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List of experiments
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<h2 id="astronomy">Astronomy</h2> <ul><li><a href="/facts/Ole_R%C3%B8mer/1lqXzA7F">Ole Rømer</a> makes the first quantitative estimate of the <a href="/facts/R%C3%B8mer%27s_determination_of_the_speed_of_light/44UvclHw">speed of light</a> in 1676 by timing the motions of Jupiter's satellite <a href="/facts/Io_(moon)/p3Uc8FmK">Io</a> with a telescope</li> <li><a href="/facts/Arno_Penzias/MEautAvP">Arno Penzias</a> and <a href="/facts/Robert_Woodrow_Wilson/CsmuvVqa">Robert Wilson</a> detect the <a href="/facts/Cosmic_microwave_background_radiation/ThB2HkLS">cosmic microwave background radiation</a>, giving support to the theory of the <a href="/facts/Big_Bang/I5T1vTnv">Big Bang</a> (1964)</li> <li><a href="/facts/Kerim_Kerimov/oxTN7K34">Kerim Kerimov</a> launches <a href="/facts/Kosmos_186_and_Kosmos_188/9Dn4IBE3">Kosmos 186 and Kosmos 188</a> as experiments on automatic docking eventually leading to the development of <a href="/facts/Space_station/2HtaLbDH">space stations</a> (1967)</li> <li>The <a href="/facts/Supernova_Cosmology_Project/PynmISN4">Supernova Cosmology Project</a> and the <a href="/facts/High-Z_Supernova_Search_Team/EH0509m1">High-Z Supernova Search Team</a> discover, by observing <a href="/facts/Type_Ia_supernova/W4rEFuDK">Type Ia supernovae</a>, that the <a href="/facts/Dark_energy/6bWIYewA">expansion of the Universe is accelerating</a> (1998)</li> <li><a href="/facts/Galileo_Galilei/98VT2z3v">Galileo Galilei</a> uses a <a href="/facts/Telescope/BDwYahhR">telescope</a> to observe that the <a href="/facts/Galilean_moons/aN6tLUFc">moons of Jupiter</a> appear to circle <a href="/facts/Jupiter/95m7XjMT">Jupiter</a>. This evidence supports the <a href="/facts/Heliocentric_model/4hoCMs7P">heliocentric model</a>, and weakens the <a href="/facts/Geocentric_model/yIc6na3w">geocentric model</a> of the cosmos (1609)</li></ul> <h2 id="biology">Biology</h2> <ul><li><a href="/facts/Robert_Hooke/T5sEElp5">Robert Hooke</a>, using a <a href="/facts/Microscope/ldJp0CI3">microscope</a>, observes <a href="/facts/Cell_(biology)/bLM9UQvy">cells</a> (1665).</li> <li><a href="/facts/Anton_van_Leeuwenhoek/HQ9dH9oo">Anton van Leeuwenhoek</a> discovers <a href="/facts/Microorganism/pysJYcE2">microorganisms</a> (1674–1676).</li> <li><a href="/facts/James_Lind/MHR0RTV8">James Lind</a>, 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).</li> <li><a href="/facts/Edward_Jenner/sXRNEXef">Edward Jenner</a> tests his hypothesis for the protective action of mild cowpox infection for <a href="/facts/Smallpox/cxNeetP4">smallpox</a>, the first <a href="/facts/Vaccine/QcXzLug2">vaccine</a> (1796).</li> <li><a href="/facts/Gregor_Mendel/4UpILWAz">Gregor Mendel</a>'s experiments with the garden <a href="/facts/Pea/hlndxpId">pea</a> led him to surmise many of the fundamental laws of genetics (<a href="/facts/Dominant_gene/DsvtPyQU">dominant</a> vs <a href="/facts/Recessive_gene/DsvtPyQU">recessive</a> genes, the 1–2–1 ratio, see <a href="/facts/Mendelian_inheritance/v2038wkl">Mendelian inheritance</a>) (1856–1863).</li> <li><a href="/facts/Charles_Darwin/uwDLGItY">Charles Darwin</a> demonstrates <a href="/facts/Evolution/Hj0qAaBk">evolution</a> by <a href="/facts/Natural_selection/JXTte6en">natural selection</a> using many examples (1859).</li> <li><a href="/facts/Louis_Pasteur/lboGfpy0">Louis Pasteur</a> uses S-shaped flasks to prevent <a href="/facts/Spore/6qDRdcrs">spores</a> from contaminating broth. This disproves the theory of <a href="/facts/Spontaneous_generation/bUVSjNam">Spontaneous generation</a> (1861) extending the rancid meat experiment of <a href="/facts/Francesco_Redi/x1q0Hmzh">Francesco Redi</a> (1668) to the micro scale.</li> <li><a href="/facts/Charles_Darwin/uwDLGItY">Charles Darwin</a> and his son <a href="/facts/Francis_Darwin/VFqzEWPF">Francis</a>, using dark-grown oat seedlings, discover the stimulus for <a href="/facts/Phototropism/9InRzq65">phototropism</a> is detected at the tip of the shoot (the <a href="/facts/Coleoptile/GgjUeHGs">coleoptile</a> tip), but the bending takes place in the region below the tip (1880).