42,772 articles
International Physics Olympiad editions 1990–2009
The International Physics Olympiad editions 1990–2009 were twenty consecutive competitions, from Groningen in 1990 to Mérida in 2009, none canceled, with participation growing from 31 delegations to 62 countries.
International Physics Olympiad records and medal statistics
Records and medal statistics for the International Physics Olympiad, an annual physics contest for secondary students where gold goes to the top 8% and China led 2009–2019 with 55 golds.
International Prototype of the Kilogram
The International Prototype of the Kilogram, nicknamed Le Grand K, is a platinum-iridium cylinder kept in Sèvres, France, that defined the SI kilogram from 1889 until 2019.
International Pulsar Timing Array
The International Pulsar Timing Array (IPTA) is a consortium founded in 2009 that combines pulsar timing data from radio telescopes worldwide to detect nanohertz gravitational waves.
International Satellite Cloud Climatology Project
The International Satellite Cloud Climatology Project (ISCCP) is the first project of the World Climate Research Programme, established in 1982 to map global cloud properties from weather satellites.
International Social Survey Programme
The International Social Survey Programme (ISSP) is a cross-national collaboration of survey organizations that has run annual social science surveys since 1984, covering topics like government, religion, and inequality.
International Standard Atmosphere
International Standard Atmosphere (ISA), ICAO/ISO 2533 standard model of temperature, pressure, and density versus altitude; sea level 15 °C, 1013.25 hPa, 1.225 kg/m³; seven layers to 84.852 km; used for altimeter calibration and aircraft performance.
International Standard Classification of Education
The International Standard Classification of Education (ISCED) is a UNESCO framework for classifying education programs and qualifications, from early childhood to tertiary levels 0 through 8, so statistics compare across countries.
International Standard Classification of Occupations
The International Standard Classification of Occupations (ISCO) is an International Labour Organization tool for classifying jobs; its current version, ISCO-08, arranges them into 436 unit groups within 10 major groups.
International System of Quantities
The International System of Quantities (ISQ) is the standardized system of physical quantities, defined by the ISO/IEC 80000 series, on which the International System of Units (SI) is based.
International System of Units
The International System of Units (Système international d'unités, SI) is the modern metric system, built on seven base units and defined since 2019 by seven constants of nature.
International Temperature Scale of 1990
The International Temperature Scale of 1990 (ITS-90) is the internationally adopted practical temperature scale defining how temperatures from 0.65 K upward are measured, adopted by the CIPM in 1989 and superseding IPTS-68.
International Terrestrial Reference Frame
The International Terrestrial Reference Frame (ITRF) is a global set of station coordinates and velocities, published by the IERS, that realizes the International Terrestrial Reference System.
International Time Bureau
The International Time Bureau, also known as the Bureau International de l'Heure, coordinated Universal Time from the Paris Observatory from 1912 until its dissolution in 1987.
International Ultraviolet Explorer
The International Ultraviolet Explorer (IUE) was a joint NASA, ESA, and UK space telescope launched on 26 January 1978 to perform ultraviolet spectroscopy of celestial objects.
International Union of Pure and Applied Chemistry
The International Union of Pure and Applied Chemistry (IUPAC) is an international, non-governmental scientific organization, founded in 1919, that serves as the world authority on chemical nomenclature and terminology.
International Union of Pure and Applied Physics
The International Union of Pure and Applied Physics (IUPAP) is an international scientific union founded in 1922 in Brussels that sponsors physics conferences and awards prizes.
International Union of Pure and Applied Physics congresses
The International Union of Pure and Applied Physics congresses are conference series sponsored or endorsed by IUPAP, classified into four types and including flagship series such as ICHEP and STATPHYS.
International Water Management Institute
The International Water Management Institute (IWMI) is a CGIAR research organization headquartered in Colombo, Sri Lanka, founded in 1984, that works with governments to solve water problems in developing countries.
Interplanetary scintillation
Interplanetary scintillation is a radio astronomy technique that measures rapid intensity fluctuations of compact radio sources caused by solar wind density irregularities, used for space weather remote sensing.
Interpolation
Interpolation is the construction of a function that passes exactly through known data points so values can be estimated between them, as in cubic splines and Lagrange polynomials.
Interpretation (logic)
In logic, also called a structure, an interpretation gives meaning to a formal language by fixing a domain of objects and assigning each non-logical symbol a denotation over it.
Interpretation of theories and interpretability strength
An interpretation of a theory T in a theory S is a syntactic translation under which S proves every translated theorem of T, enabling comparison of logical strength.
Interpretations of quantum mechanics
Interpretations of quantum mechanics, also called the philosophy of quantum mechanics, are accounts of what the theory's mathematics, especially the wave function, says about the world.
Interpretive description
Interpretive description is a qualitative research methodology for nursing and applied health disciplines, introduced by Sally Thorne and colleagues in 1997 to generate practice-relevant knowledge.
Interquartile range
The interquartile range (IQR), also known as the midspread or middle 50%, is the difference between the 75th and 25th percentiles, a robust measure of statistical dispersion less affected by extreme values than the standard deviation.
Interrill erosion
Interrill erosion, also called sheet erosion, is the removal of soil in thin layers by raindrop impact and shallow overland flow, the first stage of water erosion on a hillslope.
Intersecting Storage Rings
The Intersecting Storage Rings (ISR) was a CERN particle accelerator in Geneva, the world's first hadron collider, whose two interlaced proton rings produced the first proton-proton collisions in January 1971.
Intersection (set theory)
In set theory, the intersection of sets A and B, written A ∩ B, is the set of elements they share, the set-level counterpart of logical conjunction.
Intersection graph
An intersection graph is a graph whose vertices represent members of a family of sets, with edges between sets that intersect; every graph arises this way.