piece of string to measure the distance from New York City to Paris on a globe and from that calculated the fuel needed for the flight. The total he had carried was a tenth of the amount that the Saturn V would burn every second. The next day, the Lindberghs watched the launch of Apollo8 from a nearby dune.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Preparations", "Saturn V redesign"], "text": "The Saturn V rocket used by Apollo8 was designated AS-503, or the \"03rd\" model of the SaturnV (\"5\") Rocket to be used in the Apollo-Saturn (\"AS\") program. When it was erected in the [[Vehicle Assembly Building]] on December 20, 1967, it was thought that the rocket would be used for an uncrewed Earth-orbit test flight carrying a [[Boilerplate (spaceflight)|boilerplate]] command and service module. Apollo6 had suffered several major problems during its April 1968 flight, including severe [[pogo oscillation]] during its first stage, two second-stage engine failures, and a third stage that failed to reignite in orbit. Without assurances that these problems had been rectified, NASA administrators could not justify risking a crewed mission until additional uncrewed test flights proved the Saturn V was ready. Teams from the MSFC went to work on the problems. Of primary concern was the pogo oscillation, which would not only hamper engine performance, but could exert significant g-forces on a crew. A task force of contractors, NASA agency representatives, and MSFC researchers concluded that the engines vibrated at a frequency similar to the frequency at which the spacecraft itself vibrated, causing a resonance effect that induced oscillations in the rocket. A system that used helium gas to absorb some of these vibrations was installed. Of equal importance was the failure of three engines during flight. Researchers quickly determined that a leaking hydrogen fuel line ruptured when exposed to vacuum, causing a loss of fuel pressure in engine two. When an automatic shutoff attempted to close the liquid hydrogen valve and shut down engine two, it had accidentally shut down engine three's liquid oxygen due to a miswired connection. As a result, engine three failed within one second of engine two's shutdown. Further investigation revealed the same problem for the third-stage engine—a faulty igniter line. The team modified the igniter lines and fuel conduits, hoping to avoid similar problems on future launches. The teams tested their solutions in August 1968 at the MSFC. A Saturn stage IC was equipped with shock-absorbing devices to demonstrate the team's solution to the problem of pogo oscillation, while a Saturn Stage II was retrofitted with modified fuel lines to demonstrate their resistance to leaks and ruptures in vacuum conditions. Once NASA administrators were convinced that the problems had been solved, they gave their approval for a crewed mission using AS-503. The Apollo 8 spacecraft was placed on top of the rocket on September 21, and the rocket made the slow journey to the launch pad on October9. Testing continued all through December until the day before launch, including various levels of readiness testing from December5 through 11. Final testing of modifications to address the problems of pogo oscillation, ruptured fuel lines, and bad igniter lines took place on December 18, three days before the scheduled launch.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Parameter summary"], "text": "As the first crewed spacecraft to orbit more than one celestial body, Apollo8's profile had two different sets of orbital parameters, separated by a translunar injection maneuver. Apollo lunar missions would begin with a nominal circular Earth parking orbit. Apollo8 was launched into an initial orbit with an [[apogee]] of and a [[perigee]] of , with an [[inclination]] of 32.51° to the [[Equator]], and an [[orbital period]] of 88.19 minutes. Propellant venting increased the apogee by over the 2hours, 44 minutes, and 30 seconds spent in the parking orbit. This was followed by a [[trans-lunar injection]] (TLI) burn of the [[S-IVB]] third stage for 318 seconds, accelerating the command and service module and LM test article from an orbital velocity of to the injection velocity of which set a record for the highest speed, relative to Earth, that humans had ever traveled. This speed was slightly less than the Earth's [[escape velocity]] of , but put Apollo8 into an elongated elliptical Earth orbit, close enough to the Moon to be captured by the Moon's gravity. The standard lunar orbit for Apollo missions was planned as a nominal circular orbit above the Moon's surface. Initial lunar orbit insertion was an ellipse with a [[perilune]] of and an [[apolune]] of , at an inclination of 12° from the lunar equator. This was then circularized at by , with an orbital period of 128.7 minutes. The effect of lunar [[mass concentration (astronomy)|mass concentrations]] (\"mascons\") on the orbit was found to be greater than initially predicted; over the course of the ten lunar orbits lasting twenty hours, the orbital distance was perturbated to by . Apollo 8 achieved a maximum distance from Earth of .", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Launch and trans-lunar injection"], "text": "Apollo 8 was launched at 12:51:00 [[UTC]] (07:51:00 [[Eastern Time Zone (North America)|Eastern Standard Time]]) on December 21, 1968, using the Saturn V's [[Multistage rocket|three stages]] to achieve Earth orbit. The [[S-IC]] first stage landed in the [[Atlantic Ocean]] at , and the [[S-II]] second stage landed at . The [[S-IVB]] third stage injected the craft into Earth orbit and remained attached to perform the TLI burn that would put the spacecraft on a trajectory to the Moon. Once the [[space vehicle|vehicle]] reached Earth orbit, both the crew and [[Christopher C. Kraft Jr. Mission Control Center|Houston flight controllers]] spent the next 2hours and 38 minutes checking that the spacecraft was in proper working order and ready for TLI. The proper operation of the S-IVB third stage of the rocket was crucial, and in the last uncrewed test, it had failed to reignite for this burn. Collins was the first CAPCOM on duty, and at 2hours, 27 minutes and 22 seconds after launch he radioed, \"Apollo8. You are Go for TLI.\" This communication meant that Mission Control had given official permission for Apollo8 to go to the Moon. The S-IVB engine ignited on time and performed the TLI burn perfectly. Over the next five minutes, the spacecraft's speed increased from . After the S-IVB had placed the mission on course for the Moon, the command and service modules (CSM), the remaining Apollo8 spacecraft, separated from it. The crew then rotated the spacecraft to take photographs of the spent stage and then practiced flying in formation with it. As the crew rotated the spacecraft, they had their first views of the Earth as they moved away from it—this marked the first time humans had viewed the whole Earth at once. Borman became worried that the S-IVB was staying too close to the CSM and suggested to Mission Control that the crew perform a separation maneuver. Mission Control first suggested pointing the spacecraft towards Earth and using the small [[Apollo CSM#Reaction control system|reaction control system]] (RCS) thrusters on the [[Apollo command and service module#Service module (SM)|service module]] (SM) to add to their velocity away from the Earth, but Borman did not want to lose sight of the S-IVB. After discussion, the crew and Mission Control decided to burn in the Earth direction to increase speed, but at instead. The time needed to prepare and perform the additional burn put the crew an hour behind their onboard tasks. Five hours after launch, Mission Control sent a command to the S-IVB to vent its remaining fuel, changing its trajectory. The S-IVB, with the test article attached, posed no further hazard to Apollo8, passing the orbit of the Moon and going into a solar orbit with an [[inclination]] of 23.47° from the [[Ecliptic|plane of the ecliptic]], and an orbital period of 340.80 days. It became a [[:Category:Derelict satellites in heliocentric orbit|derelict object]], and will continue to [[heliocentric orbit|orbit the Sun]] for many years, if not retrieved.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Launch and trans-lunar injection"], "text": "The Apollo 8 crew were the first humans to pass through the [[Van Allen radiation belt]], which extend up to from Earth. Scientists predicted that passing through the belts quickly at the spacecraft's high speed would cause a radiation dosage of no more than a chest [[X-ray]], or 1[[Gray (unit)|milligray]] (mGy; during a year, the average human receives a dose of 2to 3mGy). To record the actual radiation dosages, each crew member wore a Personal Radiation [[Dosimeter]] that transmitted data to Earth, as well as three passive film dosimeters that showed the cumulative radiation experienced by the crew. By the end of the mission, the crew members experienced an average radiation dose of 1.6 mGy.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Lunar trajectory"], "text": "Lovell's main job as Command Module Pilot was as [[flight officer|navigator]]. Although Mission Control normally performed all the actual navigation calculations, it was necessary to have a crew member adept at navigation so that the crew could return to Earth in case communication with Mission Control was lost. Lovell navigated by star sightings using a [[sextant]] built into the spacecraft, measuring the angle between a star and the Earth's (or the Moon's) [[horizon]]. This task was made difficult by a large cloud of debris around the spacecraft, which made it hard to distinguish the stars. By seven hours into the mission, the crew was about 1hour and 40 minutes behind flight plan because of the problems in moving away from the S-IVB and Lovell's obscured star sightings. The crew placed the spacecraft into Passive Thermal Control (PTC), also called \"barbecue roll\", in which the spacecraft rotated about once per hour around its long axis to ensure even heat distribution across the surface of the spacecraft. In direct sunlight, parts of the spacecraft's outer surface could be heated to over , while the parts in shadow would be . These temperatures could cause the [[atmospheric reentry#Thermal protection systems|heat shield]] to crack and propellant lines to burst. Because it was impossible to get a perfect roll, the spacecraft swept out a [[Conical surface|cone]] as it rotated. The crew had to make minor adjustments every half hour as the cone pattern got larger and larger. The first mid-course correction came eleven hours into the flight. The crew had been awake for more than 16 hours. Before launch, NASA had decided at least one crew member should be awake at all times to deal with problems that might arise. Borman started the first sleep shift but found sleeping difficult because of the constant radio chatter and mechanical noises. Testing on the ground had shown that the [[Apollo command and service module#Service propulsion system|service propulsion system]] (SPS) engine had a small chance of exploding when burned for long periods unless its [[combustion chamber]] was \"coated\" first by burning the engine for a short period. This first correction burn was only 2.4 seconds and added about velocity [[Retrograde and prograde motion|prograde]] (in the direction of travel). This change was less than the planned , because of a bubble of [[helium]] in the [[nitrogen tetroxide|oxidizer]] lines, which caused unexpectedly low propellant pressure. The crew had to use the small RCS thrusters to make up the shortfall. Two later planned mid-course corrections were canceled because the Apollo8 trajectory was found to be perfect.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Lunar trajectory"], "text": "About an hour after starting his sleep shift, Borman obtained permission from [[flight controller|ground control]] to take a [[Secobarbital|Seconal]] [[Barbiturate|sleeping pill]]. The pill had little effect. Borman eventually fell asleep, and then awoke feeling ill. He vomited twice and had a bout of diarrhea; this left the spacecraft full of small globules of vomit and feces, which the crew cleaned up as well as they could. Borman initially did not want everyone to know about his medical problems, but Lovell and Anders wanted to inform Mission Control. The crew decided to use the Data Storage Equipment (DSE), which could tape voice recordings and telemetry and dump them to Mission Control at high speed. After recording a description of Borman's illness they asked Mission Control to check the recording, stating that they \"would like an evaluation of the voice comments\". The Apollo 8 crew and Mission Control medical personnel held a conference using an unoccupied second-floor control room (there were two identical control rooms in Houston, on the second and third floors, only one of which was used during a mission). The conference participants concluded that there was little to worry about and that Borman's illness was either a [[Gastroenteritis|24-hour flu]], as Borman thought, or a reaction to the sleeping pill. Researchers now believe that he was suffering from [[space adaptation syndrome]], which affects about a third of astronauts during their first day in space as their [[Labyrinth (inner ear)|vestibular system]] adapts to [[weightlessness]]. Space adaptation syndrome had not occurred on previous spacecraft ([[Project Mercury|Mercury]] and [[Project Gemini|Gemini]]), because those astronauts could not move freely in the small cabins of those spacecraft. The increased cabin space in the Apollo command module afforded astronauts greater freedom of movement, contributing to symptoms of space sickness for Borman and, later, astronaut [[Rusty Schweickart]] during Apollo9. The cruise phase was a relatively uneventful part of the flight, except for the crew's checking that the spacecraft was in working order and that they were on course. During this time, NASA scheduled a television broadcast at 31 hours after launch. The Apollo8 crew used a camera that broadcast in [[black-and-white]] only, using a [[Video camera tube|Vidicon]] tube. The camera had two [[lens (optics)|lenses]], a very [[wide-angle lens|wide-angle (160°) lens]], and a [[telephoto lens|telephoto (9°) lens]]. During this first broadcast, the crew gave a tour of the spacecraft and attempted to show how the Earth appeared from space. However, difficulties aiming the narrow-angle lens without the aid of a monitor to show what it was looking at made showing the Earth impossible. Additionally, without proper [[Optical filter|filters]], the Earth image became saturated by any bright source. In the end, all the crew could show the people watching back on Earth was a bright blob. After broadcasting for 17 minutes, the rotation of the spacecraft took the [[high-gain antenna]] out of view of the receiving stations on Earth and they ended the transmission with Lovell wishing his mother a happy birthday.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Lunar trajectory"], "text": "By this time, the crew had completely abandoned the planned sleep shifts. Lovell went to sleep 32-and-a-half hours into the flight – three-and-a-half hours before he had planned to. A short while later, Anders also went to sleep after taking a sleeping pill. The crew was unable to see the Moon for much of the outward cruise. Two factors made the Moon almost impossible to see from inside the spacecraft: three of the five windows fogging up due to out-gassed oils from the [[silicone]] [[sealant]], and the [[Orientation (geometry)|attitude]] required for passive thermal control. It was not until the crew had gone behind the Moon that they would be able to see it for the first time. Apollo 8 made a second television broadcast at 55 hours into the flight. This time, the crew rigged up filters meant for the still cameras so they could acquire images of the Earth through the telephoto lens. Although difficult to aim, as they had to maneuver the entire spacecraft, the crew was able to broadcast back to Earth the first television pictures of the Earth. The crew spent the transmission describing the Earth, what was visible, and the colors they could see. The transmission lasted 23 minutes.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Lunar sphere of influence"], "text": "At about 55 hours and 40 minutes into the flight, and 13 hours before entering lunar orbit, the crew of Apollo8 became the first humans to enter the gravitational [[Sphere of influence (astrodynamics)|sphere of influence]] of another celestial body. In other words, the effect of the Moon's [[Newton's law of universal gravitation|gravitational force]] on Apollo8 became stronger than that of the Earth. At the time it happened, Apollo8 was from the Moon and had a speed of relative to the Moon. This historic moment was of little interest to the crew, since they were still calculating their [[trajectory]] with respect to the launch pad at Kennedy Space Center. They would continue to do so until they performed their last mid-course correction, switching to a [[Frame of reference|reference frame]] based on ideal orientation for the second engine burn they would make in lunar orbit. The last major event before Lunar Orbit Insertion (LOI) was a second mid-course correction. It was in [[Retrograde and direct motion|retrograde]] (against the direction of travel) and slowed the spacecraft down by , effectively reducing the closest distance at which the spacecraft would pass the Moon. At exactly 61 hours after launch, about from the Moon, the crew burned the RCS for 11 seconds. They would now pass from the [[Geology of the Moon#Lunar landscape|lunar surface]]. At 64 hours into the flight, the crew began to prepare for Lunar Orbit Insertion1 (LOI-1). This maneuver had to be performed perfectly, and due to [[orbital mechanics]] had to be on the far side of the Moon, out of contact with the Earth. After Mission Control was polled for a \"[[Launch status check|go/no go]]\" decision, the crew was told at 68 hours that they were Go and \"riding the best bird we can find\". Lovell replied, \"We'll see you on the other side\", and for the first time in history, humans travelled behind the Moon and out of radio contact with the Earth. With ten minutes remaining before LOI-1, the crew began one last check of the spacecraft systems and made sure that every switch was in its correct position. At that time, they finally got their first glimpses of the Moon. They had been flying over the unlit side, and it was Lovell who saw the first shafts of sunlight [[wiktionary:oblique|oblique]] illuminating the lunar surface. The LOI burn was only two minutes away, so the crew had little time to appreciate the view.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Lunar orbit"], "text": "The SPS was ignited at 69 hours, 8minutes, and 16 seconds after launch and burned for 4minutes and 7seconds, placing the Apollo8 spacecraft in orbit around the Moon. The crew described the burn as being the longest four minutes of their lives. If the burn had not lasted exactly the correct amount of time, the spacecraft could have ended up in a highly [[ellipse|elliptical]] lunar orbit or even been flung off into space. If it had lasted too long, they could have struck the Moon. After making sure the spacecraft was working, they finally had a chance to look at the Moon, which they would orbit for the next 20 hours. On Earth, Mission Control continued to wait. If the crew had not burned the engine, or the burn had not lasted the planned length of time, the crew would have appeared early from behind the Moon. Exactly at the calculated moment, however, the signal was received from the spacecraft, indicating it was in a orbit around the Moon. After reporting on the status of the spacecraft, Lovell gave the first description of what the lunar surface looked like: Lovell continued to describe the terrain they were passing over. One of the crew's major tasks was [[reconnaissance]] of planned future landing sites on the Moon, especially one in [[Mare Tranquillitatis]] that was planned as the Apollo11 landing site. The launch time of Apollo8 had been chosen to give the best lighting conditions for examining the site. A [[film camera]] had been set up in one of the spacecraft windows to record one frame per second of the Moon below. Bill Anders spent much of the next 20 hours taking as many photographs as possible of targets of interest. By the end of the mission, the crew had taken over eight hundred 70 mm still photographs and of 16 mm movie film. Throughout the hour that the spacecraft was in contact with Earth, Borman kept asking how the data for the SPS looked. He wanted to make sure that the engine was working and could be used to return early to the Earth if necessary. He also asked that they receive a \"go/no go\" decision before they passed behind the Moon on each orbit. As they reappeared for their second pass in front of the Moon, the crew set up equipment to broadcast a view of the lunar surface. Anders described the craters that they were passing over. At the end of this second orbit, they performed an 11-second LOI-2 burn of the SPS to circularize the orbit to .", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Lunar orbit"], "text": "Throughout the next two orbits, the crew continued to check the spacecraft and to observe and photograph the Moon. During the third pass, Borman read a small prayer for his church. He had been scheduled to participate in a service at St. Christopher's [[Episcopal Church (United States)|Episcopal Church]] near [[Seabrook, Texas]], but due to the Apollo8 flight, he was unable to attend. A fellow parishioner and engineer at Mission Control, Rod Rose, suggested that Borman read the prayer, which could be recorded and then replayed during the service.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Earthrise"], "text": "When the spacecraft came out from behind the Moon for its fourth pass across the front, the crew witnessed an \"Earthrise\" in person for the first time in human history. NASA's [[Lunar Orbiter 1]] had taken the first picture of an Earthrise from the vicinity of the Moon, on August 23, 1966. Anders saw the Earth emerging from behind the lunar horizon and called in excitement to the others, taking a black-and-white photograph as he did so. Anders asked Lovell for color film and then took ''[[Earthrise]]'', a now famous color photo, later picked by ''[[Life (magazine)|Life]]'' magazine as one of its hundred photos of the century. Due to the [[tidal locking|synchronous rotation]] of the Moon about the Earth, Earthrise is not generally visible from the lunar surface. This is because, as seen from any one place on the Moon's surface, Earth remains in approximately the same position in the lunar sky, either above or below the horizon. Earthrise is generally visible only while orbiting the Moon, and at selected surface locations near the Moon's [[lunar limb|limb]], where [[libration]] carries the Earth slightly above and below the lunar horizon. Anders continued to take photographs while Lovell assumed control of the spacecraft so that Borman could rest. Despite the difficulty resting in the cramped and noisy spacecraft, Borman was able to sleep for two orbits, awakening periodically to ask questions about their status. Borman awoke fully, however, when he started to hear his fellow crew members make mistakes. They were beginning to not understand questions and had to ask for the answers to be repeated. Borman realized that everyone was extremely tired from not having a good night's sleep in over three days. He ordered Anders and Lovell to get some sleep and that the rest of the flight plan regarding observing the Moon be scrubbed. Anders initially protested, saying that he was fine, but Borman would not be swayed. Anders finally agreed under the condition that Borman would set up the camera to continue to take automatic pictures of the Moon. Borman also remembered that there was a second television broadcast planned, and with so many people expected to be watching, he wanted the crew to be alert. For the next two orbits, Anders and Lovell slept while Borman sat at the helm.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Earthrise"], "text": "As they rounded the Moon for the ninth time, the astronauts began the second television transmission. Borman introduced the crew, followed by each man giving his impression of the lunar surface and what it was like to be orbiting the Moon. Borman described it as being \"a vast, lonely, forbidding expanse of nothing\". Then, after talking about what they were flying over, Anders said that the crew had a message for all those on Earth. Each man on board [[Apollo 8 Genesis reading|read a section from the Biblical creation story]] from the [[Book of Genesis]]. Borman finished the broadcast by wishing a Merry Christmas to everyone on Earth. His message appeared to sum up the feelings that all three crewmen had from their vantage point in lunar orbit. Borman said, \"And from the crew of Apollo8, we close with good night, good luck, a Merry Christmas and God bless all of you—all of you on the good Earth.\" The only task left for the crew at this point was to perform the [[trans-Earth injection]] (TEI), which was scheduled for hours after the end of the television transmission. The TEI was the most critical burn of the flight, as any failure of the SPS to ignite would strand the crew in lunar orbit, with little hope of escape. As with the previous burn, the crew had to perform the maneuver above the far side of the Moon, out of contact with Earth. The burn occurred exactly on time. The spacecraft telemetry was reacquired as it re-emerged from behind the Moon at 89 hours, 28 minutes, and 39 seconds, the exact time calculated. When voice contact was regained, Lovell announced, \"Please be informed, there is a [[Santa Claus]]\", to which Ken Mattingly, the current CAPCOM, replied, \"That's affirmative, you are the best ones to know.\" The spacecraft began its journey back to Earth on December 25, [[Christmas Day]].", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Unplanned manual realignment"], "text": "Later, Lovell used some otherwise idle time to do some navigational sightings, maneuvering the module to view various stars by using the [[Apollo guidance computer|computer]] keyboard. However, he accidentally erased some of the computer's memory, which caused the [[Apollo PGNCS#Inertial measurement unit|inertial measurement unit]] (IMU) to contain data indicating that the module was in the same relative orientation it had been in before lift-off; the IMU then fired the thrusters to \"correct\" the module's attitude. Once the crew realized why the computer had changed the module's attitude, they realized that they would have to reenter data to tell the computer the module's actual orientation. It took Lovell ten minutes to figure out the right numbers, using the thrusters to get the stars [[Rigel]] and [[Sirius]] aligned, and another 15 minutes to enter the corrected data into the computer. Sixteen months later, during the [[Apollo 13|Apollo13]] mission, Lovell would have to perform a similar manual realignment under more critical conditions after the module's IMU had to be turned off to conserve energy.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Mission", "Cruise back to Earth and reentry"], "text": "The cruise back to Earth was mostly a time for the crew to relax and monitor the spacecraft. As long as the trajectory specialists had calculated everything correctly, the spacecraft would reenter Earth's atmosphere two-and-a-half days after TEI and [[splashdown (spacecraft landing)|splash down]] in the Pacific. On Christmas afternoon, the crew made their fifth television broadcast. This time, they gave a tour of the spacecraft, showing how an astronaut lived in space. When they finished broadcasting, they found a small present from Slayton in the food locker: a real turkey dinner with stuffing, in the same kind of pack given to the troops in Vietnam. Another Slayton surprise was a gift of three [[Miniature (alcohol)|miniature bottles]] of [[brandy]], which Borman ordered the crew to leave alone until after they landed. They remained unopened, even years after the flight. There were also small presents to the crew from their wives. The next day, at about 124 hours into the mission, the sixth and final TV transmission showed the mission's best video images of the Earth, during a four-minute broadcast. After two uneventful days, the crew prepared for reentry. The computer would control the reentry, and all the crew had to do was put the spacecraft in the correct attitude, with the blunt end forward. In the event of computer failure, Borman was ready to take over. Separation from the service module prepared the command module for reentry by exposing the heat shield and shedding unneeded mass. The service module would burn up in the atmosphere as planned. Six minutes before they hit the top of the atmosphere, the crew saw the Moon rising above the Earth's horizon, just as had been calculated by the trajectory specialists. As the module hit the thin outer atmosphere, the crew noticed that it was becoming hazy outside as glowing [[Plasma (physics)|plasma]] formed around the spacecraft. The spacecraft started slowing down, and the deceleration peaked at . With the computer controlling the descent by changing the [[Flight dynamics (fixed-wing aircraft)|attitude]] of the spacecraft, Apollo8 rose briefly like a skipping stone before descending to the ocean. At , the drogue parachute deployed, stabilizing the spacecraft, followed at by the three main parachutes. The spacecraft splashdown position was officially reported as in the North Pacific Ocean, southwest of Hawaii at 15:51:42 UTC on December 27, 1968. When the spacecraft hit the water, the parachutes dragged it over and left it upside down, in what was termed Stable2 position. As they were buffeted by a swell, Borman was sick, waiting for the three flotation balloons to right the spacecraft. About six minutes after splashdown, the command module was righted into a normal apex-up (Stable 1) orientation by its inflatable bag uprighting system. The first [[frogman]] from [[aircraft carrier]] arrived 43 minutes after splashdown. Forty-five minutes later, the crew was safe on the flight deck of the ''Yorktown''.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Legacy", "Historical importance"], "text": "Apollo 8 came at the end of 1968, a year that had seen much upheaval in the United States and most of the world. Even though the year saw political assassinations, political unrest in the streets of Europe and America, and the [[Prague Spring]], ''[[Time (magazine)|Time]]'' magazine chose the crew of Apollo8 as its [[Time Person of the Year|Men of the Year]] for 1968, recognizing them as the people who most influenced events in the preceding year. They had been the first people ever to leave the gravitational influence of the Earth and orbit another celestial body. They had survived a mission that even the crew themselves had rated as having only a fifty-fifty chance of fully succeeding. The effect of Apollo8 was summed up in a telegram from a stranger, received by Borman after the mission, that stated simply, \"Thank you Apollo8. You saved 1968.\" One of the most famous aspects of the flight was the ''[[Earthrise]]'' picture that the crew took as they came around for their fourth orbit of the Moon. This was the first time that humans had taken such a picture while actually behind the camera, and it has been credited as one of the inspirations of the first [[Earth Day]] in 1970. It was selected as the first of ''Life'' magazine's ''100 Photographs That Changed the World''. Apollo 11 astronaut Michael Collins said, \"Eight's momentous historic significance was foremost\"; while space historian Robert K. Poole saw Apollo8 as the most historically significant of all the Apollo missions. The mission was the most widely covered by the media since the first American orbital flight, [[Mercury-Atlas 6]] by [[John Glenn]], in 1962. There were 1,200 journalists covering the mission, with the [[BBC]]'s coverage broadcast in 54 countries in 15 different languages. The Soviet newspaper ''[[Pravda]]'' featured a quote from Boris Nikolaevich Petrov, Chairman of the Soviet [[Interkosmos]] program, who described the flight as an \"outstanding achievement of American space sciences and technology\". It is estimated that a quarter of the people alive at the time saw—either live or delayed—the Christmas Eve transmission during the ninth orbit of the Moon. The Apollo8 broadcasts won an [[Emmy Award]], the highest honor given by the [[Academy of Television Arts & Sciences]]. [[Madalyn Murray O'Hair]], an [[Atheism|atheist]], later caused controversy by bringing a lawsuit against NASA over the reading from Genesis. O'Hair wanted the courts to ban American astronauts—who were all government employees—from public prayer in space. Though the case was rejected by the [[Supreme Court of the United States]], apparently for lack of jurisdiction in outer space, it caused NASA to be skittish about the issue of religion throughout the rest of the Apollo program. Buzz Aldrin, on Apollo11, self-communicated [[Presbyterianism|Presbyterian]] [[Eucharist|Communion]] on the surface of the Moon after landing; he refrained from mentioning this publicly for several years and referred to it only obliquely at the time.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Legacy", "Historical importance"], "text": "In 1969, the [[United States Post Office Department]] issued a postage stamp ([[Scott catalogue]] #1371) commemorating the Apollo8 flight around the Moon. The stamp featured a detail of the famous photograph of the Earthrise over the Moon taken by Anders on Christmas Eve, and the words, \"In the beginning God...\", the first words of the book of Genesis. In January 1969, just 18 days after the crew's return to Earth, they appeared in the [[Super Bowl III]] pre-game show, reciting the [[Pledge of Allegiance (United States)|Pledge of Allegiance]], before the [[The Star-Spangled Banner|national anthem]] was performed by trumpeter Lloyd Geisler of the [[National Symphony Orchestra|Washington National Symphony Orchestra]].", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Legacy", "Spacecraft location"], "text": "In January 1970, the spacecraft was delivered to [[Osaka]], Japan, for display in the U.S. pavilion at [[Expo '70]]. It is now displayed at the Chicago [[Museum of Science and Industry (Chicago)|Museum of Science and Industry]], along with a collection of personal items from the flight donated by Lovell and the [[space suit]] worn by Frank Borman. Jim Lovell's Apollo8 space suit is on public display in the Visitor Center at NASA's [[Glenn Research Center]]. Bill Anders's space suit is on display at the [[Science Museum (London)|Science Museum]] in London, United Kingdom.", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": ["Legacy", "In popular culture"], "text": "Apollo 8's historic mission has been depicted and referred to in several forms, both documentary and fiction. The various television transmissions and [[16 mm film|16 mm]] footage shot by the crew of Apollo8 were compiled and released by NASA in the 1969 documentary ''Debrief: Apollo8'', hosted by [[Burgess Meredith]]. In addition, Spacecraft Films released, in 2003, a three-disc DVD set containing all of NASA's TV and 16 mm film footage related to the mission, including all TV transmissions from space, training and launch footage, and motion pictures taken in flight. Other documentaries include \"Race to the Moon\" (2005) as part of [[American Experience (season 18)|season 18 of ''American Experience'']] and ''[[In the Shadow of the Moon (2007 film)|In the Shadow of the Moon]]'' (2007). Apollo's Daring Mission aired on PBS' ''[[List of Nova episodes#Season 46: 2018–2019|Nova]]'' in December 2018, marking the flight's 50th anniversary. Parts of the mission are dramatized in the 1998 miniseries ''[[From the Earth to the Moon (miniseries)|From the Earth to the Moon]]'' episode \"[[From the Earth to the Moon (miniseries)#Episodes|1968]]\". The S-IVB stage of Apollo8 was also portrayed as the location of an alien device in the 1970 ''[[UFO (TV series)|UFO]]'' episode \"Conflict\". Apollo8's lunar orbit insertion was chronicled with actual recordings in the song \"The Other Side\", on the 2015 album ''[[The Race for Space (album)|The Race for Space]]'', by the band [[Public Service Broadcasting (band)|Public Service Broadcasting]]. A documentary film, ''[[First to the Moon: The Journey of Apollo 8]]'' was released in 2018. The choral music piece ''Earthrise'' by Luke Byrne commemorates the mission. The piece was premièred on January 19, 2020, by [[Sydney Philharmonia Choirs]] at the [[Sydney Opera House]].", "id": "663", "title": "Apollo 8", "categories": ["Apollo 8", "Apollo program missions", "Crewed missions to the Moon", "Spacecraft launched in 1968", "1968 in the United States", "Spacecraft which reentered in 1968", "December 1968 events", "Spacecraft launched by Saturn rockets", "Jim Lovell", "William Anders", "Frank Borman"], "seealso": []}