</li> <li><a href="/facts/Emil_von_Behring/bk06nMKy">Emil von Behring</a> and <a href="/facts/Kitasato_Shibasabur%C5%8D/LeC09mc1">Kitasato Shibasaburō</a> demonstrate <a href="/facts/Passive_immunity/9uQCBcXG">passive immunity</a>, protection of animals from infection by injection of <a href="/facts/Immune_serum/zt7McfLV">immune serum</a> (1890).</li> <li><a href="/facts/Thomas_Hunt_Morgan/4wswVmWC">Thomas Hunt Morgan</a> identifies a <a href="/facts/Sex_chromosome/PGYGkTQM">sex chromosome</a> linked <a href="/facts/Gene/e1swwPY6">gene</a> in <i><a href="/facts/Drosophila_melanogaster/KtnHVCcB">Drosophila melanogaster</a></i> (1910) and his student <a href="/facts/Alfred_Sturtevant/bWQEUkoI">Alfred Sturtevant</a> develops the first genetic map (1913).</li> <li><a href="/facts/Alexander_Fleming/qvMjfNVA">Alexander Fleming</a> demonstrates that the zone of inhibition around a growth of <a href="/facts/Penicillin/Abo8VQ3p">penicillin</a> mould on a culture dish of bacteria is caused by a diffusible substance secreted by the mould (1928).</li> <li><a href="/facts/Frederick_Griffith/96eJ7d7a">Frederick Griffith</a> demonstrates (<a href="/facts/Griffith%27s_experiment/RwWbSCTD">Griffith's experiment</a>) that living cells can be transformed via a <a href="/facts/Transforming_principle/RwWbSCTD">transforming principle</a>, later discovered to be <a href="/facts/DNA/nB89Iauz">DNA</a> (1928).</li> <li><a href="/facts/Karl_von_Frisch/kSwtGGqw">Karl von Frisch</a> decodes the <a href="/facts/Waggle_dance/l9MbyoBG">waggle dance</a> <a href="/facts/Honey_bee/GetXQWM0">honey bees</a> use to communicate the location of flowers (1940).</li> <li><a href="/facts/George_Wells_Beadle/lqvgR2cm">George Wells Beadle</a> and <a href="/facts/Edward_Lawrie_Tatum/1XnD76Ab">Edward Lawrie Tatum</a> moot the "<a href="/facts/One_gene-one_enzyme_hypothesis/3sk6kwpb">one gene-one enzyme hypothesis</a>" based on induced mutations in bread mold <i><a href="/facts/Neurospora_crassa/zI0Ub5p6">Neurospora crassa</a></i> (1941).</li> <li><a href="/facts/Luria%E2%80%93Delbr%C3%BCck_experiment/H4F4lyH5">Luria–Delbrück experiment</a> demonstrates that in bacteria, beneficial mutations arise in the absence of selection, rather than being a response to selection (1943).</li> <li><a href="/facts/Barbara_McClintock/aupcEqKv">Barbara McClintock</a> breeds <a href="/facts/Maize/lJ6c5xMH">maize</a> plants for color, which leads to the discovery of transposable elements or <a href="/facts/Transposon/WbVMhuWR">jumping genes</a> (1944).</li> <li><a href="/facts/Linus_Pauling/cBNBzs5c">Linus Pauling</a> and colleagues show in "<a href="/facts/Sickle_Cell_Anemia,_a_Molecular_Disease/CdMA5gmH">Sickle Cell Anemia, a Molecular Disease</a>" that a human genetic disease, <a href="/facts/Sickle_cell_anemia/93LT7ATq">sickle cell anemia</a>, is caused by a molecular change in a specific protein, <a href="/facts/Hemoglobin/RsD1MzYA">hemoglobin</a> (1949).</li> <li><a href="/facts/Hershey%E2%80%93Chase_experiment/kJJpIHIE">Hershey–Chase experiment</a> (by <a href="/facts/Alfred_Hershey/lAEvkfBe">Alfred Hershey</a> and <a href="/facts/Martha_Chase/DxNpGKp8">Martha Chase</a>) uses <a href="/facts/Bacteriophage/L2Ll0T3q">bacteriophage</a> to prove that <a href="/facts/DNA/nB89Iauz">DNA</a> is the hereditary material (1952).</li> <li><a href="/facts/Meselson%E2%80%93Stahl_experiment/IU98afWx">Meselson–Stahl experiment</a> proves that <a href="/facts/DNA_replication/wrU6RuR3">DNA replication</a> is <a href="/facts/Semiconservative_replication/rJJAglA3">semiconservative</a> (1958).</li> <li><a href="/facts/Crick,_Brenner_et_al._experiment/561c1zTM">Crick, Brenner et al. experiment</a> using frameshift mutations to support the triplet nature of the genetic code (1961).</li> <li><a href="/facts/Nirenberg_and_Matthaei_experiment/YsS7Befh">Nirenberg and Matthaei experiment</a> demonstrating <i>in vitro</i> <a href="/facts/Protein/Jxmagu3E">protein</a> synthesis using synthetic RNA as to substitute for <a href="/facts/MRNA/oUL6qxQn">messenger RNA</a> (1961).