id stringlengths 2 8 | url stringlengths 31 117 | title stringlengths 1 71 | text stringlengths 153 118k | topic stringclasses 4
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93084 | https://en.wikipedia.org/wiki/Crab | Crab | Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tail" in Greek), which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land. They are generally covered with a thick exoskeleton. They ... | Biology and health sciences | Crustaceans | null |
93099 | https://en.wikipedia.org/wiki/Ship%20of%20the%20line | Ship of the line | A ship of the line was a type of naval warship constructed during the Age of Sail from the 17th century to the mid-19th century. The ship of the line was designed for the naval tactic known as the line of battle, which involved the two columns of opposing warships manoeuvering to volley fire with the cannons along thei... | Technology | Naval warfare | null |
93188 | https://en.wikipedia.org/wiki/Triple-alpha%20process | Triple-alpha process | The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.
Triple-alpha process in stars
Helium accumulates in the cores of stars as a result of the proton–proton chain reaction and the carbon–nitrogen–oxygen cycle.
Nuclear fusion react... | Physical sciences | Stellar astronomy | Astronomy |
93817 | https://en.wikipedia.org/wiki/Data%20type | Data type | In computer science and computer programming, a data type (or simply type) is a collection or grouping of data values, usually specified by a set of possible values, a set of allowed operations on these values, and/or a representation of these values as machine types. A data type specification in a program constrains t... | Technology | Programming languages | null |
93827 | https://en.wikipedia.org/wiki/Human%20nutrition | Human nutrition | Human nutrition deals with the provision of essential nutrients in food that are necessary to support human life and good health. Poor nutrition is a chronic problem often linked to poverty, food security, or a poor understanding of nutritional requirements. Malnutrition and its consequences are large contributors to d... | Biology and health sciences | Health and fitness: General | Health |
93829 | https://en.wikipedia.org/wiki/Agricultural%20biotechnology | Agricultural biotechnology | Agricultural biotechnology, also known as agritech, is an area of agricultural science involving the use of scientific tools and techniques, including genetic engineering, molecular markers, molecular diagnostics, vaccines, and tissue culture, to modify living organisms: plants, animals, and microorganisms. Crop biotec... | Technology | Biotechnology | null |
94102 | https://en.wikipedia.org/wiki/Solid%20angle | Solid angle | In geometry, a solid angle (symbol: ) is a measure of the amount of the field of view from some particular point that a given object covers. That is, it is a measure of how large the object appears to an observer looking from that point.
The point from which the object is viewed is called the apex of the solid angle, a... | Mathematics | Three-dimensional space | null |
94124 | https://en.wikipedia.org/wiki/Muzzleloader | Muzzleloader | A muzzleloader is any firearm in which the user loads the projectile and the propellant charge into the muzzle end of the gun (i.e., from the forward, open end of the gun's barrel). This is distinct from the modern designs of breech-loading firearms, in which user loads the ammunition into the breech end of the barrel... | Technology | Mechanisms_2 | null |
94139 | https://en.wikipedia.org/wiki/Rifling | Rifling | Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such grooves.
Rifling is measured in twist rate, the distance the rifling takes to compl... | Technology | Mechanisms_2 | null |
94166 | https://en.wikipedia.org/wiki/Bolt%20action | Bolt action | Bolt-action is a type of manual firearm action that is operated by directly manipulating the bolt via a bolt handle, most commonly placed on the right-hand side of the firearm (as most users are right-handed). The majority of bolt-action firearms are rifles, but there are also some variants of shotguns and handguns tha... | Technology | Mechanisms_2 | null |
3329659 | https://en.wikipedia.org/wiki/Font | Font | In metal typesetting, a font (American English) or fount (Commonwealth English) is a particular size, weight and style of a typeface, defined as the set of fonts that share an overall design.