{"headers": [], "text": "An '''astronaut''' (from the Greek \"astron\" (ἄστρον), meaning \"star\", and \"nautes\" (ναύτης), meaning \"sailor\") is a person trained, equipped, and deployed by a [[List of human spaceflight programs|human spaceflight program]] to serve as a commander or crew member aboard a [[spacecraft]]. Although generally reserved for professional space travelers, the terms are sometimes applied to anyone who travels into space, including scientists, politicians, journalists and [[space tourism|tourists]]. \"Astronaut\" technically applies to all human space travelers regardless of nationality or allegiance; however, astronauts fielded by Russia or the [[Soviet Union]] are typically known instead as '''cosmonauts''' (from the Russian \"kosmos\" (космос), meaning \"universe\", also borrowed from Greek) in order to distinguish them from American or otherwise [[NATO]]-oriented space travellers. Comparatively recent developments in manned spaceflight made by China and other East Asian nations have also led to the rise of the term '''taikonaut''' (from the [[Standard Chinese|Mandarin]] \"tàikōng\" (太空), meaning \"space\"), although its use is somewhat informal and its origin is unclear. Until 2002, astronauts were sponsored and trained exclusively by governments, either by the military or by civilian space agencies. With the suborbital flight of the privately funded [[SpaceShipOne]] in 2004, a new category of astronaut was created: the [[commercial astronaut]].", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Definition"], "text": "The criteria for what constitutes [[human spaceflight]] vary, with some focus on the point where the atmosphere becomes so thin that [[centrifugal force]], rather than [[aerodynamic force]], carries a significant portion of the weight of the flight object. The [[Fédération Aéronautique Internationale]] (FAI) Sporting Code for astronautics recognizes only flights that exceed the [[Kármán line]], at an altitude of . In the United States, professional, military, and commercial astronauts who travel above an altitude of are awarded [[Astronaut Badge|astronaut wings]]. , 552 people from [[Timeline of space travel by nationality|36 countries]] have reached or more in altitude, of whom 549 reached [[low Earth orbit]] or beyond. Of these, [[List of Apollo astronauts|24 people]] have traveled beyond low Earth orbit, either to lunar orbit, the lunar surface, or, in one case, a loop around the [[Moon]]. Three of the 24—[[Jim Lovell]], [[John Watts Young|John Young]] and [[Eugene Cernan]]—did so twice. , under the U.S. definition, 558 people qualify as having reached space, above altitude. Of eight [[X-15]] pilots who exceeded in altitude, only one exceeded 100 kilometers (about 62 miles). Space travelers have spent over 41,790 [[Man hour|man-days]] (114.5 man-years) in space, including over 100 astronaut-days of [[extravehicular activity|spacewalks]]. , the man with the longest cumulative time in space is [[Gennady Padalka]], who has spent 879 days in space. [[Peggy Whitson|Peggy A. Whitson]] holds the record for the most time in space by a woman, 377 days.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Terminology"], "text": "In 1959, when both the United States and [[Soviet Union]] were planning, but had yet to launch humans into space, [[NASA]] Administrator [[T. Keith Glennan]] and his Deputy Administrator, [[Hugh Latimer Dryden|Hugh Dryden]], discussed whether spacecraft crew members should be called ''astronauts'' or ''cosmonauts''. Dryden preferred \"cosmonaut\", on the grounds that flights would occur in and to the broader ''[[cosmos]]'', while the \"astro\" prefix suggested flight specifically to the [[star]]. Most NASA [[Space Task Group]] members preferred \"astronaut\", which survived by common usage as the preferred American term. When the Soviet Union launched the first man into space, [[Yuri Gagarin]] in 1961, they chose a term which [[Anglicization|anglicizes]] to \"cosmonaut\".", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Terminology", "Astronaut"], "text": "A professional space traveler is called an ''astronaut''. The first known use of the term \"astronaut\" in the modern sense was by [[Neil R. Jones]] in his 1930 short story \"The Death's Head Meteor\". The word itself had been known earlier; for example, in [[Percy Greg]]'s 1880 book ''Across the Zodiac'', \"astronaut\" referred to a spacecraft. In ''Les Navigateurs de l'Infini'' (1925) by [[J.-H. Rosny aîné]], the word ''astronautique'' (astronautic) was used. The word may have been inspired by \"aeronaut\", an older term for an air traveler first applied in 1784 to [[balloon (aircraft)|balloon]]. An early use of \"astronaut\" in a non-fiction publication is [[Eric Frank Russell]]'s poem \"The Astronaut\", appearing in the November 1934 ''Bulletin of the [[British Interplanetary Society]]''. The first known formal use of the term [[astronautics]] in the scientific community was the establishment of the annual [[International Astronautical Congress]] in 1950, and the subsequent founding of the [[International Astronautical Federation]] the following year. [[NASA]] applies the term astronaut to any crew member aboard NASA spacecraft bound for Earth orbit or beyond. NASA also uses the term as a title for those selected to join its [[NASA Astronaut Corps|Astronaut Corps]]. The European Space Agency similarly uses the term astronaut for members of its [[European Astronaut Corps|Astronaut Corps]].", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Terminology", "Cosmonaut"], "text": "By convention, an astronaut employed by the [[Russian Federal Space Agency]] (or its [[Soviet space program|Soviet]] predecessor) is called a ''cosmonaut'' in English texts. The word is an [[Anglicization]] of ''kosmonavt'' ( ). Other countries of the former [[Eastern Bloc]] use variations of the Russian kosmonavt, such as the (although Polish also uses , and the two words are considered synonyms). Coinage of the term has been credited to Soviet aeronautics (or \"[[cosmonautics]]\") pioneer [[Mikhail Tikhonravov]] (1900–1974). The first cosmonaut was [[Soviet Air Force]] pilot [[Yuri Gagarin]], also the first person in space. He was part of the first six Russians, with [[German Titov]], [[Yevgeny Khrunov]], [[Andriyan Nikolayev]], [[Pavel Popovich]], and [[Grigoriy Nelyubov]], who were given the title of pilot-cosmonaut in January 1961. [[Valentina Tereshkova]] was the first female cosmonaut and the first and youngest [[Women in space|woman to have flown in space]] with a solo mission on the [[Vostok 6]] in 1963. On 14 March 1995, [[Norman Thagard]] became the first American to ride to space on board a Russian launch vehicle, and thus became the first \"American cosmonaut\".", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Terminology", "Taikonaut"], "text": "In [[Chinese language|Chinese]], the term (, \"Space-universe navigating personnel\") is used for astronauts and cosmonauts in general, while (, \"navigating [[outer space]] personnel\") is used for Chinese astronauts. Here, () is strictly defined as the navigation of outer space within the local [[star system]], i.e. [[solar system]]. The phrase (, \"spaceman\") is often used in [[Hong Kong]] and [[Taiwan]]. The term ''taikonaut'' is used by some English-language news media organizations for professional [[Chinese space program|space travelers from China]]. The word has featured in the [[Longman]] and [[Oxford English Dictionary|Oxford English]] dictionaries, and the term became more common in 2003 when China sent its first astronaut [[Yang Liwei]] into space aboard the ''[[Shenzhou 5]]'' spacecraft. This is the term used by [[Xinhua News Agency]] in the English version of the Chinese ''[[People's Daily]]'' since the advent of the Chinese space program. The origin of the term is unclear; as early as May 1998, Chiew Lee Yih () from [[Malaysia]], used it in [[newsgroup]].", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Terminology", "Parastronaut"], "text": "For its [[2022 European Space Agency Astronaut Group|2022 Astronaut Group]], ESA envisions to recruit an astronaut with a physical disability, a category they called \"parastronauts\", with the intention but not guarantee of spaceflight. The categories of disability considered for the program were individuals with lower limb deficiency (either through amputation or congenital), leg length difference, or a short stature (less than ).", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Terminology", "Other terms"], "text": "With the rise of [[space tourism]], [[NASA]] and the [[Russian Federal Space Agency]] agreed to use the term \"[[spaceflight participant]]\" to distinguish those space travelers from professional astronauts on missions coordinated by those two agencies. While no nation other than Russia (and previously the Soviet Union), the United States, and China have launched a crewed spacecraft, several other nations have sent people into space in cooperation with one of these countries, e.g. the Soviet-led [[Interkosmos]] program. Inspired partly by these missions, other synonyms for astronaut have entered occasional English usage. For example, the term ''spationaut'' () is sometimes used to describe French space travelers, from the [[Latin]] word for \"space\"; the [[Malay language|Malay]] term (deriving from ''[[Akasha|angkasa]]'' meaning 'space') was used to describe participants in the [[Angkasawan program]] (note its similarity with the [[Indonesian language|Indonesian]] term ''antariksawan''); and, the [[Indian Space Research Organisation]] hope to launch a [[Gaganyaan|spacecraft]] in 2022 that would carry ''vyomanauts'', coined from the [[Sanskrit]] word ( meaning 'sky' or 'space'). In [[Finland]], the NASA astronaut [[Timothy Kopra]], a [[Finnish Americans|Finnish American]], has sometimes been referred to as , from the [[Finnish language|Finnish]] word . Across Germanic languages, \"astronaut\" is used in conjunction with locally derived words like German's ''Raumfahrer'', Dutch's ''ruimtevaarder'', Swedish's ''rymdfarare'' and Norwegian's ''romfarer''. As of 2020 in the United States, astronaut status is conferred on a person depending on the authorizing agency: (-) one who flies in a vehicle above for NASA or the military is considered an ''astronaut'' (with no qualifier) (-) one who flies in a vehicle to the International Space Station in a mission coordinated by NASA and Roscosmos is a ''spaceflight participant'' (-) one who flies above in a non-NASA vehicle as a crewmember is considered a ''commercial astronaut'' by the Federal Aviation Administration (-) one who flies to the International Space Station as part of a \"privately funded, dedicated commercial spaceflight on a commercial launch vehicle dedicated to the mission ... to conduct approved commercial and marketing activities on the space station (or in a commercial segment attached to the station)\" is considered a ''private astronaut'' by NASA (as of 2020, nobody has yet qualified for this status) (-) a generally-accepted but unofficial term for a paying non-crew passenger who flies a private non-NASA or military vehicles above is a ''space tourist'' (as of 2020, nobody has yet qualified for this status)", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Space travel milestones"], "text": "The first human in space was Soviet [[Yuri Gagarin]], who was launched on 12 April 1961, aboard [[Vostok 1]] and orbited around the Earth for 108 minutes. The first woman in space was Soviet [[Valentina Tereshkova]], who launched on 16 June 1963, aboard [[Vostok 6]] and orbited Earth for almost three days. [[Alan Shepard]] became the first American and second person in space on 5 May 1961, on a 15-minute sub-orbital flight aboard ''[[Mercury-Redstone 3|Freedom 7]]''. The first American to orbit the Earth was [[John Glenn]], aboard ''[[Friendship 7]]'' on 20 February 1962. The first American woman in space was [[Sally Ride]], during [[Space Shuttle Challenger|Space Shuttle ''Challenger'']]'s mission [[STS-7]], on 18 June 1983. In 1992 [[Mae Jemison]] became the first African American woman to travel in space aboard [[STS-47]]. Cosmonaut [[Alexei Leonov]] was the first person to conduct an [[extravehicular activity]] (EVA), (commonly called a \"spacewalk\"), on 18 March 1965, on the Soviet Union's Voskhod 2 mission. This was followed two and a half months later by astronaut [[Ed White (astronaut)|Ed White]] who made the first American EVA on NASA's Gemini 4 mission. The first crewed mission to orbit the Moon, [[Apollo 8]], included American [[William Anders]] who was born in Hong Kong, making him the first Asian-born astronaut in 1968. The Soviet Union, through its [[Intercosmos]] program, allowed people from other \"[[socialism|socialist]]\" (i.e. [[Warsaw Pact]] and other Soviet-allied) countries to fly on its missions, with the notable exceptions of [[France]] and [[Austria]] participating in [[Soyuz TM-7]] and [[Soyuz TM-13]], respectively. An example is [[Czechoslovak]] [[Vladimír Remek]], the first cosmonaut from a country other than the [[Soviet space program|Soviet Union]] or the [[NASA|United States]], who flew to space in 1978 on a [[Soyuz-U]] rocket. [[Rakesh Sharma]] became the first Indian citizen to travel to space. He was launched aboard [[Soyuz T-11]], on 2 April 1984. On 23 July 1980, [[Pham Tuan]] of [[Vietnam]] became the first [[Asian people|Asian]] in space when he flew aboard [[Soyuz 37]]. Also in 1980, [[Cubans|Cuban]] [[Arnaldo Tamayo Méndez]] became the first person of [[Hispanic]] and black African descent to fly in space, and in 1983, [[Guion Bluford]] became the first African American to fly into space. In April 1985, [[Taylor Wang]] became the first ethnic Chinese person in space. The first person born in Africa to fly in space was [[Patrick Baudry]] (France), in 1985. In 1985, [[Saudi Arabia]] [[Sultan Salman al-Saud|Prince Sultan Bin Salman Bin AbdulAziz Al-Saud]] became the first Arab Muslim astronaut in space. In 1988, [[Abdul Ahad Mohmand]] became the first [[Afghanistan|Afghan]] to reach space, spending nine days aboard the ''[[Mir]]'' space station. With the increase of seats on the Space Shuttle, the U.S. began taking international astronauts. In 1983, [[Ulf Merbold]] of West Germany became the first non-US citizen to fly in a US spacecraft. In 1984, [[Marc Garneau]] became the first of eight [[Canadian astronauts]] to fly in space (through 2010). In 1985, [[Rodolfo Neri Vela]] became the first Mexican-born person in space. In 1991, [[Helen Sharman]] became the first Briton to fly in space.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Space travel milestones"], "text": "In 2002, [[Mark Shuttleworth]] became the first citizen of an African country to fly in space, as a paying spaceflight participant. In 2003, [[Ilan Ramon]] became the first Israeli to fly in space, although he died during a [[Space Shuttle Columbia disaster|re-entry accident]]. On 15 October 2003, [[Yang Liwei]] became China's first astronaut on the [[Shenzhou 5]] spacecraft. On 30 May 2020, [[Doug Hurley]] and [[Bob Behnken]] became the first astronauts to launch on a private crewed spacecraft, [[SpaceX Dragon 2|Crew Dragon]].", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Space travel milestones", "Age milestones"], "text": "The youngest person to fly in space is [[Gherman Titov]], who was 25 years old when he flew [[Vostok 2]]. (Titov was also the first person to suffer [[space sickness]]). The oldest person who has flown in space was [[John Glenn]], who was 77 when he flew on [[STS-95]].", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Space travel milestones", "Duration and distance milestones"], "text": "438 days is the longest time spent in space, by Russian [[Valeri Polyakov]]. As of 2006, the most spaceflights by an individual astronaut is seven, a record held by both [[Jerry L. Ross]] and [[Franklin Chang-Diaz]]. The farthest distance from Earth an astronaut has traveled was , when [[Jim Lovell]], [[Jack Swigert]], and [[Fred Haise]] went around the Moon during the [[Apollo 13]] emergency.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Space travel milestones", "Civilian and non-government milestones"], "text": "The first civilian in space was [[Valentina Tereshkova]] aboard [[Vostok 6]] (she also became the first woman in space on that mission). Tereshkova was only honorarily inducted into the USSR's Air Force, which did not accept female pilots at that time. A month later, [[Joseph Albert Walker]] became the first American civilian in space when his [[X-15 Flight 90]] crossed the line, qualifying him by the international definition of spaceflight. Walker had joined the US Army Air Force but was not a member during his flight. The first people in space who had never been a member of any country's armed forces were both [[Konstantin Feoktistov]] and [[Boris Yegorov]] aboard [[Voskhod 1]]. The first non-governmental space traveler was [[Byron K. Lichtenberg]], a researcher from the [[Massachusetts Institute of Technology]] who flew on [[STS-9]] in 1983. In December 1990, [[Toyohiro Akiyama]] became the first paying space traveler and the first journalist in space for [[Tokyo Broadcasting System]], a visit to [[Mir]] as part of an estimated $12 million ([[USD]]) deal with a Japanese TV station, although at the time, the term used to refer to Akiyama was \"Research Cosmonaut\". Akiyama suffered severe [[space adaptation syndrome|space sickness]] during his mission, which affected his productivity. The first self-funded [[space tourist]] was [[Dennis Tito]] on board the Russian spacecraft Soyuz TM-3 on 28 April 2001.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Space travel milestones", "Self-funded travelers"], "text": "The first person to fly on an entirely privately funded mission was [[Mike Melvill]], piloting [[SpaceShipOne flight 15P]] on a suborbital journey, although he was a [[test pilot]] employed by [[Scaled Composites]] and not an actual paying space tourist. Seven others have paid the [[Russian Space Agency]] to fly into space: (1) [[Dennis Tito]] (American): 28 April – 6 May 2001 ([[International Space Station|ISS]]) (2) [[Mark Shuttleworth]] (South African): 25 April – 5 May 2002 (ISS) (3) [[Gregory Olsen]] (American): 1–11 October 2005 (ISS) (4) [[Anousheh Ansari]] (Iranian / American): 18–29 September 2006 (ISS) (5) [[Charles Simonyi]] (Hungarian / American): 7–21 April 2007 (ISS), 26 March – 8 April 2009 (ISS) (6) [[Richard Garriott]] (British / American): 12–24 October 2008 (ISS) (7) [[Guy Laliberté]] (Canadian): 30 September 2009 – 11 October 2009 (ISS)", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Training"], "text": "The first NASA astronauts were selected for training in 1959. Early in the space program, military jet test piloting and engineering training were often cited as prerequisites for selection as an astronaut at NASA, although neither John Glenn nor Scott Carpenter (of the [[Mercury Seven]]) had any university degree, in engineering or any other discipline at the time of their selection. Selection was initially limited to military pilots. The earliest astronauts for both the US and the USSR tended to be [[fighter aircraft|jet fighter]] pilots, and were often test pilots. Once selected, NASA astronauts go through twenty months of training in a variety of areas, including training for [[extravehicular activity]] in a facility such as NASA's [[Neutral Buoyancy Laboratory]]. Astronauts-in-training (astronaut candidates) may also experience short periods of [[weightlessness]] ([[Micro-g environment|microgravity]]) in an aircraft called the \"[[Vomit Comet]],\" the nickname given to a pair of modified [[KC-135]] (retired in 2000 and 2004, respectively, and replaced in 2005 with a [[McDonnell Douglas C-9|C-9]]) which perform [[Parabola|parabolic]] flights. Astronauts are also required to accumulate a number of flight hours in high-performance jet aircraft. This is mostly done in [[T-38 Talon|T-38 jet aircraft]] out of [[Ellington Field]], due to its proximity to the [[Johnson Space Center]]. Ellington Field is also where the [[Shuttle Training Aircraft]] is maintained and developed, although most flights of the aircraft are conducted from [[Edwards Air Force Base]]. Astronauts in training must learn how to control and fly the Space Shuttle and, it is vital that they are familiar with the International Space Station so they know what they must do when they get there.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Training", "NASA candidacy requirements"], "text": "(-) The candidate must be a citizen of the United States. (-) The candidate must complete a master's degree in a [[STEM]] field, including [[engineering]], [[biological science]], [[physical science]], [[computer science]] or [[mathematics]]. (-) The candidate must have at least two years of related professional experience obtained after degree completion or at least 1,000 hours [[pilot-in-command]] time on [[jet aircraft]]. (-) The candidate must be able to pass the NASA long-duration flight astronaut physical. (-) The candidate must also have skills in leadership, teamwork and communications. The master's degree requirement can also be met by: (-) Two years of work toward a doctoral program in a related science, technology, engineering or math field. (-) A completed [[Doctor of Medicine]] or [[Doctor of Osteopathic Medicine]] degree. (-) Completion of a nationally recognized test pilot school program.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Training", "NASA candidacy requirements", "Mission Specialist Educator"], "text": "(-) Applicants must have a bachelor's degree with teaching experience, including work at the kindergarten through twelfth grade level. An advanced degree, such as a master's degree or a doctoral degree, is not required, but is strongly desired. [[Educator Astronaut Project|Mission Specialist Educators]], or \"Educator Astronauts\", were first selected in 2004, and as of 2007, there are three NASA Educator astronauts: [[Joseph M. Acaba]], [[Richard R. Arnold]], and [[Dorothy Metcalf-Lindenburger]]. [[Barbara Morgan]], selected as back-up teacher to [[Christa McAuliffe]] in 1985, is considered to be the first Educator astronaut by the media, but she trained as a mission specialist. The Educator Astronaut program is a successor to the [[Teacher in Space]] program from the 1980s.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Health risks of space travel"], "text": "Astronauts are susceptible to a variety of health risks including [[decompression sickness]], [[barotrauma]], [[immunodeficiencies]], loss of [[bone]] and [[muscle]], loss of [[eyesight]], [[orthostatic intolerance]], [[sleep disturbances]], and [[radiation]] injury. A variety of large scale medical studies are being conducted in space via the [[National Space Biomedical Research Institute]] (NSBRI) to address these issues. Prominent among these is the [[Advanced Diagnostic Ultrasound in Microgravity]] Study in which astronauts (including former ISS commanders [[Leroy Chiao]] and [[Gennady Padalka]]) perform [[ultrasound]] scans under the guidance of remote experts to diagnose and potentially treat hundreds of medical conditions in space. This study's techniques are now being applied to cover professional and [[Olympic Games|Olympic]] [[sports injuries]] as well as ultrasound performed by non-expert operators in medical and high school students. It is anticipated that remote guided ultrasound will have application on Earth in [[emergency]] and [[rural health|rural care]] situations, where access to a trained physician is often rare. A 2006 Space Shuttle experiment found that ''[[Salmonella typhimurium]]'', a [[bacterium]] that can cause [[food poisoning]], became more virulent when cultivated in space. More recently, in 2017, [[bacteria]] were found to be more resistant to [[antibiotic]] and to thrive in the near-weightlessness of space. [[Microorganism]] have been observed to survive the [[vacuum]] of outer space. On 31 December 2012, a [[NASA]]-supported study reported that [[human spaceflight]] may harm the brain and accelerate the onset of [[Alzheimer's disease]]. In October 2015, the [[NASA Office of Inspector General]] issued a [[Effect of spaceflight on the human body|health hazards report]] related to [[human space exploration|space exploration]], including a [[human mission to Mars]]. Over the last decade, flight surgeons and scientists at NASA have seen a pattern of vision problems in astronauts on long-duration space missions. The syndrome, known as [[Visual impairment due to intracranial pressure|visual impairment intracranial pressure (VIIP)]], has been reported in nearly two-thirds of space explorers after long periods spent aboard the International Space Station (ISS). On 2 November 2017, scientists reported that significant changes in the position and structure of the [[brain]] have been found in astronauts who have taken [[Human spaceflight|trips in space]], based on [[Magnetic resonance imaging|MRI studies]]. Astronauts who took longer space trips were associated with greater brain changes. Being in space can be physiologically deconditioning on the body. It can affect the [[otolith]] organs and adaptive capabilities of the [[central nervous system]]. [[Zero gravity]] and [[cosmic rays]] can cause many implications for astronauts. In October 2018, [[NASA]]-funded researchers found that lengthy journeys into [[outer space]], including travel to the [[Mars|planet Mars]], may substantially damage the [[Gastrointestinal tract|gastrointestinal tissues]] of astronauts. The studies support earlier work that found such journeys could significantly damage the [[brain]] of astronauts, and [[ageing|age]] them prematurely. Researchers in 2018 reported, after detecting the presence on the [[International Space Station]] (ISS) of five ''[[Enterobacter|Enterobacter bugandensis]]'' bacterial strains, none [[pathogen]] to humans, that [[microorganism]] on ISS should be carefully monitored to continue assuring a medically healthy environment for astronauts.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Health risks of space travel"], "text": "A study by Russian scientists published in April 2019 stated that astronauts facing space [[radiation]] could face temporary hindrance of their [[memory]] centers. While this does not affect their intellectual capabilities, it temporarily hinders formation of new cells in brain's memory centers. The study conducted by Moscow Institute of Physics and Technology (MIPT) concluded this after they observed that mice exposed to neutron and gamma radiation did not impact the rodents' intellectual capabilities. A 2020 [[clinical trial|study]] conducted on the brains of eight male Russian cosmonauts after they returned from long stays aboard the [[International Space Station]] showed that long-duration [[human spaceflight|spaceflight]] causes many [[physiological]] adaptions, including macro- and [[microstructure|microstructural]] changes. While [[scientists]] still know little about the effects of [[spaceflight]] on [[brain]] structure, this study showed that space travel can lead to new [[fine motor skill|motor skills (dexterity)]], but also slightly weaker [[visual perception|vision]], both of which could possibly be long lasting. It was the first study to provide clear evidence of [[neuroplasticity|sensorimotor neuroplasticity]], which is the brain's ability to change through growth and reorganization.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Food and drink"], "text": "An astronaut on the International Space Station requires about mass of food per meal each day (inclusive of about packaging mass per meal). Space Shuttle astronauts worked with nutritionists to select menus that appealed to their individual tastes. Five months before flight, menus were selected and analyzed for nutritional content by the shuttle dietician. Foods are tested to see how they will react in a reduced gravity environment. Caloric requirements are determined using a basal energy expenditure (BEE) formula. On Earth, the average American uses about of water every day. On board the ISS astronauts limit water use to only about per day.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Insignia"], "text": "In Russia, cosmonauts are awarded [[Pilot-Cosmonaut of the Russian Federation]] upon completion of their missions, often accompanied with the award of [[Hero of the Russian Federation]]. This follows the practice established in the USSR where cosmonauts were usually awarded the title [[Hero of the Soviet Union]]. At NASA, those who complete astronaut candidate training receive a silver [[Astronaut Badge#NASA Astronaut Pins|lapel pin]]. Once they have flown in space, they receive a gold pin. U.S. astronauts who also have active-duty military status receive a special qualification badge, known as the [[Astronaut Badge]], after participation on a spaceflight. The [[United States Air Force]] also presents an Astronaut Badge to its pilots who exceed in altitude.", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": ["Deaths"], "text": ", eighteen astronauts (fourteen men and four women) have lost their lives during four space flights. By nationality, thirteen were American (including one born in India), four were Russian ([[Soviet Union]]), and one was Israeli. , eleven people (all men) have lost their lives training for spaceflight: eight Americans and three Russians. Six of these were in crashes of training jet aircraft, one drowned during water recovery training, and four were due to fires in pure oxygen environments. Astronaut [[David Scott]] left a memorial consisting of a statuette titled ''[[Fallen Astronaut]]'' on the surface of the Moon during his 1971 [[Apollo 15]] mission, along with a list of the names of eight of the astronauts and six cosmonauts known at the time to have died in service. The [[Space Mirror Memorial]], which stands on the grounds of the [[Kennedy Space Center Visitor Complex]], is maintained by the Astronauts Memorial Foundation and commemorates the lives of the men and women who have died during spaceflight and during training in the space programs of the United States. In addition to twenty NASA career astronauts, the memorial includes the names of an [[X-15]] test pilot, a [[U.S. Air Force]] officer who died while training for a then-classified military space program, and a civilian [[spaceflight participant]].", "id": "664", "title": "Astronaut", "categories": ["Astronauts", "Science occupations", "1959 introductions"], "seealso": []}
{"headers": [], "text": "'''''A Modest Proposal For preventing the Children of Poor People From being a Burthen to Their Parents or Country, and For making them Beneficial to the Publick''''', commonly referred to as '''''A Modest Proposal''''', is a [[Juvenalian satire|Juvenalian satirical]] essay written and published anonymously by [[Jonathan Swift]] in 1729. The essay suggests that the impoverished Irish might ease their economic troubles by [[human cannibalism|selling their children as food]] to rich gentlemen and ladies. This satirical [[hyperbole]] mocked heartless attitudes towards the poor, as well as [[Kingdom of Great Britain|British]] policy toward the Irish in general. In English writing, the phrase \"a [[wikt:modest proposal|modest proposal]]\" is now conventionally an allusion to this style of straight-faced satire.", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Synopsis"], "text": "Swift's essay is widely held to be one of the greatest examples of sustained [[irony]] in the history of the English language. Much of its shock value derives from the fact that the first portion of the essay describes the plight of starving beggars in Ireland, so that the reader is unprepared for the surprise of Swift's solution when he states: \"A young healthy child well nursed, is, at a year old, a most delicious nourishing and wholesome food, whether stewed, roasted, baked, or boiled; and I make no doubt that it will equally serve in a [[fricassee]], or a [[ragout]].\" Swift goes to great lengths to support his argument, including a list of possible preparation styles for the children, and calculations showing the financial benefits of his suggestion. He uses methods of argument throughout his essay which [[Parody|lampoon]] the then-influential [[William Petty]] and the [[Social engineering (political science)|social engineering]] popular among followers of [[Francis Bacon]]. These lampoons include [[appeal to authority|appealing to the authority]] of \"a very knowing American of my acquaintance in London\" and \"the famous [[George Psalmanazar|Psalmanazar]], a native of the island [[Formosa]]\" (who had already confessed to ''not'' being from Formosa in 1706). In the tradition of Roman satire, Swift introduces the reforms he is actually suggesting by [[paralipsis]]:", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Population solutions"], "text": "George Wittkowsky argued that Swift's main target in ''A Modest Proposal'' was not the conditions in Ireland, but rather the can-do spirit of the times that led people to devise a number of illogical schemes that would purportedly solve social and economic ills. Swift was especially attacking projects that tried to fix population and labour issues with a simple cure-all solution. A memorable example of these sorts of schemes \"involved the idea of running the poor through a [[joint-stock company]]\". In response, Swift's ''Modest Proposal'' was \"a burlesque of projects concerning the poor\" that were in vogue during the early 18th century. ''A Modest Proposal'' also targets the calculating way people perceived the poor in designing their projects. The pamphlet targets reformers who \"regard people as commodities\". In the piece, Swift adopts the \"technique of a political arithmetician\" to show the utter ridiculousness of trying to prove any proposal with dispassionate statistics. Critics differ about Swift's intentions in using this faux-mathematical philosophy. [[Edmund Wilson]] argues that statistically \"the logic of the 'Modest proposal' can be compared with defence of crime (arrogated to [[Karl Marx|Marx]]) in which he argues that crime takes care of the superfluous population\". Wittkowsky counters that Swift's satiric use of statistical analysis is an effort to enhance his satire that \"springs from a spirit of bitter mockery, not from the delight in calculations for their own sake\".", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Rhetoric"], "text": "Author Charles K. Smith argues that Swift's rhetorical style persuades the reader to detest the speaker and pity the Irish. Swift's specific strategy is twofold, using a \"trap\" to create sympathy for the Irish and a dislike of the narrator who, in the span of one sentence, \"details vividly and with rhetorical emphasis the grinding poverty\" but feels emotion solely for members of his own class. Swift's use of gripping details of poverty and his narrator's cool approach towards them create \"two opposing points of view\" that \"alienate the reader, perhaps unconsciously, from a narrator who can view with 'melancholy' detachment a subject that Swift has directed us, rhetorically, to see in a much less detached way.\" Swift has his proposer further degrade the Irish by using language ordinarily reserved for animals. Lewis argues that the speaker uses \"the vocabulary of animal husbandry\" to describe the Irish. Once the children have been commodified, Swift's rhetoric can easily turn \"people into animals, then meat, and from meat, logically, into tonnage worth a price per pound\". Swift uses the proposer's serious tone to highlight the absurdity of his proposal. In making his argument, the speaker uses the conventional, textbook-approved order of argument from Swift's time (which was derived from the Latin rhetorician [[Quintilian]]). The contrast between the \"careful control against the almost inconceivable perversion of his scheme\" and \"the ridiculousness of the proposal\" create a situation in which the reader has \"to consider just what perverted values and assumptions would allow such a diligent, thoughtful, and conventional man to propose so perverse a plan\".", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Influences"], "text": "Scholars have speculated about which earlier works Swift may have had in mind when he wrote ''A Modest Proposal''.", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Influences", "Tertullian's ''Apology''"], "text": "James William Johnson argues that ''A Modest Proposal'' was largely influenced and inspired by [[Tertullian]]'s ''[[Apologeticus|Apology]]'': a satirical attack against early Roman persecution of Christianity. Johnson believes that Swift saw major similarities between the two situations. Johnson notes Swift's obvious affinity for Tertullian and the bold stylistic and structural similarities between the works ''A Modest Proposal'' and ''Apology''. In structure, Johnson points out the same central theme, that of cannibalism and the eating of babies as well as the same final argument, that \"human depravity is such that men will attempt to justify their own cruelty by accusing their victims of being lower than human\". Stylistically, Swift and Tertullian share the same command of sarcasm and language. In agreement with Johnson, Donald C. Baker points out the similarity between both authors' tones and use of irony. Baker notes the uncanny way that both authors imply an ironic \"justification by ownership\" over the subject of sacrificing children—Tertullian while attacking pagan parents, and Swift while attacking the English mistreatment of the Irish poor.", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Influences", "Defoe's ''The Generous Projector''"], "text": "It has also been argued that ''A Modest Proposal'' was, at least in part, a response to the 1728 essay ''The Generous Projector or, A Friendly Proposal to Prevent Murder and Other Enormous Abuses, By Erecting an Hospital for Foundlings and Bastard Children'' by Swift's rival [[Daniel Defoe]].", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Influences", "Mandeville's ''Modest Defence of Publick Stews''"], "text": "[[Bernard Mandeville]]'s ''Modest Defence of Publick Stews'' asked to introduce public and state controlled [[bordello]]. The 1726 paper acknowledges women's interests andwhile not being a completely satirical texthas also been discussed as an inspiration for Jonathan Swift's title. Mandeville had by 1705 already become famous for the [[The Fable of the Bees|Fable of The Bees]] and deliberations on private vices and public benefits.", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Influences", "John Locke's ''First Treatise of Government''"], "text": "[[John Locke]] commented: \"Be it then as Sir Robert says, that Anciently, it was usual for Men to sell and Castrate their Children. Let it be, that they exposed them; Add to it, if you please, for this is still greater Power, ''that they begat them for their Tables to fat and eat them'': If this proves a right to do so, we may, by the same Argument, justifie Adultery, Incest and Sodomy, for there are examples of these too, both Ancient and Modern; Sins, which I suppose, have the Principle Aggravation from this, that they cross the main intention of Nature, which willeth the increase of Mankind, and the continuation of the Species in the highest perfection, and the distinction of Families, with the Security of the Marriage Bed, as necessary thereunto\". (First Treatise, sec. 59).", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Economic themes"], "text": "Robert Phiddian's article \"Have you eaten yet? The Reader in A Modest Proposal\" focuses on two aspects of ''A Modest Proposal'': the voice of Swift and the voice of the Proposer. Phiddian stresses that a reader of the pamphlet must learn to distinguish between the satirical voice of Jonathan Swift and the apparent economic projections of the Proposer. He reminds readers that \"there is a gap between the narrator's meaning and the text's, and that a moral-political argument is being carried out by means of parody\". While Swift's proposal is obviously not a serious economic proposal, George Wittkowsky, author of \"Swift's Modest Proposal: The Biography of an Early Georgian Pamphlet\", argues that to understand the piece fully it is important to understand the economics of Swift's time. Wittowsky argues that not enough critics have taken the time to focus directly on the mercantilism and theories of labour in 18th century England. \"If one regards the ''Modest Proposal'' simply as a criticism of condition, about all one can say is that conditions were bad and that Swift's irony brilliantly underscored this fact\".", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Economic themes", "\"People are the riches of a nation\""], "text": "At the start of a new industrial age in the 18th century, it was believed that \"people are the riches of the nation\", and there was a general faith in an economy that paid its workers low wages because high wages meant workers would work less. Furthermore, \"in the mercantilist view no child was too young to go into industry\". In those times, the \"somewhat more humane attitudes of an earlier day had all but disappeared and the laborer had come to be regarded as a commodity\". Louis A. Landa composed a conducive analysis when he noted that it would have been healthier for the Irish economy to more appropriately utilize their human assets by giving the people an opportunity to \"become a source of wealth to the nation\" or else they \"must turn to begging and thievery\". This opportunity may have included giving the farmers more coin to work for, diversifying their professions, or even consider enslaving their people to lower coin usage and build up financial stock in Ireland. Landa wrote that, \"Swift is maintaining that the maxim—people are the riches of a nation—applies to Ireland only if Ireland is permitted slavery or cannibalism\" Landa presents Swift's ''A Modest Proposal'' as a critique of the popular and unjustified maxim of mercantilism in the 18th century that \"people are the riches of a nation\". Swift presents the dire state of Ireland and shows that mere population itself, in Ireland's case, did not always mean greater wealth and economy. The uncontrolled maxim fails to take into account that a person who does not produce in an economic or political way makes a country poorer, not richer. Swift also recognises the implications of this fact in making mercantilist philosophy a paradox: the wealth of a country is based on the poverty of the majority of its citizens. Swift however, Landa argues, is not merely criticising economic maxims but also addressing the fact that England was denying Irish citizens their natural rights and dehumanising them by viewing them as a mere commodity.", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["The public's reaction"], "text": "Swift's essay created a backlash within the community after its publication. The work was aimed at the aristocracy, and they responded in turn. Several members of society wrote to Swift regarding the work. [[Allen Bathurst, 1st Earl Bathurst|Lord Bathurst]]'s letter intimated that he certainly understood the message, and interpreted it as a work of comedy: 12 February 1729–30:\"I did immediately propose it to Lady Bathurst, as your advice, particularly for her last boy, which was born the plumpest, finest thing, that could be seen; but she fell in a passion, and bid me send you word, that she would not follow your direction, but that she would breed him up to be a parson, and he should live upon the fat of the land; or a lawyer, and then, instead of being eat himself, he should devour others. You know women in passion never mind what they say; but, as she is a very reasonable woman, I have almost brought her over now to your opinion; and having convinced her, that as matters stood, we could not possibly maintain all the nine, she does begin to think it reasonable the youngest should raise fortunes for the eldest: and upon that foot a man may perform family duty with more courage and zeal; for, if he should happen to get twins, the selling of one might provide for the other. Or if, by any accident, while his wife lies in with one child, he should get a second upon the body of another woman, he might dispose of the fattest of the two, and that would help to breed up the other.The more I think upon this scheme, the more reasonable it appears to me; and it ought by no means to be confined to Ireland; for, in all probability, we shall, in a very little time, be altogether as poor here as you are there. I believe, indeed, we shall carry it farther, and not confine our luxury only to the eating of children; for I happened to peep the other day into a large assembly [Parliament] not far from Westminster-hall, and I found them roasting a great fat fellow, [Walpole again] For my own part, I had not the least inclination to a slice of him; but, if I guessed right, four or five of the company had a devilish mind to be at him. Well, adieu, you begin now to wish I had ended, when I might have done it so conveniently\".", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": ["Modern usage"], "text": "''A Modest Proposal'' is included in many literature courses as an example of [[Satire#Early modern western satire|early modern western satire]]. It also serves as an introduction to the concept and use of argumentative language, lending itself to secondary and post-secondary essay courses. Outside of the realm of English studies, ''A Modest Proposal'' is included in many comparative and global literature and history courses, as well as those of numerous other disciplines in the arts, humanities, and even the social sciences. The essay's approach has been copied many times. In his book ''A Modest Proposal'' (1984), the evangelical author [[Francis Schaeffer]] emulated Swift's work in a social conservative polemic against abortion and [[euthanasia]], imagining a future [[dystopia]] that advocates [[recycling]] of aborted [[embryos]], [[fetuses]], and some disabled infants with compound intellectual, physical and physiological difficulties. (Such [[Baby Doe Rules]] cases were then a major concern of the US [[anti-abortion]] movement of the early 1980s, which viewed selective treatment of those infants as [[disability discrimination]].) In his book ''A Modest Proposal for America'' (2013), statistician [[Howard Friedman]] opens with a satirical reflection of the extreme drive to fiscal stability by ultra-conservatives. In the 1998 edition of ''[[The Handmaid's Tale]]'' by [[Margaret Atwood]] there is a quote from ''A Modest Proposal'' before the introduction. ''[[A Modest Video Game Proposal]]'' is the title of an open letter sent by activist/former attorney [[Jack Thompson (activist)|Jack Thompson]] on 10 October 2005. He proposed that someone should \"create, manufacture, distribute, and sell a video game\" that would allow players to act out a scenario in which the game character kills video game developers. [[Hunter S. Thompson]]'s ''[[Fear and Loathing in America|Fear and Loathing in America: The Brutal Odyssey of an Outlaw Journalist]]'' includes a letter in which he uses Swift's approach in connection with the [[Vietnam War]]. Thompson writes a letter to a local [[Aspen, Colorado|Aspen]] newspaper informing them that, on Christmas Eve, he is going to use [[napalm]] to burn a number of dogs and hopefully any humans they find. The letter protests against the burning of Vietnamese people occurring overseas. The 2013 horror film ''Butcher Boys,'' written by the original [[The Texas Chain Saw Massacre]] scribe [[Kim Henkel]], is said to be an updating of Jonathan Swift's ''A Modest Proposal.'' Henkel imagined the descendants of folks who actually took Swift up on his proposal. The film opens with a quote from J. Swift.  On 30 November 2017, Jonathan Swift's 350th birthday, ''[[The Washington Post]]'' published a column entitled \"Why Alabamians should consider eating Democrats' babies\", by [[Alexandra Petri]]. In July 2019, [[E. Jean Carroll]] published a book titled ''[[What Do We Need Men For?: A Modest Proposal]]'', discussing problematic behaviour of male humans. On 3 October 2019, a satirist spoke up at an event for [[Alexandria Ocasio-Cortez]], claiming that a solution to the [[climate crisis]] was \"we need to eat the babies\". The individual also wore a T-shirt saying \"Save The Planet, Eat The Children\". This stunt was understood by many as a modern application of ''A Modest Proposal''.", "id": "665", "title": "A Modest Proposal", "categories": ["Essays by Jonathan Swift", "Satirical essays", "Pamphlets", "18th-century essays", "Works published anonymously", "British satire", "1729 in Great Britain", "Cannibalism in fiction", "1729 books"], "seealso": []}
