Editing List of experiments

{{Short description|none}}

{{No references|date=November 2023}}

The following is a list of historically important scientific [[experiment]]s and observations demonstrating something of great scientific interest, typically in an elegant or clever manner.

==Astronomy==
* [[Ole Rømer]] makes the first quantitative estimate of the [[Rømer's determination of the speed of light|speed of light]] in 1676 by timing the motions of Jupiter's satellite [[Io (moon)|Io]] with a telescope
* [[Arno Penzias]] and [[Robert Woodrow Wilson|Robert Wilson]] detect the [[cosmic microwave background radiation]], giving support to the theory of the [[Big Bang]] (1964)
* [[Kerim Kerimov]] launches [[Kosmos 186 and Kosmos 188]] as experiments on automatic docking eventually leading to the development of [[space station]]s (1967)
* The [[Supernova Cosmology Project]] and the [[High-Z Supernova Search Team]] discover, by observing [[Type Ia supernova]]e, that the [[dark energy|expansion of the Universe is accelerating]] (1998)
*[[Galileo Galilei]] uses a [[telescope]] to observe that the [[Galilean moons|moons of Jupiter]] appear to circle [[Jupiter]]. This evidence supports the [[heliocentric model]], and weakens the [[geocentric model]] of the cosmos (1609)

==Biology==
* [[Robert Hooke]], using a [[microscope]], observes [[cell (biology)|cell]]s (1665).
* [[Anton van Leeuwenhoek]] discovers [[microorganism]]s (1674–1676).
* [[James Lind]], publishes 'A Treatise of the Scurvy' which describes a controlled shipboard experiment using two identical populations but with only one variable, the consumption of citrus fruit (1753). 
* [[Edward Jenner]] tests his hypothesis for the protective action of mild cowpox infection for [[smallpox]], the first [[vaccine]] (1796).
* [[Gregor Mendel]]'s experiments with the garden [[pea]] led him to surmise many of the fundamental laws of genetics ([[dominant gene|dominant]] vs [[recessive gene|recessive]] genes, the 1–2–1 ratio, see [[Mendelian inheritance]]) (1856–1863).
*[[Charles Darwin]] demonstrates [[evolution]] by [[natural selection]] using many examples (1859).
* [[Louis Pasteur]] uses S-shaped flasks to prevent [[spore]]s from contaminating broth. This disproves the theory of [[Spontaneous generation]] (1861) extending the rancid meat experiment of [[Francesco Redi]] (1668) to the micro scale.
*[[Charles Darwin]] and his son [[Francis Darwin|Francis]], using dark-grown oat seedlings, discover the stimulus for [[phototropism]] is detected at the tip of the shoot (the [[coleoptile]] tip), but the bending takes place in the region below the tip (1880).
* [[Emil von Behring]] and [[Kitasato Shibasaburō]] demonstrate [[passive immunity]], protection of animals from infection by injection of [[immune serum]] (1890).
* [[Thomas Hunt Morgan]] identifies a [[sex chromosome]] linked [[gene]] in ''[[Drosophila melanogaster]]'' (1910) and his student [[Alfred Sturtevant]] develops the first genetic map (1913).
*[[Alexander Fleming]] demonstrates that the zone of inhibition around a growth of [[penicillin]] mould on a culture dish of bacteria is caused by a diffusible substance secreted by the mould (1928).
* [[Frederick Griffith]] demonstrates ([[Griffith's experiment]]) that living cells can be transformed via a [[transforming principle]], later discovered to be [[DNA]] (1928). 
* [[Karl von Frisch]] decodes the [[waggle dance]] [[honey bee]]s use to communicate the location of flowers (1940). 
* [[George Wells Beadle]] and [[Edward Lawrie Tatum]] moot the "[[one gene-one enzyme hypothesis]]" based on induced mutations in bread mold ''[[Neurospora crassa]]'' (1941). 
* [[Luria–Delbrück experiment]] demonstrates that in bacteria, beneficial mutations arise in the absence of selection, rather than being a response to selection (1943). 
* [[Barbara McClintock]] breeds [[maize]] plants for color, which leads to the discovery of transposable elements or [[Transposon|jumping genes]] (1944). 
* [[Linus Pauling]] and colleagues show in "[[Sickle Cell Anemia, a Molecular Disease]]" that a human genetic disease, [[sickle cell anemia]], is caused by a molecular change in a specific protein, [[hemoglobin]] (1949). 
* [[Hershey–Chase experiment]] (by [[Alfred Hershey]] and [[Martha Chase]]) uses [[bacteriophage]] to prove that [[DNA]] is the hereditary material (1952).
* [[Meselson–Stahl experiment]] proves that [[DNA replication]] is [[semiconservative replication|semiconservative]] (1958). 
* [[Crick, Brenner et al. experiment]] using frameshift mutations to support the triplet nature of the genetic code (1961). 
* [[Nirenberg and Matthaei experiment]] demonstrating ''in vitro'' [[protein]] synthesis using synthetic RNA as to substitute for [[mRNA|messenger RNA]] (1961).
* [[John Gurdon]] [[cloning|clones]] an animal, a [[frog]] tadpole, from an [[ovum|egg cell]] using the nucleus from an [[intestine|intestinal]] cell (1962).
* [[Roger W. Sperry]] shows the potential independence of the two sides of the human brain using ''split-brain'' patients (1962–1965). 
* [[Nirenberg and Leder experiment]], binding [[tRNA]] to ribosomes with synthetic RNA to decipher the genetic code (1964). 
* Demonstration of the role of [[reverse transcriptase]]s in tumor [[virus]]es, independently by [[Howard Temin]] and [[David Baltimore]], 1970. 
* [[Herbert Boyer]] and [[Stanley Cohen (biochemist)|Stanley Cohen]] selectively clone genes in bacteria, using bacterial plasmids cut by specific endonucleases (1975).
* [[Mary-Dell Chilton]] shows that crown gall tumors of plants are caused by the transfer of a small piece of DNA from the bacterium ''[[Agrobacterium tumefaciens]]'' into the host plant, where it becomes part of its genome (1977). 
* Napoli, Lemieux and Jorgensen discover the principle of [[RNA interference]] (1990).