For instance, the typeface Bauer Bodoni (shown in the figure) includes fonts "Roman" (or "regular"), "" and ""; each of these e... | Technology | Printing | null |
3331228 | https://en.wikipedia.org/wiki/Optical%20power | Optical power | In optics, optical power (also referred to as dioptric power, refractive power, focusing power, or convergence power) is the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the reciprocal of the focal length of the device: . High optical power corresponds to short foc... | Physical sciences | Optics | Physics |
3331499 | https://en.wikipedia.org/wiki/Thin%20lens | Thin lens | In optics, a thin lens is a lens with a thickness (distance along the optical axis between the two surfaces of the lens) that is negligible compared to the radii of curvature of the lens surfaces. Lenses whose thickness is not negligible are sometimes called thick lenses.
The thin lens approximation ignores optical ef... | Technology | Optical components | null |
16946852 | https://en.wikipedia.org/wiki/Rabies | Rabies | Rabies is a viral disease that causes encephalitis in humans and other mammals. It was historically referred to as hydrophobia ("fear of water") because its victims would panic when offered liquids to drink. Early symptoms can include fever and abnormal sensations at the site of exposure. These symptoms are followed by... | Biology and health sciences | Infectious disease | null |
414958 | https://en.wikipedia.org/wiki/Paleobotany | Paleobotany | Paleobotany, also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeography), and the evolutionary history of plants, with a bearing upon the evolution of l... | Biology and health sciences | Paleontology | Biology |
415070 | https://en.wikipedia.org/wiki/Chinese%20herbology | Chinese herbology | Chinese herbology () is the theory of traditional Chinese herbal therapy, which accounts for the majority of treatments in traditional Chinese medicine (TCM). A Nature editorial described TCM as "fraught with pseudoscience", and said that the most obvious reason why it has not delivered many cures is that the majority ... | Biology and health sciences | Alternative and traditional medicine | Health |
415088 | https://en.wikipedia.org/wiki/River%20source | River source | The headwater of a river or stream is the point on each of its tributaries upstream from its mouth or estuary into a lake, sea, or confluence with another river. Each headwater is considered one of the river's sources, as it is the place where surface runoffs from rainwater, meltwater, or spring water begin accumulati... | Physical sciences | Hydrology | Earth science |
415513 | https://en.wikipedia.org/wiki/Net%20force | Net force | In mechanics, the net force is the sum of all the forces acting on an object. For example, if two forces are acting upon an object in opposite directions, and one force is greater than the other, the forces can be replaced with a single force that is the difference of the greater and smaller force. That force is the ne... | Physical sciences | Classical mechanics | Physics |
415691 | https://en.wikipedia.org/wiki/Pith | Pith | Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which in some cases can store starch. In eudicotyledons, pith is located in the center of the stem. In monocotyledons, it extends only into roots. The pith is encircled by a ring of xylem; the xylem, in tur... | Biology and health sciences | Plant stem | Biology |
415810 | https://en.wikipedia.org/wiki/Hector%27s%20dolphin | Hector's dolphin | Hector's dolphin (Cephalorhynchus hectori) is one of four dolphin species belonging to the genus Cephalorhynchus. Hector's dolphin is the only cetacean endemic to New Zealand, and comprises two subspecies: C. h. hectori, the more numerous subspecies, also referred to as South Island Hector's dolphin; and the critically... | Biology and health sciences | Toothed whale | Animals |
415883 | https://en.wikipedia.org/wiki/Hydrogen-alpha | Hydrogen-alpha | Hydrogen-alpha, typically shortened to H-alpha or Hα, is a deep-red visible spectral line of the hydrogen atom with a wavelength of 656.28 nm in air and 656.46 nm in vacuum. It is the first spectral line in the Balmer series and is emitted when an electron falls from a hydrogen atom's third- to second-lowest energy le... | Physical sciences | Atomic physics | Physics |