{"headers": [], "text": "The '''alkali metals''' consist of the [[chemical element]] [[lithium]] (Li), [[sodium]] (Na), [[potassium]] (K), [[rubidium]] (Rb), [[caesium]] (Cs), and [[francium]] (Fr). Together with [[hydrogen]] they constitute [[Group (periodic table)#Group names|group 1]], which lies in the [[s-block]] of the [[periodic table]]. All alkali metals have their outermost electron in an [[atomic orbital|s-orbital]]: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of [[periodic trends|group trends]] in properties in the periodic table, with elements exhibiting well-characterised [[homology (chemistry)|homologous]] behaviour. This family of elements is also known as the '''lithium family''' after its leading element. The alkali metals are all shiny, [[hardness|soft]], highly [[reactivity (chemistry)|reactive]] metals at [[standard temperature and pressure]] and readily lose their [[valence electron|outermost electron]] to form [[cations]] with [[electric charge|charge]] +1. They can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to [[redox|oxidation]] by atmospheric moisture and [[oxygen]] (and in the case of lithium, [[nitrogen]]). Because of their high reactivity, they must be stored under oil to prevent reaction with air, and are found naturally only in [[salt (chemistry)|salts]] and never as the free elements. Caesium, the fifth alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones. All of the discovered alkali metals occur in nature as their compounds: in order of [[abundance of the chemical elements|abundance]], sodium is the most abundant, followed by potassium, lithium, rubidium, caesium, and finally francium, which is very rare due to its extremely high [[radioactivity]]; francium occurs only in minute [[trace radioisotope|traces]] in nature as an intermediate step in some obscure side branches of the natural [[decay chain]]. Experiments have been conducted to attempt the synthesis of [[ununennium]] (Uue), which is likely to be the next member of the group; none was successful. However, ununennium may not be an alkali metal due to [[relativistic quantum chemistry|relativistic effects]], which are predicted to have a large influence on the chemical properties of [[superheavy element]]; even if it does turn out to be an alkali metal, it is predicted to have some differences in physical and chemical properties from its lighter homologues. Most alkali metals have many different applications. One of the best-known applications of the pure elements is the use of rubidium and caesium in [[atomic clock]], of which caesium atomic clocks form the basis of the [[second]]. A common application of the compounds of sodium is the [[sodium-vapour lamp]], which emits light very efficiently. [[Salt|Table salt]], or sodium chloride, has been used since antiquity. [[Lithium (medication)|Lithium]] finds use as a psychiatric medication and as an [[anode]] in [[lithium batteries]]. Sodium and potassium are also [[essential element]], having major biological roles as [[electrolytes]], and although the other alkali metals are not essential, they also have various effects on the body, both beneficial and harmful.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["History"], "text": "Sodium compounds have been known since ancient times; salt ([[sodium chloride]]) has been an important commodity in human activities, as testified by the English word ''salary'', referring to ''salarium'', money paid to Roman soldiers for the purchase of salt. While [[potash]] has been used since ancient times, it was not understood for most of its history to be a fundamentally different substance from sodium mineral salts. [[Georg Ernst Stahl]] obtained experimental evidence which led him to suggest the fundamental difference of sodium and potassium salts in 1702, and [[Henri-Louis Duhamel du Monceau]] was able to prove this difference in 1736. The exact chemical composition of potassium and sodium compounds, and the status as chemical element of potassium and sodium, was not known then, and thus [[Antoine Lavoisier]] did not include either alkali in his list of chemical elements in 1789. Pure potassium was first isolated in 1807 in England by [[Humphry Davy]], who derived it from [[Potassium hydroxide|caustic potash]] (KOH, potassium hydroxide) by the use of electrolysis of the molten salt with the newly invented [[voltaic pile]]. Previous attempts at electrolysis of the aqueous salt were unsuccessful due to potassium's extreme reactivity. Potassium was the first metal that was isolated by electrolysis. Later that same year, Davy reported extraction of sodium from the similar substance [[caustic soda]] (NaOH, lye) by a similar technique, demonstrating the elements, and thus the salts, to be different. [[Petalite]] ([[Lithium|Li]] [[Aluminium|Al]] [[Silicon|Si]][[Oxygen|O]]) was discovered in 1800 by the [[Brazil]] chemist [[José Bonifácio de Andrada]] in a mine on the island of [[Utö, Sweden]]. However, it was not until 1817 that [[Johan August Arfwedson]], then working in the laboratory of the chemist [[Jöns Jacob Berzelius]], [[discovery of the chemical elements|detected]] the presence of a new element while analysing petalite [[ore]]. This new element was noted by him to form compounds similar to those of sodium and potassium, though its [[lithium carbonate|carbonate]] and [[lithium hydroxide|hydroxide]] were less [[solubility|soluble in water]] and more [[Base (chemistry)|alkaline]] than the other alkali metals. Berzelius gave the unknown material the name \"''lithion''/''lithina''\", from the [[Ancient Greek|Greek]] word ''λιθoς'' (transliterated as ''lithos'', meaning \"stone\"), to reflect its discovery in a solid mineral, as opposed to potassium, which had been discovered in plant ashes, and sodium, which was known partly for its high abundance in animal blood. He named the metal inside the material \"''lithium''\". Lithium, sodium, and potassium were part of the discovery of [[periodic table|periodicity]], as they are among a series of triads of elements in the same [[group (periodic table)|group]] that were noted by [[Johann Wolfgang Döbereiner]] in 1850 as having similar properties.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["History"], "text": "Rubidium and caesium were the first elements to be discovered using the [[spectroscope]], invented in 1859 by [[Robert Bunsen]] and [[Gustav Kirchhoff]]. The next year, they discovered caesium in the [[mineral water]] from [[Bad Dürkheim]], Germany. Their discovery of rubidium came the following year in [[Heidelberg]], Germany, finding it in the mineral [[lepidolite]]. The names of rubidium and caesium come from the most prominent lines in their [[emission spectrum|emission spectra]]: a bright red line for rubidium (from the [[Latin]] word ''rubidus'', meaning dark red or bright red), and a sky-blue line for caesium (derived from the Latin word ''caesius'', meaning sky-blue). Around 1865 [[John Alexander Reina Newlands|John Newlands]] produced a series of papers where he listed the elements in order of increasing atomic weight and similar physical and chemical properties that recurred at intervals of eight; he likened such periodicity to the [[octave]] of music, where notes an octave apart have similar musical functions. His version put all the alkali metals then known (lithium to caesium), as well as [[copper]], [[silver]], and [[thallium]] (which show the +1 oxidation state characteristic of the alkali metals), together into a group. His table placed hydrogen with the [[halogen]]. After 1869, [[Dmitri Mendeleev]] proposed his periodic table placing lithium at the top of a group with sodium, potassium, rubidium, caesium, and thallium. Two years later, Mendeleev revised his table, placing hydrogen in group 1 above lithium, and also moving thallium to the [[boron group]]. In this 1871 version, copper, silver, and [[gold]] were placed twice, once as part of [[group 11 element|group IB]], and once as part of a \"group VIII\" encompassing today's groups [[group 8 element|8]] to 11. After the introduction of the 18-column table, the group IB elements were moved to their current position in the [[d-block]], while alkali metals were left in ''group IA''. Later the group's name was changed to ''group 1'' in 1988. The [[trivial name]] \"alkali metals\" comes from the fact that the hydroxides of the group 1 elements are all strong [[alkali]] when dissolved in water. There were at least four erroneous and incomplete discoveries before [[Marguerite Perey]] of the [[Curie Institute (Paris)|Curie Institute]] in Paris, France discovered francium in 1939 by purifying a sample of [[actinium-227]], which had been reported to have a decay energy of 220 [[electronvolt|keV]]. However, Perey noticed decay particles with an energy level below 80 keV. Perey thought this decay activity might have been caused by a previously unidentified decay product, one that was separated during purification, but emerged again out of the pure [[actinium]]-227. Various tests eliminated the possibility of the unknown element being [[thorium]], [[radium]], [[lead]], [[bismuth]], or [[thallium]]. The new product exhibited chemical properties of an alkali metal (such as coprecipitating with caesium salts), which led Perey to believe that it was element 87, caused by the [[alpha decay]] of actinium-227. Perey then attempted to determine the proportion of [[beta decay]] to alpha decay in actinium-227. Her first test put the alpha branching at 0.6%, a figure that she later revised to 1%.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["History"], "text": "The next element below francium ([[Mendeleev's predicted elements|eka]]-francium) in the periodic table would be [[ununennium]] (Uue), element 119. The synthesis of ununennium was first attempted in 1985 by bombarding a target of [[einsteinium]]-254 with [[calcium]]-48 ions at the superHILAC accelerator at Berkeley, California. No atoms were identified, leading to a limiting yield of 300 [[barn (unit)|nb]].  + → * → ''no atoms'' It is highly unlikely that this reaction will be able to create any atoms of ununennium in the near future, given the extremely difficult task of making sufficient amounts of einsteinium-254, which is favoured for production of [[superheavy element|ultraheavy elements]] because of its large mass, relatively long half-life of 270 days, and availability in significant amounts of several micrograms, to make a large enough target to increase the sensitivity of the experiment to the required level; einsteinium has not been found in nature and has only been produced in laboratories, and in quantities smaller than those needed for effective synthesis of superheavy elements. However, given that ununennium is only the first [[period 8 element]] on the [[extended periodic table]], it may well be discovered in the near future through other reactions, and indeed an attempt to synthesise it is currently ongoing in Japan. Currently, none of the period 8 elements has been discovered yet, and it is also possible, due to [[nucleon drip line|drip instabilities]], that only the lower period 8 elements, up to around element 128, are physically possible. No attempts at synthesis have been made for any heavier alkali metals: due to their extremely high atomic number, they would require new, more powerful methods and technology to make.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Occurrence", "In the Solar System"], "text": "The [[Oddo–Harkins rule]] holds that elements with even atomic numbers are more common that those with odd atomic numbers, with the exception of hydrogen. This rule argues that elements with odd atomic numbers have one unpaired proton and are more likely to capture another, thus increasing their atomic number. In elements with even atomic numbers, protons are paired, with each member of the pair offsetting the spin of the other, enhancing stability. All the alkali metals have odd atomic numbers and they are not as common as the elements with even atomic numbers adjacent to them (the [[noble gas]] and the [[alkaline earth metal]]) in the Solar System. The heavier alkali metals are also less abundant than the lighter ones as the alkali metals from rubidium onward can only be synthesised in [[supernova]] and not in [[stellar nucleosynthesis]]. Lithium is also much less abundant than sodium and potassium as it is poorly synthesised in both [[Big Bang nucleosynthesis]] and in stars: the Big Bang could only produce trace quantities of lithium, [[beryllium]] and [[boron]] due to the absence of a stable nucleus with 5 or 8 [[nucleon]], and stellar nucleosynthesis could only pass this bottleneck by the [[triple-alpha process]], fusing three helium nuclei to form [[carbon]], and skipping over those three elements.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Occurrence", "On Earth"], "text": "The [[Earth]] formed from the same cloud of matter that formed the Sun, but the planets acquired different compositions during the [[formation and evolution of the solar system]]. In turn, the [[history of Earth|natural history of the Earth]] caused parts of this planet to have differing concentrations of the elements. The mass of the Earth is approximately 5.98 kg. It is composed mostly of [[iron]] (32.1%), [[oxygen]] (30.1%), [[silicon]] (15.1%), [[magnesium]] (13.9%), [[sulfur]] (2.9%), [[nickel]] (1.8%), [[calcium]] (1.5%), and [[aluminium]] (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Due to [[planetary differentiation]], the core region is believed to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. The alkali metals, due to their high reactivity, do not occur naturally in pure form in nature. They are [[Goldschmidt classification|lithophiles]] and therefore remain close to the Earth's surface because they combine readily with [[oxygen]] and so associate strongly with [[silica]], forming relatively low-density minerals that do not sink down into the Earth's core. Potassium, rubidium and caesium are also [[incompatible element]] due to their large [[ionic radius|ionic radii]]. Sodium and potassium are very abundant in earth, both being among the ten [[abundance of elements in Earth's crust|most common elements in Earth's crust]]; sodium makes up approximately 2.6% of the [[Earth]]'s crust measured by weight, making it the [[Abundance of the chemical elements|sixth most abundant element]] overall and the most abundant alkali metal. Potassium makes up approximately 1.5% of the Earth's crust and is the seventh most abundant element. Sodium is found in many different minerals, of which the most common is ordinary salt (sodium chloride), which occurs in vast quantities dissolved in seawater. Other solid deposits include [[Halite (mineral)|halite]], [[amphibole]], [[cryolite]], [[nitratine]], and [[zeolite]]. Many of these solid deposits occur as a result of ancient seas evaporating, which still occurs now in places such as [[Utah]]'s [[Great Salt Lake]] and the [[Dead Sea]]. Despite their near-equal abundance in Earth's crust, sodium is far more common than potassium in the ocean, both because potassium's larger size makes its salts less soluble, and because potassium is bound by silicates in soil and what potassium leaches is absorbed far more readily by plant life than sodium. Despite its chemical similarity, lithium typically does not occur together with sodium or potassium due to its smaller size. Due to its relatively low reactivity, it can be found in seawater in large amounts; it is estimated that seawater is approximately 0.14 to 0.25 parts per million (ppm) or 25 [[micromolar]]. Its diagonal relationship with magnesium often allows it to replace magnesium in [[ferromagnesium]] minerals, where its crustal concentration is about 18 [[parts per million|ppm]], comparable to that of [[gallium]] and [[niobium]]. Commercially, the most important lithium mineral is [[spodumene]], which occurs in large deposits worldwide.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Occurrence", "On Earth"], "text": "Rubidium is approximately as abundant as [[zinc]] and more abundant than copper. It occurs naturally in the minerals [[leucite]], [[pollucite]], [[carnallite]], [[zinnwaldite]], and [[lepidolite]], although none of these contain only rubidium and no other alkali metals. Caesium is more abundant than some commonly known elements, such as [[antimony]], [[cadmium]], [[tin]], and [[tungsten]], but is much less abundant than rubidium. [[Francium-223]], the only naturally occurring isotope of francium, is the [[decay product|product]] of the [[alpha decay]] of actinium-227 and can be found in trace amounts in [[uranium]] minerals. In a given sample of uranium, there is estimated to be only one francium atom for every 10 uranium atoms. It has been calculated that there are at most 30 grams of francium in the [[crust (geology)|earth's crust]] at any time, due to its extremely short [[half-life]] of 22 minutes.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Physical and chemical"], "text": "The physical and chemical properties of the alkali metals can be readily explained by their having an ns valence [[electron configuration]], which results in weak [[metallic bonding]]. Hence, all the alkali metals are soft and have low [[density|densities]], [[melting point|melting]] and [[boiling point]], as well as [[heat of sublimation|heats of sublimation]], [[heat of vaporization|vaporisation]], and [[dissociation (chemistry)|dissociation]]. They all crystallise in the [[body-centered cubic]] crystal structure, and have distinctive [[flame test|flame colours]] because their outer s electron is very easily excited. The ns configuration also results in the alkali metals having very large [[atomic radius|atomic]] and [[ionic radius|ionic radii]], as well as very high [[thermal conductivity|thermal]] and [[electrical conductivity]]. Their chemistry is dominated by the loss of their lone valence electron in the outermost s-orbital to form the +1 oxidation state, due to the ease of ionising this electron and the very high second ionisation energy. Most of the chemistry has been observed only for the first five members of the group. The chemistry of francium is not well established due to its extreme [[radioactive decay|radioactivity]]; thus, the presentation of its properties here is limited. What little is known about francium shows that it is very close in behaviour to caesium, as expected. The physical properties of francium are even sketchier because the bulk element has never been observed; hence any data that may be found in the literature are certainly speculative extrapolations. The alkali metals are more similar to each other than the elements in any other [[group (periodic table)|group]] are to each other. Indeed, the similarity is so great that it is quite difficult to separate potassium, rubidium, and caesium, due to their similar [[ionic radius|ionic radii]]; lithium and sodium are more distinct. For instance, when moving down the table, all known alkali metals show increasing [[atomic radius]], decreasing [[electronegativity]], increasing [[Reactivity (chemistry)|reactivity]], and decreasing melting and boiling points as well as heats of fusion and vaporisation. In general, their [[density|densities]] increase when moving down the table, with the exception that potassium is less dense than sodium. One of the very few properties of the alkali metals that does not display a very smooth trend is their [[reduction potential]]: lithium's value is anomalous, being more negative than the others. This is because the Li ion has a very high [[hydration energy]] in the gas phase: though the lithium ion disrupts the structure of water significantly, causing a higher change in entropy, this high hydration energy is enough to make the reduction potentials indicate it as being the most electropositive alkali metal, despite the difficulty of ionising it in the gas phase.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Physical and chemical"], "text": "The stable alkali metals are all silver-coloured metals except for caesium, which has a pale golden tint: it is one of only three metals that are clearly coloured (the other two being copper and gold). Additionally, the heavy [[alkaline earth metal]] [[calcium]], [[strontium]], and [[barium]], as well as the divalent [[lanthanide]] [[europium]] and [[ytterbium]], are pale yellow, though the colour is much less prominent than it is for caesium. Their lustre tarnishes rapidly in air due to oxidation. They all crystallise in the [[body-centered cubic]] crystal structure, and have distinctive [[flame test|flame colours]] because their outer s electron is very easily excited. Indeed, these flame test colours are the most common way of identifying them since all their salts with common ions are soluble. All the alkali metals are highly reactive and are never found in elemental forms in nature. Because of this, they are usually stored in [[mineral oil]] or [[kerosene]] (paraffin oil). They react aggressively with the [[halogen]] to form the [[alkali metal halide]], which are white [[ionic crystal]] compounds that are all [[solubility|soluble]] in water except [[lithium fluoride]] ([[lithium|Li]] [[fluorine|F]]). The alkali metals also react with water to form strongly [[alkali]] [[hydroxide]] and thus should be handled with great care. The heavier alkali metals react more vigorously than the lighter ones; for example, when dropped into water, caesium produces a larger explosion than potassium if the same number of moles of each metal is used. The alkali metals have the lowest first [[ionization energy|ionisation energies]] in their respective periods of the [[periodic table]] because of their low [[effective nuclear charge]] and the ability to attain a [[noble gas]] configuration by losing just one [[electron]]. Not only do the alkali metals react with water, but also with proton donors like [[alcohol]] and [[phenols]], gaseous [[ammonia]], and [[alkyne]], the last demonstrating the phenomenal degree of their reactivity. Their great power as reducing agents makes them very useful in liberating other metals from their oxides or halides.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Physical and chemical"], "text": "The second ionisation energy of all of the alkali metals is very high as it is in a full shell that is also closer to the nucleus; thus, they almost always lose a single electron, forming cations. The [[alkalide]] are an exception: they are unstable compounds which contain alkali metals in a −1 oxidation state, which is very unusual as before the discovery of the alkalides, the alkali metals were not expected to be able to form [[anion]] and were thought to be able to appear in [[salt (chemistry)|salts]] only as cations. The alkalide anions have filled [[s-orbital|s-subshells]], which gives them enough stability to exist. All the stable alkali metals except lithium are known to be able to form alkalides, and the alkalides have much theoretical interest due to their unusual [[stoichiometry]] and low [[ionization potential|ionisation potentials]]. Alkalides are chemically similar to the [[electride]], which are salts with trapped [[electron]] acting as anions. A particularly striking example of an alkalide is \"inverse [[sodium hydride]]\", HNa (both ions being [[coordination complex|complexed]]), as opposed to the usual sodium hydride, NaH: it is unstable in isolation, due to its high energy resulting from the displacement of two electrons from hydrogen to sodium, although several derivatives are predicted to be [[metastability|metastable]] or stable.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Physical and chemical"], "text": "In aqueous solution, the alkali metal ions form [[metal ions in aqueous solution|aqua ions]] of the formula [M(HO)], where ''n'' is the solvation number. Their [[coordination number]] and shapes agree well with those expected from their ionic radii. In aqueous solution the water molecules directly attached to the metal ion are said to belong to the [[first coordination sphere]], also known as the first, or primary, solvation shell. The bond between a water molecule and the metal ion is a [[dative covalent bond]], with the oxygen atom donating both electrons to the bond. Each coordinated water molecule may be attached by [[hydrogen bond]] to other water molecules. The latter are said to reside in the second coordination sphere. However, for the alkali metal cations, the second coordination sphere is not well-defined as the +1 charge on the cation is not high enough to [[Polarizability|polarise]] the water molecules in the primary solvation shell enough for them to form strong hydrogen bonds with those in the second coordination sphere, producing a more stable entity. The solvation number for Li has been experimentally determined to be 4, forming the [[tetrahedron|tetrahedral]] [Li(HO)]: while solvation numbers of 3 to 6 have been found for lithium aqua ions, solvation numbers less than 4 may be the result of the formation of contact [[ion pair]], and the higher solvation numbers may be interpreted in terms of water molecules that approach [Li(HO)] through a face of the tetrahedron, though molecular dynamic simulations may indicate the existence of an [[octahedron|octahedral]] hexaaqua ion. There are also probably six water molecules in the primary solvation sphere of the sodium ion, forming the octahedral [Na(HO)] ion. While it was previously thought that the heavier alkali metals also formed octahedral hexaaqua ions, it has since been found that potassium and rubidium probably form the [K(HO)] and [Rb(HO)] ions, which have the [[square antiprism]] structure, and that caesium forms the 12-coordinate [Cs(HO)] ion.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Physical and chemical", "Lithium"], "text": "The chemistry of lithium shows several differences from that of the rest of the group as the small Li cation [[chemical polarity|polarises]] [[anion]] and gives its compounds a more [[covalent bond|covalent]] character. Lithium and [[magnesium]] have a [[diagonal relationship]] due to their similar atomic radii, so that they show some similarities. For example, lithium forms a stable [[nitride]], a property common among all the [[alkaline earth metal]] (magnesium's group) but unique among the alkali metals. In addition, among their respective groups, only lithium and magnesium form [[organometallic compound]] with significant covalent character (e.g. Li[[methyl group|Me]] and MgMe). Lithium fluoride is the only alkali metal halide that is poorly soluble in water, and [[lithium hydroxide]] is the only alkali metal hydroxide that is not [[deliquescent]]. Conversely, [[lithium perchlorate]] and other lithium salts with large anions that cannot be polarised are much more stable than the analogous compounds of the other alkali metals, probably because Li has a high [[solvation energy]]. This effect also means that most simple lithium salts are commonly encountered in hydrated form, because the anhydrous forms are extremely [[hygroscopic]]: this allows salts like [[lithium chloride]] and [[lithium bromide]] to be used in [[dehumidifier]] and [[air-conditioner]].", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Physical and chemical", "Francium"], "text": "Francium is also predicted to show some differences due to its high [[atomic weight]], causing its electrons to travel at considerable fractions of the speed of light and thus making [[relativistic quantum chemistry|relativistic effects]] more prominent. In contrast to the trend of decreasing [[electronegativity|electronegativities]] and [[ionisation energy|ionisation energies]] of the alkali metals, francium's electronegativity and ionisation energy are predicted to be higher than caesium's due to the relativistic stabilisation of the 7s electrons; also, its [[atomic radius]] is expected to be abnormally low. Thus, contrary to expectation, caesium is the most reactive of the alkali metals, not francium. All known physical properties of francium also deviate from the clear trends going from lithium to caesium, such as the first ionisation energy, electron affinity, and anion polarisability, though due to the paucity of known data about francium many sources give extrapolated values, ignoring that relativistic effects make the trend from lithium to caesium become inapplicable at francium. Some of the few properties of francium that have been predicted taking relativity into account are the electron affinity (47.2 kJ/mol) and the enthalpy of dissociation of the Fr molecule (42.1 kJ/mol). The CsFr molecule is polarised as CsFr, showing that the 7s subshell of francium is much more strongly affected by relativistic effects than the 6s subshell of caesium. Additionally, francium superoxide (FrO) is expected to have significant covalent character, unlike the other alkali metal superoxides, because of bonding contributions from the 6p electrons of francium.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Nuclear"], "text": "All the alkali metals have odd atomic numbers; hence, their isotopes must be either [[odd–odd nuclei|odd–odd]] (both proton and [[neutron number]] are odd) or [[odd–even nuclei|odd–even]] ([[proton number]] is odd, but neutron number is even). Odd–odd nuclei have even [[mass number]], whereas odd–even nuclei have odd mass numbers. Odd–odd [[primordial nuclide]] are rare because most odd–odd nuclei are highly unstable with respect to [[beta decay]], because the decay products are even–even, and are therefore more strongly bound, due to [[Semi-empirical mass formula#Pairing term|nuclear pairing effects]]. Due to the great rarity of odd–odd nuclei, almost all the primordial isotopes of the alkali metals are odd–even (the exceptions being the light stable isotope lithium-6 and the long-lived [[radioisotope]] potassium-40). For a given odd mass number, there can be only a single [[beta-decay stable isobars|beta-stable nuclide]], since there is not a difference in binding energy between even–odd and odd–even comparable to that between even–even and odd–odd, leaving other nuclides of the same mass number ([[isobar (nuclide)|isobars]]) free to [[beta decay]] toward the lowest-mass nuclide. An effect of the instability of an odd number of either type of nucleons is that odd-numbered elements, such as the alkali metals, tend to have fewer stable isotopes than even-numbered elements. Of the 26 [[monoisotopic element]] that have only a single stable isotope, all but one have an odd atomic number and all but one also have an even number of neutrons. [[Beryllium]] is the single exception to both rules, due to its low atomic number. All of the alkali metals except lithium and caesium have at least one naturally occurring [[radioisotope]]: [[sodium-22]] and [[sodium-24]] are [[trace radioisotope]] produced [[cosmogenic]], potassium-40 and [[rubidium-87]] have very long [[half-life|half-lives]] and thus occur naturally, and all [[isotopes of francium]] are [[radioactive decay|radioactive]]. Caesium was also thought to be radioactive in the early 20th century, although it has no naturally occurring radioisotopes. (Francium had not been discovered yet at that time.) The natural long-lived radioisotope of potassium, potassium-40, makes up about 0.012% of natural potassium, and thus natural potassium is weakly radioactive. This natural radioactivity became a basis for a mistaken claim of the discovery for element 87 (the next alkali metal after caesium) in 1925. Natural rubidium is similarly slightly radioactive, with 27.83% being the long-lived radioisotope rubidium-87.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Properties", "Nuclear"], "text": "[[Caesium-137]], with a half-life of 30.17 years, is one of the two principal [[medium-lived fission product]], along with [[strontium-90]], which are responsible for most of the [[radioactivity]] of [[spent nuclear fuel]] after several years of cooling, up to several hundred years after use. It constitutes most of the radioactivity still left from the [[Chernobyl accident]]. Caesium-137 undergoes high-energy beta decay and eventually becomes stable [[barium-137]]. It is a strong emitter of gamma radiation. Caesium-137 has a very low rate of neutron capture and cannot be feasibly disposed of in this way, but must be allowed to decay. Caesium-137 has been used as a [[Flow tracer|tracer]] in hydrologic studies, analogous to the use of [[tritium]]. Small amounts of [[caesium-134]] and caesium-137 were released into the environment during nearly all [[nuclear weapon test]] and some [[nuclear accident]], most notably the [[Goiânia accident]] and the [[Chernobyl disaster]]. As of 2005, caesium-137 is the principal source of radiation in the [[zone of alienation]] around the [[Chernobyl nuclear power plant]]. Its chemical properties as one of the alkali metals make it one of most problematic of the short-to-medium-lifetime fission products because it easily moves and spreads in nature due to the high water solubility of its salts, and is taken up by the body, which mistakes it for its essential congeners sodium and potassium.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends"], "text": "The alkali metals are more similar to each other than the elements in any other [[group (periodic table)|group]] are to each other. For instance, when moving down the table, all known alkali metals show increasing [[atomic radius]], decreasing [[electronegativity]], increasing [[reactivity (chemistry)|reactivity]], and decreasing melting and boiling points as well as heats of fusion and vaporisation. In general, their [[density|densities]] increase when moving down the table, with the exception that potassium is less dense than sodium.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends", "Atomic and ionic radii"], "text": "The atomic radii of the alkali metals increase going down the group. Because of the [[shielding effect]], when an atom has more than one [[electron shell]], each electron feels electric repulsion from the other electrons as well as electric attraction from the nucleus. In the alkali metals, the [[valence electron|outermost electron]] only feels a net charge of +1, as some of the [[nuclear charge]] (which is equal to the [[atomic number]]) is cancelled by the inner electrons; the number of inner electrons of an alkali metal is always one less than the nuclear charge. Therefore, the only factor which affects the atomic radius of the alkali metals is the number of electron shells. Since this number increases down the group, the atomic radius must also increase down the group. The [[ionic radius|ionic radii]] of the alkali metals are much smaller than their atomic radii. This is because the outermost electron of the alkali metals is in a different [[electron shell]] than the inner electrons, and thus when it is removed the resulting atom has one fewer electron shell and is smaller. Additionally, the [[effective nuclear charge]] has increased, and thus the electrons are attracted more strongly towards the nucleus and the ionic radius decreases.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends", "First ionisation energy"], "text": "The first ionisation energy of an [[chemical element|element]] or [[molecule]] is the energy required to move the most loosely held electron from one [[mole (unit)|mole]] of gaseous atoms of the element or molecules to form one mole of gaseous ions with [[electric charge]] +1. The factors affecting the first ionisation energy are the [[nuclear charge]], the amount of [[shielding effect|shielding]] by the inner electrons and the distance from the most loosely held electron from the nucleus, which is always an outer electron in [[main group element]]. The first two factors change the effective nuclear charge the most loosely held electron feels. Since the outermost electron of alkali metals always feels the same effective nuclear charge (+1), the only factor which affects the first ionisation energy is the distance from the outermost electron to the nucleus. Since this distance increases down the group, the outermost electron feels less attraction from the nucleus and thus the first ionisation energy decreases. (This trend is broken in francium due to the [[relativistic quantum chemistry|relativistic]] stabilisation and contraction of the 7s orbital, bringing francium's valence electron closer to the nucleus than would be expected from non-relativistic calculations. This makes francium's outermost electron feel more attraction from the nucleus, increasing its first ionisation energy slightly beyond that of caesium.) The second ionisation energy of the alkali metals is much higher than the first as the second-most loosely held electron is part of a fully filled [[electron shell]] and is thus difficult to remove.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends", "Reactivity"], "text": "The reactivities of the alkali metals increase going down the group. This is the result of a combination of two factors: the first ionisation energies and [[atomisation energy|atomisation energies]] of the alkali metals. Because the first ionisation energy of the alkali metals decreases down the group, it is easier for the outermost electron to be removed from the atom and participate in [[chemical reaction]], thus increasing reactivity down the group. The atomisation energy measures the strength of the [[metallic bond]] of an element, which falls down the group as the atoms increase in [[atomic radius|radius]] and thus the metallic bond must increase in length, making the [[delocalized electron|delocalised electrons]] further away from the attraction of the nuclei of the heavier alkali metals. Adding the atomisation and first ionisation energies gives a quantity closely related to (but not equal to) the [[activation energy]] of the reaction of an alkali metal with another substance. This quantity decreases going down the group, and so does the activation energy; thus, chemical reactions can occur faster and the reactivity increases down the group.