==Chemistry==
*[[Robert Boyle]] uses an [[air pump]] to determine the inverse relationship between the [[pressure]] and [[volume]] of a [[gas]]. This relationship came to be known as [[Boyle's law]] (1660–1662).
*[[Joseph Priestley]] suspends a bowl of water above a beer vat at a brewery and synthesizes [[carbonated water]] (1767).
*[[Antoine Lavoisier]] determines that [[oxygen]] combines with materials upon [[combustion]], thus disproving [[phlogiston theory]] (1783).
*[[Antoine Lavoisier]] determines that [[chemical reactions]] in a closed container do not alter total mass. From these observations he establishes the law of [[conservation of mass]] (1789).
*[[Benjamin Thompson|Benjamin Thompson, Count Rumford]] demonstrates that the [[An Inquiry Concerning the Source of the Heat Which Is Excited by Friction|heat developed by the friction of boring cannon]] is nearly inexhaustible. This result was presented in opposition to [[caloric theory]] (1798).
*[[Humphry Davy]] uses [[electrolysis]] to isolate elemental [[potassium]], [[sodium]], [[calcium]], [[strontium]], [[barium]], [[magnesium]], and [[chlorine]] (1807–1810).
*[[Joseph Louis Gay-Lussac]] studies reactions among gases and determines that their volumes combine chemically in simple integer ratios (1809).
*[[Robert Brown (Scottish botanist from Montrose)|Robert Brown]] studies very small particles in water under the microscope and observes [[Brownian motion]] which was later named in his honor (1827).
*[[Friedrich Wöhler]] [[Wöhler synthesis|synthesizes]] the [[organic compound]] [[urea]] using [[inorganic compound|inorganic reactants]], disproving the application of [[vitalism]] to chemical processes (1828).
*[[Thomas Graham (chemist)|Thomas Graham]] measures the rates of [[effusion]] for different gases and establishes [[Graham's law]] of effusion and [[diffusion]] (1833).
*[[Julius Robert von Mayer]] and [[James Prescott Joule]] measure the [[Mechanical equivalent of heat|heat generated by mechanical work]]. This establishes the principle of [[conservation of energy]] and the [[Kinematics|kinetic theory]] of heat (1842–1843).
*[[Louis Pasteur]] separates a [[racemic]] mixture of two [[enantiomers]] by sorting individual [[crystals]], and demonstrates their impact on the [[polarization of light]] (1849).
*[[Anders Jonas Ångström]] observes the presence of [[hydrogen]] and other elements in the [[spectrum]] of the sun (1862).
*[[François-Marie Raoult]] demonstrates that the decrease in the [[vapor pressure]] and [[freezing-point depression|freezing point]] of liquids caused by the addition of solutes is proportional to the number of solute molecules present. This establishes the concept of [[colligative properties]] (1878).
*[[Svante Arrhenius]] studies the [[electrical conductivity|conductivity]] of [[salt (chemistry)|salt]] solutions and determines that salts [[dissociate]] into [[ions]] in water (1884). 
*[[Svante Arrhenius]] determines the impact of temperature on [[reaction rates]] and formulates the concept of [[activation energy]] (1889). 
*[[William Ramsay]] and [[John Strutt, 3rd Baron Rayleigh|Lord Rayleigh (John Strutt)]] isolate the [[noble gases]] (1894–1898). 
*[[Henri Becquerel]], [[Marie Curie]], and [[Pierre Curie]] discover [[radioactivity]] and describe its properties (1896). 
*[[Mikhail Tsvet]] (Mikhail Semyonovich Tsvet) separates [[chlorophyll]] from other plant pigments using [[chromatography]] (1901). 
*[[Frederick Soddy]] and [[William Ramsay]] observe the production of [[helium]] from [[alpha particles]] during [[radioactive decay]] (1903). 
*[[Ernest Rutherford]] discovers that atoms have a very small positively charged nucleus in the gold-foil experiment, also known as the [[Geiger–Marsden experiment]] (1909).
*[[Otto Hahn]] discovers [[nuclear isomerism]] (1921).
*[[Albert Szent-Györgyi]] and [[Hans Adolf Krebs]] discover the [[citric acid cycle]] of [[oxidative metabolism]] (1935-1937).
*[[Otto Hahn]] and [[Fritz Strassmann]] discover the [[nuclear fission]] of uranium (1938). 
*[[Glenn Theodore Seaborg]] and colleagues create and isolate five [[transuranium elements]]. They reorganize the [[periodic table]] to its current form. (1941–1950). 
*[[Miller–Urey experiment]] demonstrates that [[organic compound]]s can arise spontaneously from [[inorganic compound|inorganic ones]] (1953). 
*[[Melvin Calvin]] and [[Andrew Benson]] delineate the path of carbon in [[photosynthesis]] using ''[[Chlorella]]'' and [[carbon dioxide]] labeled with [[carbon-14]] (<sup>14</sup>CO<sub>2</sub>) (1945–1954). 
*[[Erwin Chargaff]] disproves the "tetranucleoide theory" of [[DNA]] structure and determines that the composition of double-stranded DNA follows the rule, %A = %T and %G = %C ([[Chargaff's rule]]). This discovery was critical to the formulation of the Watson-Crick Model of DNA structure. 
*[[Neil Bartlett (chemist)|Neil Bartlett]] mixes [[xenon]] and [[platinum hexafluoride]] leading to the first synthesis of a [[noble gas compound]], [[xenon hexafluoroplatinate]] (1962). 
*[[Robert Burns Woodward]] announces the total synthesis of [[Vitamin B-12]] by a team he led (1973). Insights from this work lead him and [[Roald Hoffmann]] to formulate the [[Woodward–Hoffmann rules]] for elucidating the [[stereochemistry]] of the products of organic reactions. 
*[[Frederick Sanger]] demonstrates the dideoxy- or [[chain termination method]] for determining DNA sequences (1975). 
*[[Kary Mullis]] demonstrates the [[polymerase chain reaction]], a method for amplifying specific bits of DNA (1983).