</li> <li><a href="/facts/John_Gurdon/ahY231IR">John Gurdon</a> <a href="/facts/Cloning/Vb6SM4c7">clones</a> an animal, a <a href="/facts/Frog/IxYhbeda">frog</a> tadpole, from an <a href="/facts/Ovum/gJyW3W3W">egg cell</a> using the nucleus from an <a href="/facts/Intestine/nK2zwqBS">intestinal</a> cell (1962).</li> <li><a href="/facts/Roger_W._Sperry/u6bduW2R">Roger W. Sperry</a> shows the potential independence of the two sides of the human brain using <i>split-brain</i> patients (1962–1965).</li> <li><a href="/facts/Nirenberg_and_Leder_experiment/0PdyVPty">Nirenberg and Leder experiment</a>, binding <a href="/facts/TRNA/pR9T5XSl">tRNA</a> to ribosomes with synthetic RNA to decipher the genetic code (1964).</li> <li>Demonstration of the role of <a href="/facts/Reverse_transcriptase/Vc1lGk8P">reverse transcriptases</a> in tumor <a href="/facts/Virus/mf88Bcbl">viruses</a>, independently by <a href="/facts/Howard_Temin/DbRNLnl2">Howard Temin</a> and <a href="/facts/David_Baltimore/aWvjhsDv">David Baltimore</a>, 1970.</li> <li><a href="/facts/Herbert_Boyer/l01hVY8x">Herbert Boyer</a> and <a href="/facts/Stanley_Cohen_(biochemist)/cdMoov8t">Stanley Cohen</a> selectively clone genes in bacteria, using bacterial plasmids cut by specific endonucleases (1975).</li> <li><a href="/facts/Mary-Dell_Chilton/Ln561wGE">Mary-Dell Chilton</a> shows that crown gall tumors of plants are caused by the transfer of a small piece of DNA from the bacterium <i><a href="/facts/Agrobacterium_tumefaciens/aN1LUWQY">Agrobacterium tumefaciens</a></i> into the host plant, where it becomes part of its genome (1977).</li> <li>Napoli, Lemieux and Jorgensen discover the principle of <a href="/facts/RNA_interference/oJRWBXJH">RNA interference</a> (1990).</li></ul> <h2 id="chemistry">Chemistry</h2> <ul><li><a href="/facts/Robert_Boyle/6tUs448C">Robert Boyle</a> uses an <a href="/facts/Air_pump/SMuF9abx">air pump</a> to determine the inverse relationship between the <a href="/facts/Pressure/eyc37GRG">pressure</a> and <a href="/facts/Volume/aeAXCBUd">volume</a> of a <a href="/facts/Gas/hVVAoodV">gas</a>. This relationship came to be known as <a href="/facts/Boyle%27s_law/EuguIP5A">Boyle's law</a> (1660–1662).</li> <li><a href="/facts/Joseph_Priestley/hQGV26wA">Joseph Priestley</a> suspends a bowl of water above a beer vat at a brewery and synthesizes <a href="/facts/Carbonated_water/ng6yNLsq">carbonated water</a> (1767).</li> <li><a href="/facts/Antoine_Lavoisier/UheVQrhu">Antoine Lavoisier</a> determines that <a href="/facts/Oxygen/acyn6o8r">oxygen</a> combines with materials upon <a href="/facts/Combustion/ohQoWj8z">combustion</a>, thus disproving <a href="/facts/Phlogiston_theory/6PDveBmv">phlogiston theory</a> (1783).</li> <li><a href="/facts/Antoine_Lavoisier/UheVQrhu">Antoine Lavoisier</a> determines that <a href="/facts/Chemical_reactions/GpqWlKrz">chemical reactions</a> in a closed container do not alter total mass. From these observations he establishes the law of <a href="/facts/Conservation_of_mass/fRu05SS1">conservation of mass</a> (1789).</li> <li><a href="/facts/Benjamin_Thompson/bgCKB0C1">Benjamin Thompson, Count Rumford</a> demonstrates that the <a href="/facts/An_Experimental_Enquiry_Concerning_the_Source_of_the_Heat_which_is_Excited_by_Friction/9Xtgss18">heat developed by the friction of boring cannon</a> is nearly inexhaustible. This result was presented in opposition to <a href="/facts/Caloric_theory/getpJK96">caloric theory</a> (1798).</li> <li><a href="/facts/Humphry_Davy/aDNRfNou">Humphry Davy</a> uses <a href="/facts/Electrolysis/pU75nCDI">electrolysis</a> to isolate elemental <a href="/facts/Potassium/FWPwS7Rj">potassium</a>, <a href="/facts/Sodium/eYuSPu2V">sodium</a>, <a href="/facts/Calcium/hf252CC0">calcium</a>, <a href="/facts/Strontium/ABaA5qQK">strontium</a>, <a href="/facts/Barium/IkL09XHQ">barium</a>, <a href="/facts/Magnesium/XyIhd2FG">magnesium</a>, and <a href="/facts/Chlorine/y27UwYBM">chlorine</a> (1807–1810).