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends", "Electronegativity"], "text": "Electronegativity is a [[chemical property]] that describes the tendency of an [[atom]] or a [[functional group]] to attract [[electron]] (or [[electron density]]) towards itself. If the bond between [[sodium]] and [[chlorine]] in [[sodium chloride]] were [[covalent bond|covalent]], the pair of shared electrons would be attracted to the chlorine because the effective nuclear charge on the outer electrons is +7 in chlorine but is only +1 in sodium. The electron pair is attracted so close to the chlorine atom that they are practically transferred to the chlorine atom (an [[ionic bond]]). However, if the sodium atom was replaced by a lithium atom, the electrons will not be attracted as close to the chlorine atom as before because the lithium atom is smaller, making the electron pair more strongly attracted to the closer effective nuclear charge from lithium. Hence, the larger alkali metal atoms (further down the group) will be less electronegative as the bonding pair is less strongly attracted towards them. As mentioned previously, francium is expected to be an exception. Because of the higher electronegativity of lithium, some of its compounds have a more covalent character. For example, [[lithium iodide]] ([[lithium|Li]] [[iodine|I]]) will dissolve in [[organic solvent]], a property of most covalent compounds. [[Lithium fluoride]] (Li[[fluorine|F]]) is the only [[alkali halide]] that is not soluble in water, and [[lithium hydroxide]] (Li[[hydroxide|OH]]) is the only [[alkali hydroxide|alkali metal hydroxide]] that is not [[deliquescent]].", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends", "Melting and boiling points"], "text": "The melting point of a substance is the point where it changes [[state of matter|state]] from [[solid]] to [[liquid]] while the boiling point of a substance (in liquid state) is the point where the [[vapor pressure|vapour pressure]] of the liquid equals the environmental pressure surrounding the liquid and all the liquid changes state to [[gas]]. As a metal is heated to its melting point, the [[metallic bond]] keeping the atoms in place weaken so that the atoms can move around, and the metallic bonds eventually break completely at the metal's boiling point. Therefore, the falling melting and boiling points of the alkali metals indicate that the strength of the metallic bonds of the alkali metals decreases down the group. This is because metal atoms are held together by the electromagnetic attraction from the positive ions to the delocalised electrons. As the atoms increase in size going down the group (because their atomic radius increases), the nuclei of the ions move further away from the delocalised electrons and hence the metallic bond becomes weaker so that the metal can more easily melt and boil, thus lowering the melting and boiling points. (The increased nuclear charge is not a relevant factor due to the shielding effect.)", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Periodic trends", "Density"], "text": "The alkali metals all have the same [[crystal structure]] ([[body-centered cubic|body-centred cubic]]) and thus the only relevant factors are the number of atoms that can fit into a certain volume and the mass of one of the atoms, since density is defined as mass per unit volume. The first factor depends on the volume of the atom and thus the atomic radius, which increases going down the group; thus, the volume of an alkali metal atom increases going down the group. The mass of an alkali metal atom also increases going down the group. Thus, the trend for the densities of the alkali metals depends on their atomic weights and atomic radii; if figures for these two factors are known, the ratios between the densities of the alkali metals can then be calculated. The resultant trend is that the densities of the alkali metals increase down the table, with an exception at potassium. Due to having the lowest atomic weight and the largest atomic radius of all the elements in their periods, the alkali metals are the least dense metals in the periodic table. Lithium, sodium, and potassium are the only three metals in the periodic table that are less dense than water: in fact, lithium is the least dense known solid at [[room temperature]].", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds"], "text": "The alkali metals form complete series of compounds with all usually encountered anions, which well illustrate group trends. These compounds can be described as involving the alkali metals losing electrons to acceptor species and forming monopositive ions. This description is most accurate for alkali halides and becomes less and less accurate as cationic and anionic charge increase, and as the anion becomes larger and more polarisable. For instance, [[ionic bond]] gives way to [[metallic bond]] along the series NaCl, NaO, NaS, NaP, NaAs, NaSb, NaBi, Na.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Hydroxides"], "text": "All the alkali metals react vigorously or explosively with cold water, producing an [[aqueous solution]] of a strongly [[base (chemistry)|basic]] alkali metal [[hydroxide]] and releasing hydrogen gas. This reaction becomes more vigorous going down the group: lithium reacts steadily with [[effervescence]], but sodium and potassium can ignite and rubidium and caesium sink in water and generate hydrogen gas so rapidly that shock waves form in the water that may shatter glass containers. When an alkali metal is dropped into water, it produces an explosion, of which there are two separate stages. The metal reacts with the water first, breaking the hydrogen bonds in the water and producing [[hydrogen]] gas; this takes place faster for the more reactive heavier alkali metals. Second, the heat generated by the first part of the reaction often ignites the hydrogen gas, causing it to burn explosively into the surrounding air. This secondary hydrogen gas explosion produces the visible flame above the bowl of water, lake or other body of water, not the initial reaction of the metal with water (which tends to happen mostly under water). The alkali metal hydroxides are the most basic known hydroxides. Recent research has suggested that the explosive behavior of alkali metals in water is driven by a [[Coulomb explosion]] rather than solely by rapid generation of hydrogen itself. All alkali metals melt as a part of the reaction with water. Water molecules ionise the bare metallic surface of the liquid metal, leaving a positively charged metal surface and negatively charged water ions. The attraction between the charged metal and water ions will rapidly increase the surface area, causing an exponential increase of ionisation. When the repulsive forces within the liquid metal surface exceeds the forces of the surface tension, it vigorously explodes. The hydroxides themselves are the most basic hydroxides known, reacting with acids to give salts and with alcohols to give [[oligomer]] [[alkoxide]]. They easily react with [[carbon dioxide]] to form [[carbonate]] or [[bicarbonate]], or with [[hydrogen sulfide]] to form [[sulfide]] or [[bisulfide]], and may be used to separate [[thiol]] from petroleum. They react with amphoteric oxides: for example, the oxides of [[aluminium oxide|aluminium]], [[zinc oxide|zinc]], [[tin(IV) oxide| tin]], and [[lead dioxide|lead]] react with the alkali metal hydroxides to give aluminates, zincates, stannates, and plumbates. [[Silicon dioxide]] is acidic, and thus the alkali metal hydroxides can also attack [[silicate glass]].", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Intermetallic compounds"], "text": "The alkali metals form many [[intermetallic compound]] with each other and the elements from groups [[alkaline earth metal|2]] to [[boron group|13]] in the periodic table of varying stoichiometries, such as the [[sodium amalgam]] with [[mercury (element)|mercury]], including NaHg and NaHg. Some of these have ionic characteristics: taking the alloys with [[gold]], the most electronegative of metals, as an example, NaAu and KAu are metallic, but RbAu and [[caesium auride|CsAu]] are semiconductors. [[NaK]] is an alloy of sodium and potassium that is very useful because it is liquid at room temperature, although precautions must be taken due to its extreme reactivity towards water and air. The [[eutectic mixture]] melts at −12.6 °C. An alloy of 41% caesium, 47% sodium, and 12% potassium has the lowest known melting point of any metal or alloy, −78 °C.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Compounds with the group 13 elements"], "text": "The intermetallic compounds of the alkali metals with the heavier group 13 elements ([[aluminium]], [[gallium]], [[indium]], and [[thallium]]), such as NaTl, are poor [[Electrical conductor|conductors]] or [[semiconductor]], unlike the normal alloys with the preceding elements, implying that the alkali metal involved has lost an electron to the [[Zintl phase|Zintl anions]] involved. Nevertheless, while the elements in group 14 and beyond tend to form discrete anionic clusters, group 13 elements tend to form polymeric ions with the alkali metal cations located between the giant ionic lattice. For example, NaTl consists of a polymeric anion (—Tl—) with a covalent [[diamond cubic]] structure with Na ions located between the anionic lattice. The larger alkali metals cannot fit similarly into an anionic lattice and tend to force the heavier group 13 elements to form anionic clusters. [[Boron]] is a special case, being the only nonmetal in group 13. The alkali metal [[boride]] tend to be boron-rich, involving appreciable boron–boron bonding involving [[deltahedron|deltahedral]] structures, and are thermally unstable due to the alkali metals having a very high [[vapour pressure]] at elevated temperatures. This makes direct synthesis problematic because the alkali metals do not react with boron below 700 °C, and thus this must be accomplished in sealed containers with the alkali metal in excess. Furthermore, exceptionally in this group, reactivity with boron decreases down the group: lithium reacts completely at 700 °C, but sodium at 900 °C and potassium not until 1200 °C, and the reaction is instantaneous for lithium but takes hours for potassium. Rubidium and caesium borides have not even been characterised. Various phases are known, such as LiB, NaB, NaB, and KB. Under high pressure the boron–boron bonding in the lithium borides changes from following [[polyhedral skeletal electron pair theory|Wade's rules]] to forming Zintl anions like the rest of group 13.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Compounds with the group 14 elements"], "text": "Lithium and sodium react with [[carbon]] to form [[acetylide]], LiC and NaC, which can also be obtained by reaction of the metal with [[acetylene]]. Potassium, rubidium, and caesium react with [[graphite]]; their atoms are [[intercalation (chemistry)|intercalated]] between the hexagonal graphite layers, forming [[graphite intercalation compound]] of formulae MC (dark grey, almost black), MC (dark grey, almost black), MC (blue), MC (steel blue), and MC (bronze) (M = K, Rb, or Cs). These compounds are over 200 times more electrically conductive than pure graphite, suggesting that the valence electron of the alkali metal is transferred to the graphite layers (e.g. ). Upon heating of KC, the elimination of potassium atoms results in the conversion in sequence to KC, KC, KC and finally KC. KC is a very strong [[reducing agent]] and is pyrophoric and explodes on contact with water. While the larger alkali metals (K, Rb, and Cs) initially form MC, the smaller ones initially form MC, and indeed they require reaction of the metals with graphite at high temperatures around 500 °C to form. Apart from this, the alkali metals are such strong reducing agents that they can even reduce [[buckminsterfullerene]] to produce solid [[fullerides]] MC; sodium, potassium, rubidium, and caesium can form fullerides where ''n'' = 2, 3, 4, or 6, and rubidium and caesium additionally can achieve ''n'' = 1. When the alkali metals react with the heavier elements in the [[carbon group]] ([[silicon]], [[germanium]], [[tin]], and [[lead]]), ionic substances with cage-like structures are formed, such as the [[silicide]] M[[silicon|Si]] (M = K, Rb, or Cs), which contains M and tetrahedral ions. The chemistry of alkali metal [[germanide]], involving the germanide ion [[germanium|Ge]] and other cluster ([[Zintl ion|Zintl]]) ions such as , , , and [(Ge)], is largely analogous to that of the corresponding silicides. Alkali metal [[stannide]] are mostly ionic, sometimes with the stannide ion ([[tin|Sn]]), and sometimes with more complex Zintl ions such as , which appears in tetrapotassium nonastannide (KSn). The monatomic [[plumbide]] ion ([[lead|Pb]]) is unknown, and indeed its formation is predicted to be energetically unfavourable; alkali metal plumbides have complex Zintl ions, such as . These alkali metal germanides, stannides, and plumbides may be produced by reducing germanium, tin, and lead with sodium metal in liquid ammonia.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Nitrides and pnictides"], "text": "Lithium, the lightest of the alkali metals, is the only alkali metal which reacts with [[nitrogen]] at [[standard conditions]], and its [[nitride]] is the only stable alkali metal nitride. Nitrogen is an [[reactivity (chemistry)|unreactive]] gas because breaking the strong [[triple bond]] in the [[dinitrogen]] molecule (N) requires a lot of energy. The formation of an alkali metal nitride would consume the ionisation energy of the alkali metal (forming M ions), the energy required to break the triple bond in N and the formation of N ions, and all the energy released from the formation of an alkali metal nitride is from the [[lattice energy]] of the alkali metal nitride. The lattice energy is maximised with small, highly charged ions; the alkali metals do not form highly charged ions, only forming ions with a charge of +1, so only lithium, the smallest alkali metal, can release enough lattice energy to make the reaction with nitrogen [[exothermic]], forming [[lithium nitride]]. The reactions of the other alkali metals with nitrogen would not release enough lattice energy and would thus be [[endothermic]], so they do not form nitrides at standard conditions. [[Sodium nitride]] (NaN) and [[potassium nitride]] (KN), while existing, are extremely unstable, being prone to decomposing back into their constituent elements, and cannot be produced by reacting the elements with each other at standard conditions. Steric hindrance forbids the existence of rubidium or caesium nitride. However, sodium and potassium form colourless [[azide]] salts involving the linear anion; due to the large size of the alkali metal cations, they are thermally stable enough to be able to melt before decomposing. All the alkali metals react readily with [[phosphorus]] and [[arsenic]] to form phosphides and arsenides with the formula MPn (where M represents an alkali metal and Pn represents a [[pnictogen]] – phosphorus, arsenic, [[antimony]], or [[bismuth]]). This is due to the greater size of the P and As ions, so that less lattice energy needs to be released for the salts to form. These are not the only phosphides and arsenides of the alkali metals: for example, potassium has nine different known phosphides, with formulae KP, KP, KP, KP, KP, KP, KP, KP, and KP. While most metals form arsenides, only the alkali and alkaline earth metals form mostly ionic arsenides. The structure of NaAs is complex with unusually short Na–Na distances of 328–330 pm which are shorter than in sodium metal, and this indicates that even with these electropositive metals the bonding cannot be straightforwardly ionic. Other alkali metal arsenides not conforming to the formula MAs are known, such as LiAs, which has a metallic lustre and electrical conductivity indicating the presence of some [[metallic bond]]. The [[antimonide]] are unstable and reactive as the [[antimony|Sb]] ion is a strong reducing agent; reaction of them with acids form the toxic and unstable gas [[stibine]] (SbH). Indeed, they have some metallic properties, and the alkali metal antimonides of stoichiometry MSb involve antimony atoms bonded in a spiral Zintl structure. [[Bismuth]] are not even wholly ionic; they are [[intermetallic compound]] containing partially metallic and partially ionic bonds.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Oxides and chalcogenides"], "text": "All the alkali metals react vigorously with [[oxygen]] at standard conditions. They form various types of oxides, such as simple [[oxide]] (containing the O ion), [[peroxide]] (containing the ion, where there is a [[single bond]] between the two oxygen atoms), [[superoxide]] (containing the ion), and many others. Lithium burns in air to form [[lithium oxide]], but sodium reacts with oxygen to form a mixture of [[sodium oxide]] and [[sodium peroxide]]. Potassium forms a mixture of [[potassium peroxide]] and [[potassium superoxide]], while rubidium and caesium form the superoxide exclusively. Their reactivity increases going down the group: while lithium, sodium and potassium merely burn in air, rubidium and caesium are [[pyrophoric]] (spontaneously catch fire in air). The smaller alkali metals tend to polarise the larger anions (the peroxide and superoxide) due to their small size. This attracts the electrons in the more complex anions towards one of its constituent oxygen atoms, forming an oxide ion and an oxygen atom. This causes lithium to form the oxide exclusively on reaction with oxygen at room temperature. This effect becomes drastically weaker for the larger sodium and potassium, allowing them to form the less stable peroxides. Rubidium and caesium, at the bottom of the group, are so large that even the least stable superoxides can form. Because the superoxide releases the most energy when formed, the superoxide is preferentially formed for the larger alkali metals where the more complex anions are not polarised. (The oxides and peroxides for these alkali metals do exist, but do not form upon direct reaction of the metal with oxygen at standard conditions.) In addition, the small size of the Li and O ions contributes to their forming a stable ionic lattice structure. Under controlled conditions, however, all the alkali metals, with the exception of francium, are known to form their oxides, peroxides, and superoxides. The alkali metal peroxides and superoxides are powerful [[oxidising agent]]. [[Sodium peroxide]] and [[potassium superoxide]] react with [[carbon dioxide]] to form the alkali metal carbonate and oxygen gas, which allows them to be used in [[submarine]] air purifiers; the presence of [[water vapour]], naturally present in breath, makes the removal of carbon dioxide by potassium superoxide even more efficient. All the stable alkali metals except lithium can form red [[ozonide]] (MO) through low-temperature reaction of the powdered anhydrous hydroxide with [[ozone]]: the ozonides may be then extracted using liquid [[ammonia]]. They slowly decompose at standard conditions to the superoxides and oxygen, and hydrolyse immediately to the hydroxides when in contact with water. Potassium, rubidium, and caesium also form sesquioxides MO, which may be better considered peroxide disuperoxides, . Rubidium and caesium can form a great variety of suboxides with the metals in formal oxidation states below +1. Rubidium can form RbO and RbO (copper-coloured) upon oxidation in air, while caesium forms an immense variety of oxides, such as the ozonide CsO and several brightly coloured [[suboxide]], such as CsO (bronze), CsO (red-violet), CsO (violet), CsO (dark green), CsO, CsO, as well as CsO. The last of these may be heated under vacuum to generate CsO.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Oxides and chalcogenides"], "text": "The alkali metals can also react analogously with the heavier chalcogens ([[sulfur]], [[selenium]], [[tellurium]], and [[polonium]]), and all the alkali metal chalcogenides are known (with the exception of francium's). Reaction with an excess of the chalcogen can similarly result in lower chalcogenides, with chalcogen ions containing chains of the chalcogen atoms in question. For example, sodium can react with sulfur to form the [[sulfide]] ([[sodium sulfide|NaS]]) and various [[polysulfide]] with the formula NaS (''x'' from 2 to 6), containing the ions. Due to the basicity of the Se and Te ions, the alkali metal [[selenide]] and [[telluride (chemistry)|tellurides]] are alkaline in solution; when reacted directly with selenium and tellurium, alkali metal polyselenides and polytellurides are formed along with the selenides and tellurides with the and ions. They may be obtained directly from the elements in liquid ammonia or when air is not present, and are colourless, water-soluble compounds that air oxidises quickly back to selenium or tellurium. The alkali metal [[polonide]] are all ionic compounds containing the Po ion; they are very chemically stable and can be produced by direct reaction of the elements at around 300–400 °C.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Halides, hydrides, and pseudohalides"], "text": "The alkali metals are among the most [[electropositive]] elements on the periodic table and thus tend to [[ionic bond|bond ionically]] to the most [[electronegative]] elements on the periodic table, the [[halogen]] ([[fluorine]], [[chlorine]], [[bromine]], [[iodine]], and [[astatine]]), forming [[salt (chemistry)|salts]] known as the alkali metal halides. The reaction is very vigorous and can sometimes result in explosions. All twenty stable alkali metal halides are known; the unstable ones are not known, with the exception of sodium astatide, because of the great instability and rarity of astatine and francium. The most well-known of the twenty is certainly [[sodium chloride]], otherwise known as common salt. All of the stable alkali metal halides have the formula MX where M is an alkali metal and X is a halogen. They are all white ionic crystalline solids that have high melting points. All the alkali metal halides are [[solubility|soluble]] in water except for [[lithium fluoride]] (LiF), which is insoluble in water due to its very high [[lattice enthalpy]]. The high lattice enthalpy of lithium fluoride is due to the small sizes of the Li and F ions, causing the [[electrostatic interaction]] between them to be strong: a similar effect occurs for [[magnesium fluoride]], consistent with the diagonal relationship between lithium and magnesium. The alkali metals also react similarly with hydrogen to form ionic alkali metal hydrides, where the [[hydride]] anion acts as a [[pseudohalogen|pseudohalide]]: these are often used as reducing agents, producing hydrides, complex metal hydrides, or hydrogen gas. Other pseudohalides are also known, notably the [[cyanide]]. These are isostructural to the respective halides except for [[lithium cyanide]], indicating that the cyanide ions may rotate freely. Ternary alkali metal halide oxides, such as NaClO, KBrO (yellow), NaBrO, NaIO, and KBrO, are also known. The polyhalides are rather unstable, although those of rubidium and caesium are greatly stabilised by the feeble polarising power of these extremely large cations.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Coordination complexes"], "text": "Alkali metal cations do not usually form [[coordination complex]] with simple [[Lewis base]] due to their low charge of just +1 and their relatively large size; thus the Li ion forms most complexes and the heavier alkali metal ions form less and less (though exceptions occur for weak complexes). Lithium in particular has a very rich coordination chemistry in which it exhibits [[coordination number]] from 1 to 12, although octahedral hexacoordination is its preferred mode. In [[aqueous solution]], the alkali metal ions exist as octahedral hexahydrate complexes ([M(HO))]), with the exception of the lithium ion, which due to its small size forms tetrahedral tetrahydrate complexes ([Li(HO))]); the alkali metals form these complexes because their ions are attracted by electrostatic forces of attraction to the polar water molecules. Because of this, [[anhydrous]] salts containing alkali metal cations are often used as [[desiccant]]. Alkali metals also readily form complexes with [[crown ether]] (e.g. [[12-crown-4]] for Li, [[15-crown-5]] for Na, [[18-crown-6]] for K, and [[21-crown-7]] for Rb) and [[cryptand]] due to electrostatic attraction.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Ammonia solutions"], "text": "The alkali metals dissolve slowly in liquid [[ammonia]], forming ammoniacal solutions of solvated metal cation M and [[solvated electron]] e, which react to form hydrogen gas and the [[metal amide#Alkali metal amides|alkali metal amide]] (MNH, where M represents an alkali metal): this was first noted by [[Humphry Davy]] in 1809 and rediscovered by W. Weyl in 1864. The process may be speeded up by a [[catalyst]]. Similar solutions are formed by the heavy divalent [[alkaline earth metal]] [[calcium]], [[strontium]], [[barium]], as well as the divalent [[lanthanide]], [[europium]] and [[ytterbium]]. The amide salt is quite insoluble and readily precipitates out of solution, leaving intensely coloured ammonia solutions of the alkali metals. In 1907, Charles Krause identified the colour as being due to the presence of [[solvated electron]], which contribute to the high electrical conductivity of these solutions. At low concentrations (below 3 M), the solution is dark blue and has ten times the conductivity of aqueous [[sodium chloride]]; at higher concentrations (above 3 M), the solution is copper-coloured and has approximately the conductivity of liquid metals like [[mercury (element)|mercury]]. In addition to the alkali metal amide salt and solvated electrons, such ammonia solutions also contain the alkali metal cation (M), the neutral alkali metal atom (M), [[diatomic molecule|diatomic]] alkali metal molecules (M) and alkali metal anions (M). These are unstable and eventually become the more thermodynamically stable alkali metal amide and hydrogen gas. Solvated electrons are powerful [[reducing agent]] and are often used in chemical synthesis.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Organometallic", "Organolithium"], "text": "Being the smallest alkali metal, lithium forms the widest variety of and most stable [[organometallic compound]], which are bonded covalently. [[Organolithium reagent|Organolithium]] compounds are electrically non-conducting volatile solids or liquids that melt at low temperatures, and tend to form [[oligomer]] with the structure (RLi) where R is the organic group. As the electropositive nature of lithium puts most of the [[charge density]] of the bond on the carbon atom, effectively creating a [[carbanion]], organolithium compounds are extremely powerful [[base (chemistry)|bases]] and [[carbon nucleophile|nucleophiles]]. For use as bases, [[butyllithium]] are often used and are commercially available. An example of an organolithium compound is [[methyllithium]] ((CHLi)), which exists in tetrameric (''x'' = 4, tetrahedral) and hexameric (''x'' = 6, octahedral) forms. Organolithium compounds, especially ''n''-butyllithium, are useful reagents in organic synthesis, as might be expected given lithium's diagonal relationship with magnesium, which plays an important role in the [[Grignard reaction]]. For example, alkyllithiums and aryllithiums may be used to synthesise [[aldehyde]] and [[ketone]] by reaction with metal [[carbonyl]]. The reaction with [[nickel tetracarbonyl]], for example, proceeds through an unstable acyl nickel carbonyl complex which then undergoes [[electrophilic substitution]] to give the desired aldehyde (using H as the electrophile) or ketone (using an alkyl halide) product. LiR + [Ni(CO)] Li[RCONi(CO)] Li[RCONi(CO)] Li + RCHO + [(solvent)Ni(CO)] Li[RCONi(CO)] Li + R'COR + [(solvent)Ni(CO)] Alkyllithiums and aryllithiums may also react with ''N'',''N''-disubstituted [[amide]] to give aldehydes and ketones, and symmetrical ketones by reacting with [[carbon monoxide]]. They thermally decompose to eliminate a β-hydrogen, producing [[alkene]] and [[lithium hydride]]: another route is the reaction of [[ether]] with alkyl- and aryllithiums that act as strong bases. In non-polar solvents, aryllithiums react as the carbanions they effectively are, turning carbon dioxide to aromatic [[carboxylic acid]] (ArCOH) and aryl ketones to tertiary carbinols (Ar'C(Ar)OH). Finally, they may be used to synthesise other organometallic compounds through metal-halogen exchange.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Compounds", "Organometallic", "Heavier alkali metals"], "text": "Unlike the organolithium compounds, the organometallic compounds of the heavier alkali metals are predominantly ionic. The application of [[organosodium chemistry|organosodium]] compounds in chemistry is limited in part due to competition from [[organolithium compound]], which are commercially available and exhibit more convenient reactivity. The principal organosodium compound of commercial importance is [[sodium cyclopentadienide]]. [[Sodium tetraphenylborate]] can also be classified as an organosodium compound since in the solid state sodium is bound to the aryl groups. Organometallic compounds of the higher alkali metals are even more reactive than organosodium compounds and of limited utility. A notable reagent is [[Schlosser's base]], a mixture of [[n-Butyllithium|''n''-butyllithium]] and [[potassium tert-butoxide|potassium ''tert''-butoxide]]. This reagent reacts with [[propene]] to form the compound [[allylpotassium]] (KCHCHCH). [[cis-2-butene|''cis''-2-Butene]] and [[trans-2-butene|''trans''-2-butene]] equilibrate when in contact with alkali metals. Whereas [[isomerisation]] is fast with lithium and sodium, it is slow with the heavier alkali metals. The heavier alkali metals also favour the [[steric hindrance|sterically]] congested conformation. Several crystal structures of organopotassium compounds have been reported, establishing that they, like the sodium compounds, are polymeric. Organosodium, organopotassium, organorubidium and organocaesium compounds are all mostly ionic and are insoluble (or nearly so) in nonpolar solvents. Alkyl and aryl derivatives of sodium and potassium tend to react with air. They cause the cleavage of [[ether]], generating alkoxides. Unlike alkyllithium compounds, alkylsodiums and alkylpotassiums cannot be made by reacting the metals with alkyl halides because [[Wurtz coupling]] occurs: RM + R'X → R–R' + MX As such, they have to be made by reacting [[organomercury compound|alkylmercury]] compounds with sodium or potassium metal in inert hydrocarbon solvents. While methylsodium forms tetramers like methyllithium, methylpotassium is more ionic and has the [[nickel arsenide]] structure with discrete methyl anions and potassium cations. The alkali metals and their hydrides react with acidic hydrocarbons, for example [[cyclopentadiene]] and terminal alkynes, to give salts. Liquid ammonia, ether, or hydrocarbon solvents are used, the most common of which being [[tetrahydrofuran]]. The most important of these compounds is [[sodium cyclopentadienide]], NaCH, an important precursor to many transition metal cyclopentadienyl derivatives. Similarly, the alkali metals react with [[cyclooctatetraene]] in tetrahydrofuran to give alkali metal [[cyclooctatetraenide]]; for example, [[dipotassium cyclooctatetraenide]] (KCH) is an important precursor to many metal cyclooctatetraenyl derivatives, such as [[uranocene]]. The large and very weakly polarising alkali metal cations can stabilise large, aromatic, polarisable radical anions, such as the dark-green [[sodium naphthalenide]], Na[CH•], a strong reducing agent.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Representative reactions of alkali metals"], "text": "'''''Reaction with oxygen''''' Upon reacting with oxygen, alkali metals form [[oxides]], [[peroxides]], [[superoxides]] and [[suboxides]]. However, the first three are more common. The table below shows the types of compounds formed in reaction with oxygen. The compound in brackets represents the minor product of combustion. The alkali metal peroxides are ionic compounds that are unstable in water. The peroxide anion is weakly bound to the cation, and it is hydrolysed, forming stronger covalent bonds. NaO + 2HO → 2NaOH + HO The other oxygen compounds are also unstable in water. 2KO + 2HO → 2KOH + HO + O LiO + HO → 2LiOH '''''Reaction with sulphur''''' With sulphur, they form sulphides and polysulphides. 2Na + 1/8S → NaS + 1/8S → NaS...NaS Because alkali metal sulphides are essentially salts of a weak acid and a strong base, they form basic solutions. S + HO → HS + HO HS + HO → HS + HO '''''Reaction with nitrogen''''' Lithium is the only metal that combines directly with nitrogen at room temperature. 3Li + 1/3N → LiN LiN can react with water to liberate ammonia. LiN + 3HO → 3LiOH + NH '''''Reaction with hydrogen''''' With hydrogen, alkali metals form saline hydrides that hydrolyse in water. Na + H → NaH (at high temperatures) NaH + HO → NaOH + H '''''Reaction with carbon''''' Lithium is the only metal that reacts directly with carbon to give dilithium acetylide. Na and K can react with [[acetylene]] to give acetylides. 2Li + 2C → LiC Na + CH → NaCH + 1/2H (at 150C) Na + NaCH → NaC (at 220C) '''''Reaction with water''''' On reaction with water, they generate hydroxide ions and [[hydrogen]] gas. This reaction is vigorous and highly exothermic and the hydrogen resulted may ignite in air or even explode in the case of Rb and Cs. Na + HO → NaOH + 1/2H '''''Reaction with other salts''''' The alkali metals are very good reducing agents. They can reduce metal cations that are less electropositive. [[Titanium]] is produced industrially by the reduction of titanium tetrachloride with Na at 400C ([[van Arkel process]]). TiCl + 4Na → 4NaCl + Ti '''''Reaction with organohalide compounds''''' Alkali metals react with halogen derivatives to generate hydrocarbon via the [[Wurtz reaction]]. 2CH-Cl + 2Na → HC-CH + 2NaCl '''''Alkali metals in liquid ammonia''''' Alkali metals dissolve in liquid ammonia or other donor solvents like aliphatic amines or hexamethylphosphoramide to give blue solutions. These solutions are believed to contain free electrons. Na + xNH → Na + e(NH) Due to the presence of [[solvated electrons]], these solutions are very powerful reducing agents used in organic synthesis. Reaction 1) is known as [[Birch reduction]]. Other reductions that can be carried by these solutions are: S + 2e → S Fe(CO) + 2e → Fe(CO) + CO", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Extensions"], "text": "Although francium is the heaviest alkali metal that has been discovered, there has been some theoretical work predicting the physical and chemical characteristics of hypothetical heavier alkali metals. Being the first [[period 8 element]], the undiscovered element [[ununennium]] (element 119) is predicted to be the next alkali metal after francium and behave much like their lighter [[Congener (chemistry)|congeners]]; however, it is also predicted to differ from the lighter alkali metals in some properties. Its chemistry is predicted to be closer to that of potassium or rubidium instead of caesium or francium. This is unusual as [[periodic trends]], ignoring relativistic effects would predict ununennium to be even more reactive than caesium and francium. This lowered [[reactivity (chemistry)|reactivity]] is due to the relativistic stabilisation of ununennium's valence electron, increasing ununennium's first ionisation energy and decreasing the [[metallic radius|metallic]] and [[ionic radius|ionic radii]]; this effect is already seen for francium. This assumes that ununennium will behave chemically as an alkali metal, which, although likely, may not be true due to relativistic effects. The relativistic stabilisation of the 8s orbital also increases ununennium's [[electron affinity]] far beyond that of caesium and francium; indeed, ununennium is expected to have an electron affinity higher than all the alkali metals lighter than it. Relativistic effects also cause a very large drop in the [[polarisability]] of ununennium. On the other hand, ununennium is predicted to continue the trend of melting points decreasing going down the group, being expected to have a melting point between 0 °C and 30 °C. The stabilisation of ununennium's valence electron and thus the contraction of the 8s orbital cause its atomic radius to be lowered to 240 [[picometer|pm]], very close to that of rubidium (247 pm), so that the chemistry of ununennium in the +1 oxidation state should be more similar to the chemistry of rubidium than to that of francium. On the other hand, the ionic radius of the Uue ion is predicted to be larger than that of Rb, because the 7p orbitals are destabilised and are thus larger than the p-orbitals of the lower shells. Ununennium may also show the +3 [[oxidation state]], which is not seen in any other alkali metal, in addition to the +1 oxidation state that is characteristic of the other alkali metals and is also the main oxidation state of all the known alkali metals: this is because of the destabilisation and expansion of the 7p spinor, causing its outermost electrons to have a lower ionisation energy than what would otherwise be expected. Indeed, many ununennium compounds are expected to have a large [[covalent]] character, due to the involvement of the 7p electrons in the bonding.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Extensions"], "text": "Not as much work has been done predicting the properties of the alkali metals beyond ununennium. Although a simple extrapolation of the periodic table (by the [[aufbau principle]]) would put element 169, unhexennium, under ununennium, Dirac-Fock calculations predict that the next element after ununennium with alkali-metal-like properties may be element 165, unhexpentium, which is predicted to have the electron configuration [Og] 5g 6f 7d 8s 8p 9s. This element would be intermediate in properties between an alkali metal and a [[group 11 element]], and while its physical and atomic properties would be closer to the former, its chemistry may be closer to that of the latter. Further calculations show that unhexpentium would follow the trend of increasing ionisation energy beyond caesium, having an ionisation energy comparable to that of sodium, and that it should also continue the trend of decreasing atomic radii beyond caesium, having an atomic radius comparable to that of potassium. However, the 7d electrons of unhexpentium may also be able to participate in chemical reactions along with the 9s electron, possibly allowing oxidation states beyond +1, whence the likely transition metal behaviour of unhexpentium. Due to the alkali and [[alkaline earth metal]] both being [[s-block]] elements, these predictions for the trends and properties of ununennium and unhexpentium also mostly hold quite similarly for the corresponding alkaline earth metals [[unbinilium]] (Ubn) and unhexhexium (Uhh). Unsepttrium, element 173, may be an even better heavier homologue of ununennium; with a predicted electron configuration of [Usb] 6g, it returns to the alkali-metal-like situation of having one easily removed electron far above a closed p-shell in energy, and is expected to be even more reactive than caesium. The probable properties of further alkali metals beyond unsepttrium have not been explored yet as of 2019, and they may or may not be able to exist. In periods 8 and above of the periodic table, relativistic and shell-structure effects become so strong that extrapolations from lighter congeners become completely inaccurate. In addition, the relativistic and shell-structure effects (which stabilise the s-orbitals and destabilise and expand the d-, f-, and g-orbitals of higher shells) have opposite effects, causing even larger difference between relativistic and non-relativistic calculations of the properties of elements with such high atomic numbers. Interest in the chemical properties of ununennium, unhexpentium, and unsepttrium stems from the fact that they are located close to the expected locations of [[island of stability|islands of stability]], centered at elements 122 (Ubb) and 164 (Uhq).", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals"], "text": "Many other substances are similar to the alkali metals in their tendency to form monopositive cations. Analogously to the [[pseudohalogen]], they have sometimes been called \"pseudo-alkali metals\". These substances include some elements and many more [[polyatomic ion]]; the polyatomic ions are especially similar to the alkali metals in their large size and weak polarising power.