==Economics and political science==
* The experiments of [[Muhammad Yunus]] on the applications of [[microcredit]] and [[microfinance]] in rural [[Bangladesh]] (1971)
* [[Robert Axelrod (political scientist)|Robert Axelrod]]'s [[prisoner's dilemma]] computer tournaments, later documented in ''[[The Evolution of Cooperation]]'' (1984)

==Geology==
*[[Charles Mason]] conducts an experiment near the Scottish mountain of [[Schiehallion]] that attempts to measure the mean density of the Earth for the first time. Known as the [[Schiehallion experiment]] (1774)

==Physics==
{{Main|List of experiments in physics}}
*Inclined plane experiment (1602–07): [[Galileo Galilei]] uses rolling balls to disprove the [[Aristotelian physics|Aristotelian theory of motion]].
* [[Blaise Pascal#First atmospheric pressure vs. altitude experiment|Atmospheric pressure vs. altitude experiment]] (1648): [[Blaise Pascal]] carries a [[barometer]] up a church tower and a mountain to determine that atmospheric pressure is due to a column of air.
*[[Magdeburg hemispheres]] (1654): [[Otto von Guericke]] demonstrates atmospheric pressure using a pair of hollow copper hemisphere.
*Spring of air experiment (1660): [[Robert Boyle]] shows that the volume of a given amount of gas is inversely related to the pressure upon it.
<!--*[[Isaac Newton]] [[dispersion (optics)|decomposes]] sunlight with a [[triangular prism (optics)|prism]]. -->
*[[Kite experiment]] (1700s): [[Benjamin Franklin]] beginning in 1747 describes experiments in letters to [[Peter Collinson (botanist)|Peter Collinson]] demonstrating electrical principles which were published in a book called [[Experiments and Observations on Electricity]].
*[[Voltaic pile]] (1796): [[Alessandro Volta]] constructs a new source of electricity, the [[electrical battery]].
*[[Cavendish experiment]] (1798): [[Henry Cavendish]]'s torsion bar experiment measures the force of gravity in a laboratory.
*[[Double-slit experiment]] (c.1805): [[Thomas Young (scientist)|Thomas Young]] shows that light is a wave in his double-slit experiment. 
*[[Arago spot]] (1819): Observation of circular diffraction by [[François Arago]], validated a new [[wave theory of light]] by [[Augustin-Jean Fresnel]] disproving skeptics like [[Siméon Denis Poisson]].
*Ørsted experiment (1820): [[Hans Christian Ørsted]] demonstrates the connection of [[electricity]] and [[magnetism]] by experiments involving a [[compass]] and [[electric circuit]]s.
*Discovery of electromagnetic induction (1831): [[Michael Faraday]] discovers [[Electromagnetic induction|magnetic induction]] in an experiment with a closed ring of soft iron, with two windings of wire.
*Joule's experiment (1834):[[James Prescott Joule]] demonstrates the [[mechanical equivalent of heat]], an important step in the development of [[thermodynamics]].
*Doppler experiment (1845): [[Christian Doppler]] arranges to have trumpets played from a passing [[train]]. The ground-observed pitch was higher than that played when the train was approaching then lower than that played as the train passed and moved away, demonstrating the [[Doppler effect]].