</li> <li><a href="/facts/Joseph_Louis_Gay-Lussac/co1Ne63y">Joseph Louis Gay-Lussac</a> studies reactions among gases and determines that their volumes combine chemically in simple integer ratios (1809).</li> <li><a href="/facts/Robert_Brown_(Scottish_botanist_from_Montrose)/Yf68N7tb">Robert Brown</a> studies very small particles in water under the microscope and observes <a href="/facts/Brownian_motion/Th0g0wkr">Brownian motion</a> which was later named in his honor (1827).</li> <li><a href="/facts/Friedrich_W%C3%B6hler/D7uh7ySD">Friedrich Wöhler</a> <a href="/facts/W%C3%B6hler_synthesis/RbaT7wh9">synthesizes</a> the <a href="/facts/Organic_compound/gqCNaN45">organic compound</a> <a href="/facts/Urea/6j84AoCG">urea</a> using <a href="/facts/Inorganic_compound/TfFfzxSz">inorganic reactants</a>, disproving the application of <a href="/facts/Vitalism/wYrVvfUf">vitalism</a> to chemical processes (1828).</li> <li><a href="/facts/Thomas_Graham_(chemist)/RQhhKdCs">Thomas Graham</a> measures the rates of <a href="/facts/Effusion/2mTFdQau">effusion</a> for different gases and establishes <a href="/facts/Graham%27s_law/h7tpRVEH">Graham's law</a> of effusion and <a href="/facts/Diffusion/KbAxroBa">diffusion</a> (1833).</li> <li><a href="/facts/Julius_Robert_von_Mayer/jt3kXTpy">Julius Robert von Mayer</a> and <a href="/facts/James_Prescott_Joule/uzfj0eSG">James Prescott Joule</a> measure the <a href="/facts/Mechanical_equivalent_of_heat/I3cdvl5h">heat generated by mechanical work</a>. This establishes the principle of <a href="/facts/Conservation_of_energy/12CdN4Ik">conservation of energy</a> and the <a href="/facts/Kinematics/o7mSyeJA">kinetic theory</a> of heat (1842–1843).</li> <li><a href="/facts/Louis_Pasteur/lboGfpy0">Louis Pasteur</a> separates a <a href="/facts/Racemic/STEagtrD">racemic</a> mixture of two <a href="/facts/Enantiomers/wjPv5J3y">enantiomers</a> by sorting individual <a href="/facts/Crystals/e2R2mk3E">crystals</a>, and demonstrates their impact on the <a href="/facts/Polarization_of_light/fP33m0eD">polarization of light</a> (1849).</li> <li><a href="/facts/Anders_Jonas_%C3%85ngstr%C3%B6m/y1QnJFy6">Anders Jonas Ångström</a> observes the presence of <a href="/facts/Hydrogen/BoYHjl0J">hydrogen</a> and other elements in the <a href="/facts/Spectrum/wPUjkpqI">spectrum</a> of the sun (1862).</li> <li><a href="/facts/Fran%C3%A7ois-Marie_Raoult/GRVRW4tr">François-Marie Raoult</a> demonstrates that the decrease in the <a href="/facts/Vapor_pressure/whrEr96T">vapor pressure</a> and <a href="/facts/Freezing-point_depression/B5fSARUv">freezing point</a> of liquids caused by the addition of solutes is proportional to the number of solute molecules present. This establishes the concept of <a href="/facts/Colligative_properties/8LEPNRpn">colligative properties</a> (1878).</li> <li><a href="/facts/Svante_Arrhenius/S2rlyzYr">Svante Arrhenius</a> studies the <a href="/facts/Electrical_conductivity/akyCKvMy">conductivity</a> of <a href="/facts/Salt_(chemistry)/lsSKwGpn">salt</a> solutions and determines that salts <a href="/facts/Dissociate/gDRGdeSN">dissociate</a> into <a href="/facts/Ions/wrbwhF3z">ions</a> in water (1884).</li> <li><a href="/facts/Svante_Arrhenius/S2rlyzYr">Svante Arrhenius</a> determines the impact of temperature on <a href="/facts/Reaction_rates/Prwvxq0y">reaction rates</a> and formulates the concept of <a href="/facts/Activation_energy/GqkgPvo0">activation energy</a> (1889).</li> <li><a href="/facts/William_Ramsay/fGzWlHlP">William Ramsay</a> and <a href="/facts/John_Strutt,_3rd_Baron_Rayleigh/HcJyYdk5">Lord Rayleigh (John Strutt)</a> isolate the <a href="/facts/Noble_gases/j0yHMEAE">noble gases</a> (1894–1898).</li> <li><a href="/facts/Henri_Becquerel/wN7DSsVL">Henri Becquerel</a>, <a href="/facts/Marie_Curie/EGjeuJ14">Marie Curie</a>, and <a href="/facts/Pierre_Curie/Sbtlw2xj">Pierre Curie</a> discover <a href="/facts/Radioactivity/Ya6FVjt4">radioactivity</a> and describe its properties (1896).</li> <li><a href="/facts/Mikhail_Tsvet/Hm4oIlCT">Mikhail Tsvet</a> (Mikhail Semyonovich Tsvet) separates <a href="/facts/Chlorophyll/1Sb0NyyM">chlorophyll</a> from other plant pigments using <a href="/facts/Chromatography/2FrvPjNV">chromatography</a> (1901).