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Hydrogen"], "text": "The element [[hydrogen]], with one electron per neutral atom, is usually placed at the top of Group 1 of the periodic table for convenience, but hydrogen is not normally considered to be an alkali metal; when it is considered to be an alkali metal, it is because of its atomic properties and not its chemical properties. Under typical conditions, pure hydrogen exists as a [[diatomic]] gas consisting of two atoms per [[molecule]] (H); however, the alkali metals only form diatomic molecules (such as [[dilithium]], Li) at high temperatures, when they are in the [[gas]] state. Hydrogen, like the alkali metals, has one [[valence electron]] and reacts easily with the [[halogen]], but the similarities mostly end there because of the small size of a bare proton H compared to the alkali metal cations. Its placement above lithium is primarily due to its [[electron configuration]]. It is sometimes placed above [[fluorine]] due to their similar chemical properties, though the resemblance is likewise not absolute. The first ionisation energy of hydrogen (1312.0 [[kilojoule per mole|kJ/mol]]) is much higher than that of the alkali metals. As only one additional electron is required to fill in the outermost shell of the hydrogen atom, hydrogen often behaves like a halogen, forming the negative [[hydride]] ion, and is very occasionally considered to be a halogen on that basis. (The alkali metals can also form negative ions, known as [[alkalide]], but these are little more than laboratory curiosities, being unstable.) An argument against this placement is that formation of hydride from hydrogen is endothermic, unlike the exothermic formation of halides from halogens. The radius of the H anion also does not fit the trend of increasing size going down the halogens: indeed, H is very diffuse because its single proton cannot easily control both electrons. It was expected for some time that liquid hydrogen would show metallic properties; while this has been shown to not be the case, under extremely high [[pressure]], such as those found at the cores of [[Jupiter]] and [[Saturn]], hydrogen does become metallic and behaves like an alkali metal; in this phase, it is known as [[metallic hydrogen]]. The [[resistivity|electrical resistivity]] of liquid [[metallic hydrogen]] at 3000 K is approximately equal to that of liquid [[rubidium]] and [[caesium]] at 2000 K at the respective pressures when they undergo a nonmetal-to-metal transition.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Hydrogen"], "text": "The 1s electron configuration of hydrogen, while analogous to that of the alkali metals (ns), is unique because there is no 1p subshell. Hence it can lose an electron to form the [[hydron (chemistry)|hydron]] H, or gain one to form the [[hydride]] ion H. In the former case it resembles superficially the alkali metals; in the latter case, the halogens, but the differences due to the lack of a 1p subshell are important enough that neither group fits the properties of hydrogen well. Group 14 is also a good fit in terms of thermodynamic properties such as [[ionisation energy]] and [[electron affinity]], but hydrogen cannot be tetravalent. Thus none of the three placements are entirely satisfactory, although group 1 is the most common placement (if one is chosen) because the hydron is by far the most important of all monatomic hydrogen species, being the foundation of acid-base chemistry. As an example of hydrogen's unorthodox properties stemming from its unusual electron configuration and small size, the hydrogen ion is very small (radius around 150 [[femtometre|fm]] compared to the 50–220 pm size of most other atoms and ions) and so is nonexistent in condensed systems other than in association with other atoms or molecules. Indeed, transferring of protons between chemicals is the basis of [[acid-base chemistry]]. Also unique is hydrogen's ability to form [[hydrogen bond]], which are an effect of charge-transfer, [[electrostatic]], and electron correlative contributing phenomena. While analogous lithium bonds are also known, they are mostly electrostatic. Nevertheless, hydrogen can take on the same structural role as the alkali metals in some molecular crystals, and has a close relationship with the lightest alkali metals (especially lithium).", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Ammonium and derivatives"], "text": "The [[ammonium]] ion () has very similar properties to the heavier alkali metals, acting as an alkali metal intermediate between potassium and rubidium, and is often considered a close relative. For example, most alkali metal [[salt (chemistry)|salts]] are [[solubility|soluble]] in water, a property which ammonium salts share. Ammonium is expected to behave stably as a metal ( ions in a sea of delocalised electrons) at very high pressures (though less than the typical pressure where transitions from insulating to metallic behaviour occur around, 100 [[pascal (unit)|GPa]]), and could possibly occur inside the [[Gas giant#Uranus and Neptune|ice giants]] [[Uranus]] and [[Neptune]], which may have significant impacts on their interior magnetic fields. It has been estimated that the transition from a mixture of [[ammonia]] and dihydrogen molecules to metallic ammonium may occur at pressures just below 25 GPa. Under standard conditions, ammonium can form a metallic amalgam with mercury. Other \"pseudo-alkali metals\" include the [[alkylammonium]] cations, in which some of the hydrogen atoms in the ammonium cation are replaced by alkyl or aryl groups. In particular, the [[quaternary ammonium cation]] () are very useful since they are permanently charged, and they are often used as an alternative to the expensive Cs to stabilise very large and very easily polarisable anions such as . Tetraalkylammonium hydroxides, like alkali metal hydroxides, are very strong bases that react with atmospheric carbon dioxide to form carbonates. Furthermore, the nitrogen atom may be replaced by a phosphorus, arsenic, or antimony atom (the heavier nonmetallic [[pnictogen]]), creating a [[phosphonium]] () or [[arsonium]] () cation that can itself be substituted similarly; while [[stibonium]] () itself is not known, some of its organic derivatives are characterised.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Cobaltocene and derivatives"], "text": "[[Cobaltocene]], Co(CH), is a [[metallocene]], the [[cobalt]] analogue of [[ferrocene]]. It is a dark purple solid. Cobaltocene has 19 valence electrons, one more than usually found in organotransition metal complexes, such as its very stable relative, ferrocene, in accordance with the [[18-electron rule]]. This additional electron occupies an orbital that is antibonding with respect to the Co–C bonds. Consequently, many chemical reactions of Co(CH) are characterized by its tendency to lose this \"extra\" electron, yielding a very stable 18-electron cation known as cobaltocenium. Many cobaltocenium salts coprecipitate with caesium salts, and cobaltocenium hydroxide is a strong base that absorbs atmospheric carbon dioxide to form cobaltocenium carbonate. Like the alkali metals, cobaltocene is a strong reducing agent, and [[decamethylcobaltocene]] is stronger still due to the combined [[inductive effect]] of the ten methyl groups. Cobalt may be substituted by its heavier congener [[rhodium]] to give [[rhodocene]], an even stronger reducing agent. [[Iridocene]] (involving [[iridium]]) would presumably be still more potent, but is not very well-studied due to its instability.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Thallium"], "text": "[[Thallium]] is the heaviest stable element in group 13 of the periodic table. At the bottom of the periodic table, the [[inert pair effect]] is quite strong, because of the [[relativistic effects|relativistic]] stabilisation of the 6s orbital and the decreasing bond energy as the atoms increase in size so that the amount of energy released in forming two more bonds is not worth the high ionisation energies of the 6s electrons. It displays the +1 [[oxidation state]] that all the known alkali metals display, and thallium compounds with thallium in its +1 [[oxidation state]] closely resemble the corresponding potassium or [[silver]] compounds stoichiometrically due to the similar ionic radii of the Tl (164 [[picometer|pm]]), K (152 pm) and Ag (129 pm) ions. It was sometimes considered an alkali metal in [[continental Europe]] (but not in England) in the years immediately following its discovery, and was placed just after caesium as the sixth alkali metal in [[Dmitri Mendeleev]]'s 1869 [[periodic table]] and [[Julius Lothar Meyer]]'s 1868 periodic table. (Mendeleev's 1871 periodic table and Meyer's 1870 periodic table put thallium in its current position in the [[boron group]] and left the space below caesium blank.) However, thallium also displays the oxidation state +3, which no known alkali metal displays (although ununennium, the undiscovered seventh alkali metal, is predicted to possibly display the +3 oxidation state). The sixth alkali metal is now considered to be francium. While Tl is stabilised by the inert pair effect, this inert pair of 6s electrons is still able to participate chemically, so that these electrons are [[stereochemistry|stereochemically]] active in aqueous solution. Additionally, the thallium halides (except [[thallium(I) fluoride|TlF]]) are quite insoluble in water, and [[thallium(I) iodide|TlI]] has an unusual structure because of the presence of the stereochemically active inert pair in thallium.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Copper, silver, and gold"], "text": "The [[group 11 element|group 11 metals]] (or coinage metals), [[copper]], [[silver]], and [[gold]], are typically categorised as transition metals given they can form ions with incomplete d-shells. Physically, they have the relatively low melting points and high electronegativity values associated with [[post-transition metal]]. \"The filled ''d'' subshell and free ''s'' electron of Cu, Ag, and Au contribute to their high electrical and thermal conductivity. Transition metals to the left of group 11 experience interactions between ''s'' electrons and the partially filled ''d'' subshell that lower electron mobility.\" Chemically, the group 11 metals behave like main-group metals in their +1 valence states, and are hence somewhat related to the alkali metals: this is one reason for their previously being labelled as \"group IB\", paralleling the alkali metals' \"group IA\". They are occasionally classified as post-transition metals. Their spectra are analogous to those of the alkali metals. Their monopositive ions are [[paramagnetic]] and contribute no colour to their salts, like those of the alkali metals. In Mendeleev's 1871 periodic table, copper, silver, and gold are listed twice, once under group VIII (with the [[iron triad]] and [[platinum group metal]]), and once under group IB. Group IB was nonetheless parenthesised to note that it was tentative. Mendeleev's main criterion for group assignment was the maximum oxidation state of an element: on that basis, the group 11 elements could not be classified in group IB, due to the existence of copper(II) and gold(III) compounds being known at that time. However, eliminating group IB would make group I the only main group (group VIII was labelled a transition group) to lack an A–B bifurcation. Soon afterward, a majority of chemists chose to classify these elements in group IB and remove them from group VIII for the resulting symmetry: this was the predominant classification until the rise of the modern medium-long 18-column periodic table, which separated the alkali metals and group 11 metals.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Pseudo-alkali metals", "Copper, silver, and gold"], "text": "The coinage metals were traditionally regarded as a subdivision of the alkali metal group, due to them sharing the characteristic s electron configuration of the alkali metals (group 1: ps; group 11: ds). However, the similarities are largely confined to the [[stochiometry|stoichiometries]] of the +1 compounds of both groups, and not their chemical properties. This stems from the filled d subshell providing a much weaker shielding effect on the outermost s electron than the filled p subshell, so that the coinage metals have much higher first ionisation energies and smaller ionic radii than do the corresponding alkali metals. Furthermore, they have higher melting points, hardnesses, and densities, and lower reactivities and solubilities in liquid [[ammonia]], as well as having more covalent character in their compounds. Finally, the alkali metals are at the top of the [[electrochemical series]], whereas the coinage metals are almost at the very bottom. The coinage metals' filled d shell is much more easily disrupted than the alkali metals' filled p shell, so that the second and third ionisation energies are lower, enabling higher oxidation states than +1 and a richer coordination chemistry, thus giving the group 11 metals clear [[transition metal]] character. Particularly noteworthy is gold forming ionic compounds with rubidium and caesium, in which it forms the auride ion (Au) which also occurs in solvated form in liquid ammonia solution: here gold behaves as a [[pseudohalogen]] because its 5d6s configuration has one electron less than the quasi-closed shell 5d6s configuration of [[mercury (element)|mercury]].", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Production and isolation"], "text": "The production of pure alkali metals is somewhat complicated due to their extreme reactivity with commonly used substances, such as water. From their [[silicate]] ores, all the stable alkali metals may be obtained the same way: [[sulfuric acid]] is first used to dissolve the desired alkali metal ion and [[aluminium]](III) ions from the ore (leaching), whereupon basic precipitation removes aluminium ions from the mixture by precipitating it as the [[aluminium hydroxide|hydroxide]]. The remaining insoluble alkali metal [[carbonate]] is then precipitated selectively; the salt is then dissolved in [[hydrochloric acid]] to produce the chloride. The result is then left to evaporate and the alkali metal can then be isolated. Lithium and sodium are typically isolated through electrolysis from their liquid chlorides, with [[calcium chloride]] typically added to lower the melting point of the mixture. The heavier alkali metals, however, is more typically isolated in a different way, where a reducing agent (typically sodium for potassium and [[magnesium]] or [[calcium]] for the heaviest alkali metals) is used to reduce the alkali metal chloride. The liquid or gaseous product (the alkali metal) then undergoes [[fractional distillation]] for purification. Most routes to the pure alkali metals require the use of electrolysis due to their high reactivity; one of the few which does not is the [[pyrolysis]] of the corresponding alkali metal [[azide]], which yields the metal for sodium, potassium, rubidium, and caesium and the nitride for lithium. Lithium salts have to be extracted from the water of [[mineral spring]], [[brine]] pools, and brine deposits. The metal is produced electrolytically from a mixture of fused [[lithium chloride]] and [[potassium chloride]]. Sodium occurs mostly in seawater and dried [[seabed]], but is now produced through [[electrolysis]] of [[sodium chloride]] by lowering the melting point of the substance to below 700 °C through the use of a [[Downs cell]]. Extremely pure sodium can be produced through the thermal decomposition of [[sodium azide]]. Potassium occurs in many minerals, such as [[sylvite]] ([[potassium chloride]]). Previously, potassium was generally made from the electrolysis of [[potassium chloride]] or [[potassium hydroxide]], found extensively in places such as Canada, Russia, Belarus, Germany, Israel, United States, and Jordan, in a method similar to how sodium was produced in the late 1800s and early 1900s. It can also be produced from [[seawater]]. However, these methods are problematic because the potassium metal tends to dissolve in its molten chloride and vaporises significantly at the operating temperatures, potentially forming the explosive superoxide. As a result, pure potassium metal is now produced by reducing molten potassium chloride with sodium metal at 850 °C. Na (g) + KCl (l) NaCl (l) + K (g) Although sodium is less reactive than potassium, this process works because at such high temperatures potassium is more volatile than sodium and can easily be distilled off, so that the equilibrium shifts towards the right to produce more potassium gas and proceeds almost to completion.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Production and isolation"], "text": "For several years in the 1950s and 1960s, a by-product of the potassium production called Alkarb was a main source for rubidium. Alkarb contained 21% rubidium while the rest was potassium and a small fraction of caesium. Today the largest producers of caesium, for example the [[Tanco Mine]] in Manitoba, Canada, produce rubidium as by-product from [[pollucite]]. Today, a common method for separating rubidium from potassium and caesium is the [[fractional crystallization (chemistry)|fractional crystallisation]] of a rubidium and caesium [[alum]] ([[Caesium|Cs]], [[Rubidium|Rb]])[[Aluminium|Al]]([[Sulfate|SO]])·12[[Water|HO]], which yields pure rubidium alum after approximately 30 recrystallisations. The limited applications and the lack of a mineral rich in rubidium limit the production of rubidium compounds to 2 to 4 [[tonne]] per year. Caesium, however, is not produced from the above reaction. Instead, the mining of [[pollucite]] ore is the main method of obtaining pure caesium, extracted from the ore mainly by three methods: acid digestion, alkaline decomposition, and direct reduction. Both metals are produced as by-products of lithium production: after 1958, when interest in lithium's thermonuclear properties increased sharply, the production of rubidium and caesium also increased correspondingly. Pure rubidium and caesium metals are produced by reducing their chlorides with [[calcium]] metal at 750 °C and low pressure. As a result of its extreme rarity in nature, most francium is synthesised in the nuclear reaction [[Gold|Au]] + [[Oxygen|O]] → [[Francium|Fr]] + 5 [[neutron|n]], yielding [[francium-209]], [[francium-210]], and [[francium-211]]. The greatest quantity of francium ever assembled to date is about 300,000 neutral atoms, which were synthesised using the nuclear reaction given above. When the only natural isotope francium-223 is specifically required, it is produced as the alpha daughter of actinium-227, itself produced synthetically from the neutron irradiation of natural radium-226, one of the daughters of natural uranium-238.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Applications"], "text": "Lithium, sodium, and potassium have many applications, while rubidium and caesium are very useful in academic contexts but do not have many applications yet. Lithium is often used in [[lithium-ion battery|lithium-ion batteries]], and [[lithium oxide]] can help process silica. [[Lithium stearate]] is a thickener and can be used to make lubricating greases; it is produced from lithium hydroxide, which is also used to absorb [[carbon dioxide]] in space capsules and submarines. [[Lithium chloride]] is used as a brazing alloy for aluminium parts. Metallic lithium is used in alloys with magnesium and aluminium to give very tough and light alloys. Sodium compounds have many applications, the most well-known being sodium chloride as [[table salt]]. Sodium salts of [[fatty acid]] are used as soap. Pure sodium metal also has many applications, including use in [[sodium-vapor lamp|sodium-vapour lamps]], which produce very efficient light compared to other types of lighting, and can help smooth the surface of other metals. Being a strong reducing agent, it is often used to reduce many other metals, such as [[titanium]] and [[zirconium]], from their chlorides. Furthermore, it is very useful as a heat-exchange liquid in [[fast breeder nuclear reactor]] due to its low melting point, viscosity, and [[cross-section (physics)|cross-section]] towards neutron absorption. Potassium compounds are often used as [[fertiliser]] as potassium is an important element for plant nutrition. [[Potassium hydroxide]] is a very strong base, and is used to control the [[pH]] of various substances. [[Potassium nitrate]] and [[potassium permanganate]] are often used as powerful oxidising agents. [[Potassium superoxide]] is used in breathing masks, as it reacts with carbon dioxide to give potassium carbonate and oxygen gas. Pure potassium metal is not often used, but its alloys with sodium may substitute for pure sodium in fast breeder nuclear reactors. Rubidium and caesium are often used in [[atomic clock]]. Caesium atomic clocks are extraordinarily accurate; if a clock had been made at the time of the dinosaurs, it would be off by less than four seconds (after 80 million years). For that reason, caesium atoms are used as the definition of the second. Rubidium ions are often used in purple [[firework]], and caesium is often used in drilling fluids in the petroleum industry. Francium has no commercial applications, but because of francium's relatively simple [[atomic structure]], among other things, it has been used in [[spectroscopy]] experiments, leading to more information regarding [[energy level]] and the [[coupling constant]] between [[subatomic particle]]. Studies on the light emitted by laser-trapped francium-210 ions have provided accurate data on transitions between atomic energy levels, similar to those predicted by [[quantum mechanics|quantum theory]].", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Biological role and precautions", "Metals"], "text": "Pure alkali metals are dangerously reactive with air and water and must be kept away from heat, fire, oxidising agents, acids, most organic compounds, [[halocarbon]], [[plastic]], and moisture. They also react with carbon dioxide and carbon tetrachloride, so that normal fire extinguishers are counterproductive when used on alkali metal fires. Some Class D dry powder [[fire extinguisher|extinguishers]] designed for metal fires are effective, depriving the fire of oxygen and cooling the alkali metal. Experiments are usually conducted using only small quantities of a few grams in a [[fume hood]]. Small quantities of lithium may be disposed of by reaction with cool water, but the heavier alkali metals should be dissolved in the less reactive [[isopropanol]]. The alkali metals must be stored under [[mineral oil]] or an inert atmosphere. The inert atmosphere used may be [[argon]] or nitrogen gas, except for lithium, which reacts with nitrogen. Rubidium and caesium must be kept away from air, even under oil, because even a small amount of air diffused into the oil may trigger formation of the dangerously explosive peroxide; for the same reason, potassium should not be stored under oil in an oxygen-containing atmosphere for longer than 6 months.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Biological role and precautions", "Ions"], "text": "The bioinorganic chemistry of the alkali metal ions has been extensively reviewed. Solid state crystal structures have been determined for many complexes of alkali metal ions in small peptides, nucleic acid constituents, carbohydrates and ionophore complexes. Lithium naturally only occurs in traces in biological systems and has no known biological role, but does have effects on the body when ingested. [[Lithium carbonate]] is used as a [[mood stabiliser]] in [[psychiatry]] to treat [[bipolar disorder]] ([[manic-depression]]) in daily doses of about 0.5 to 2 grams, although there are side-effects. Excessive ingestion of lithium causes drowsiness, slurred speech and vomiting, among other symptoms, and [[poison]] the [[central nervous system]], which is dangerous as the required dosage of lithium to treat bipolar disorder is only slightly lower than the toxic dosage. Its biochemistry, the way it is handled by the human body and studies using rats and goats suggest that it is an [[essential element|essential]] [[trace element]], although the natural biological function of lithium in humans has yet to be identified. Sodium and potassium occur in all known biological systems, generally functioning as [[electrolytes]] inside and outside [[cell (biology)|cells]]. Sodium is an essential nutrient that regulates blood volume, blood pressure, osmotic equilibrium and [[pH]]; the minimum physiological requirement for sodium is 500 milligrams per day. [[Sodium chloride]] (also known as common salt) is the principal source of sodium in the diet, and is used as seasoning and preservative, such as for [[pickling]] and [[jerky (food)|jerky]]; most of it comes from processed foods. The [[Dietary Reference Intake]] for sodium is 1.5 grams per day, but most people in the United States consume more than 2.3 grams per day, the minimum amount that promotes hypertension; this in turn causes 7.6 million premature deaths worldwide. Potassium is the major [[cation]] (positive ion) inside [[cell (biology)|animal cells]], while sodium is the major cation outside animal cells. The [[concentration]] differences of these charged particles causes a difference in [[electric potential]] between the inside and outside of cells, known as the [[membrane potential]]. The balance between potassium and sodium is maintained by [[ion transporter]] proteins in the [[cell membrane]]. The cell membrane potential created by potassium and sodium ions allows the cell to generate an [[action potential]]—a \"spike\" of electrical discharge. The ability of cells to produce electrical discharge is critical for body functions such as [[neurotransmission]], muscle contraction, and heart function. Disruption of this balance may thus be fatal: for example, ingestion of large amounts of potassium compounds can lead to [[hyperkalemia]] strongly influencing the cardiovascular system. Potassium chloride is used in the [[United States]] for [[lethal injection]] executions.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": ["Biological role and precautions", "Ions"], "text": "Due to their similar atomic radii, rubidium and caesium in the body mimic potassium and are taken up similarly. Rubidium has no known biological role, but may help stimulate [[metabolism]], and, similarly to caesium, replace potassium in the body causing [[hypokalemia|potassium deficiency]]. Partial substitution is quite possible and rather non-toxic: a 70 kg person contains on average 0.36 g of rubidium, and an increase in this value by 50 to 100 times did not show negative effects in test persons. Rats can survive up to 50% substitution of potassium by rubidium. Rubidium (and to a much lesser extent caesium) can function as temporary cures for hypokalemia; while rubidium can adequately physiologically substitute potassium in some systems, caesium is never able to do so. There is only very limited evidence in the form of deficiency symptoms for rubidium being possibly essential in goats; even if this is true, the trace amounts usually present in food are more than enough. Caesium compounds are rarely encountered by most people, but most caesium compounds are mildly toxic. Like rubidium, caesium tends to substitute potassium in the body, but is significantly larger and is therefore a poorer substitute. Excess caesium can lead to [[hypokalemia]], [[arrythmia]], and acute [[cardiac arrest]], but such amounts would not ordinarily be encountered in natural sources. As such, caesium is not a major chemical environmental pollutant. The [[median lethal dose]] (LD) value for [[caesium chloride]] in mice is 2.3 g per kilogram, which is comparable to the LD values of [[potassium chloride]] and [[sodium chloride]]. Caesium chloride has been promoted as an alternative cancer therapy, but has been linked to the deaths of over 50 patients, on whom it was used as part of a scientifically unvalidated cancer treatment. [[Radioisotope]] of caesium require special precautions: the improper handling of caesium-137 [[gamma ray]] sources can lead to release of this radioisotope and radiation injuries. Perhaps the best-known case is the Goiânia accident of 1987, in which an improperly-disposed-of radiation therapy system from an abandoned clinic in the city of [[Goiânia]], [[Brazil]], was scavenged from a junkyard, and the glowing [[caesium chloride|caesium salt]] sold to curious, uneducated buyers. This led to four deaths and serious injuries from radiation exposure. Together with [[caesium-134]], [[iodine-131]], and [[strontium-90]], caesium-137 was among the isotopes distributed by the [[Chernobyl disaster]] which constitute the greatest risk to health. Radioisotopes of francium would presumably be dangerous as well due to their high decay energy and short half-life, but none have been produced in large enough amounts to pose any serious risk.", "id": "666", "title": "Alkali metal", "categories": ["Chemical compounds by element", "Alkali metals", "Groups (periodic table)", "Periodic table", "Articles containing video clips"], "seealso": []}
{"headers": [], "text": "An '''alphabet''' is a standardized set of basic written [[symbols]] or [[graphemes]] (called [[letter (alphabet)|letters]]) that represent the [[phoneme]] of certain [[spoken language]]. Not all [[writing system]] represent language in this way; in a [[syllabary]], each character represents a [[syllable]], for instance, and [[Logogram|logographic systems]] use characters to represent words, [[morphemes]], or other semantic units. The first fully phonemic script, the [[Proto-Sinaitic script|Proto-Canaanite script]], later known as the [[Phoenician alphabet]], is considered to be the first alphabet, and is the ancestor of most modern alphabets, including [[Arabic alphabet|Arabic]], [[Cyrillic alphabet|Cyrillic]], [[Greek alphabet|Greek]], [[Hebrew alphabet|Hebrew]], [[Latin alphabet|Latin]], and possibly [[Brahmic scripts|Brahmic]]. It was created by Semitic-speaking workers and slaves in the [[Sinai Peninsula]] (as the [[Proto-Sinaitic script]]), by selecting a small number of [[Egyptian hieroglyphs|hieroglyphs]] commonly seen in their [[Ancient Egypt|Egyptian surroundings]] to [[Acrophony|describe the sounds]], as opposed to the semantic values, of their own [[Canaanite languages|Canaanite language]]. [[Peter T. Daniels]], however, distinguishes an [[abugida]] or alphasyllabary, a set of graphemes that represent consonantal base letters which [[diacritic]] modify to represent vowels (as in [[Devanagari]] and other South Asian scripts), an [[abjad]], in which letters predominantly or exclusively represent consonants (as in the original Phoenician, [[Hebrew alphabet|Hebrew]] or [[Arabic script|Arabic]]), and an \"alphabet\", a set of graphemes that represent both [[vowel]] and [[consonant]]. In this narrow sense of the word the first true alphabet was the [[Greek alphabet]], which was developed on the basis of the earlier [[Phoenician alphabet]]. Of the dozens of alphabets in use today, the most popular is the [[Latin alphabet]], which was derived from the [[Greek alphabet|Greek]], and which many [[language]] modify by adding letters formed using diacritical marks. While most alphabets have letters composed of lines ([[linear writing]]), there are also [[non-linear writing|exceptions]] such as the alphabets used in [[Braille]]. The [[Khmer alphabet]] (for [[Cambodian language|Cambodian]]) is the longest, with 74 letters. Alphabets are usually associated with a standard ordering of letters. This makes them useful for purposes of [[collation]], specifically by allowing words to be sorted in [[alphabetical order]]. It also means that their letters can be used as an alternative method of \"numbering\" ordered items, in such contexts as [[numbered list]] and number placements.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Etymology"], "text": "The English word ''alphabet'' came into [[Middle English]] from the [[Late Latin]] word ''alphabetum'', which in turn originated in the [[Greek language|Greek]] ἀλφάβητος (''alphabētos''). The Greek word was made from the first two letters, ''[[alpha (letter)|alpha]]''(α) and ''[[beta (letter)|beta]]''(β). The names for the Greek letters came from the first two letters of the [[Phoenician alphabet]]; ''[[aleph]]'', which also meant ''ox'', and ''[[bet (letter)|bet]]'', which also meant ''house''. Sometimes, like in the [[alphabet song]] in English, the term \"ABCs\" is used instead of the word \"alphabet\" (''Now I know my ABCs''...). \"Knowing one's ABCs\", in general, can be used as a [[metaphor]] for knowing the basics about anything.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["History", "Ancient Northeast African and Middle Eastern scripts"], "text": "The history of the alphabet started in [[ancient Egypt]]. Egyptian writing had a set of some [[Egyptian uniliteral signs|24 hieroglyphs]] that are called uniliterals, to represent syllables that begin with a single [[consonant]] of their language, plus a vowel (or no vowel) to be supplied by the native speaker. These glyphs were used as pronunciation guides for [[logogram]], to write grammatical inflections, and, later, to transcribe loan words and foreign names. In the [[Middle Bronze Age]], an apparently \"alphabetic\" system known as the [[Proto-Sinaitic script]] appears in Egyptian turquoise mines in the [[Sinai peninsula]] dated to circa the 15th century BC, apparently left by Canaanite workers. In 1999, John and Deborah Darnell discovered an even earlier version of this first alphabet at Wadi el-Hol dated to circa 1800 BC and showing evidence of having been adapted from specific forms of Egyptian hieroglyphs that could be dated to circa 2000 BC, strongly suggesting that the first alphabet had been developed about that time. Based on letter appearances and names, it is believed to be based on Egyptian hieroglyphs. This script had no characters representing vowels, although originally it probably was a syllabary, but unneeded symbols were discarded. An alphabetic [[cuneiform]] script with 30 signs including three that indicate the following vowel was invented in [[Ugarit]] before the 15th century BC. This script was not used after the destruction of Ugarit. The Proto-Sinaitic script eventually developed into the [[Phoenician alphabet]], which is conventionally called \"Proto-Canaanite\" before c. 1050 BC. The oldest text in Phoenician script is an inscription on the sarcophagus of King [[Ahiram]]. This script is the parent script of all western alphabets. By the tenth century, two other forms can be distinguished, namely [[Canaanite language|Canaanite]] and [[Aramaic alphabet|Aramaic]]. The Aramaic gave rise to the [[Hebrew alphabet|Hebrew]] script. The [[South Arabian alphabet]], a sister script to the Phoenician alphabet, is the script from which the [[Ge'ez alphabet]] (an [[abugida]]) is descended. Vowelless alphabets are called [[abjad]], currently exemplified in scripts including [[Arabic alphabet|Arabic]], [[Hebrew alphabet|Hebrew]], and [[Syriac alphabet|Syriac]]. The omission of vowels was not always a satisfactory solution and some \"weak\" consonants are sometimes used to indicate the vowel quality of a syllable ([[Mater lectionis|matres lectionis]]). These letters have a dual function since they are also used as pure consonants. The Proto-Sinaitic or Proto-Canaanite script and the [[Ugaritic script]] were the first scripts with a limited number of signs, in contrast to the other widely used writing systems at the time, [[Cuneiform]], [[Egyptian hieroglyphs]], and [[Linear B]]. The Phoenician script was probably the first phonemic script and it contained only about two dozen distinct letters, making it a script simple enough for common traders to learn. Another advantage of Phoenician was that it could be used to write down many different languages, since it recorded words phonemically.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["History", "Ancient Northeast African and Middle Eastern scripts"], "text": "The script was spread by the Phoenicians across the Mediterranean. In Greece, the script was modified to add vowels, giving rise to the ancestor of all alphabets in the West. It was the first alphabet in which vowels have independent letter forms separate from those of consonants. The Greeks chose letters representing sounds that did not exist in Greek to represent vowels. Vowels are significant in the Greek language, and the syllabical [[Linear B]] script that was used by the [[Mycenaean Greece|Mycenaean]] Greeks from the 16th century BC had 87 symbols, including 5 vowels. In its early years, there were many variants of the Greek alphabet, a situation that caused many different alphabets to evolve from it.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["History", "European alphabets"], "text": "The [[Greek alphabet]], in its [[Euboean alphabet|Euboean form]], was carried over by Greek colonists to the Italian peninsula, where it gave rise to a variety of alphabets used to write the [[Italic languages]]. One of these became the [[Latin alphabet]], which was spread across Europe as the Romans expanded their empire. Even after the fall of the Roman state, the alphabet survived in intellectual and religious works. It eventually became used for the descendant languages of Latin (the [[Romance languages]]) and then for most of the other languages of Europe. Some adaptations of the Latin alphabet are augmented with [[ligature (typography)|ligatures]], such as [[æ]] in [[Danish language|Danish]] and [[Icelandic language|Icelandic]] and [[Ou (letter)|Ȣ]] in [[Algonquian languages|Algonquian]]; by borrowings from other alphabets, such as the [[thorn (letter)|thorn]] þ in [[Old English language|Old English]] and [[Icelandic language|Icelandic]], which came from the [[Runic alphabet|Futhark]] runes; and by modifying existing letters, such as the [[Eth (letter)|eth]] ð of Old English and Icelandic, which is a modified ''d''. Other alphabets only use a subset of the Latin alphabet, such as Hawaiian, and [[Italian language|Italian]], which uses the letters ''j, k, x, y'' and ''w'' only in foreign words. Another notable script is [[Elder Futhark]], which is believed to have evolved out of one of the [[Old Italic alphabet]]. Elder Futhark gave rise to a variety of alphabets known collectively as the [[Runic alphabet]]. The Runic alphabets were used for Germanic languages from AD 100 to the late Middle Ages. Its usage is mostly restricted to engravings on stone and jewelry, although inscriptions have also been found on bone and wood. These alphabets have since been replaced with the Latin alphabet, except for decorative usage for which the runes remained in use until the 20th century. The [[Old Hungarian script]] is a contemporary writing system of the Hungarians. It was in use during the entire history of Hungary, albeit not as an official writing system. From the 19th century it once again became more and more popular. The [[Glagolitic alphabet]] was the initial script of the liturgical language [[Old Church Slavonic]] and became, together with the Greek uncial script, the basis of the [[Cyrillic script]]. Cyrillic is one of the most widely used modern alphabetic scripts, and is notable for its use in Slavic languages and also for other languages within the former [[Soviet Union]]. [[Cyrillic alphabets]] include the [[Serbian Cyrillic alphabet|Serbian]], [[Macedonian alphabet|Macedonian]], [[Bulgarian alphabet|Bulgarian]], [[Russian alphabet|Russian]], [[Belarusian alphabet|Belarusian]] and [[Ukrainian alphabet|Ukrainian]]. The Glagolitic alphabet is believed to have been created by [[Saints Cyril and Methodius]], while the Cyrillic alphabet was invented by [[Clement of Ohrid]], who was their disciple. They feature many letters that appear to have been borrowed from or influenced by the [[Greek alphabet]] and the [[Hebrew alphabet]]. The longest European alphabet is the Latin-derived [[Slovak alphabet]] which has 46 letters.