416103 | https://en.wikipedia.org/wiki/Helsinki%20Metro | Helsinki Metro | The Helsinki Metro (, ) is a rapid transit system serving the Helsinki capital region, Finland. It is the world's northernmost metro system. It was opened to the general public on 2 August 1982 after 27 years of planning. It is operated by Helsinki City Transport and Metropolitan Area Transport Ltd for Helsinki Region... | Technology | Scandinavia | null |
416246 | https://en.wikipedia.org/wiki/Loratadine | Loratadine | Loratadine, sold under the brand name Claritin among others, is a medication used to treat allergies. This includes allergic rhinitis (hay fever) and hives. It is also available in drug combinations such as loratadine/pseudoephedrine, in which it is combined with pseudoephedrine, a nasal decongestant. It is taken orall... | Biology and health sciences | Antihistamines | Health |
416369 | https://en.wikipedia.org/wiki/Picea%20mariana | Picea mariana | Picea mariana, the black spruce, is a North American species of spruce tree in the pine family. It is widespread across Canada, found in all 10 provinces and all 3 territories. It is the official tree of Newfoundland and Labrador and is that province's most abundant tree. Its range extends into northern parts of the Un... | Biology and health sciences | Pinaceae | Plants |
416499 | https://en.wikipedia.org/wiki/Mass%20Rapid%20Transit%20%28Singapore%29 | Mass Rapid Transit (Singapore) | The Mass Rapid Transit system, locally known by the initialism MRT, is a rapid transit system in Singapore and the island country's principal mode of railway transportation. After two decades of planning the system commenced operations in November 1987 with an initial stretch consisting of five stations. The network h... | Technology | Asia_2 | null |
416549 | https://en.wikipedia.org/wiki/Morpho%20%28genus%29 | Morpho (genus) | The morpho butterflies comprise many species of Neotropical butterfly under the genus Morpho. This genus includes more than 29 accepted species and 147 accepted subspecies, found mostly in South America, Mexico, and Central America. Morpho wingspans range from for M. rhodopteron to for M. hecuba, the imposing sunset ... | Biology and health sciences | Lepidoptera | Animals |
416651 | https://en.wikipedia.org/wiki/Continental%20shelf | Continental shelf | A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an "insular shelf."
The continental margin, between the contin... | Physical sciences | Oceanic and coastal landforms | null |
416681 | https://en.wikipedia.org/wiki/Reversible%20process%20%28thermodynamics%29 | Reversible process (thermodynamics) | In thermodynamics, a reversible process is a process, involving a system and its surroundings, whose direction can be reversed by infinitesimal changes in some properties of the surroundings, such as pressure or temperature.
Throughout an entire reversible process, the system is in thermodynamic equilibrium, both phys... | Physical sciences | Thermodynamics | Physics |
416765 | https://en.wikipedia.org/wiki/Application%20checkpointing | Application checkpointing | Checkpointing is a technique that provides fault tolerance for computing systems. It involves saving a snapshot of an application's state, so that it can restart from that point in case of failure. This is particularly important for long-running applications that are executed in failure-prone computing systems.
Checkp... | Technology | Software development: General | null |
416954 | https://en.wikipedia.org/wiki/Viral%20evolution | Viral evolution | Viral evolution is a subfield of evolutionary biology and virology that is specifically concerned with the evolution of viruses. Viruses have short generation times, and many—in particular RNA viruses—have relatively high mutation rates (on the order of one point mutation or more per genome per round of replication). A... | Biology and health sciences | Basics_4 | Biology |
417014 | https://en.wikipedia.org/wiki/Passive%20transport | Passive transport | Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes. Instead of using cellular energy, like active transport, passive transport relies on the second law of thermodynamics to drive the movement of substances across cell membranes. Fundamentally, substan... | Biology and health sciences | Cell processes | Biology |
417048 | https://en.wikipedia.org/wiki/Ground%20beetle | Ground beetle | Ground beetles are a large, cosmopolitan family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it is one of the 10 most species-rich animal families. They belong to the Adephaga. Members of the family are primarily ca... | Biology and health sciences | Beetles (Coleoptera) | Animals |