*[[Foucault pendulum]] (1851): [[Léon Foucault]]'s creates a pendulum to demonstrate the [[Coriolis effect]] and the rotation of the Earth.
*[[Michelson–Morley experiment]] (1887): exposes weaknesses of the prevailing variant of the theory of [[luminiferous aether]].
*Hertz wireless experiments (1887): [[Heinrich Hertz]] demonstrates [[free space]] [[electromagnetic waves]], predicted by [[Maxwell's equations]], with a simple [[dipole antenna]] and spark gap [[oscillator]].
*Thomson's experiments with [[Cathode ray|cathode rays]] (1897): [[J. J. Thomson|J. J. Thomson's]] cathode ray tube experiments (discovers the [[electron]] and its negative charge).
*[[Eötvös experiment]] (1909): [[Loránd Eötvös]] publishes the result of the second series of experiments, clearly demonstrating that inertial and gravitational mass are one and the same. 
*[[Oil-drop experiment]] (1909): [[Robert Millikan]] demonstrates that [[electric charge]] occurs as ''[[quantum|quanta]]'' (whole units).
*[[Geiger–Marsden experiments]] (1911): [[Ernest Rutherford]]'s gold foil experiment demonstrated that the positive charge and mass of an atom is concentrated in a small, central [[atomic nucleus]], disproving the then-popular [[plum pudding model]] of the [[atom]].
[[Image:1919 eclipse negative.jpg|right|200px|thumb|Plate produced by [[Arthur Eddington]] of the [[Solar eclipse of May 29, 1919|1919 eclipse]].]]
*[[Eddington experiment]] (1919): [[Arthur Eddington]] leads an expedition to the island of [[São Tomé and Príncipe|Principe]] to observe a total solar eclipse ([[gravitational lens]]ing). This allows for an observation of the bending of starlight under gravity, a prediction of [[Albert Einstein]]'s [[theory of relativity]]. It was confirmed (although it was later shown that the margin of error was as great as the observed bending).
*[[Stern–Gerlach experiment]] (1920): [[Otto Stern]] and [[Walther Gerlach]] demonstrates particle [[Spin (physics)|spin]].
*<!--*[[The Manhattan Project]] A team of scientists led by [[J. Robert Oppenheimer]] developed the [[atomic bomb]] in New Mexico. (1945)-->[[Chicago Pile-1]] (1942): [[Enrico Fermi]] and [[Leó Szilárd]] build the first critical nuclear reactor (1942)
*[[Wu experiment]] (1956): [[Chien-Shiung Wu]] leads the team that disproves the conservation of [[parity (physics)|parity]] in particle physics.
*[[Cowan–Reines neutrino experiment]] (1955): [[Clyde L. Cowan]] and [[Frederick Reines]] confirm the existence of the [[neutrino]].
*[[Hafele-Keating experiment]] (1971): [[Joseph C. Hafele]] and [[Richard E. Keating]] show that [[atomic clock]]s flown around the world exhibit differences which are consistent with the predictions of special and general relativity.
*[[Scout rocket experiment]] (1976): confirms the [[time dilation]] effect of [[gravity]]. 
*[[Aspect's experiment]]L [[Alain Aspect]] demonstrates the violation of [[Bell inequalities]] in [[quantum entanglement]] in the 1980s.