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["History", "Asian alphabets"], "text": "Beyond the logographic [[Written Chinese|Chinese writing]], many phonetic scripts are in existence in Asia. The [[Arabic alphabet]], [[Hebrew alphabet]], [[Syriac alphabet]], and other [[abjad]] of the Middle East are developments of the [[Aramaic alphabet]]. Most alphabetic scripts of India and Eastern Asia are descended from the [[Brahmi script]], which is often believed to be a descendant of Aramaic. In [[Korea]], the [[Hangul]] alphabet was created by [[Sejong the Great]]. Hangul is a unique alphabet: it is a [[featural alphabet]], where many of the letters are designed from a sound's place of articulation (P to look like the widened mouth, L to look like the tongue pulled in, etc.); its design was planned by the government of the day; and it places individual letters in syllable clusters with equal dimensions, in the same way as [[Chinese characters]], to allow for mixed-script writing (one syllable always takes up one type-space no matter how many letters get stacked into building that one sound-block). [[Zhuyin]] (sometimes called ''Bopomofo'') is a [[semi-syllabary]] used to phonetically transcribe [[Standard Chinese|Mandarin Chinese]] in the [[Taiwan|Republic of China]]. After the later establishment of the [[China|People's Republic of China]] and its adoption of [[Pinyin|Hanyu Pinyin]], the use of Zhuyin today is limited, but it is still widely used in [[Taiwan]] where the Republic of China still governs. Zhuyin developed out of a form of Chinese shorthand based on Chinese characters in the early 1900s and has elements of both an alphabet and a syllabary. Like an alphabet the phonemes of [[syllable onset|syllable initials]] are represented by individual symbols, but like a syllabary the phonemes of the [[syllable rime|syllable finals]] are not; rather, each possible final (excluding the [[Syllable medial|medial glide]]) is represented by its own symbol. For example, ''luan'' is represented as ㄌㄨㄢ (''l-u-an''), where the last symbol ㄢ represents the entire final ''-an''. While Zhuyin is not used as a mainstream writing system, it is still often used in ways similar to a [[romanization]] system—that is, for aiding in pronunciation and as an input method for Chinese characters on computers and cellphones. European alphabets, especially Latin and Cyrillic, have been adapted for many languages of Asia. Arabic is also widely used, sometimes as an abjad (as with [[Urdu alphabet|Urdu]] and [[Persian alphabet|Persian]]) and sometimes as a complete alphabet (as with [[Kurdish alphabet|Kurdish]] and [[Uyghur alphabet|Uyghur]]).", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Types"], "text": "The term \"alphabet\" is used by [[Linguistics|linguists]] and [[paleographer]] in both a wide and a narrow sense. In the wider sense, an alphabet is a script that is ''segmental'' at the [[phoneme]] level—that is, it has separate glyphs for individual sounds and not for larger units such as syllables or words. In the narrower sense, some scholars distinguish \"true\" alphabets from two other types of segmental script, [[abjad]] and [[abugida]]. These three differ from each other in the way they treat vowels: abjads have letters for consonants and leave most vowels unexpressed; abugidas are also consonant-based, but indicate vowels with [[diacritic]] to or a systematic graphic modification of the consonants. In alphabets in the narrow sense, on the other hand, consonants and vowels are written as independent letters. The earliest known alphabet in the wider sense is the [[Middle Bronze Age alphabets|Wadi el-Hol script]], believed to be an abjad, which through its successor [[Phoenician alphabet|Phoenician]] is the ancestor of modern alphabets, including [[Arabic alphabet|Arabic]], [[Greek alphabet|Greek]], [[Latin alphabet|Latin]] (via the [[Old Italic alphabet]]), [[Cyrillic]] (via the Greek alphabet) and [[Hebrew alphabet|Hebrew]] (via [[Aramaic alphabet|Aramaic]]). Examples of present-day abjads are the [[Arabic script|Arabic]] and [[Hebrew script]]; true alphabets include [[Latin script|Latin]], Cyrillic, and Korean [[hangul]]; and abugidas are used to write [[tigrinya language|Tigrinya]], [[Amharic language|Amharic]], [[Hindi]], and [[Thai language|Thai]]. The [[Canadian Aboriginal syllabics]] are also an abugida rather than a syllabary as their name would imply, since each glyph stands for a consonant that is modified by rotation to represent the following vowel. (In a true syllabary, each consonant-vowel combination would be represented by a separate glyph.) All three types may be augmented with syllabic glyphs. [[Ugaritic script|Ugaritic]], for example, is basically an abjad, but has syllabic letters for . (These are the only time vowels are indicated.) Cyrillic is basically a true alphabet, but has syllabic letters for (я, е, ю); [[Coptic alphabet|Coptic]] has a letter for . [[Devanagari]] is typically an abugida augmented with dedicated letters for initial vowels, though some traditions use अ as a [[zero consonant]] as the graphic base for such vowels.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Types"], "text": "The boundaries between the three types of segmental scripts are not always clear-cut. For example, [[Sorani]] [[Kurdish language|Kurdish]] is written in the [[Arabic script]], which is normally an abjad. However, in Kurdish, writing the vowels is mandatory, and full letters are used, so the script is a true alphabet. Other languages may use a Semitic abjad with mandatory vowel diacritics, effectively making them abugidas. On the other hand, the [[Phagspa script]] of the [[Mongol Empire]] was based closely on the [[Tibetan script|Tibetan abugida]], but all vowel marks were written after the preceding consonant rather than as diacritic marks. Although short ''a'' was not written, as in the Indic abugidas, one could argue that the linear arrangement made this a true alphabet. Conversely, the vowel marks of the [[Ge'ez alphabet|Tigrinya abugida]] and the [[Ge'ez alphabet|Amharic abugida]] (ironically, the original source of the term \"abugida\") have been so completely assimilated into their consonants that the modifications are no longer systematic and have to be learned as a syllabary rather than as a segmental script. Even more extreme, the Pahlavi abjad eventually became [[logogram|logographic]]. (See below.) Thus the primary [[Categorisation|classification]] of alphabets reflects how they treat vowels. For [[Tone (linguistics)|tonal languages]], further classification can be based on their treatment of tone, though names do not yet exist to distinguish the various types. Some alphabets disregard tone entirely, especially when it does not carry a heavy functional load, as in [[Somali language|Somali]] and many other languages of Africa and the Americas. Such scripts are to tone what abjads are to vowels. Most commonly, tones are indicated with diacritics, the way vowels are treated in abugidas. This is the case for [[Vietnamese alphabet|Vietnamese]] (a true alphabet) and [[Thai alphabet|Thai]] (an abugida). In Thai, tone is determined primarily by the choice of consonant, with diacritics for disambiguation. In the [[Pollard script]], an abugida, vowels are indicated by diacritics, but the placement of the diacritic relative to the consonant is modified to indicate the tone. More rarely, a script may have separate letters for tones, as is the case for [[Hmong alphabet|Hmong]] and [[Zhuang alphabet|Zhuang]]. For most of these scripts, regardless of whether letters or diacritics are used, the most common tone is not marked, just as the most common vowel is not marked in Indic abugidas; in [[Zhuyin]] not only is one of the tones unmarked, but there is a diacritic to indicate lack of tone, like the [[virama]] of Indic.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Types"], "text": "The number of letters in an alphabet can be quite small. The Book [[Pahlavi scripts|Pahlavi]] script, an abjad, had only twelve letters at one point, and may have had even fewer later on. Today the [[Rotokas alphabet]] has only twelve letters. (The [[Hawaiian alphabet]] is sometimes claimed to be as small, but it actually consists of 18 letters, including the [[ʻOkina|ʻokina]] and five long vowels. However, [[Hawaiian Braille]] has only 13 letters.) While Rotokas has a small alphabet because it has few phonemes to represent (just eleven), Book Pahlavi was small because many letters had been ''conflated''—that is, the graphic distinctions had been lost over time, and diacritics were not developed to compensate for this as they were in [[Arabic alphabet|Arabic]], another script that lost many of its distinct letter shapes. For example, a comma-shaped letter represented ''g'', ''d'', ''y'', ''k'', or ''j''. However, such apparent simplifications can perversely make a script more complicated. In later Pahlavi [[papyrus|papyri]], up to half of the remaining graphic distinctions of these twelve letters were lost, and the script could no longer be read as a sequence of letters at all, but instead each word had to be learned as a whole—that is, they had become [[logogram]] as in Egyptian [[Demotic Egyptian|Demotic]]. The largest segmental script is probably an abugida, [[Devanagari]]. When written in Devanagari, Vedic [[Sanskrit]] has an alphabet of 53 letters, including the ''visarga'' mark for final aspiration and special letters for ''kš'' and ''jñ,'' though one of the letters is theoretical and not actually used. The Hindi alphabet must represent both Sanskrit and modern vocabulary, and so has been expanded to 58 with the ''khutma'' letters (letters with a dot added) to represent sounds from Persian and English. Thai has a total of 59 symbols, consisting of 44 consonants, 13 vowels and 2 syllabics, not including 4 diacritics for tone marks and one for vowel length. The largest known abjad is [[Sindhi language|Sindhi]], with 51 letters. The largest alphabets in the narrow sense include [[Kabardian language|Kabardian]] and [[Abkhaz language|Abkhaz]] (for [[Cyrillic]]), with 58 and 56 letters, respectively, and [[Slovak language|Slovak]] (for the [[Latin script]]), with 46. However, these scripts either count [[digraph (orthography)|di- and tri-graphs]] as separate letters, as Spanish did with ''ch'' and ''ll'' until recently, or uses [[diacritic]] like Slovak ''č''.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Types"], "text": "The [[Georgian alphabet]] ( '''') is an alphabetic writing system. With 33 letters, it is the largest true alphabet where each letter is graphically independent. The original Georgian alphabet had 38 letters but 5 letters were removed in the 19th century by [[Ilia Chavchavadze]]. The Georgian alphabet is much closer to Greek than the other Caucasian alphabets. The letter order parallels the Greek, with the consonants without a Greek equivalent organized at the end of the alphabet. The origins of the alphabet are still unknown. Some Armenian and Western scholars believe it was created by Mesrop Mashtots (Armenian: Մեսրոպ Մաշտոց Mesrop Maštoc') also known as Mesrob the Vartabed, who was an early medieval Armenian linguist, theologian, statesman and hymnologist, best known for inventing the Armenian alphabet c. 405 AD; other Georgian and Western scholars are against this theory. Most scholars link the creation of the Georgian script to the process of [[Christianization of Iberia]], a core Georgian kingdom of [[Kartli]]. The alphabet was therefore most probably created between the conversion of Iberia under King [[Mirian III of Iberia|Mirian III]] (326 or 337) and the [[Bir el Qutt inscriptions]] of 430, contemporaneously with the Armenian alphabet. Syllabaries typically contain 50 to 400 glyphs, and the glyphs of logographic systems typically number from the many hundreds into the thousands. Thus a simple count of the number of distinct symbols is an important clue to the nature of an unknown script. The [[Armenian alphabet]] ( '''' or '''') is a graphically unique alphabetical writing system that has been used to write the Armenian language. It was created in year 405 A.D. originally contained 36 letters. Two more letters, օ (o) and ֆ (f), were added in the Middle Ages. During the 1920s orthography reform, a new letter և (capital ԵՎ) was added, which was a ligature before ե+ւ, while the letter Ւ ւ was discarded and reintroduced as part of a new letter ՈՒ ու (which was a digraph before). The Armenian script's directionality is horizontal left-to-right, like the Latin and Greek alphabets. It also uses [[bicameral script]] like those. The Armenian word for \"alphabet\" is '''' (), named after the first two letters of the Armenian alphabet Ա այբ ayb and Բ բեն ben.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Alphabetical order"], "text": "Alphabets often come to be associated with a standard ordering of their letters, which can then be used for purposes of [[collation]]—namely for the listing of words and other items in what is called ''[[alphabetical order]]''. The basic ordering of the [[Latin alphabet]] ([[A]] [[B]] [[C]] [[D]] [[E]] [[F]] [[G]] [[H]] [[I]] [[J]] [[K]] [[L]] [[M]] [[N]] [[O]] [[P]] [[Q]] [[R]] [[S]] [[T]] [[U]] [[V]] [[W]] [[X]] [[Y]] [[Z]]), which is derived from the Northwest Semitic \"Abgad\" order, is well established, although languages using this alphabet have different conventions for their treatment of modified letters (such as the [[French language|French]] ''é'', ''à'', and ''ô'') and of certain combinations of letters ([[Multigraph (orthography)|multigraphs]]). In French, these are not considered to be additional letters for the purposes of collation. However, in [[Icelandic language|Icelandic]], the accented letters such as ''á'', ''í'', and ''ö'' are considered distinct letters representing different vowel sounds from the sounds represented by their unaccented counterparts. In Spanish, ''ñ'' is considered a separate letter, but accented vowels such as ''á'' and ''é'' are not. The ''ll'' and ''ch'' were also considered single letters, but in 1994 the [[Real Academia Española]] changed the collating order so that ''ll'' is between ''lk'' and ''lm'' in the dictionary and ''ch'' is between ''cg'' and ''ci'', and in 2010 the tenth congress of the [[Association of Spanish Language Academies]] changed it so they were no longer letters at all. In German, words starting with ''sch-'' (which spells the German phoneme ) are inserted between words with initial ''sca-'' and ''sci-'' (all incidentally loanwords) instead of appearing after initial ''sz'', as though it were a single letter—in contrast to several languages such as [[Albanian alphabet|Albanian]], in which ''dh-'', ''ë-'', ''gj-'', ''ll-'', ''rr-'', ''th-'', ''xh-'' and ''zh-'' (all representing phonemes and considered separate single letters) would follow the letters ''d'', ''e'', ''g'', ''l'', ''n'', ''r'', ''t'', ''x'' and ''z'' respectively, as well as Hungarian and Welsh. Further, German words with an [[Diaeresis (diacritic)#Umlaut|umlaut]] are collated ignoring the umlaut—contrary to [[Turkish alphabet|Turkish]] that adopted the [[grapheme]] '''ö''' and '''ü''', and where a word like ''tüfek'', would come after ''tuz'', in the dictionary. An exception is the German telephone directory where umlauts are sorted like ''ä'' = ''ae'' since names such as ''Jäger'' also appear with the spelling ''Jaeger'', and are not distinguished in the spoken language. The [[Danish orthography|Danish]] and [[Norwegian orthography|Norwegian]] alphabets end with ''æ''—''ø''—''å'', whereas the Swedish and [[Finnish orthography|Finnish]] ones conventionally put ''å''—''ä''—''ö'' at the end.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Alphabetical order"], "text": "It is unknown whether the earliest alphabets had a defined sequence. Some alphabets today, such as the [[Hanuno'o script]], are learned one letter at a time, in no particular order, and are not used for [[collation]] where a definite order is required. However, a dozen [[Ugaritic alphabet|Ugaritic]] tablets from the fourteenth century BC preserve the alphabet in two sequences. One, the ''ABCDE'' order later used in Phoenician, has continued with minor changes in [[Hebrew alphabet|Hebrew]], [[Greek alphabet|Greek]], [[Armenian alphabet|Armenian]], [[Gothic alphabet|Gothic]], [[Cyrillic]], and [[Latin alphabet|Latin]]; the other, ''HMĦLQ,'' was used in southern Arabia and is preserved today in [[Ge'ez alphabet|Ethiopic]]. Both orders have therefore been stable for at least 3000 years. [[Runic alphabet|Runic]] used an unrelated [[Elder Futhark|Futhark]] sequence, which was later [[Younger Futhark|simplified]]. [[Arabic alphabet|Arabic]] uses its own sequence, although Arabic retains the traditional [[abjadi order]] for numbering. The [[Brahmic family]] of alphabets used in India use a unique order based on [[phonology]]: The letters are arranged according to how and where they are produced in the mouth. This organization is used in Southeast Asia, Tibet, Korean [[hangul]], and even Japanese [[kana]], which is not an alphabet.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Names of letters"], "text": "The Phoenician letter names, in which each letter was associated with a word that begins with that sound ([[acrophony]]), continue to be used to varying degrees in [[Samaritan alphabet|Samaritan]], [[Aramaic alphabet|Aramaic]], [[Syriac alphabet|Syriac]], [[Hebrew alphabet|Hebrew]], [[Greek alphabet|Greek]] and [[Arabic alphabet|Arabic]]. The names were abandoned in [[Latin alphabet|Latin]], which instead referred to the letters by adding a vowel (usually e) before or after the consonant; the two exceptions were [[Y]] and [[Z]], which were borrowed from the Greek alphabet rather than Etruscan, and were known as ''Y Graeca'' \"Greek Y\" (pronounced ''I Graeca'' \"Greek I\") and ''zeta'' (from Greek)—this discrepancy was inherited by many European languages, as in the term ''zed'' for Z in all forms of English other than American English. Over time names sometimes shifted or were added, as in ''double U'' for [[W]] (\"double V\" in French), the English name for Y, and American ''zee'' for Z. Comparing names in English and French gives a clear reflection of the [[Great Vowel Shift]]: A, B, C and D are pronounced in today's English, but in contemporary French they are . The French names (from which the English names are derived) preserve the qualities of the English vowels from before the Great Vowel Shift. By contrast, the names of F, L, M, N and S () remain the same in both languages, because \"short\" vowels were largely unaffected by the Shift. In Cyrillic originally the letters were given names based on Slavic words; this was later abandoned as well in favor of a system similar to that used in Latin. Letters of [[Armenian alphabet]] also have distinct letter names.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Orthography and pronunciation"], "text": "When an alphabet is adopted or developed to represent a given language, an [[orthography]] generally comes into being, providing rules for the [[spelling]] of words in that language. In accordance with the principle on which alphabets are based, these rules will generally map letters of the alphabet to the [[phoneme]] (significant sounds) of the spoken language. In a perfectly [[phonemic orthography]] there would be a consistent one-to-one correspondence between the letters and the phonemes, so that a writer could predict the spelling of a word given its pronunciation, and a speaker would always know the pronunciation of a word given its spelling, and vice versa. However this ideal is not usually achieved in practice; some languages (such as [[Spanish language|Spanish]] and [[Finnish language|Finnish]]) come close to it, while others (such as English) deviate from it to a much larger degree. The pronunciation of a language often evolves independently of its writing system, and writing systems have been borrowed for languages they were not designed for, so the degree to which letters of an alphabet correspond to phonemes of a language varies greatly from one language to another and even within a single language. Languages may fail to achieve a one-to-one correspondence between letters and sounds in any of several ways: (-) A language may represent a given phoneme by a combination of letters rather than just a single letter. Two-letter combinations are called [[digraph (orthography)|digraphs]] and three-letter groups are called [[trigraph (orthography)|trigraphs]]. [[German language|German]] uses the [[tetragraph]] (four letters) \"tsch\" for the phoneme and (in a few borrowed words) \"dsch\" for . [[Kabardian language|Kabardian]] also uses a tetragraph for one of its phonemes, namely \"кхъу\". Two letters representing one sound occur in several instances in Hungarian as well (where, for instance, ''cs'' stands for [tʃ], ''sz'' for [s], ''zs'' for [ʒ], ''dzs'' for [dʒ]). (-) A language may represent the same phoneme with two or more different letters or combinations of letters. An example is [[modern Greek]] which may write the phoneme in six different ways: , , , , , and (though the last is rare). (-) A language may spell some words with unpronounced letters that exist for historical or other reasons. For example, the spelling of the Thai word for \"beer\" [เบียร์] retains a letter for the final consonant \"r\" present in the English word it was borrowed from, but silences it. (-) Pronunciation of individual words may change according to the presence of surrounding words in a sentence ([[sandhi]]). (-) Different dialects of a language may use different phonemes for the same word. (-) A language may use different sets of symbols or different rules for distinct sets of vocabulary items, such as the Japanese [[hiragana]] and [[katakana]] syllabaries, or the various rules in English for spelling words from Latin and Greek, or the original [[Germanic languages|Germanic]] vocabulary.", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": ["Orthography and pronunciation"], "text": "National languages sometimes elect to address the problem of dialects by simply associating the alphabet with the national standard. Some national languages like [[Finnish language|Finnish]], [[Armenian language|Armenian]], [[Turkish language|Turkish]], [[Russian language|Russian]], [[Serbo-Croatian language|Serbo-Croatian]] ([[Serbian language|Serbian]], [[Croatian language|Croatian]] and [[Bosnian language|Bosnian]]) and [[Bulgarian language|Bulgarian]] have a very regular spelling system with a nearly one-to-one correspondence between letters and phonemes. Strictly speaking, these national languages lack a word corresponding to the verb \"to spell\" (meaning to split a word into its letters), the closest match being a verb meaning to split a word into its syllables. Similarly, the [[Italian language|Italian]] verb corresponding to 'spell (out)', ''compitare'', is unknown to many Italians because spelling is usually trivial, as Italian spelling is highly phonemic. In standard [[Spanish language|Spanish]], one can tell the pronunciation of a word from its spelling, but not vice versa, as certain phonemes can be represented in more than one way, but a given letter is consistently pronounced. [[French language|French]], with its [[silent letter]] and its heavy use of [[nasal vowel]] and [[elision]], may seem to lack much correspondence between spelling and pronunciation, but its rules on pronunciation, though complex, are actually consistent and predictable with a fair degree of accuracy. At the other extreme are languages such as English, where the pronunciations of many words simply have to be memorized as they do not correspond to the spelling in a consistent way. For English, this is partly because the [[Great Vowel Shift]] occurred after the orthography was established, and because English has acquired a large number of loanwords at different times, retaining their original spelling at varying levels. Even English has general, albeit complex, rules that predict pronunciation from spelling, and these rules are successful most of the time; rules to predict spelling from the pronunciation have a higher failure rate. Sometimes, countries have the written language undergo a [[spelling reform]] to realign the writing with the contemporary spoken language. These can range from simple spelling changes and word forms to switching the entire writing system itself, as when [[Turkey]] switched from the Arabic alphabet to a Latin-based [[Turkish alphabet]]. The standard system of symbols used by [[linguist]] to represent sounds in any language, independently of orthography, is called the [[International Phonetic Alphabet]].", "id": "670", "title": "Alphabet", "categories": ["Alphabets", "Orthography"], "seealso": ["Akshara", "Lipogram", "ICAO (NATO) spelling alphabet", "Pangram", "Alphabet book", "A Is For Aardvark", "Hangul", "Abecedarium", "Alphabetical order", "Acrophony", "Alphabet effect", "Constructed script", "List of alphabets", "Unicode", "Thai script", "Butterfly Alphabet", "English alphabet", "Transliteration", "Cyrillic", "Alphabet song", "Thoth", "Character encoding"]}
{"headers": [], "text": "[[Image:Bohr atom model.svg|thumb|right|300px|The '''Rutherford–Bohr model''' of the [[hydrogen atom]] () or a hydrogen-like ion (). In this model it is an essential feature that the photon energy (or frequency) of the electromagnetic radiation emitted (shown) when an electron jumps from one orbital to another be proportional to the mathematical square of atomic charge (). Experimental measurement by [[Henry Moseley]] of this radiation for many elements (from ) showed the results as predicted by Bohr. Both the concept of atomic number and the Bohr model were thereby given scientific credence.]] The '''atomic number''' or '''proton number''' (symbol ''Z'') of a [[chemical element]] is the number of [[proton]] found in the [[atomic nucleus|nucleus]] of every [[atom]] of that element. The atomic number uniquely identifies a [[chemical element]]. It is identical to the [[charge number]] of the nucleus. In an [[electric charge|uncharged]] atom, the atomic number is also equal to the number of [[electron]]. The sum of the atomic number ''Z'' and the [[neutron number|number of neutrons]] ''N'' gives the [[mass number]] ''A'' of an atom. Since protons and neutrons have approximately the same mass (and the mass of the electrons is negligible for many purposes) and the [[Binding energy#Mass change|mass defect]] of [[nucleon]] binding is always small compared to the nucleon mass, the [[atomic mass]] of any atom, when expressed in [[Atomic mass unit|unified atomic mass units]] (making a quantity called the \"[[atomic mass|relative isotopic mass]]\"), is within 1% of the whole number ''A''. Atoms with the same atomic number but different neutron numbers, and hence different mass numbers, are known as [[isotope]]. A little more than three-quarters of naturally occurring elements exist as a mixture of isotopes (see [[monoisotopic element]]), and the average isotopic mass of an isotopic mixture for an element (called the relative atomic mass) in a defined environment on Earth, determines the element's standard [[atomic weight]]. Historically, it was these atomic weights of elements (in comparison to hydrogen) that were the quantities measurable by chemists in the 19th century. The conventional symbol ''Z'' comes from the [[German language|German]] word meaning ''number'', which, before the modern synthesis of ideas from chemistry and physics, merely denoted an element's numerical place in the [[periodic table]], whose order is approximately, but not completely, consistent with the order of the elements by atomic weights. Only after 1915, with the suggestion and evidence that this ''Z'' number was also the nuclear charge and a physical characteristic of atoms, did the word (and its English equivalent ''atomic number'') come into common use in this context.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["History", "The periodic table and a natural number for each element"], "text": "Loosely speaking, the existence or construction of a [[periodic table]] of elements creates an ordering of the elements, and so they can be numbered in order. [[Dmitri Mendeleev]] claimed that he arranged his first periodic tables (first published on March 6, 1869) in order of [[atomic weight]] (\"Atomgewicht\"). However, in consideration of the elements' observed chemical properties, he changed the order slightly and placed [[tellurium]] (atomic weight 127.6) ahead of [[iodine]] (atomic weight 126.9). This placement is consistent with the modern practice of ordering the elements by proton number, ''Z'', but that number was not known or suspected at the time. A simple numbering based on periodic table position was never entirely satisfactory, however. Besides the case of iodine and tellurium, later several other pairs of elements (such as [[argon]] and [[potassium]], [[cobalt]] and [[nickel]]) were known to have nearly identical or reversed atomic weights, thus requiring their placement in the periodic table to be determined by their chemical properties. However the gradual identification of more and more chemically similar [[lanthanide]] elements, whose atomic number was not obvious, led to inconsistency and uncertainty in the periodic numbering of elements at least from [[lutetium]] (element 71) onward ([[hafnium]] was not known at this time).", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["History", "The Rutherford-Bohr model and van den Broek"], "text": "In 1911, [[Ernest Rutherford]] gave a [[Rutherford model|model]] of the atom in which a central nucleus held most of the atom's mass and a positive charge which, in units of the electron's charge, was to be approximately equal to half of the atom's atomic weight, expressed in numbers of hydrogen atoms. This central charge would thus be approximately half the atomic weight (though it was almost 25% different from the atomic number of gold , ), the single element from which Rutherford made his guess). Nevertheless, in spite of Rutherford's estimation that gold had a central charge of about 100 (but was element on the periodic table), a month after Rutherford's paper appeared, [[Antonius van den Broek]] first formally suggested that the central charge and number of electrons in an atom was ''exactly'' equal to its place in the periodic table (also known as element number, atomic number, and symbolized ''Z''). This proved eventually to be the case.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["History", "Moseley's 1913 experiment"], "text": "The experimental position improved dramatically after research by [[Henry Moseley]] in 1913. Moseley, after discussions with Bohr who was at the same lab (and who had used Van den Broek's hypothesis in his [[Bohr model]] of the atom), decided to test Van den Broek's and Bohr's hypothesis directly, by seeing if [[spectral line]] emitted from excited atoms fitted the Bohr theory's postulation that the frequency of the spectral lines be proportional to the square of ''Z''. To do this, Moseley measured the wavelengths of the innermost photon transitions (K and L lines) produced by the elements from aluminum (''Z'' = 13) to gold (''Z'' = 79) used as a series of movable anodic targets inside an [[x-ray tube]]. The square root of the frequency of these photons increased from one target to the next in an arithmetic progression. This led to the conclusion ([[Moseley's law]]) that the atomic number does closely correspond (with an offset of one unit for K-lines, in Moseley's work) to the calculated [[electric charge]] of the nucleus, i.e. the element number ''Z''. Among other things, Moseley demonstrated that the [[lanthanide]] series (from [[lanthanum]] to [[lutetium]] inclusive) must have 15 members—no fewer and no more—which was far from obvious from known chemistry at that time.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["History", "Missing elements"], "text": "After Moseley's death in 1915, the atomic numbers of all known elements from hydrogen to uranium (''Z'' = 92) were examined by his method. There were seven elements (with ''Z'' < 92) which were not found and therefore identified as still undiscovered, corresponding to atomic numbers 43, 61, 72, 75, 85, 87 and 91. From 1918 to 1947, all seven of these missing elements were discovered. By this time, the first four transuranium elements had also been discovered, so that the periodic table was complete with no gaps as far as curium (''Z'' = 96).", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["History", "The proton and the idea of nuclear electrons"], "text": "In 1915, the reason for nuclear charge being quantized in units of ''Z'', which were now recognized to be the same as the element number, was not understood. An old idea called [[Prout's hypothesis]] had postulated that the elements were all made of residues (or \"protyles\") of the lightest element hydrogen, which in the Bohr-Rutherford model had a single electron and a nuclear charge of one. However, as early as 1907, Rutherford and [[Thomas Royds]] had shown that alpha particles, which had a charge of +2, were the nuclei of helium atoms, which had a mass four times that of hydrogen, not two times. If Prout's hypothesis were true, something had to be neutralizing some of the charge of the hydrogen nuclei present in the nuclei of heavier atoms. In 1917, Rutherford succeeded in generating hydrogen nuclei from a [[nuclear reaction]] between alpha particles and nitrogen gas, and believed he had proven Prout's law. He called the new heavy nuclear particles protons in 1920 (alternate names being proutons and protyles). It had been immediately apparent from the work of Moseley that the nuclei of heavy atoms have more than twice as much mass as would be expected from their being made of [[hydrogen]] nuclei, and thus there was required a hypothesis for the neutralization of the extra [[protons]] presumed present in all heavy nuclei. A helium nucleus was presumed to be composed of four protons plus two \"nuclear electrons\" (electrons bound inside the nucleus) to cancel two of the charges. At the other end of the periodic table, a nucleus of gold with a mass 197 times that of hydrogen was thought to contain 118 nuclear electrons in the nucleus to give it a residual charge of +79, consistent with its atomic number.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["History", "The discovery of the neutron makes ''Z'' the proton number"], "text": "All consideration of nuclear electrons ended with [[James Chadwick]]'s [[discovery of the neutron]] in 1932. An atom of gold now was seen as containing 118 neutrons rather than 118 nuclear electrons, and its positive charge now was realized to come entirely from a content of 79 protons. After 1932, therefore, an element's atomic number ''Z'' was also realized to be identical to the [[proton number]] of its nuclei.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["The symbol of ''Z''"], "text": "The conventional symbol ''Z'' possibly comes from the [[German language|German]] word (atomic number). However, prior to 1915, the word ''Zahl'' (simply ''number'') was used for an element's assigned number in the periodic table.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["Chemical properties"], "text": "Each element has a specific set of chemical properties as a consequence of the number of electrons present in the neutral atom, which is ''Z'' (the atomic number). The [[electron configuration|configuration]] of these electrons follows from the principles of [[quantum mechanics]]. The number of electrons in each element's [[electron shell]], particularly the outermost [[valence shell]], is the primary factor in determining its [[chemical bonding]] behavior. Hence, it is the atomic number alone that determines the chemical properties of an element; and it is for this reason that an element can be defined as consisting of ''any'' mixture of atoms with a given atomic number.", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": ["New elements"], "text": "The quest for new elements is usually described using atomic numbers. As of , all elements with atomic numbers 1 to 118 have been observed. Synthesis of new elements is accomplished by bombarding target atoms of heavy elements with ions, such that the sum of the atomic numbers of the target and ion elements equals the atomic number of the element being created. In general, the [[half-life]] of a [[nuclide]] becomes shorter as atomic number increases, though undiscovered nuclides with certain \"[[magic number (physics)|magic]]\" numbers of protons and neutrons may have relatively longer half-lives and comprise an [[island of stability]].", "id": "673", "title": "Atomic number", "categories": ["Chemical properties", "Nuclear physics", "Atoms", "Dimensionless numbers of chemistry", "Numbers"], "seealso": ["Mass number", "Atomic theory", "List of elements by atomic number", "Prout's hypothesis", "Effective atomic number", "Chemical element", "History of the periodic table", "Neutron number"]}