417068 | https://en.wikipedia.org/wiki/Anesthesiology | Anesthesiology | Anesthesiology, anaesthesiology or anaesthesia is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medicine, and pain medicine. A physician specialized in anesthesiology is called an ane... | Biology and health sciences | Fields of medicine | Health |
1752439 | https://en.wikipedia.org/wiki/Commelinaceae | Commelinaceae | Commelinaceae is a family of flowering plants. In less formal contexts, the group is referred to as the dayflower family or spiderwort family. It is one of five families in the order Commelinales and by far the largest of these with about 731 known species in 41 genera. Well known genera include Commelina (dayflowers) ... | Biology and health sciences | Commelinales | Plants |
1753667 | https://en.wikipedia.org/wiki/Galvanic%20series | Galvanic series | The galvanic series (or electropotential series) determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experience galvanic corrosion. The rate of corrosion is determined by the electrol... | Physical sciences | Electrochemistry | Chemistry |
19166474 | https://en.wikipedia.org/wiki/Hand | Hand | A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints extremely similar to human fingerprints) are often descri... | Biology and health sciences | Human anatomy | null |
19167553 | https://en.wikipedia.org/wiki/Goat | Goat | The goat or domestic goat (Capra hircus) is a species of goat-antelope that is mostly kept as livestock. It was domesticated from the wild goat (C. aegagrus) of Southwest Asia and Eastern Europe. The goat is a member of the family Bovidae, meaning it is closely related to the sheep. It was one of the first animals to b... | Biology and health sciences | Artiodactyla | null |
19167644 | https://en.wikipedia.org/wiki/Toilet | Toilet | A toilet is a piece of sanitary hardware that collects human waste (urine and feces), and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry or non-flush toilets do not. They can be designed for a sitting position popular in Europe and North America with a toilet seat, with additional cons... | Technology | Household appliances | null |
19167679 | https://en.wikipedia.org/wiki/Virus | Virus | A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Si... | Biology and health sciences | Biology | null |
19167840 | https://en.wikipedia.org/wiki/Chronology%20of%20the%20universe | Chronology of the universe | The chronology of the universe describes the history and future of the universe according to Big Bang cosmology.
Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level.
Over... | Physical sciences | Physical cosmology | null |
19172225 | https://en.wikipedia.org/wiki/Prokaryote | Prokaryote | A prokaryote (; less commonly spelled procaryote) is a single-celled organism whose cell lacks a nucleus and other membrane-bound organelles. The word prokaryote comes from the Ancient Greek (), meaning 'before', and (), meaning 'nut' or 'kernel'. In the earlier two-empire system arising from the work of Édouard Chat... | Biology and health sciences | Other organisms | null |
19174720 | https://en.wikipedia.org/wiki/Electric%20battery | Electric battery | An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of elect... | Technology | Energy | null |
2434557 | https://en.wikipedia.org/wiki/Non-inertial%20reference%20frame | Non-inertial reference frame | A non-inertial reference frame (also known as an accelerated reference frame) is a frame of reference that undergoes acceleration with respect to an inertial frame. An accelerometer at rest in a non-inertial frame will, in general, detect a non-zero acceleration. While the laws of motion are the same in all inertial fr... | Physical sciences | Classical mechanics | Physics |
5959843 | https://en.wikipedia.org/wiki/Vector%20notation | Vector notation | In mathematics and physics, vector notation is a commonly used notation for representing vectors, which may be Euclidean vectors, or more generally, members of a vector space.
For denoting a vector, the common typographic convention is lower case, upright boldface type, as in . The International Organization for Stan... | Mathematics | Linear algebra | null |
10099478 | https://en.wikipedia.org/wiki/Hectorite | Hectorite | Hectorite is a rare soft, greasy, white clay mineral with a chemical formula of .