</li> <li><a href="/facts/Frederick_Soddy/gR9Qk6tc">Frederick Soddy</a> and <a href="/facts/William_Ramsay/fGzWlHlP">William Ramsay</a> observe the production of <a href="/facts/Helium/yRul93TG">helium</a> from <a href="/facts/Alpha_particles/dzNMs9WP">alpha particles</a> during <a href="/facts/Radioactive_decay/Ya6FVjt4">radioactive decay</a> (1903).</li> <li><a href="/facts/Ernest_Rutherford/hjjMEskl">Ernest Rutherford</a> discovers that atoms have a very small positively charged nucleus in the gold-foil experiment, also known as the <a href="/facts/Geiger%E2%80%93Marsden_experiment/cmgI1Ha9">Geiger–Marsden experiment</a> (1909).</li> <li><a href="/facts/Otto_Hahn/7alx1Db7">Otto Hahn</a> discovers <a href="/facts/Nuclear_isomerism/L8DHcqnk">nuclear isomerism</a> (1921).</li> <li><a href="/facts/Albert_Szent-Gy%C3%B6rgyi/DTBenFpC">Albert Szent-Györgyi</a> and <a href="/facts/Hans_Adolf_Krebs/85r0QSC8">Hans Adolf Krebs</a> discover the <a href="/facts/Citric_acid_cycle/EGJL9NXP">citric acid cycle</a> of <a href="/facts/Oxidative_metabolism/kb6gpsvL">oxidative metabolism</a> (1935-1937).</li> <li><a href="/facts/Otto_Hahn/7alx1Db7">Otto Hahn</a> and <a href="/facts/Fritz_Strassmann/UJLrswVu">Fritz Strassmann</a> discover the <a href="/facts/Nuclear_fission/LfkIylvm">nuclear fission</a> of uranium (1938).</li> <li><a href="/facts/Glenn_Theodore_Seaborg/w1a3mume">Glenn Theodore Seaborg</a> and colleagues create and isolate five <a href="/facts/Transuranium_elements/a12PwdAw">transuranium elements</a>. They reorganize the <a href="/facts/Periodic_table/umdGIfUb">periodic table</a> to its current form. (1941–1950).</li> <li><a href="/facts/Miller%E2%80%93Urey_experiment/SYTLzGJu">Miller–Urey experiment</a> demonstrates that <a href="/facts/Organic_compound/gqCNaN45">organic compounds</a> can arise spontaneously from <a href="/facts/Inorganic_compound/TfFfzxSz">inorganic ones</a> (1953).</li> <li><a href="/facts/Melvin_Calvin/2PnPFS1n">Melvin Calvin</a> and <a href="/facts/Andrew_Benson/4VsKBAud">Andrew Benson</a> delineate the path of carbon in <a href="/facts/Photosynthesis/TMV7w693">photosynthesis</a> using <i><a href="/facts/Chlorella/rgLhG9DI">Chlorella</a></i> and <a href="/facts/Carbon_dioxide/xGzpppEp">carbon dioxide</a> labeled with <a href="/facts/Carbon-14/Ut8SBNNa">carbon-14</a> (14CO2) (1945–1954).</li> <li><a href="/facts/Erwin_Chargaff/fc55NAAv">Erwin Chargaff</a> disproves the "tetranucleoide theory" of <a href="/facts/DNA/nB89Iauz">DNA</a> structure and determines that the composition of double-stranded DNA follows the rule, %A = %T and %G = %C (<a href="/facts/Chargaff%27s_rule/lTk2B87f">Chargaff's rule</a>). This discovery was critical to the formulation of the Watson-Crick Model of DNA structure.</li> <li><a href="/facts/Neil_Bartlett_(chemist)/l9jReu2S">Neil Bartlett</a> mixes <a href="/facts/Xenon/9E3XR69R">xenon</a> and <a href="/facts/Platinum_hexafluoride/Nqqdd4Xc">platinum hexafluoride</a> leading to the first synthesis of a <a href="/facts/Noble_gas_compound/vkIWeVeF">noble gas compound</a>, <a href="/facts/Xenon_hexafluoroplatinate/RtRHxpjp">xenon hexafluoroplatinate</a> (1962).</li> <li><a href="/facts/Robert_Burns_Woodward/bAQeInCb">Robert Burns Woodward</a> announces the total synthesis of <a href="/facts/Vitamin_B-12/vCk613gD">Vitamin B-12</a> by a team he led (1973). Insights from this work lead him and <a href="/facts/Roald_Hoffmann/DHMcXIff">Roald Hoffmann</a> to formulate the <a href="/facts/Woodward%E2%80%93Hoffmann_rules/4tW2tBIF">Woodward–Hoffmann rules</a> for elucidating the <a href="/facts/Stereochemistry/XkcRVNwd">stereochemistry</a> of the products of organic reactions.</li> <li><a href="/facts/Frederick_Sanger/M460rBQg">Frederick Sanger</a> demonstrates the dideoxy- or <a href="/facts/Chain_termination_method/PzqMpaaM">chain termination method</a> for determining DNA sequences (1975).</li> <li><a href="/facts/Kary_Mullis/Ad33QwQe">Kary Mullis</a> demonstrates the <a href="/facts/Polymerase_chain_reaction/G0jWzJy1">polymerase chain reaction</a>, a method for amplifying specific bits of DNA (1983).