==Psychology==
[[Image:One of Pavlov's dogs.jpg|thumb|250px|right|One of Pavlov's dogs with a surgically implanted [[cannula]] to measure [[saliva]]tion, Pavlov Museum, 2005]]
* [[Ivan Pavlov]]'s experiments with dogs and [[classical conditioning]] (1900s)
* [[John B. Watson]] and [[Rosalie Rayner]] conduct the [[Little Albert experiment]] showing evidence of [[classical conditioning]] (1920)
* The [[Asch conformity experiments]] shows how group pressure can persuade an individual to conform to an obviously wrong opinion (1951)
* [[B. F. Skinner]]'s demonstrations of [[operant conditioning]] (1930s–1960s)
* [[Harry Harlow]]'s experiments with baby monkeys and wire and cloth surrogate mothers (1957–1974)
* [[Stanley Milgram]]'s [[Milgram experiment|experiments on human obedience]] (1963)
* [[Walter Mischel]]'s [[Stanford marshmallow experiment|marshmallow experiment]] showing the importance to life outcomes of the ability to delay gratification (beginning late 1960s)
* [[Philip Zimbardo]]'s [[Stanford prison experiment]] (1971)
* [[Allan Gardner|Allan]] and [[Beatrix Gardner]]'s attempts to teach [[American Sign Language]] to the [[Common chimpanzee|chimpanzee]] [[Washoe (chimpanzee)|Washoe]] (1970s)
* [[Martin Seligman]] studies [[learned helplessness]] in dogs (1970s)
* [[Rosenhan experiment]] (1972). It involved the use of healthy associates or "pseudopatients", who briefly simulated auditory hallucinations in an attempt to gain admission to 12 different psychiatric hospitals. The hospital staff failed to detect a single pseudopatient. The study is considered an important and influential criticism of psychiatric diagnosis.
* [[Kansas City preventive patrol experiment]] (1972–1973) It was designed to test the assumption that the presence (or potential presence) of police officers in marked cars reduced the likelihood of a crime being committed. No relationship was found.
* [[Elizabeth Loftus]]' and [[John C. Palmer]]'s car crash experiment shows that [[leading question]]s can produce [[False memory|false memories]] (1974)
* [[Benjamin Libet]]'s experiment on free will shows that a readiness potential appears before the notion of doing the task enters conscious experience, sparking debate about the illusory nature of free will yet again. (1983)
* [[Vilayanur S. Ramachandran]]'s experiment on phantom limbs with the Mirror Box throw light on the nature of 'learned paralysis' (1998)

==See also==
*[[List of thought experiments]]
*[[Timeline of scientific experiments]]

==References==
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{{histOfScience}}

{{Portal|Science}}

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