Hectorite was first described in 1941 and named for an occurrence in the United States near Hector (in San Bernardino County, California, 30 miles east of Barstow.) Hectorite occurs with bentonite as an alteration product of clinoptiloli... | Physical sciences | Silicate minerals | Earth science |
10101126 | https://en.wikipedia.org/wiki/Kinder%20goat | Kinder goat | The Kinder is an American breed of domestic goat. It originated on a farm in Snohomish, Washington, where in about 1985 an American Pygmy buck was cross-bred with Nubian does. The resulting stock was selectively bred to create a compact but well-muscled goat, suitable both for milk and for meat production. A herd-book ... | Biology and health sciences | Goats | Animals |
10101941 | https://en.wikipedia.org/wiki/Bortle%20scale | Bortle scale | The Bortle dark-sky scale (usually referred to as simply the Bortle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. Amateur astronomer John E. Bortle... | Physical sciences | Basics | Astronomy |
11539646 | https://en.wikipedia.org/wiki/Knife%20switch | Knife switch | A knife switch is a type of switch used to control the flow of electricity in a circuit. It is composed of a hinge which allows a metal lever, or knife, to be lifted from or inserted into a slot or jaw. The hinge and jaw are both fixed to an insulated base, and the knife has an insulated handle. Current flows through ... | Technology | Components | null |
708839 | https://en.wikipedia.org/wiki/Loschmidt%27s%20paradox | Loschmidt's paradox | In physics, Loschmidt's paradox (named for J.J. Loschmidt), also known as the reversibility paradox, irreversibility paradox, or (), is the objection that it should not be possible to deduce an irreversible process from time-symmetric dynamics. This puts the time reversal symmetry of (almost) all known low-level funda... | Physical sciences | Thermodynamics | Physics |
708974 | https://en.wikipedia.org/wiki/Rapini | Rapini | Rapini (broccoli rabe or raab) () is a green cruciferous vegetable, with the leaves, buds, and stems all being edible; the buds somewhat resemble broccoli. Rapini is known for its bitter taste, and is particularly associated with Mediterranean cuisine. It is a particularly rich dietary source of vitamin K.
Classifica... | Biology and health sciences | Leafy vegetables | Plants |
709427 | https://en.wikipedia.org/wiki/Micro%20black%20hole | Micro black hole | Micro black holes, also called mini black holes or quantum mechanical black holes, are hypothetical tiny (<1 ) black holes, for which quantum mechanical effects play an important role. The concept that black holes may exist that are smaller than stellar mass was introduced in 1971 by Stephen Hawking.
It is possible th... | Physical sciences | Basics_2 | Astronomy |
709548 | https://en.wikipedia.org/wiki/Redcurrant | Redcurrant | The redcurrant or red currant (Ribes rubrum) is a member of the genus Ribes in the gooseberry family. It is native to western Europe. The species is widely cultivated and has escaped into the wild in many regions.
Description
Ribes rubrum is a deciduous shrub normally growing to tall, occasionally , with five-lobed l... | Biology and health sciences | Berries | Plants |
710174 | https://en.wikipedia.org/wiki/Bridge%20circuit | Bridge circuit | A bridge circuit is a topology of electrical circuitry in which two circuit branches (usually in parallel with each other) are "bridged" by a third branch connected between the first two branches at some intermediate point along them. The bridge was originally developed for laboratory measurement purposes and one of t... | Technology | Functional circuits | null |
710251 | https://en.wikipedia.org/wiki/Wind%20wave | Wind wave | In fluid dynamics, a wind wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result of the wind blowing over the water's surface. The contact distance in the direction of the wind is known as the fetch. Waves in the oceans can travel thousands of kilometers bef... | Physical sciences | Oceanography | Earth science |
710897 | https://en.wikipedia.org/wiki/Gardenia | Gardenia | Gardenia is a genus of flowering plants in the coffee family, Rubiaceae, native to the tropical and subtropical regions of Africa, Asia, Madagascar, Pacific Islands, and Australia.
The genus was named by Carl Linnaeus and John Ellis after Alexander Garden (1730–1791), a Scottish naturalist. The type species is Gardeni... | Biology and health sciences | Others | null |
711147 | https://en.wikipedia.org/wiki/Takah%C4%93 | Takahē | The South Island takahē (Porphyrio hochstetteri) is a flightless swamphen indigenous to New Zealand and the largest living member of the rail family. It is often known by the abbreviated name takahē, which it shares with the recently extinct North Island takahē. The two takahē species are also known as notornis.