</li></ul> <h2 id="economics-and-political-science">Economics and political science</h2> <ul><li>The experiments of <a href="/facts/Muhammad_Yunus/e496WHh8">Muhammad Yunus</a> on the applications of <a href="/facts/Microcredit/SHwNL2lM">microcredit</a> and <a href="/facts/Microfinance/AfzqeeLR">microfinance</a> in rural <a href="/facts/Bangladesh/NXk4f78Y">Bangladesh</a> (1971)</li> <li><a href="/facts/Robert_Axelrod_(political_scientist)/uooPMXYe">Robert Axelrod</a>'s <a href="/facts/Prisoner%27s_dilemma/44kueSBQ">prisoner's dilemma</a> computer tournaments, later documented in <i><a href="/facts/The_Evolution_of_Cooperation/AhlMIaa5">The Evolution of Cooperation</a></i> (1984)</li></ul> <h2 id="geology">Geology</h2> <ul><li><a href="/facts/Charles_Mason/XNXmN29l">Charles Mason</a> conducts an experiment near the Scottish mountain of <a href="/facts/Schiehallion/fjjWHhhc">Schiehallion</a> that attempts to measure the mean density of the Earth for the first time. Known as the <a href="/facts/Schiehallion_experiment/bfRhkYgX">Schiehallion experiment</a> (1774)</li></ul> <h2 id="physics">Physics</h2> <p class="note">Main article: <a href="/facts/List_of_experiments_in_physics/7S2nxMUK">List of experiments in physics</a></p> <ul><li>Inclined plane experiment (1602–07): <a href="/facts/Galileo_Galilei/98VT2z3v">Galileo Galilei</a> uses rolling balls to disprove the <a href="/facts/Aristotelian_physics/1EpHTb2Q">Aristotelian theory of motion</a>.</li> <li><a href="/facts/Blaise_Pascal/Huy5LenL">Atmospheric pressure vs. altitude experiment</a> (1648): <a href="/facts/Blaise_Pascal/Huy5LenL">Blaise Pascal</a> carries a <a href="/facts/Barometer/M8VQc69q">barometer</a> up a church tower and a mountain to determine that atmospheric pressure is due to a column of air.</li> <li><a href="/facts/Magdeburg_hemispheres/lyeQhq5s">Magdeburg hemispheres</a> (1654): <a href="/facts/Otto_von_Guericke/0cFxQxbB">Otto von Guericke</a> demonstrates atmospheric pressure using a pair of hollow copper hemisphere.</li> <li>Spring of air experiment (1660): <a href="/facts/Robert_Boyle/6tUs448C">Robert Boyle</a> shows that the volume of a given amount of gas is inversely related to the pressure upon it.</li> <li><a href="/facts/Kite_experiment/0XrKoNH4">Kite experiment</a> (1700s): <a href="/facts/Benjamin_Franklin/Dmfv5URr">Benjamin Franklin</a> beginning in 1747 describes experiments in letters to <a href="/facts/Peter_Collinson_(botanist)/NNjbjVUr">Peter Collinson</a> demonstrating electrical principles which were published in a book called <a href="/facts/Experiments_and_Observations_on_Electricity/k7c1kIw9">Experiments and Observations on Electricity</a>.</li> <li><a href="/facts/Voltaic_pile/9KoUfqGE">Voltaic pile</a> (1796): <a href="/facts/Alessandro_Volta/W9rIYxmv">Alessandro Volta</a> constructs a new source of electricity, the <a href="/facts/Electrical_battery/bqEpm4ue">electrical battery</a>.</li> <li><a href="/facts/Cavendish_experiment/18j8qa8d">Cavendish experiment</a> (1798): <a href="/facts/Henry_Cavendish/UsIDwP3F">Henry Cavendish</a>'s torsion bar experiment measures the force of gravity in a laboratory.</li> <li><a href="/facts/Double-slit_experiment/TR8zwEcy">Double-slit experiment</a> (c.1805): <a href="/facts/Thomas_Young_(scientist)/X4RtR47L">Thomas Young</a> shows that light is a wave in his double-slit experiment.</li> <li><a href="/facts/Arago_spot/WbtkMvSN">Arago spot</a> (1819): Observation of circular diffraction by <a href="/facts/Fran%C3%A7ois_Arago/IATC1SNF">François Arago</a>, validated a new <a href="/facts/Wave_theory_of_light/jeofpMn4">wave theory of light</a> by <a href="/facts/Augustin-Jean_Fresnel/jb64tyGc">Augustin-Jean Fresnel</a> disproving skeptics like <a href="/facts/Sim%C3%A9on_Denis_Poisson/zmsDITrY">Siméon Denis Poisson</a>.</li> <li>Ørsted experiment (1820): <a href="/facts/Hans_Christian_%C3%98rsted/qjmmHgIy">Hans Christian Ørsted</a> demonstrates the connection of <a href="/facts/Electricity/hNC8D65W">electricity</a> and <a href="/facts/Magnetism/eo75vApl">magnetism</a> by experiments involving a <a href="/facts/Compass/86MaeFXu">compass</a> and <a href="/facts/Electric_circuit/zt94kTW0">electric circuits</a>.