{"headers": [], "text": "'''Anatomy''' (Greek ''anatomē'', 'dissection') is the branch of [[biology]] concerned with the study of the structure of [[organism]] and their parts. Anatomy is a branch of natural [[science]] which deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to [[developmental biology]], [[embryology]], [[comparative anatomy]], [[evolutionary biology]], and [[phylogeny]], as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and [[physiology]], which study the structure and [[function (biology)|function]] of organisms and their parts respectively, make a natural pair of [[multidisciplinary approach|related disciplines]], and are often studied together. [[Human body|Human anatomy]] is one of the essential [[basic sciences]] that are [[Applied science|applied]] in [[medicine]]. The discipline of anatomy is divided into [[macroscopic scale|macroscopic]] and [[microscopic scale|microscopic]]. [[Gross anatomy|Macroscopic anatomy]], or [[gross anatomy]], is the examination of an animal's body parts using unaided [[eyesight]]. Gross anatomy also includes the branch of [[superficial anatomy]]. Microscopic anatomy involves the use of optical instruments in the study of the [[tissue (biology)|tissues]] of various structures, known as [[histology]], and also in the study of [[cell biology|cells]]. The [[history of anatomy]] is characterized by a progressive understanding of the functions of the [[organ (anatomy)|organs]] and structures of the human body. Methods have also improved dramatically, advancing from the examination of animals by [[dissection]] of carcasses and [[cadaver]] (corpses) to 20th century [[medical imaging]] techniques including [[Radiography|X-ray]], [[Ultrasound imaging|ultrasound]], and [[magnetic resonance imaging]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Definition"], "text": "Derived from the [[Ancient Greek|Greek]] ''anatomē'' \"dissection\" (from ''anatémnō'' \"I cut up, cut open\" from ἀνά ''aná'' \"up\", and τέμνω ''témnō'' \"I cut\"), anatomy is the scientific study of the structure of [[organism]] including their systems, organs and [[tissue (biology)|tissues]]. It includes the appearance and position of the various parts, the materials from which they are composed, their locations and their relationships with other parts. Anatomy is quite distinct from [[physiology]] and [[biochemistry]], which deal respectively with the functions of those parts and the chemical processes involved. For example, an anatomist is concerned with the shape, size, position, structure, blood supply and innervation of an organ such as the liver; while a physiologist is interested in the production of [[bile]], the role of the liver in nutrition and the regulation of bodily functions. The discipline of anatomy can be subdivided into a number of branches including gross or [[Macroscopic scale|macroscopic]] anatomy and [[Microscopic scale|microscopic]] anatomy. [[Gross anatomy]] is the study of structures large enough to be seen with the naked eye, and also includes [[superficial anatomy]] or surface anatomy, the study by sight of the external body features. [[Microscopic anatomy]] is the study of structures on a microscopic scale, along with [[histology]] (the study of tissues), and [[embryology]] (the study of an organism in its immature condition). Anatomy can be studied using both invasive and non-invasive methods with the goal of obtaining information about the structure and organization of organs and systems. Methods used include [[dissection]], in which a body is opened and its organs studied, and [[endoscopy]], in which a [[video camera]]-equipped instrument is inserted through a small incision in the body wall and used to explore the internal organs and other structures. [[Angiography]] using [[X-ray]] or [[magnetic resonance angiography]] are methods to visualize blood vessels. The term \"anatomy\" is commonly taken to refer to [[human anatomy]]. However, substantially the same structures and tissues are found throughout the rest of the animal kingdom and the term also includes the anatomy of other animals. The term ''zootomy'' is also sometimes used to specifically refer to non-human animals. The structure and tissues of plants are of a dissimilar nature and they are studied in [[plant anatomy]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Animal tissues"], "text": "The [[Kingdom (biology)|kingdom]] [[Animalia]] contains [[multicellular organism]] that are [[heterotroph]] and [[Motility|motile]] (although some have secondarily adopted a [[Sessility (zoology)|sessile]] lifestyle). Most animals have bodies differentiated into separate [[Tissue (biology)|tissues]] and these animals are also known as [[eumetazoa]]. They have an internal [[digestion|digestive]] chamber, with one or two openings; the [[gamete]] are produced in multicellular sex organs, and the [[zygote]] include a [[blastula]] stage in their [[Embryogenesis|embryonic development]]. Metazoans do not include the [[sponge]], which have undifferentiated cells. Unlike [[plant cell]], [[animal cells]] have neither a cell wall nor [[chloroplast]]. Vacuoles, when present, are more in number and much smaller than those in the plant cell. The body tissues are composed of numerous types of cell, including those found in [[muscle]], [[nerve]] and [[skin]]. Each typically has a cell membrane formed of [[phospholipid]], [[cytoplasm]] and a [[Cell nucleus|nucleus]]. All of the different cells of an animal are derived from the embryonic [[germ layer]]. Those simpler invertebrates which are formed from two germ layers of ectoderm and endoderm are called [[diploblasty|diploblastic]] and the more developed animals whose structures and organs are formed from three germ layers are called [[triploblasty|triploblastic]]. All of a triploblastic animal's tissues and organs are derived from the three germ layers of the embryo, the [[ectoderm]], [[mesoderm]] and [[endoderm]]. Animal tissues can be grouped into four basic types: [[connective tissue|connective]], [[epithelium|epithelial]], [[muscle tissue|muscle]] and [[nervous tissue]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Animal tissues", "Connective tissue"], "text": "[[Connective tissue]] are fibrous and made up of cells scattered among inorganic material called the [[extracellular matrix]]. Connective tissue gives shape to organs and holds them in place. The main types are loose connective tissue, [[adipose tissue]], fibrous connective tissue, [[cartilage]] and [[bone]]. The extracellular matrix contains [[protein]], the chief and most abundant of which is [[collagen]]. Collagen plays a major part in organizing and maintaining tissues. The matrix can be modified to form a [[skeleton]] to support or protect the body. An [[exoskeleton]] is a thickened, rigid [[cuticle]] which is stiffened by [[mineralisation (biology)|mineralization]], as in [[crustacean]] or by the cross-linking of its proteins as in [[insect]]. An [[endoskeleton]] is internal and present in all developed animals, as well as in many of those less developed.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Animal tissues", "Epithelium"], "text": "[[Epithelial tissue]] is composed of closely packed cells, bound to each other by [[cell adhesion molecule]], with little intercellular space. Epithelial cells can be [[Squamous epithelial cell|squamous]] (flat), [[Simple cuboidal epithelium|cuboidal]] or [[Columnar epithelial cell|columnar]] and rest on a [[basal lamina]], the upper layer of the [[basement membrane]], the lower layer is the reticular lamina lying next to the connective tissue in the extracellular matrix secreted by the epithelial cells. There are many different types of epithelium, modified to suit a particular function. In the [[respiratory tract]] there is a type of [[pseudostratified ciliated columnar epithelium|ciliated]] epithelial lining; in the small intestine there are [[Microvillus|microvilli]] on the epithelial lining and in the large intestine there are [[Intestinal villus|intestinal villi]]. [[Skin]] consists of an outer layer of [[keratin]] stratified squamous epithelium that covers the exterior of the vertebrate body. [[Keratinocyte]] make up to 95% of the cells in the [[epidermis (skin)|skin]]. The epithelial cells on the external surface of the body typically secrete an extracellular matrix in the form of a [[cuticle]]. In simple animals this may just be a coat of [[glycoproteins]]. In more advanced animals, many [[gland]] are formed of epithelial cells.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Animal tissues", "Muscle tissue"], "text": "[[Myocyte|Muscle cells]] (myocytes) form the active contractile tissue of the body. [[Muscle tissue]] functions to produce force and cause motion, either locomotion or movement within internal organs. Muscle is formed of contractile [[Myofibril|filaments]] and is separated into three main types; [[Smooth muscle tissue|smooth muscle]], [[Skeletal striated muscle|skeletal muscle]] and [[cardiac muscle]]. Smooth muscle has no [[Striated muscle tissue|striations]] when examined microscopically. It contracts slowly but maintains contractibility over a wide range of stretch lengths. It is found in such organs as [[sea anemone]] tentacles and the body wall of [[sea cucumber]]. Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found in [[earthworm]] that can extend slowly or make rapid contractions. In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle is found in the walls of the [[uterus]], [[bladder]], [[intestines]], [[stomach]], [[oesophagus]], [[respiratory airways]], and [[blood vessel]]. [[Cardiac muscle]] is found only in the [[heart]], allowing it to contract and pump blood round the body.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Animal tissues", "Nervous tissue"], "text": "[[Nervous tissue]] is composed of many nerve cells known as [[neuron]] which transmit information. In some slow-moving [[Radial symmetry|radially symmetrical]] marine animals such as [[ctenophore]] and [[cnidarian]] (including [[sea anemone]] and [[jellyfish]]), the nerves form a [[nerve net]], but in most animals they are organized longitudinally into bundles. In simple animals, receptor neurons in the body wall cause a local reaction to a stimulus. In more complex animals, specialized receptor cells such as [[chemoreceptor]] and [[photoreceptor cell|photoreceptors]] are found in groups and send messages along [[biological neural network|neural networks]] to other parts of the organism. Neurons can be connected together in [[Ganglion|ganglia]]. In higher animals, specialized receptors are the basis of sense organs and there is a [[central nervous system]] (brain and spinal cord) and a [[peripheral nervous system]]. The latter consists of [[Sensory neuron|sensory nerves]] that transmit information from sense organs and [[Motor neuron|motor nerves]] that influence target organs. The peripheral nervous system is divided into the [[somatic nervous system]] which conveys sensation and controls [[voluntary muscle]], and the [[autonomic nervous system]] which involuntarily controls [[smooth muscle]], certain glands and internal organs, including the [[stomach]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy"], "text": "All [[vertebrate]] have a similar basic [[body plan]] and at some point in their lives, mostly in the [[embryogenesis|embryonic]] stage, share the major [[chordate]] characteristics; a stiffening rod, the [[notochord]]; a dorsal hollow tube of nervous material, the [[neural tube]]; [[pharyngeal arch]]; and a tail posterior to the anus. The [[spinal cord]] is protected by the [[vertebral column]] and is above the notochord and the [[Gut (anatomy)|gastrointestinal tract]] is below it. Nervous tissue is derived from the [[ectoderm]], connective tissues are derived from [[mesoderm]], and gut is derived from the [[endoderm]]. At the posterior end is a [[tail]] which continues the spinal cord and vertebrae but not the gut. The mouth is found at the anterior end of the animal, and the [[anus]] at the base of the tail. The defining characteristic of a vertebrate is the [[vertebral column]], formed in the development of the segmented series of [[vertebra]]. In most vertebrates the notochord becomes the [[nucleus pulposus]] of the [[intervertebral disc]]. However, a few vertebrates, such as the [[sturgeon]] and the [[coelacanth]] retain the notochord into adulthood. [[Gnathostomata|Jawed vertebrates]] are typified by paired appendages, fins or legs, which may be secondarily lost. The limbs of vertebrates are considered to be [[Homology (biology)|homologous]] because the same underlying skeletal structure was inherited from their last common ancestor. This is one of the arguments put forward by [[Charles Darwin]] to support his theory of [[evolution]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Fish anatomy"], "text": "The body of a [[fish]] is divided into a head, trunk and tail, although the divisions between the three are not always externally visible. The skeleton, which forms the support structure inside the fish, is either made of cartilage, in [[cartilaginous fish]], or bone in [[bony fish]]. The main skeletal element is the vertebral column, composed of articulating [[vertebra]] which are lightweight yet strong. The ribs attach to the spine and there are no [[Limb (anatomy)|limbs]] or limb girdles. The main external features of the fish, the [[fish fin|fins]], are composed of either bony or soft spines called rays, which with the exception of the [[caudal fin]], have no direct connection with the spine. They are supported by the muscles which compose the main part of the trunk. The heart has two chambers and pumps the blood through the respiratory surfaces of the [[gill]] and on round the body in a single circulatory loop. The eyes are adapted for seeing underwater and have only local vision. There is an inner ear but no external or [[middle ear]]. Low frequency vibrations are detected by the [[lateral line]] system of sense organs that run along the length of the sides of fish, and these respond to nearby movements and to changes in water pressure. Sharks and rays are [[Basal (phylogenetics)|basal]] fish with numerous [[Primitive (phylogenetics)|primitive]] anatomical features similar to those of ancient fish, including skeletons composed of cartilage. Their bodies tend to be dorso-ventrally flattened, they usually have five pairs of gill slits and a large mouth set on the underside of the head. The dermis is covered with separate dermal [[placoid scales]]. They have a [[cloaca]] into which the urinary and genital passages open, but not a [[swim bladder]]. Cartilaginous fish produce a small number of large, [[Egg yolk|yolky]] eggs. Some species are [[ovoviviparous]] and the young develop internally but others are [[oviparous]] and the larvae develop externally in egg cases. The bony fish lineage shows more [[Derived trait|derived]] anatomical traits, often with major evolutionary changes from the features of ancient fish. They have a bony skeleton, are generally laterally flattened, have five pairs of gills protected by an [[operculum (fish)|operculum]], and a mouth at or near the tip of the snout. The dermis is covered with overlapping [[Fish scale|scales]]. Bony fish have a swim bladder which helps them maintain a constant depth in the water column, but not a cloaca. They mostly [[Spawn (biology)|spawn]] a large number of small eggs with little yolk which they broadcast into the water column.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Amphibian anatomy"], "text": "[[Amphibian]] are a [[Class (biology)|class]] of animals comprising [[frog]], [[salamander]] and [[caecilian]]. They are [[tetrapod]], but the caecilians and a few species of salamander have either no limbs or their limbs are much reduced in size. Their main bones are hollow and lightweight and are fully ossified and the vertebrae interlock with each other and have [[articular processes]]. Their ribs are usually short and may be fused to the vertebrae. Their skulls are mostly broad and short, and are often incompletely ossified. Their skin contains little [[keratin]] and lacks scales, but contains many [[mucous gland]] and in some species, poison glands. The hearts of amphibians have three chambers, two [[atrium (heart)|atria]] and one [[ventricle (heart)|ventricle]]. They have a [[urinary bladder]] and [[metabolic waste#nitrogen wastes|nitrogenous waste products]] are excreted primarily as [[urea]]. Amphibians breathe by means of [[buccal pumping]], a pump action in which air is first drawn into the [[Buccopharyngeal membrane|buccopharyngeal]] region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat. They supplement this with [[gas exchange]] through the skin which needs to be kept moist. In frogs the pelvic girdle is robust and the hind legs are much longer and stronger than the forelimbs. The feet have four or five digits and the toes are often webbed for swimming or have suction pads for climbing. Frogs have large eyes and no tail. Salamanders resemble lizards in appearance; their short legs project sideways, the belly is close to or in contact with the ground and they have a long tail. Caecilians superficially resemble [[earthworm]] and are limbless. They burrow by means of zones of muscle contractions which move along the body and they swim by undulating their body from side to side.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Reptile anatomy"], "text": "'''[[Reptile]]''' are a class of animals comprising [[turtle]], [[tuatara]], [[lizard]], [[snake]] and [[crocodile]]. They are [[tetrapod]], but the snakes and a few species of [[lizard]] either have no limbs or their limbs are much reduced in size. Their bones are better ossified and their skeletons stronger than those of amphibians. The teeth are conical and mostly uniform in size. The surface cells of the epidermis are modified into horny scales which create a waterproof layer. Reptiles are unable to use their skin for respiration as do amphibians and have a more efficient respiratory system drawing air into their [[lung]] by expanding their chest walls. The heart resembles that of the amphibian but there is a septum which more completely separates the oxygenated and deoxygenated bloodstreams. The reproductive system has evolved for internal fertilization, with a [[Sex organ|copulatory organ]] present in most species. The eggs are surrounded by [[Amniote|amniotic membranes]] which prevents them from drying out and are laid on land, or [[Ovoviviparity|develop internally]] in some species. The bladder is small as nitrogenous waste is excreted as [[uric acid]]. '''[[Turtles]]''' are notable for their protective shells. They have an inflexible trunk encased in a horny [[carapace]] above and a [[plastron]] below. These are formed from bony plates embedded in the dermis which are overlain by horny ones and are partially fused with the ribs and spine. The neck is long and flexible and the head and the legs can be drawn back inside the shell. Turtles are vegetarians and the typical reptile teeth have been replaced by sharp, horny plates. In aquatic species, the front legs are modified into flippers. '''[[Tuataras]]''' superficially resemble lizards but the lineages diverged in the [[Triassic]] period. There is one living species, ''[[Sphenodon punctatus]]''. The skull has two openings (fenestrae) on either side and the jaw is rigidly attached to the skull. There is one row of teeth in the lower jaw and this fits between the two rows in the upper jaw when the animal chews. The teeth are merely projections of bony material from the jaw and eventually wear down. The brain and heart are more primitive than those of other reptiles, and the lungs have a single chamber and lack [[Bronchus|bronchi]]. The tuatara has a well-developed [[parietal eye]] on its forehead. '''[[Lizards]]''' have skulls with only one [[Nasal fenestra|fenestra]] on each side, the lower bar of bone below the second fenestra having been lost. This results in the jaws being less rigidly attached which allows the mouth to open wider. Lizards are mostly quadrupeds, with the trunk held off the ground by short, sideways-facing legs, but a few species have no limbs and resemble snakes. Lizards have moveable eyelids, eardrums are present and some species have a central parietal eye.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Reptile anatomy"], "text": "'''[[Snakes]]''' are closely related to lizards, having branched off from a common ancestral lineage during the [[Cretaceous]] period, and they share many of the same features. The skeleton consists of a skull, a hyoid bone, spine and ribs though a few species retain a vestige of the pelvis and rear limbs in the form of [[pelvic spur]]. The bar under the second fenestra has also been lost and the jaws have extreme flexibility allowing the snake to swallow its prey whole. Snakes lack moveable eyelids, the eyes being covered by transparent \"spectacle\" scales. They do not have eardrums but can detect ground vibrations through the bones of their skull. Their forked tongues are used as organs of taste and smell and some species have sensory pits on their heads enabling them to locate warm-blooded prey. '''[[Crocodilians]]''' are large, low-slung aquatic reptiles with long snouts and large numbers of teeth. The head and trunk are dorso-ventrally flattened and the tail is laterally compressed. It undulates from side to side to force the animal through the water when swimming. The tough keratinized scales provide body armour and some are fused to the skull. The nostrils, eyes and ears are elevated above the top of the flat head enabling them to remain above the surface of the water when the animal is floating. Valves seal the nostrils and ears when it is submerged. Unlike other reptiles, crocodilians have hearts with four chambers allowing complete separation of oxygenated and deoxygenated blood.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Bird anatomy"], "text": "[[Birds]] are [[tetrapod]] but though their hind limbs are used for walking or hopping, their front limbs are [[wing]] covered with [[feather]] and adapted for flight. Birds are [[endotherm]], have a high [[metabolic rate]], a light [[Skeleton|skeletal system]] and powerful [[muscle]]. The long bones are thin, hollow and very light. Air sac extensions from the lungs occupy the centre of some bones. The sternum is wide and usually has a keel and the caudal vertebrae are fused. There are no teeth and the narrow jaws are adapted into a horn-covered beak. The eyes are relatively large, particularly in nocturnal species such as owls. They face forwards in predators and sideways in ducks. The feathers are outgrowths of the [[epidermis (zoology)|epidermis]] and are found in localized bands from where they fan out over the skin. Large flight feathers are found on the wings and tail, contour feathers cover the bird's surface and fine down occurs on young birds and under the contour feathers of water birds. The only cutaneous gland is the single [[uropygial gland]] near the base of the tail. This produces an oily secretion that waterproofs the feathers when the bird [[personal grooming|preens]]. There are scales on the legs, feet and claws on the tips of the toes.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Mammal anatomy"], "text": "[[Mammal]] are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight. They mostly have four limbs but some aquatic mammals have no limbs or limbs modified into fins and the forelimbs of bats are modified into wings. The legs of most mammals are situated below the trunk, which is held well clear of the ground. The bones of mammals are well ossified and their teeth, which are usually differentiated, are coated in a layer of [[Tooth enamel|prismatic enamel]]. The teeth are shed once ([[Deciduous teeth|milk teeth]]) during the animal's lifetime or not at all, as is the case in [[cetacea]]. Mammals have three bones in the middle ear and a [[cochlea]] in the [[inner ear]]. They are clothed in hair and their skin contains glands which secrete [[sweat gland|sweat]]. Some of these glands are specialized as [[mammary gland]], producing milk to feed the young. Mammals breathe with [[lung]] and have a muscular [[Thoracic diaphragm|diaphragm]] separating the thorax from the abdomen which helps them draw air into the lungs. The mammalian heart has four chambers and oxygenated and deoxygenated blood are kept entirely separate. Nitrogenous waste is excreted primarily as urea. Mammals are [[amniote]], and most are [[Viviparity|viviparous]], giving birth to live young. The exception to this are the egg-laying [[monotreme]], the [[platypus]] and the [[echidna]] of Australia. Most other mammals have a [[placenta]] through which the developing [[foetus]] obtains nourishment, but in [[marsupial]], the foetal stage is very short and the immature young is born and finds its way to its mother's [[Pouch (marsupial)|pouch]] where it latches on to a [[nipple]] and completes its development.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Vertebrate anatomy", "Mammal anatomy", "Human anatomy"], "text": "Humans have the overall body plan of a mammal. Humans have a [[human head|head]], [[neck]], [[Trunk (anatomy)|trunk]] (which includes the [[thorax]] and [[abdomen]]), two [[arm]] and [[hand]], and two [[human leg|legs]] and [[foot|feet]]. Generally, students of certain [[biology|biological sciences]], [[paramedic]], prosthetists and orthotists, [[physical therapy|physiotherapists]], [[occupational therapy|occupational therapists]], [[nursing|nurses]], [[podiatry|podiatrists]], and [[medical school|medical students]] learn gross anatomy and microscopic anatomy from anatomical models, skeletons, textbooks, diagrams, photographs, lectures and tutorials and in addition, medical students generally also learn gross anatomy through practical experience of [[dissection]] and inspection of [[cadaver]]. The study of microscopic anatomy (or [[histology]]) can be aided by practical experience examining histological preparations (or slides) under a [[microscope]]. Human anatomy, physiology and biochemistry are complementary basic medical sciences, which are generally taught to medical students in their first year at medical school. Human anatomy can be taught regionally or systemically; that is, respectively, studying anatomy by bodily regions such as the head and chest, or studying by specific systems, such as the nervous or respiratory systems. The major anatomy textbook, [[Gray's Anatomy]], has been reorganized from a systems format to a regional format, in line with modern teaching methods. A thorough working knowledge of anatomy is required by physicians, especially [[surgery|surgeons]] and doctors working in some diagnostic specialties, such as [[histopathology]] and [[radiology]]. Academic anatomists are usually employed by universities, medical schools or teaching hospitals. They are often involved in teaching anatomy, and research into certain systems, organs, tissues or cells.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Invertebrate anatomy"], "text": "[[Invertebrate]] constitute a vast array of living organisms ranging from the simplest unicellular [[eukaryote]] such as ''[[Paramecium]]'' to such complex multicellular animals as the [[octopus]], [[lobster]] and [[dragonfly]]. They constitute about 95% of the animal species. By definition, none of these creatures has a backbone. The cells of single-cell [[protozoa]] have the same basic structure as those of multicellular animals but some parts are specialized into the equivalent of tissues and organs. Locomotion is often provided by [[Cilium|cilia]] or [[Flagellum|flagella]] or may proceed via the advance of [[pseudopodia]], food may be gathered by [[phagocytosis]], energy needs may be supplied by [[photosynthesis]] and the cell may be supported by an [[endoskeleton]] or an [[exoskeleton]]. Some protozoans can form multicellular colonies. [[Metazoa]] are a multicellular organism, with different groups of cells serving different functions. The most basic types of metazoan tissues are epithelium and connective tissue, both of which are present in nearly all invertebrates. The outer surface of the epidermis is normally formed of epithelial cells and secretes an [[extracellular matrix]] which provides support to the organism. An endoskeleton derived from the [[mesoderm]] is present in [[echinoderm]], [[sponge]] and some [[cephalopod]]. [[Exoskeleton]] are derived from the epidermis and is composed of [[chitin]] in [[arthropod]] (insects, spiders, ticks, shrimps, crabs, lobsters). [[Calcium carbonate]] constitutes the shells of [[Mollusca|molluscs]], [[brachiopod]] and some tube-building [[Polychaete|polychaete worms]] and [[silica]] forms the exoskeleton of the microscopic [[diatom]] and [[radiolaria]]. Other invertebrates may have no rigid structures but the epidermis may secrete a variety of surface coatings such as the [[pinacoderm]] of sponges, the gelatinous cuticle of cnidarians ([[polyp (zoology)|polyp]], [[sea anemone]], [[jellyfish]]) and the [[collagen]] cuticle of [[annelid]]. The outer epithelial layer may include cells of several types including sensory cells, gland cells and stinging cells. There may also be protrusions such as [[Microvillus|microvilli]], cilia, bristles, [[Spine (zoology)|spines]] and [[tubercle]]. [[Marcello Malpighi]], the father of microscopical anatomy, discovered that plants had tubules similar to those he saw in insects like the silk worm. He observed that when a ring-like portion of bark was removed on a trunk a swelling occurred in the tissues above the ring, and he unmistakably interpreted this as growth stimulated by food coming down from the leaves, and being captured above the ring.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Invertebrate anatomy", "Arthropod anatomy"], "text": "[[Arthropod]] comprise the largest phylum in the animal kingdom with over a million known invertebrate species. [[Insect]] possess [[segmentation (biology)|segmented]] bodies supported by a hard-jointed outer covering, the [[exoskeleton]], made mostly of chitin. The segments of the body are organized into three distinct parts, a head, a [[Thorax (insect anatomy)|thorax]] and an [[abdomen]]. The head typically bears a pair of sensory [[Antenna (biology)|antennae]], a pair of [[compound eye]], one to three simple eyes ([[ocelli]]) and three sets of modified appendages that form the [[insect mouthparts|mouthparts]]. The thorax has three pairs of segmented [[arthropod leg|legs]], one pair each for the three segments that compose the thorax and one or two pairs of [[insect wing|wings]]. The abdomen is composed of eleven segments, some of which may be fused and houses the [[digestion|digestive]], [[Respiration (physiology)|respiratory]], [[Excretion|excretory]] and reproductive systems. There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts. [[Spider]] a class of [[arachnid]] have four pairs of legs; a body of two segments—a [[cephalothorax]] and an [[abdomen]]. Spiders have no wings and no antennae. They have mouthparts called [[chelicerae]] which are often connected to venom glands as most spiders are venomous. They have a second pair of appendages called [[pedipalp]] attached to the cephalothorax. These have similar segmentation to the legs and function as taste and smell organs. At the end of each male pedipalp is a spoon-shaped cymbium that acts to support the [[palpal bulb|copulatory organ]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["Other branches of anatomy"], "text": "(-) [[Superficial anatomy|Superficial or surface anatomy]] is important as the study of anatomical landmarks that can be readily seen from the exterior contours of the body. It enables physicians or [[veterinary surgeon]] to gauge the position and anatomy of the associated deeper structures. Superficial is a directional term that indicates that structures are located relatively close to the surface of the body. (-) [[Comparative anatomy]] relates to the comparison of anatomical structures (both gross and microscopic) in different animals. (-) Artistic anatomy relates to anatomic studies for artistic reasons.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["History", "Ancient"], "text": "In 1600 BCE, the [[Edwin Smith Papyrus]], an [[Ancient Egyptian medicine|Ancient Egyptian]] [[Medical manual|medical text]], described the [[heart]], its vessels, [[liver]], [[spleen]], [[kidneys]], [[hypothalamus]], [[uterus]] and [[Urinary bladder|bladder]], and showed the [[blood vessel]] diverging from the heart. The [[Ebers Papyrus]] (c. 1550 BCE) features a \"treatise on the heart\", with vessels carrying all the body's fluids to or from every member of the body. Ancient Greek anatomy and physiology underwent great changes and advances throughout the early medieval world. Over time, this medical practice expanded by a continually developing understanding of the functions of organs and structures in the body. Phenomenal anatomical observations of the human body were made, which have contributed towards the understanding of the brain, eye, liver, reproductive organs and the nervous system. The [[Hellenistic Egypt]] city of [[Alexandria]] was the stepping-stone for Greek anatomy and physiology. Alexandria not only housed the biggest library for medical records and books of the liberal arts in the world during the time of the Greeks, but was also home to many medical practitioners and philosophers. Great patronage of the arts and sciences from the [[Ptolemy]] rulers helped raise Alexandria up, further rivalling the cultural and scientific achievements of other Greek states.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["History", "Ancient"], "text": "Some of the most striking advances in early anatomy and physiology took place in Hellenistic Alexandria. Two of the most famous anatomists and physiologists of the third century were [[Herophilus]] and [[Erasistratus]]. These two physicians helped pioneer human [[dissection]] for medical research. They also conducted [[vivisection]] on the cadavers of condemned criminals, which was considered taboo until the Renaissance—Herophilus was recognized as the first person to perform systematic dissections. Herophilus became known for his anatomical works making impressing contributions to many branches of anatomy and many other aspects of medicine. Some of the works included classifying the system of the pulse, the discovery that human arteries had thicker walls than veins, and that the atria were parts of the heart. Herophilus's knowledge of the human body has provided vital input towards understanding the brain, eye, liver, reproductive organs and nervous system, and characterizing the course of disease. Erasistratus accurately described the structure of the brain, including the cavities and membranes, and made a distinction between its cerebrum and cerebellum During his study in Alexandria, Erasistratus was particularly concerned with studies of the circulatory and nervous systems. He was able to distinguish the sensory and the motor nerves in the human body and believed that air entered the lungs and heart, which was then carried throughout the body. His distinction between the arteries and veins—the arteries carrying the air through the body, while the veins carried the blood from the heart was a great anatomical discovery. Erasistratus was also responsible for naming and describing the function of the epiglottis and the valves of the heart, including the tricuspid. During the third century, Greek physicians were able to differentiate nerves from blood vessels and tendons and to realize that the nerves convey neural impulses. It was Herophilus who made the point that damage to motor nerves induced paralysis. Herophilus named the meninges and ventricles in the brain, appreciated the division between cerebellum and cerebrum and recognized that the brain was the \"seat of intellect\" and not a \"cooling chamber\" as propounded by Aristotle Herophilus is also credited with describing the optic, oculomotor, motor division of the trigeminal, facial, vestibulocochlear and hypoglossal nerves. Great feats were made during the third century BCE in both the digestive and reproductive systems. Herophilus was able to discover and describe not only the salivary glands, but the small intestine and liver. He showed that the uterus is a hollow organ and described the ovaries and uterine tubes. He recognized that spermatozoa were produced by the testes and was the first to identify the prostate gland. The anatomy of the muscles and skeleton is described in the ''[[Hippocratic Corpus]]'', an Ancient Greek medical work written by unknown authors. [[Aristotle]] described [[vertebrate]] anatomy based on animal [[dissection]]. [[Praxagoras]] identified the difference between [[artery|arteries]] and [[vein]]. Also in the 4th century BCE, [[Herophilos]] and [[Erasistratus]] produced more accurate anatomical descriptions based on [[vivisection]] of criminals in [[Alexandria]] during the [[Ptolemaic Kingdom|Ptolemaic dynasty]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["History", "Ancient"], "text": "In the 2nd century, [[Galen of Pergamum]], an [[anatomist]], [[clinician]], writer and [[Philosophy|philosopher]], wrote the final and highly influential anatomy treatise of ancient times. He compiled existing knowledge and studied anatomy through dissection of animals. He was one of the first experimental physiologists through his [[vivisection]] experiments on animals. Galen's drawings, based mostly on dog anatomy, became effectively the only anatomical textbook for the next thousand years. His work was known to [[Renaissance]] doctors only through [[Islamic Golden Age]] medicine until it was translated from the Greek some time in the 15th century.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["History", "Medieval to early modern"], "text": "Anatomy developed little from classical times until the sixteenth century; as the historian Marie Boas writes, \"Progress in anatomy before the sixteenth century is as mysteriously slow as its development after 1500 is startlingly rapid\". Between 1275 and 1326, the anatomists [[Mondino de Luzzi]], [[Alessandro Achillini]] and [[Antonio Benivieni]] at [[Bologna]] carried out the first systematic human dissections since ancient times. Mondino's ''Anatomy'' of 1316 was the first textbook in the medieval rediscovery of human anatomy. It describes the body in the order followed in Mondino's dissections, starting with the abdomen, then the thorax, then the head and limbs. It was the standard anatomy textbook for the next century. [[Leonardo da Vinci]] (1452–1519) was trained in anatomy by [[Andrea del Verrocchio]]. He made use of his anatomical knowledge in his artwork, making many sketches of skeletal structures, muscles and organs of humans and other vertebrates that he dissected. [[Andreas Vesalius]] (1514–1564) (Latinized from Andries van Wezel), professor of anatomy at the [[University of Padua]], is considered the founder of modern human anatomy. Originally from [[Duchy of Brabant|Brabant]], Vesalius published the influential book ''[[De humani corporis fabrica]]'' (\"the structure of the human body\"), a large format book in seven volumes, in 1543. The accurate and intricately detailed illustrations, often in [[allegory|allegorical]] poses against Italianate landscapes, are thought to have been made by the artist [[Jan van Calcar]], a pupil of [[Titian]]. In England, anatomy was the subject of the first public lectures given in any science; these were given by the [[Barber surgeon|Company of Barbers and Surgeons]] in the 16th century, joined in 1583 by the Lumleian lectures in surgery at the [[Royal College of Physicians]].", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["History", "Late modern"], "text": "In the United States, medical schools began to be set up towards the end of the 18th century. Classes in anatomy needed a continual stream of cadavers for dissection and these were difficult to obtain. Philadelphia, Baltimore and New York were all renowned for [[body snatching]] activity as criminals raided graveyards at night, removing newly buried corpses from their coffins. A similar problem existed in Britain where demand for bodies became so great that grave-raiding and even [[anatomy murder]] were practised to obtain cadavers. Some graveyards were in consequence protected with watchtowers. The practice was halted in Britain by the [[Anatomy Act]] of 1832, while in the United States, similar legislation was enacted after the physician [[William S. Forbes]] of [[Jefferson Medical College]] was found guilty in 1882 of \"complicity with resurrectionists in the despoliation of graves in Lebanon Cemetery\". The teaching of anatomy in Britain was transformed by Sir [[John Struthers (anatomist)|John Struthers]], [[Regius Professor of Anatomy (Aberdeen)|Regius Professor of Anatomy]] at the [[University of Aberdeen]] from 1863 to 1889. He was responsible for setting up the system of three years of \"pre-clinical\" academic teaching in the sciences underlying medicine, including especially anatomy. This system lasted until the reform of medical training in 1993 and 2003. As well as teaching, he collected many vertebrate skeletons for his museum of [[comparative anatomy]], published over 70 research papers, and became famous for his public dissection of the [[Tay Whale]]. From 1822 the Royal College of Surgeons regulated the teaching of anatomy in medical schools. Medical museums provided examples in comparative anatomy, and were often used in teaching. [[Ignaz Semmelweis]] investigated [[puerperal fever]] and he discovered how it was caused. He noticed that the frequently fatal fever occurred more often in mothers examined by medical students than by midwives. The students went from the dissecting room to the hospital ward and examined women in childbirth. Semmelweis showed that when the trainees washed their hands in chlorinated lime before each clinical examination, the incidence of puerperal fever among the mothers could be reduced dramatically.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": ["History", "Late modern"], "text": "Before the modern medical era, the main means for studying the internal structures of the body were [[dissection]] of the dead and [[inspection]], [[palpation]] and [[auscultation]] of the living. It was the advent of [[microscopy]] that opened up an understanding of the building blocks that constituted living tissues. Technical advances in the development of [[achromatic lens]] increased the [[Angular resolution|resolving power]] of the microscope and around 1839, [[Matthias Jakob Schleiden]] and [[Theodor Schwann]] identified that cells were the fundamental unit of organization of all living things. Study of small structures involved passing light through them and the [[microtome]] was invented to provide sufficiently thin slices of tissue to examine. Staining techniques using artificial dyes were established to help distinguish between different types of tissue. Advances in the fields of [[histology]] and [[Cell biology|cytology]] began in the late 19th century along with advances in surgical techniques allowing for the painless and safe removal of [[biopsy]] specimens. The invention of the [[electron microscope]] brought a great advance in resolution power and allowed research into the [[ultrastructure]] of cells and the [[organelle]] and other structures within them. About the same time, in the 1950s, the use of [[X-ray diffraction]] for studying the crystal structures of proteins, nucleic acids and other biological molecules gave rise to a new field of [[molecular anatomy]]. Equally important advances have occurred in ''non-invasive'' techniques for examining the interior structures of the body. [[X-ray]] can be passed through the body and used in medical [[radiography]] and [[fluoroscopy]] to differentiate interior structures that have varying degrees of opaqueness. [[Magnetic resonance imaging]], [[X-ray computed tomography|computed tomography]], and [[Medical ultrasonography|ultrasound imaging]] have all enabled examination of internal structures in unprecedented detail to a degree far beyond the imagination of earlier generations.", "id": "674", "title": "Anatomy", "categories": ["Anatomy", "Anatomical terminology", "Branches of biology", "Morphology (biology)"], "seealso": ["Plastination", "Outline of human anatomy", "Anatomical model"]}
{"headers": [], "text": "'''Affirming the consequent''', sometimes called '''converse error''', '''fallacy of the converse''', or '''confusion of necessity and sufficiency''', is a [[formal fallacy]] of taking a true [[indicative conditional|conditional]] statement (e.g., \"If the lamp were broken, then the room would be dark,\") and invalidly inferring its converse (\"The room is dark, so the lamp is broken,\") even though the converse may not be true. This arises when a consequent (\"the room would be dark\") has more than one ''other'' possible antecedents (for example, \"the lamp is not plugged in\" or \"the lamp is in working order, but is switched off\"). Converse errors are common in everyday thinking and communication and can result from, among other causes, communication issues, misconceptions about logic, and failure to consider other causes. The opposite statement, [[modus tollens|denying the consequent]], ''is'' a valid form of argument.", "id": "675", "title": "Affirming the consequent", "categories": ["Propositional fallacies"], "seealso": ["Appeal to consequences", "Fallacy of the single cause", "Fallacy of the undistributed middle", "Inference to the best explanation", "ELIZA effect", "Necessity and sufficiency", "Post hoc ergo propter hoc", "Modus tollens", "List of fallacies", "Confusion of the inverse", "Modus ponens", "Abductive reasoning", "Denying the antecedent"]}
{"headers": ["Formal description"], "text": "Affirming the consequent is the action of taking a true statement formula_1 and invalidly concluding its converse formula_2. The name ''affirming the [[consequent]]'' derives from using the consequent, ''Q'', of formula_1, to conclude the antecedent ''P''. This illogic can be summarized formally as formula_4 or, alternatively, formula_5. The root cause of such a logic error is sometimes failure to realize that just because ''P'' is a ''possible'' condition for ''Q'', ''P'' may not be the ''only'' condition for ''Q'', i.e. ''Q'' may follow from another condition as well. Affirming the consequent can also result from overgeneralizing the experience of many statements ''having'' true converses. If ''P'' and ''Q'' are \"equivalent\" statements, i.e. formula_6, it ''is'' possible to infer ''P'' under the condition ''Q''. For example, the statements \"It is August 13, so it is my birthday\" formula_1 and \"It is my birthday, so it is August 13\" formula_2 are equivalent and both true consequences of the statement \"August 13 is my birthday\" (an abbreviated form of formula_6). Using one statement to conclude the other is ''not'' an example of affirming the consequent, but some people may misapply the approach.", "id": "675", "title": "Affirming the consequent", "categories": ["Propositional fallacies"], "seealso": ["Appeal to consequences", "Fallacy of the single cause", "Fallacy of the undistributed middle", "Inference to the best explanation", "ELIZA effect", "Necessity and sufficiency", "Post hoc ergo propter hoc", "Modus tollens", "List of fallacies", "Confusion of the inverse", "Modus ponens", "Abductive reasoning", "Denying the antecedent"]}