Takah... | Biology and health sciences | Gruiformes | Animals |
711157 | https://en.wikipedia.org/wiki/Extensive%20farming | Extensive farming | Extensive farming or extensive agriculture (as opposed to intensive farming) is an agricultural production system that uses small inputs of labour, fertilizers, and capital, relative to the land area being farmed.
Systems
Extensive farming most commonly means raising sheep and cattle in areas with low agricultural pr... | Technology | Agriculture_2 | null |
711783 | https://en.wikipedia.org/wiki/Splint%20%28medicine%29 | Splint (medicine) | A splint is defined as "a rigid or flexible device that maintains in position a displaced or movable part; also used to keep in place and protect an injured part" or as "a rigid or flexible material used to protect, immobilize, or restrict motion in a part". Splints can be used for injuries that are not severe enough t... | Technology | Devices | null |
12474403 | https://en.wikipedia.org/wiki/Climate%20change%20denial | Climate change denial | Climate change denial (also global warming denial) is a form of science denial characterized by rejecting, refusing to acknowledge, disputing, or fighting the scientific consensus on climate change. Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is ... | Physical sciences | Climate change | Earth science |
27058 | https://en.wikipedia.org/wiki/Steel | Steel | Steel is an alloy of iron and carbon with improved strength and fracture resistance compared to other forms of iron. Because of its high tensile strength and low cost, steel is one of the most commonly manufactured materials in the world. Steel is used in buildings, as concrete reinforcing rods, in bridges, infrastruct... | Physical sciences | Chemistry | null |
27059 | https://en.wikipedia.org/wiki/Stainless%20steel | Stainless steel | Stainless steel, also known as inox, corrosion-resistant steel (CRES), and rustless steel, is an iron-based alloy containing a minimum level of chromium that is resistant to rusting and corrosion. Stainless steel's resistance to corrosion results from the 10.5%, or more, chromium content which forms a passive film th... | Physical sciences | Specific alloys | null |
27065 | https://en.wikipedia.org/wiki/Standardization | Standardization | Standardization (American English) or standardisation (British English) is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization can help maximize compatibility, inte... | Technology | Basics_6 | null |
27114 | https://en.wikipedia.org/wiki/Silicon | Silicon | Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It... | Physical sciences | Chemistry | null |
27116 | https://en.wikipedia.org/wiki/Scandium | Scandium | Scandium is a chemical element with the symbol Sc and atomic number 21. It is a silvery-white metallic d-block element. Historically, it has been classified as a rare-earth element, together with yttrium and the lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Sca... | Physical sciences | Chemical elements_2 | null |
27117 | https://en.wikipedia.org/wiki/Selenium | Selenium | Selenium is a chemical element; it has the symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elemental state or as pure ore compounds in Earth's crust. Selenium () was discovered in 1817 b... | Physical sciences | Chemical elements_2 | null |
27118 | https://en.wikipedia.org/wiki/Strontium | Strontium | Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those o... | Physical sciences | Chemical elements_2 | null |
27119 | https://en.wikipedia.org/wiki/Silver | Silver | Silver is a chemical element; it has symbol Ag (, derived from Proto-Indo-European *h₂erǵ ) and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. Silver is found in the Earth's crust in the pure, free element... | Physical sciences | Chemistry | null |
27121 | https://en.wikipedia.org/wiki/Samarium | Samarium | Samarium is a chemical element; it has symbol Sm and atomic number 62. It is a moderately hard silvery metal that slowly oxidizes in air. Being a typical member of the lanthanide series, samarium usually has the oxidation state +3. Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenid... | Physical sciences | Chemical elements_2 | null |
27127 | https://en.wikipedia.org/wiki/Sulfur | Sulfur | Sulfur (also spelled sulphur in British English) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room te... | Physical sciences | Chemistry | null |
27154 | https://en.wikipedia.org/wiki/Seizure | Seizure | A seizure is a sudden change in behavior, movement or consciousness due to abnormal electrical activity in the brain. Seizures can look different in different people. It can be uncontrolled shaking of the whole body (tonic-clonic seizures) or a person spacing out for a few seconds (absence seizures). Most seizures last... | Biology and health sciences | Symptoms and signs | Health |
27488 | https://en.wikipedia.org/wiki/Software%20documentation | Software documentation | Software documentation is written text or illustration that accompanies computer software or is embedded in the source code. The documentation either explains how the software operates or how to use it, and may mean different things to people in different roles.