</li> <li>Discovery of electromagnetic induction (1831): <a href="/facts/Michael_Faraday/NDcc3lyt">Michael Faraday</a> discovers <a href="/facts/Electromagnetic_induction/T36JjtgY">magnetic induction</a> in an experiment with a closed ring of soft iron, with two windings of wire.</li> <li>Joule's experiment (1834):<a href="/facts/James_Prescott_Joule/uzfj0eSG">James Prescott Joule</a> demonstrates the <a href="/facts/Mechanical_equivalent_of_heat/I3cdvl5h">mechanical equivalent of heat</a>, an important step in the development of <a href="/facts/Thermodynamics/q4hIx3yP">thermodynamics</a>.</li> <li>Doppler experiment (1845): <a href="/facts/Christian_Doppler/RoyG6Qsn">Christian Doppler</a> arranges to have trumpets played from a passing <a href="/facts/Train/0mkFQDg9">train</a>. 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 <a href="/facts/Doppler_effect/bzrK1BKf">Doppler effect</a>.</li> <li><a href="/facts/Foucault_pendulum/IdB9XaGt">Foucault pendulum</a> (1851): <a href="/facts/L%C3%A9on_Foucault/xG7tEDjk">Léon Foucault</a>'s creates a pendulum to demonstrate the <a href="/facts/Coriolis_effect/SqCyUY6d">Coriolis effect</a> and the rotation of the Earth.</li> <li><a href="/facts/Michelson%E2%80%93Morley_experiment/yyrNEgA4">Michelson–Morley experiment</a> (1887): exposes weaknesses of the prevailing variant of the theory of <a href="/facts/Luminiferous_aether/UzRf78a2">luminiferous aether</a>.</li> <li>Hertz wireless experiments (1887): <a href="/facts/Heinrich_Hertz/sbL2MSpM">Heinrich Hertz</a> demonstrates <a href="/facts/Free_space/BTk3goyV">free space</a> <a href="/facts/Electromagnetic_waves/Ynx7ujCW">electromagnetic waves</a>, predicted by <a href="/facts/Maxwell%27s_equations/LfJ1drHS">Maxwell's equations</a>, with a simple <a href="/facts/Dipole_antenna/GYWgnX72">dipole antenna</a> and spark gap <a href="/facts/Oscillator/6vSrm84a">oscillator</a>.</li> <li>Thomson's experiments with <a href="/facts/Cathode_ray/9jRXSquS">cathode rays</a> (1897): <a href="/facts/J._J._Thomson/Y4jyndJF">J. J. Thomson's</a> cathode ray tube experiments (discovers the <a href="/facts/Electron/L0KBo5cW">electron</a> and its negative charge).</li> <li><a href="/facts/E%C3%B6tv%C3%B6s_experiment/0VADaCqR">Eötvös experiment</a> (1909): <a href="/facts/Lor%C3%A1nd_E%C3%B6tv%C3%B6s/CP0YgoTC">Loránd Eötvös</a> publishes the result of the second series of experiments, clearly demonstrating that inertial and gravitational mass are one and the same.</li> <li><a href="/facts/Oil-drop_experiment/C2BBYkKh">Oil-drop experiment</a> (1909): <a href="/facts/Robert_Millikan/rrWMCh2y">Robert Millikan</a> demonstrates that <a href="/facts/Electric_charge/xxsBfmlB">electric charge</a> occurs as <i><a href="/facts/Quantum/4x5QTxGB">quanta</a></i> (whole units).</li> <li><a href="/facts/Geiger%E2%80%93Marsden_experiments/cmgI1Ha9">Geiger–Marsden experiments</a> (1911): <a href="/facts/Ernest_Rutherford/hjjMEskl">Ernest Rutherford</a>'s gold foil experiment demonstrated that the positive charge and mass of an atom is concentrated in a small, central <a href="/facts/Atomic_nucleus/orpIm5Xl">atomic nucleus</a>, disproving the then-popular <a href="/facts/Plum_pudding_model/Bw7K1yXo">plum pudding model</a> of the <a href="/facts/Atom/FoQ4kGN5">atom</a>.</li></ul> <ul><li><a href="/facts/Eddington_experiment/e5tlPKWq">Eddington experiment</a> (1919): <a href="/facts/Arthur_Eddington/b0jPBaSA">Arthur Eddington</a> leads an expedition to the island of <a href="/facts/S%C3%A3o_Tom%C3%A9_and_Pr%C3%ADncipe/7EbNfgsJ">Principe</a> to observe a total solar eclipse (<a href="/facts/Gravitational_lens/LmxzvLs8">gravitational lensing</a>). This allows for an observation of the bending of starlight under gravity, a prediction of <a href="/facts/Albert_Einstein/CNTet8qu">Albert Einstein</a>'s <a href="/facts/Theory_of_relativity/qGHj3eTC">theory of relativity</a>. It was confirmed (although it was later shown that the margin of error was as great as the observed bending).