{"headers": ["Additional examples"], "text": "'''Example 1''' One way to demonstrate the invalidity of this argument form is with a counterexample with true premises but an obviously false conclusion. For example: If [[Bill Gates]] owns [[United States Bullion Depository|Fort Knox]], then Bill Gates is [[Wealth|rich]]. Bill Gates is rich. Therefore, Bill Gates owns Fort Knox. Owning Fort Knox is not the ''only'' way to be rich. Any number of other ways to be rich exist. However, one can affirm with certainty that \"if someone is not rich\" (''non-Q''), then \"this person does not own Fort Knox\" (''non-P''). This is the [[contrapositive]] of the first statement, and it must be true if and only if the original statement is true. '''Example 2''' Here is another useful, obviously-fallacious example, but one that does not require familiarity with who [[Bill Gates]] is and what [[United States Bullion Depository|Fort Knox]] is: If an animal is a dog, then it has four legs. My cat has four legs. Therefore, my cat is a dog. Here, it is immediately intuitive that any number of other antecedents (\"If an animal is a deer...\", \"If an animal is an elephant...\", \"If an animal is a moose...\", ''etc.'') can give rise to the consequent (\"then it has four legs\"), and that it is preposterous to suppose that having four legs ''must'' imply that the animal is a dog and nothing else. This is useful as a teaching example since most people can immediately recognize that the conclusion reached must be wrong (intuitively, a cat cannot be a dog), and that the method by which it was reached must therefore be fallacious. '''Example 3''' Arguments of the same form can sometimes seem superficially convincing, as in the following example: If Brian had been thrown off the top of the [[Eiffel Tower]], then he would be dead. Brian is dead. Therefore, Brian was thrown off the top of the Eiffel Tower. Being thrown off the top of the Eiffel Tower is not the ''only'' cause of death, since there exist numerous different causes of death. Affirming the consequent is commonly used in [[rationalization (psychology)|rationalization]], and thus appears as a [[coping mechanism]] in some people. '''Example 4''' In ''[[Catch-22]]'', the chaplain is interrogated for supposedly being \"Washington Irving\"/\"Irving Washington\", who has been blocking out large portions of soldiers' letters home. The colonel has found such a letter, but with the Chaplain's name signed. \"You can read, though, can't you?\" the colonel persevered sarcastically. \"The author signed his name.\" \"That's my name there.\" \"Then you wrote it. [[Q.E.D.]]\" ''P'' in this case is 'The chaplain signs his own name', and ''Q'' 'The chaplain's name is written'. The chaplain's name may be written, but he did not necessarily write it, as the colonel falsely concludes.''", "id": "675", "title": "Affirming the consequent", "categories": ["Propositional fallacies"], "seealso": ["Appeal to consequences", "Fallacy of the single cause", "Fallacy of the undistributed middle", "Inference to the best explanation", "ELIZA effect", "Necessity and sufficiency", "Post hoc ergo propter hoc", "Modus tollens", "List of fallacies", "Confusion of the inverse", "Modus ponens", "Abductive reasoning", "Denying the antecedent"]}
{"headers": [], "text": "'''Andrei Arsenyevich Tarkovsky''' (; 4 April 1932 – 29 December 1986) was a Soviet-era Russian filmmaker, theatre director, writer, and [[film theory|film theorist]]. He is widely considered one of the greatest and most influential directors in the history of Russian and world cinema. His films explored spiritual and metaphysical themes, and are noted for their slow pacing and long takes, dreamlike visual imagery, and preoccupation with nature and memory. Tarkovsky studied film at Moscow's [[Gerasimov Institute of Cinematography|VGIK]] under filmmaker [[Mikhail Romm]], and subsequently directed his first five [[feature film]] in the [[Soviet Union]]: ''[[Ivan's Childhood]]'' (1962), ''[[Andrei Rublev (film)|Andrei Rublev]]'' (1966), ''[[Solaris (1972 film)|Solaris]]'' (1972), ''[[Mirror (1975 film)|Mirror]]'' (1975), and ''[[Stalker (1979 film)|Stalker]]'' (1979). After years of creative conflict with [[State Committee for Cinematography|state film authorities]], Tarkovsky left the country in 1979 and made his final two films abroad; ''[[Nostalghia]]'' (1983) and ''[[The Sacrifice (1986 film)|The Sacrifice]]'' (1986) were produced in Italy and Sweden respectively. In 1986, he also published a book about cinema and art entitled ''[[Sculpting in Time]]''. He died of cancer later that year. Tarkovsky was the recipient of several awards at the [[Cannes Film Festival]] throughout his career (including the [[International Federation of Film Critics|FIPRESCI prize]], the [[Prize of the Ecumenical Jury]], and the [[Grand Prix (Cannes Film Festival)|Grand Prix Spécial du Jury]]) and winner of the [[Golden Lion]] award at the [[Venice Film Festival]] for his debut film ''Ivan's Childhood''. In 1990, he was posthumously awarded the Soviet Union's prestigious [[Lenin Prize]]. Three of his films—''Andrei Rublev'', ''Mirror'', and ''Stalker''—featured in [[Sight & Sound]]'s [[The Sight & Sound Top 50 Greatest Films of All Time#Critics' poll|2012 poll of the 100 greatest films of all time]].", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Childhood and early life"], "text": "Andrei Tarkovsky was born in the village of Zavrazhye in the [[Yuryevetsky District]] of the [[Ivanovo Oblast|Ivanovo Industrial Oblast]] (modern-day [[Kadyysky District]] of the [[Kostroma Oblast]], Russia) to the poet and translator [[Arseny Tarkovsky|Arseny Alexandrovich Tarkovsky]], a native of [[Kropyvnytskyi|Yelisavetgrad]], [[Kherson Governorate]], and Maria Ivanova Vishnyakova, a graduate of the [[Maxim Gorky Literature Institute]] who later worked as a [[corrector]]; she was born in Moscow in the Dubasov family estate. Andrei's paternal grandfather Aleksandr Karlovich Tarkovsky (in ) was a [[Poles|Polish]] nobleman who worked as a bank clerk. His wife Maria Danilovna Rachkovskaya was a [[Romanians|Romanian]] teacher who arrived from [[Iași]]. Andrei's maternal grandmother Vera Nikolaevna Vishnyakova (née Dubasova) belonged to an old Dubasov family of [[Russian nobility]] that traces its history back to the 17th century; among her relatives was Admiral [[Fyodor Dubasov]], a fact she had to conceal during the Soviet days. She was married to Ivan Ivanovich Vishnyakov, a native of the [[Kaluga Governorate]] who studied law at the [[Moscow State University]] and served as a judge in [[Kozelsk]]. According to the family legend, Tarkovsky's ancestors on his father's side were princes from the [[Shamkhalate of Tarki]], [[Dagestan]], although his sister Marina Tarkovskaya who did a detailed research on their genealogy called it \"a myth, even a prank of sorts,\" stressing that none of the documents confirms this version. Tarkovsky spent his childhood in [[Yuryevets, Ivanovo Oblast|Yuryevets]]. He was described by childhood friends as active and popular, having many friends and being typically in the center of action. His father left the family in 1937, subsequently volunteering for the army in 1941. He returned home in 1943, having been awarded a [[Order of the Red Star|Red Star]] after being shot in one of his legs (which he would eventually need to amputate due to [[gangrene]]). Tarkovsky stayed with his mother, moving with her and his sister Marina to Moscow, where she worked as a proofreader at a printing press. In 1939 Tarkovsky enrolled at the Moscow School No. 554. During the war, the three evacuated to [[Yuryevets, Ivanovo Oblast|Yuryevets]], living with his maternal grandmother. In 1943 the family returned to Moscow. Tarkovsky continued his studies at his old school, where the poet [[Andrei Voznesensky]] was one of his classmates. He studied piano at a music school and attended classes at an art school. The family lived on Shchipok Street in the [[Zamoskvorechye District]] in Moscow. From November 1947 to spring 1948 he was in the hospital with [[tuberculosis]]. Many themes of his childhood—the evacuation, his mother and her two children, the withdrawn father, the time in the hospital—feature prominently in his film ''[[Mirror (1975 film)|Mirror]]''.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Childhood and early life"], "text": "In his school years, Tarkovsky was a troublemaker and a poor student. He still managed to graduate, and from 1951 to 1952 studied [[Arabic]] at the Oriental Institute in Moscow, a branch of the [[Academy of Sciences of the Soviet Union]]. Although he already spoke some Arabic and was a successful student in his first semesters, he did not finish his studies and dropped out to work as a prospector for the Academy of Science Institute for Non-Ferrous Metals and Gold. He participated in a year-long research expedition to the river Kureikye near [[Turukhansk]] in the [[Krasnoyarsk Krai|Krasnoyarsk Province]]. During this time in the [[taiga]], Tarkovsky decided to study film.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Film school student"], "text": "Upon returning from the research expedition in 1954, Tarkovsky applied at the State Institute of Cinematography ([[Gerasimov Institute of Cinematography|VGIK]]) and was admitted to the film-directing program. He was in the same class as [[Irma Raush]] whom he married in April 1957. The early [[History of the Soviet Union (1953–1964)|Khrushchev era]] offered good opportunities for young film directors. Before 1953, annual film production was low and most films were directed by veteran directors. After 1953, more films were produced, many of them by young directors. The [[Khrushchev Thaw]] relaxed Soviet social restrictions a bit and permitted a limited influx of European and North American literature, films and music. This allowed Tarkovsky to see films of the [[Italian neorealism|Italian neorealists]], [[French New Wave]], and of directors such as [[Akira Kurosawa|Kurosawa]], [[Luis Buñuel|Buñuel]], [[Ingmar Bergman|Bergman]], [[Robert Bresson|Bresson]], [[Andrzej Wajda|Wajda]] (whose film ''[[Ashes and Diamonds (film)|Ashes and Diamonds]]'' influenced Tarkovsky) and [[Kenji Mizoguchi|Mizoguchi]]. Tarkovsky's teacher and mentor was [[Mikhail Romm]], who taught many film students who would later become influential film directors. In 1956 Tarkovsky directed his first student short film, ''[[The Killers (1956 film)|The Killers]]'', from a short story of [[Ernest Hemingway]]. The short film ''[[There Will Be No Leave Today]]'' and the [[screenplay]] ''[[Concentrate (screenplay)|Concentrate]]'' followed in 1958 and 1959. An important influence on Tarkovsky was the film director [[Grigory Chukhray]], who was teaching at the VGIK. Impressed by the talent of his student, Chukhray offered Tarkovsky a position as assistant director for his film ''Clear Skies''. Tarkovsky initially showed interest but then decided to concentrate on his studies and his own projects. During his third year at the VGIK, Tarkovsky met [[Andrei Konchalovsky]]. They found much in common as they liked the same film directors and shared ideas on cinema and films. In 1959 they wrote the script ''Antarctica – Distant Country'', which was later published in the ''[[Moskovsky Komsomolets]]''. Tarkovsky submitted the script to [[Lenfilm]], but it was rejected. They were more successful with the script ''[[The Steamroller and the Violin]]'', which they sold to [[Mosfilm]]. This became Tarkovsky's graduation project, earning him his diploma in 1960 and winning First Prize at the New York Student Film Festival in 1961.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Film career in the Soviet Union"], "text": "Tarkovsky's first feature film was ''[[Ivan's Childhood]]'' in 1962. He had inherited the film from director Eduard Abalov, who had to abort the project. The film earned Tarkovsky international acclaim and won the [[Golden Lion]] award at the [[Venice Film Festival]] in the year 1962. In the same year, on 30 September, his first son Arseny (called Senka in Tarkovsky's diaries) Tarkovsky was born. In 1965, he directed the film ''[[Andrei Rublev (film)|Andrei Rublev]]'' about the life of [[Andrei Rublev]], the fifteenth-century Russian [[iconography|icon painter]]. ''Andrei Rublev'' was not, except for a single screening in Moscow in 1966, immediately released after completion due to problems with Soviet authorities. Tarkovsky had to cut the film several times, resulting in several different versions of varying lengths. The film was widely released in the Soviet Union in a cut version in 1971. Nevertheless, the film had a budget of more than 1 million rubles – a significant sum for that period. A version of the film was presented at the [[Cannes Film Festival]] in 1969 and won the [[International Federation of Film Critics|FIPRESCI prize]]. He divorced his wife, [[Irma Raush]], in June 1970. In the same year, he married [[Larisa Tarkovskaya|Larissa Kizilova]] (née Egorkina), who had been a production assistant for the film ''[[Andrei Rublev (film)|Andrei Rublev]]'' (they had been living together since 1965). Their son, Andrei Andreyevich Tarkovsky, was born in the same year on 7 August. In 1972, he completed ''[[Solaris (1972 film)|Solaris]]'', an adaptation of the novel ''[[Solaris (novel)|Solaris]]'' by [[Stanisław Lem]]. He had worked on this together with screenwriter [[Friedrich Gorenstein]] as early as 1968. The film was presented at the [[Cannes Film Festival]], won the [[Grand Prix (Cannes Film Festival)|Grand Prix Spécial du Jury]], and was nominated for the [[Palme d'Or]]. From 1973 to 1974, he shot the film ''[[Mirror (1975 film)|Mirror]]'', a highly autobiographical and unconventionally structured film drawing on his childhood and incorporating some of his father's poems. In this film Tarkovsky portrayed the plight of childhood affected by war. Tarkovsky had worked on the screenplay for this film since 1967, under the consecutive titles ''Confession'', ''White day'' and ''A white, white day''. From the beginning the film was not well received by Soviet authorities due to its content and its perceived elitist nature. Soviet authorities placed the film in the \"third category\", a severely limited distribution, and only allowed it to be shown in third-class cinemas and workers' clubs. Few prints were made and the film-makers received no returns. Third category films also placed the film-makers in danger of being accused of wasting public funds, which could have serious effects on their future productivity. These difficulties are presumed to have made Tarkovsky play with the idea of going abroad and producing a film outside the Soviet film industry.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Film career in the Soviet Union"], "text": "During 1975, Tarkovsky also worked on the screenplay ''[[Hoffmanniana]]'', about the German writer and poet [[E. T. A. Hoffmann]]. In December 1976, he directed ''[[Hamlet]]'', his only stage play, at the [[Lenkom Theatre]] in Moscow. The main role was played by [[Anatoly Solonitsyn]], who also acted in several of Tarkovsky's films. At the end of 1978, he also wrote the screenplay ''Sardor'' together with the writer Aleksandr Misharin. The last film Tarkovsky completed in the Soviet Union was ''[[Stalker (1979 film)|Stalker]]'', inspired by the novel ''[[Roadside Picnic]]'' by the brothers [[Arkady and Boris Strugatsky]]. Tarkovsky had met the brothers first in 1971 and was in contact with them until his death in 1986. Initially he wanted to shoot a film based on their novel ''[[Dead Mountaineer's Hotel]]'' and he developed a raw script. Influenced by a discussion with Arkady Strugatsky he changed his plan and began to work on the script based on ''Roadside Picnic''. Work on this film began in 1976. The production was mired in troubles; improper development of the negatives had ruined all the exterior shots. Tarkovsky's relationship with cinematographer [[Georgy Rerberg]] deteriorated to the point where he hired [[Alexander Knyazhinsky]] as a new first cinematographer. Furthermore, Tarkovsky suffered a heart attack in April 1978, resulting in further delay. The film was completed in 1979 and won the Prize of the Ecumenical Jury at the [[Cannes Film Festival]]. In a question and answer session at the [[Edinburgh Filmhouse]] on 11 February 1981, Tarkovsky trenchantly rejected suggestions that the film was either impenetrably mysterious or a political [[allegory]]. In 1979 Tarkovsky began production of the film ''The First Day'' (Russian: Первый День ''Pervyj Dyen''), based on a script by his friend and long-term collaborator [[Andrei Konchalovsky]]. The film was set in 18th-century Russia during the reign of [[Peter the Great]] and starred [[Natalya Bondarchuk]] and [[Anatoli Papanov]]. To get the project approved by [[State Committee for Cinematography|Goskino]], Tarkovsky submitted a script that was different from the original script, omitting several scenes that were critical of the [[Religion in the Soviet Union|official atheism in the Soviet Union]]. After shooting roughly half of the film the project was stopped by Goskino after it became apparent that the film differed from the script submitted to the censors. Tarkovsky was reportedly infuriated by this interruption and destroyed most of the film.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Film career outside the Soviet Union"], "text": "During the summer of 1979, Tarkovsky traveled to Italy, where he shot the documentary ''[[Voyage in Time]]'' together with his long-time friend [[Tonino Guerra]]. Tarkovsky returned to Italy in 1980 for an extended trip, during which he and Guerra completed the script for the film ''[[Nostalghia]]''. During this period, he took Polaroid photographs depicting his personal life. Tarkovsky returned to Italy in 1982 to start shooting ''Nostalghia''. He did not return to his home country. As [[Mosfilm]] withdrew from the project, he had to complete the film with financial support provided by the Italian [[RAI]]. Tarkovsky completed the film in 1983. ''Nostalghia'' was presented at the [[Cannes Film Festival]] and won the [[International Federation of Film Critics|FIPRESCI prize]] and the Prize of the Ecumenical Jury. Tarkovsky also shared a special prize called ''Grand Prix du cinéma de creation'' with [[Robert Bresson]]. Soviet authorities prevented the film from winning the [[Palme d'Or]], a fact that hardened Tarkovsky's resolve to never work in the Soviet Union again. He also said: \"I am not a Soviet dissident, I have no conflict with the Soviet Government.\" But if he returned home, he added, \"[he] would be unemployed.\" In the same year, he also staged the opera ''[[Boris Godunov (opera)|Boris Godunov]]'' at the [[Royal Opera House]] in London under the musical direction of [[Claudio Abbado]]. He spent most of 1984 preparing the film ''[[The Sacrifice (1986 film)|The Sacrifice]]''. At a press conference in [[Milan]] on 10 July 1984, he announced that he would never return to the Soviet Union and would remain in Europe. At that time, his son Andrei Andreyevich was still in the Soviet Union and not allowed to leave the country. On 28 August 1985, Tarkovsky arrived at Latina Refugee Camp in [[Latina, Lazio|Latina]], where he was registered with the serial number 13225/379. ''The Sacrifice'' was Tarkovsky's last film, dedicated to his son, Andrei Andreyevich. ''Directed by Andrei Tarkovsky'', which documents the making of ''The Sacrifice'', was released after the filmmaker's death in 1986. In a particularly poignant scene, writer/director [[Michal Leszczylowski]] follows Tarkovsky on a walk as he expresses his sentiments on death — he claims himself to be immortal and has no fear of dying.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Life and career", "Death"], "text": "During 1985, he shot the film ''The Sacrifice'' in Sweden. At the end of the year he was diagnosed with terminal lung cancer. In January 1986, he began treatment in Paris and was joined there by his son, who was finally allowed to leave the Soviet Union. ''The Sacrifice'' was presented at the [[Cannes Film Festival]] and received the [[Grand Prix (Cannes Film Festival)|Grand Prix Spécial du Jury]], the [[International Federation of Film Critics|FIPRESCI prize]] and the Prize of the Ecumenical Jury. As Tarkovsky was unable to attend due to his illness, the prizes were collected by his son, Andrei Andreyevich. In Tarkovsky's last [[Time Within Time: The Diaries 1970–1986|diary]] entry (15 December 1986), he wrote: \"But now I have no strength left — that is the problem\". The diaries are sometimes also known as ''[[Time Within Time: The Diaries 1970–1986|Martyrolog]]'' and were published posthumously in 1989 and in English in 1991. Tarkovsky died in Paris on 29 December 1986. His funeral ceremony was held at the [[Alexander Nevsky Cathedral, Paris|Alexander Nevsky Cathedral]]. He was buried on 3 January 1987 in the [[Sainte-Geneviève-des-Bois Russian Cemetery|Russian Cemetery]] in [[Sainte-Geneviève-des-Bois, Essonne|Sainte-Geneviève-des-Bois]] in France. The inscription on his gravestone, which was conceived by Tarkovsky's wife, Larisa Tarkovskaya, reads: ''To the man who saw the Angel''. A conspiracy theory emerged in Russia in the early 1990s when it was alleged that Tarkovsky did not die of natural causes, but was assassinated by the [[KGB]]. Evidence for this hypothesis includes testimonies by former KGB agents who claim that [[Viktor Chebrikov]] gave the order to eradicate Tarkovsky to curtail what the Soviet government and the KGB saw as [[Anti-Soviet agitation|anti-Soviet propaganda]] by Tarkovsky. Other evidence includes several memoranda that surfaced after the [[1991 Soviet coup d'état attempt|1991 coup]] and the claim by one of Tarkovsky's doctors that his cancer could not have developed from a natural cause. As with Tarkovsky, his wife [[Larisa Tarkovskaya]] and actor [[Anatoly Solonitsyn]] all died from the very same type of lung cancer. Vladimir Sharun, sound designer in ''[[Stalker (1979 film)|Stalker]]'', is convinced that they were all poisoned by the chemical plant where they were shooting the film.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Influences"], "text": "Tarkovsky became a film director during the mid and late 1950s, a period referred to as the [[Khrushchev Thaw]], during which Soviet society opened to foreign films, literature and music, among other things. This allowed Tarkovsky to see films of European, American and Japanese directors, an experience that influenced his own film making. His teacher and mentor at the film school, [[Mikhail Romm]], allowed his students considerable freedom and emphasized the independence of the film director. Tarkovsky was, according to fellow student Shavkat Abdusalmov, fascinated by Japanese films. He was amazed by how every character on the screen is exceptional and how everyday events such as a Samurai cutting bread with his sword are elevated to something special and put into the limelight. Tarkovsky has also expressed interest in the art of [[Haiku]] and its ability to create \"images in such a way that they mean nothing beyond themselves\". Tarkovsky was also a deeply religious Orthodox Christian, who believed great art should have a higher spiritual purpose. He was a perfectionist not given to humor or humility: his signature style was ponderous and literary, having many characters that pondered over religious themes and issues regarding faith. Tarkovsky perceived that the art of cinema has only been truly mastered by very few filmmakers, stating in a 1970 interview with Naum Abramov that \"they can be counted on the fingers of one hand\". In 1972, Tarkovsky told film historian [[Leonid Kozlov]] his ten favorite films. The list includes: ''[[Diary of a Country Priest]]'' and ''[[Mouchette]]'' by [[Robert Bresson]]; ''[[Winter Light]]'', ''[[Wild Strawberries (film)|Wild Strawberries]]'', and ''[[Persona (1966 film)|Persona]]'' by [[Ingmar Bergman]]; ''[[Nazarín]]'' by [[Luis Buñuel]]; ''[[City Lights]]'' by [[Charlie Chaplin]]; ''[[Ugetsu]]'' by [[Kenji Mizoguchi]]; ''[[Seven Samurai]]'' by [[Akira Kurosawa]], and ''[[Woman in the Dunes]]'' by [[Hiroshi Teshigahara]]. Among his favorite directors were Buñuel, Mizoguchi, Bergman, Bresson, Kurosawa, [[Michelangelo Antonioni]], [[Jean Vigo]], and [[Carl Theodor Dreyer]]. With the exception of ''City Lights'', the list does not contain any films of the early silent era. The reason is that Tarkovsky saw film as an art as only a relatively recent phenomenon, with the early film-making forming only a prelude. The list has also no films or directors from Tarkovsky's native Russia, although he rated Soviet directors such as [[Boris Barnet]], [[Sergei Parajanov]] and [[Alexander Dovzhenko]] highly. He said of Dovzhenko's ''[[Earth (1930 film)|Earth]]'': \"I have lived a lot among very simple farmers and met extraordinary people. They spread calmness, had such tact, they conveyed a feeling of dignity and displayed wisdom that I have seldom come across on such a scale. Dovzhenko had obviously understood wherein the sense of life resides. [...] This trespassing of the border between nature and mankind is an ideal place for the existence of man. Dovzhenko understood this.\"", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Influences"], "text": "Andrei Tarkovsky was not a fan of science fiction, largely dismissing it for its \"comic book\" trappings and vulgar commercialism. However, in a famous exception Tarkovsky praised the blockbuster film ''[[The Terminator]]'', saying that its \"vision of the future and the relation between man and its destiny is pushing the frontier of cinema as an art\". He was critical of the \"brutality and low acting skills\", but was nevertheless impressed by the film.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Cinematic style"], "text": "In a 1962 interview, Tarkovsky argued: \"All art, of course, is intellectual, but for me, all the arts, and cinema even more so, must above all be emotional and act upon the heart.\" His films are characterized by [[metaphysics|metaphysical]] themes, extremely [[long take]], and images often considered by critics to be of exceptional beauty. Recurring motifs are dreams, memory, childhood, running water accompanied by fire, rain indoors, reflections, levitation, and characters re-appearing in the foreground of long panning movements of the camera. He once said: \"Juxtaposing a person with an environment that is boundless, collating him with a countless number of people passing by close to him and far away, relating a person to the whole world, that is the meaning of cinema.\" Tarkovsky incorporated levitation scenes into several of his films, most notably ''Solaris''. To him these scenes possess great power and are used for their photogenic value and magical inexplicability. Water, clouds, and reflections were used by him for their surreal beauty and photogenic value, as well as their symbolism, such as waves or the forms of brooks or running water. Bells and candles are also frequent symbols. These are symbols of film, sight and sound, and Tarkovsky's film frequently has themes of self-reflection. Tarkovsky developed a theory of cinema that he called \"sculpting in time\". By this he meant that the unique characteristic of cinema as a medium was to take our experience of time and alter it. Unedited movie footage transcribes time in [[Real time (media)|real time]]. By using long takes and few cuts in his films, he aimed to give the viewers a sense of time passing, time lost, and the relationship of one moment in time to another. Up to, and including, his film ''[[Mirror (1975 film)|Mirror]]'', Tarkovsky focused his cinematic works on exploring this theory. After ''Mirror'', he announced that he would focus his work on exploring the [[Classical unities|dramatic unities]] proposed by [[Aristotle]]: a concentrated action, happening in one place, within the span of a single day. Several of Tarkovsky's films have color or black-and-white sequences. This first occurs in the otherwise monochrome ''[[Andrei Rublev (film)|Andrei Rublev]]'', which features a color epilogue of [[Andrei Rublev|Rublev's]] authentic religious icon paintings. All of his films afterwards contain monochrome, and in ''[[Stalker (1979 film)|Stalker's]]'' case [[Photographic print toning|sepia]] sequences, while otherwise being in color. In 1966, in an interview conducted shortly after finishing ''Andrei Rublev'', Tarkovsky dismissed color film as a \"commercial gimmick\" and cast doubt on the idea that contemporary films meaningfully use color. He claimed that in everyday life one does not consciously notice colors most of the time, and that color should therefore be used in film mainly to emphasize certain moments, but not all the time, as this distracts the viewer. To him, films in color were like moving paintings or photographs, which are too beautiful to be a realistic depiction of life.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Cinematic style", "Bergman on Tarkovsky"], "text": "[[Ingmar Bergman]], a renowned director, commented on Tarkovsky: Contrarily, however, Bergman conceded the truth in the claim made by a critic who wrote that \"with ''[[Autumn Sonata]]'' Bergman does Bergman\", adding: \"Tarkovsky began to make Tarkovsky films, and that [[Federico Fellini|Fellini]] began to make Fellini films [...] [[Luis Buñuel|Buñuel]] nearly always made Buñuel films.\" This [[pastiche]] of one's own work has been derogatorily termed as \"self-karaoke\".", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Cinematic style", "Vadim Yusov"], "text": "Tarkovsky worked in close collaboration with cinematographer [[Vadim Yusov]] from 1958 to 1972, and much of the visual style of Tarkovsky's films can be attributed to this collaboration. Tarkovsky would spend two days preparing for Yusov to film a single long take, and due to the preparation, usually only a single take was needed.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Cinematic style", "Sven Nykvist"], "text": "In his last film, ''[[The Sacrifice (1986 film)|The Sacrifice]]'', Tarkovsky worked with cinematographer [[Sven Nykvist]], who had worked on many films with director [[Ingmar Bergman]]. (Nykvist was not alone: several people involved in the production had previously collaborated with Bergman, notably lead actor [[Erland Josephson]], who had also acted for Tarkovsky in ''[[Nostalghia]]''.) Nykvist complained that Tarkovsky would frequently look through the camera and even direct actors through it, but ultimately stated that choosing to work with Tarkovsky was one of the best choices he had ever made.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Filmography"], "text": "Tarkovsky is mainly known as a film director. During his career he directed seven feature films, as well as three shorts from his time at VGIK. His features are: (-) ''[[Ivan's Childhood]]'' (1962) (-) ''[[Andrei Rublev (film)|Andrei Rublev]]'' (1966) (-) ''[[Solaris (1972 film)|Solaris]]'' (1972) (-) ''[[Mirror (1975 film)|Mirror]]'' (1975) (-) ''[[Stalker (1979 film)|Stalker]]'' (1979) (-) ''[[Nostalghia]]'' (1983) (-) ''[[The Sacrifice (1986 film)|The Sacrifice]]'' (1986) He also wrote several screenplays. Furthermore, he directed the play ''[[Hamlet]]'' for the stage in Moscow, directed the opera ''[[Boris Godunov (opera)|Boris Godunov]]'' in London, and he directed a radio production of the short story ''Turnabout'' by [[William Faulkner]]. He also wrote ''[[Sculpting in Time]]'', a book on film theory. Tarkovsky's first feature film was ''[[Ivan's Childhood]]'' in 1962. He then directed ''[[Andrei Rublev (film)|Andrei Rublev]]'' in 1966, ''[[Solaris (1972 film)|Solaris]]'' in 1972, ''[[Mirror (1975 film)|Mirror]]'' in 1975 and ''[[Stalker (1979 film)|Stalker]]'' in 1979. The documentary ''[[Voyage in Time]]'' was produced in Italy in 1982, as was ''[[Nostalghia]]'' in 1983. His last film ''[[The Sacrifice (1986 film)|The Sacrifice]]'' was produced in Sweden in 1986. Tarkovsky was personally involved in writing the screenplays for all his films, sometimes with a cowriter. Tarkovsky once said that a director who realizes somebody else's screenplay without being involved in it becomes a mere illustrator, resulting in dead and monotonous films.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Published books"], "text": "(-) ''[[Sculpting in Time]]'', published in 1986 (-) ''[[Time Within Time: The Diaries 1970–1986|Time Within Time: The Diaries 1970'''''–'''''1986]]'', published in 1989 A book of 60 photos, ''Instant Light, Tarkovsky Polaroids'', taken by Tarkovsky in Russia and Italy between 1979 and 1984 was published in 2006. The collection was selected by Italian photographer Giovanni Chiaramonte and Tarkovsky's son Andrey A. Tarkovsky.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Unproduced screenplays", "''Concentrate''"], "text": "'''''Concentrate''''' (, ''Kontsentrat'') is a never-filmed 1958 screenplay by Tarkovsky. The screenplay is based on Tarkovsky's year in the [[taiga]] as a member of a research expedition, prior to his enrollment in film school. It's about the leader of a geological expedition, who waits for the boat that brings back the [[concentrate]] collected by the expedition. The expedition is surrounded by mystery, and its purpose is a state secret. Although some authors claim that the screenplay was filmed, according to Marina Tarkovskaya, Tarkovsky's sister (and wife of Aleksandr Gordon, a fellow student of Tarkovsky during his film school years) the screenplay was never filmed. Tarkovsky wrote the screenplay during his entrance examination at the State Institute of Cinematography ([[Gerasimov Institute of Cinematography|VGIK]]) in a single sitting. He earned the highest possible grade, \"excellent\" () for this work. In 1994 fragments of ''Concentrate'' were filmed and used in the documentary ''Andrei Tarkovsky's Taiga Summer'' by Marina Tarkovskaya and Aleksandr Gordon.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Unproduced screenplays", "''Hoffmanniana''"], "text": "'''''Hoffmanniana''''' () is a never-filmed 1974 screenplay by Tarkovsky. The screenplay is based on the life and work of German author [[E. T. A. Hoffmann]]. In 1974 an acquaintance from [[Tallinnfilm]] approached Tarkovsky to write a screenplay on a German theme. Tarkovsky considered [[Thomas Mann]] and E. T. A. Hoffmann, and also thought about [[Henrik Ibsen|Ibsen]]'s ''[[Peer Gynt]]''. In the end Tarkovsky signed a contract for a script based on the life and work of Hoffmann. He planned to write the script during the summer of 1974 at his [[dacha]]. Writing was not without difficulty, less than a month before the deadline he had not written a single page. He finally finished the project in late 1974 and submitted the final script to Tallinnfilm in October. Although the script was well received by the officials at Tallinnfilm, it was the consensus that no one but Tarkovsky would be able to direct it. The script was sent to [[State Committee for Cinematography|Goskino]] in February 1976, and although approval was granted for proceeding with making the film, the screenplay was never realized. In 1984, during the time of his exile in the West, Tarkovsky revisited the screenplay and made a few changes. He also considered to finally direct a film based on the screenplay but ultimately dropped this idea.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Films about Tarkovsky"], "text": "(-) ''[[Voyage in Time]]'' (1983): documents the travels in Italy of Andrei Tarkovsky in preparation for the making of his film ''Nostalghia'', [[Tonino Guerra]]. (-) ''Tarkovsky: A Poet in the Cinema'' (1984): directed by Donatella Baglivo. (-) Moscow Elegy (1987): a documentary/homage to Tarkovsky by Aleksandr Sokurov. (-) ''Auf der Suche nach der verlorenen Zeit'' (1988): Andrej Tarkowskijs Exil und Tod. Documentary directed by Ebbo Demant. Germany. (-) ''[[One Day in the Life of Andrei Arsenevich]]'' (1999): French documentary film directed by [[Chris Marker]]. (-) \"Andrey\" (color/b&w, short-fiction, 35 mm, 15 min, 2006) A film by Nariné Mktchyan and Arsen Azatyan. Festivals: Yerevan IFF 2006, Rotterdam IFF 2007, Busan IFF 2007, Sydney IFF 2007, Zerkalo FF Ivanovo (Special Prize) 2008, Kinoshock FF 2014. (-) ''Tarkovsky: Time Within Time'' (2015): documentary by P. J. Letofsky.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Awards and commemoration"], "text": "Numerous awards were bestowed on Tarkovsky throughout his lifetime. (-) At the [[Venice Film Festival]], the [[Golden Lion]] of the for ''[[Ivan's Childhood]]'' (-) At the [[Cannes Film Festival]], the [[International Federation of Film Critics|FIPRESCI prize]] three times, the [[Prize of the Ecumenical Jury]] three times (more than any other director), the [[Grand Prix (Cannes Film Festival)|Grand Prix Spécial du Jury]] twice, and the [[Cannes Film Festival Award for Best Director|Best Director]] award once. He was also nominated for the [[Palme d'Or]] three times. (-) In 1987, the [[BAFTA Award for Best Film Not in the English Language#1980s|BAFTA Award for Best Foreign Language Film]] of the [[British Academy of Film and Television Arts]] for ''[[The Sacrifice (1986 film)|The Sacrifice]]''. Under the influence of [[Glasnost]] and [[Perestroika]], Tarkovsky was finally recognized in the Soviet Union in the Autumn of 1986, shortly before his death, by a retrospective of his films in Moscow. After his death, an entire issue of the film magazine ''Iskusstvo Kino'' was devoted to Tarkovsky. In their obituaries, the film committee of the [[Council of Ministers of the Soviet Union]] and the Union of Soviet Film Makers expressed their sorrow that Tarkovsky had to spend the last years of his life in exile. Posthumously, he was awarded the [[Lenin Prize]] in 1990, one of the highest state honors in the Soviet Union. In 1989 the ''Andrei Tarkovsky Memorial Prize'' was established, with its first recipient being the Russian animator [[Yuri Norstein]]. In three consecutive events, the [[Moscow International Film Festival]] awarded the ''Andrei Tarkovsky Award'' in 1993, 1995, and 1997. In 1996 the Andrei Tarkovsky Museum opened in [[Yuryevets, Ivanovo Oblast|Yuryevets]], his childhood town. A [[minor planet]], [[3345 Tarkovskij]], discovered by Soviet astronomer [[Lyudmila Karachkina]] in 1982, has been named after him. Tarkovsky has been the subject of several documentaries. Most notable is the 1988 documentary ''[[Moscow Elegy]]'', by Russian film director [[Alexander Sokurov]]. Sokurov's own work has been heavily influenced by Tarkovsky. The film consists mostly of narration over stock footage from Tarkovsky's films. ''Directed by Andrei Tarkovsky'' is a 1988 documentary film by [[Michal Leszczylowski]], an editor of the film ''The Sacrifice''. Film director [[Chris Marker]] produced the television documentary ''[[One Day in the Life of Andrei Arsenevich]]'' as an homage to Andrei Tarkovsky in 2000. At the entrance to the [[Gerasimov Institute of Cinematography]] in [[Moscow]], there is a monument that includes statues of Tarkovsky, [[Gennady Shpalikov]] and [[Vasily Shukshin]].", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}
{"headers": ["Reception and influence on others"], "text": "[[Ingmar Bergman]] was quoted as saying: \"Tarkovsky for me is the greatest [of us all], the one who invented a new language, true to the nature of film, as it captures life as a reflection, life as a dream\". Film historian [[Steven Dillon (writer and professor)|Steven Dillon]] says that much of subsequent film was deeply influenced by the films of Tarkovsky.", "id": "676", "title": "Andrei Tarkovsky", "categories": ["Andrei Tarkovsky", "1932 births", "1986 deaths", "20th-century Russian male actors", "Burials at Sainte-Geneviève-des-Bois Russian Cemetery", "Cannes Film Festival Award for Best Director winners", "Deaths from cancer in France", "Deaths from lung cancer", "Directors of Golden Lion winners", "Filmmakers who won the Best Foreign Language Film BAFTA Award", "Gerasimov Institute of Cinematography alumni", "High Courses for Scriptwriters and Film Directors faculty", "Lenin Prize winners", "People from Kadyysky District", "People's Artists of the RSFSR", "Russian film directors", "Russian male actors", "Russian opera directors", "Russian Orthodox Christians from Russia", "Russian people of Polish descent", "Russian people of Romanian descent", "Science fiction film directors", "Soviet emigrants to France", "Soviet emigrants to Italy", "Soviet film directors", "Soviet male actors"], "seealso": ["European art cinema", "Moscow International Film Festival", "Slow cinema"]}