Documentation is an important part of software engineer... | Technology | Software development: General | null |
27529 | https://en.wikipedia.org/wiki/September | September | September is the ninth month of the year in the Julian and Gregorian calendars. Its length is 30 days.
September in the Northern Hemisphere and March in the Southern Hemisphere are seasonally equivalent.
In the Northern hemisphere, the beginning of the meteorological autumn is on 1 September. In the Southern hemisphe... | Technology | Months | null |
27553 | https://en.wikipedia.org/wiki/Set%20theory | Set theory | Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects. Although objects of any kind can be collected into a set, set theory – as a branch of mathematics – is mostly concerned with those that are relevant to mathematics as a whole.
The modern study... | Mathematics | Discrete mathematics | null |
27558 | https://en.wikipedia.org/wiki/Salt%20%28chemistry%29 | Salt (chemistry) | In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions (cations) and negatively charged ions (anions), which results in a compound with no net electric charge (electrically neutral). The constituent ions are held together by electrostatic forces termed ionic b... | Physical sciences | Salts | null |
27573 | https://en.wikipedia.org/wiki/Superfluid%20helium-4 | Superfluid helium-4 | Superfluid helium-4 (helium II or He-II) is the superfluid form of helium-4, an isotope of the element helium. A superfluid is a state of matter in which matter behaves like a fluid with zero viscosity. The substance, which resembles other liquids such as helium I (conventional, non-superfluid liquid helium), flows wit... | Physical sciences | s-Block | Chemistry |
27577 | https://en.wikipedia.org/wiki/Statistical%20inference | Statistical inference | Statistical inference is the process of using data analysis to infer properties of an underlying probability distribution. Inferential statistical analysis infers properties of a population, for example by testing hypotheses and deriving estimates. It is assumed that the observed data set is sampled from a larger popul... | Mathematics | Statistics | null |
27585 | https://en.wikipedia.org/wiki/Statistical%20population | Statistical population | In statistics, a population is a set of similar items or events which is of interest for some question or experiment. A statistical population can be a group of existing objects (e.g. the set of all stars within the Milky Way galaxy) or a hypothetical and potentially infinite group of objects conceived as a generaliza... | Mathematics | Statistics and probability | null |
27590 | https://en.wikipedia.org/wiki/Standard%20deviation | Standard deviation | In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its mean. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out ... | Mathematics | Statistics and probability | null |
27593 | https://en.wikipedia.org/wiki/Independence%20%28probability%20theory%29 | Independence (probability theory) | Independence is a fundamental notion in probability theory, as in statistics and the theory of stochastic processes. Two events are independent, statistically independent, or stochastically independent if, informally speaking, the occurrence of one does not affect the probability of occurrence of the other or, equivale... | Mathematics | Probability | null |
27609 | https://en.wikipedia.org/wiki/Skeleton | Skeleton | A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal frame to which the organs and soft tissues attach; and the hydroskeleton, a flexi... | Biology and health sciences | Biology | null |
27616 | https://en.wikipedia.org/wiki/Sunspot | Sunspot | Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually affect the entire solar atmosphere. They are regions of reduced surface temperature c... | Physical sciences | Solar System | Astronomy |
27631 | https://en.wikipedia.org/wiki/Subset | Subset | In mathematics, a set A is a subset of a set B if all elements of A are also elements of B; B is then a superset of A. It is possible for A and B to be equal; if they are unequal, then A is a proper subset of B. The relationship of one set being a subset of another is called inclusion (or sometimes containment). A is a... | Mathematics | Discrete mathematics | null |
27637 | https://en.wikipedia.org/wiki/Structural%20geology | Structural geology | Structural geology is the study of the three-dimensional distribution of rock units with respect to their deformational histories. The primary goal of structural geology is to use measurements of present-day rock geometries to uncover information about the history of deformation (strain) in the rocks, and ultimately, t... | Physical sciences | Structural geology | Earth science |
27661 | https://en.wikipedia.org/wiki/Source%20code | Source code | In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer.
Since a computer, at base, only understands machine code, source code must be translated before a computer c... | Technology | Software development: General | null |
27667 | https://en.wikipedia.org/wiki/Space | Space | Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to... | Physical sciences | Physics | null |
27672 | https://en.wikipedia.org/wiki/Sailing | Sailing | Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the water (sailing ship, sailboat, raft, windsurfer, or kitesurfer), on ice (iceboat) or on land (land yacht) over a chosen course, which is often part of a larger plan of navigation.
From prehistory until the second half ... | Technology | Maritime transport | null |
27675 | https://en.wikipedia.org/wiki/Simple%20Mail%20Transfer%20Protocol | Simple Mail Transfer Protocol | The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and ty... | Technology | Networks | null |
27680 | https://en.wikipedia.org/wiki/Supernova | Supernova | A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the progenitor, either collapses to a neutron star or black hole,... | Physical sciences | Astronomy | null |
27683 | https://en.wikipedia.org/wiki/Satellite | Satellite | A satellite or artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, e... | Technology | Space | null |
27686 | https://en.wikipedia.org/wiki/Spreadsheet | Spreadsheet | A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the res... | Technology | Computer software | null |
27692 | https://en.wikipedia.org/wiki/Steam%20engine | Steam engine | A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed by a connecting rod and crank into rotational force for work. The term "stea... | Technology | Tools and machinery | null |
27695 | https://en.wikipedia.org/wiki/Structured%20programming | Structured programming | Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making specific disciplined use of the structured control flow constructs of selection (if/then/else) and repetition (while and for), block structures, and subroutines.
It emerged in ... | Technology | Programming | null |
27709 | https://en.wikipedia.org/wiki/Semiconductor | Semiconductor | A semiconductor is a material that is between the conductor and insulator in ability to conduct electrical current. In many cases their conducting properties may be altered in useful ways by introducing impurities ("doping") into the crystal structure. When two differently doped regions exist in the same crystal, a sem... | Physical sciences | Electrical circuits | null |
27711 | https://en.wikipedia.org/wiki/Starch | Starch | Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets, and is contained in large amounts in staple foods such as wheat, potatoes, ... | Biology and health sciences | Biochemistry and molecular biology | null |
27725 | https://en.wikipedia.org/wiki/Surface%20area | Surface area | The surface area (symbol A) of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc length of one-dimensional curves, or of the surface area for polyh... | Mathematics | Measurement | null |
27743 | https://en.wikipedia.org/wiki/Solar%20energy | Solar energy | Solar energy is the radiant energy from the Sun's light and heat, which can be harnessed using a range of technologies such as solar electricity, solar thermal energy (including solar water heating) and solar architecture. It is an essential source of renewable energy, and its technologies are broadly characterized as ... | Technology | Energy | null |
27751 | https://en.wikipedia.org/wiki/SVG | SVG | Scalable Vector Graphics (SVG) is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation. The SVG specification is an open standard developed by the World Wide Web Consortium since 1999.
SVG images are defined in a vector graphics format and stored in XML... | Technology | File formats | null |
27752 | https://en.wikipedia.org/wiki/Spectroscopy | Spectroscopy | Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum.
Spectroscopy, primarily in the electromagnetic spectrum, is a fundamental exploratory... | Physical sciences | Analytical chemistry | null |
27764 | https://en.wikipedia.org/wiki/Systems%20engineering | Systems engineering | Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their life cycles. At its core, systems engineering utilizes systems thinking principles to organize this body of knowledge. The individual outcome of suc... | Technology | Disciplines | null |
27772 | https://en.wikipedia.org/wiki/Sandstone | Sandstone | Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains, cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar, because they are the most resistant minerals to the weathering proce... | Physical sciences | Petrology | null |
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