</li> <li><a href="/facts/Stern%E2%80%93Gerlach_experiment/PCWPE56v">Stern–Gerlach experiment</a> (1920): <a href="/facts/Otto_Stern/9eP2K5rB">Otto Stern</a> and <a href="/facts/Walther_Gerlach/qEjsbn0c">Walther Gerlach</a> demonstrates particle <a href="/facts/Spin_(physics)/4Jvp7e8P">spin</a>.</li> <li><a href="/facts/Chicago_Pile-1/YCHuT9Mm">Chicago Pile-1</a> (1942): <a href="/facts/Enrico_Fermi/cmYcY15H">Enrico Fermi</a> and <a href="/facts/Le%C3%B3_Szil%C3%A1rd/VslvyPwI">Leó Szilárd</a> build the first critical nuclear reactor (1942)</li> <li><a href="/facts/Wu_experiment/rL9B4nQ1">Wu experiment</a> (1956): <a href="/facts/Chien-Shiung_Wu/ULvYEPgU">Chien-Shiung Wu</a> leads the team that disproves the conservation of <a href="/facts/Parity_(physics)/emSbJ4hD">parity</a> in particle physics.</li> <li><a href="/facts/Cowan%E2%80%93Reines_neutrino_experiment/2XaJzDRC">Cowan–Reines neutrino experiment</a> (1955): <a href="/facts/Clyde_L._Cowan/kdySD9zb">Clyde L. Cowan</a> and <a href="/facts/Frederick_Reines/sdWH4hNg">Frederick Reines</a> confirm the existence of the <a href="/facts/Neutrino/yGWVfSg2">neutrino</a>.</li> <li><a href="/facts/Hafele-Keating_experiment/Q5oAgc6W">Hafele-Keating experiment</a> (1971): <a href="/facts/Joseph_C._Hafele/mCbJUtf2">Joseph C. Hafele</a> and <a href="/facts/Richard_E._Keating/JumNW6Vy">Richard E. Keating</a> show that <a href="/facts/Atomic_clock/MF8nsXDR">atomic clocks</a> flown around the world exhibit differences which are consistent with the predictions of special and general relativity.</li> <li><a href="/facts/Scout_rocket_experiment/Iqd0T03B">Scout rocket experiment</a> (1976): confirms the <a href="/facts/Time_dilation/fYj7FYbK">time dilation</a> effect of <a href="/facts/Gravity/bqAN7DdQ">gravity</a>.</li> <li><a href="/facts/Aspect%27s_experiment/KxSjIhCn">Aspect's experiment</a>L <a href="/facts/Alain_Aspect/03n8MHjT">Alain Aspect</a> demonstrates the violation of <a href="/facts/Bell_inequalities/lg1V6kpk">Bell inequalities</a> in <a href="/facts/Quantum_entanglement/afzslwN0">quantum entanglement</a> in the 1980s.</li></ul> <h2 id="psychology">Psychology</h2> <ul><li><a href="/facts/Ivan_Pavlov/z0csSjkm">Ivan Pavlov</a>'s experiments with dogs and <a href="/facts/Classical_conditioning/ddtohoz3">classical conditioning</a> (1900s)</li> <li><a href="/facts/John_B._Watson/fqy4Q5ng">John B. Watson</a> and <a href="/facts/Rosalie_Rayner/BqhVcNe9">Rosalie Rayner</a> conduct the <a href="/facts/Little_Albert_experiment/sLE5jc35">Little Albert experiment</a> showing evidence of <a href="/facts/Classical_conditioning/ddtohoz3">classical conditioning</a> (1920)</li> <li>The <a href="/facts/Asch_conformity_experiments/0DWU6sET">Asch conformity experiments</a> shows how group pressure can persuade an individual to conform to an obviously wrong opinion (1951)</li> <li><a href="/facts/B._F._Skinner/cexUumu1">B. F. Skinner</a>'s demonstrations of <a href="/facts/Operant_conditioning/8TqfQQGq">operant conditioning</a> (1930s–1960s)</li> <li><a href="/facts/Harry_Harlow/F79dJgrP">Harry Harlow</a>'s experiments with baby monkeys and wire and cloth surrogate mothers (1957–1974)</li> <li><a href="/facts/Stanley_Milgram/F2dcafH0">Stanley Milgram</a>'s <a href="/facts/Milgram_experiment/c4HHnnKd">experiments on human obedience</a> (1963)</li> <li><a href="/facts/Walter_Mischel/ruffo7CT">Walter Mischel</a>'s <a href="/facts/Stanford_marshmallow_experiment/W4xqTWBg">marshmallow experiment</a> showing the importance to life outcomes of the ability to delay gratification (beginning late 1960s)</li> <li><a href="/facts/Philip_Zimbardo/laPJ7n66">Philip Zimbardo</a>'s <a href="/facts/Stanford_prison_experiment/8VKHGLq6">Stanford prison experiment</a> (1971)</li> <li>Allan and <a href="/facts/Beatrix_Gardner/cUYhvIJJ">Beatrix Gardner</a>'s attempts to teach <a href="/facts/American_Sign_Language/MGTCXaGb">American Sign Language</a> to the <a href="/facts/Common_chimpanzee/JXSpFsHy">chimpanzee</a> <a href="/facts/Washoe_(chimpanzee)/KmxY7sxr">Washoe</a> (1970s)</li> <li><a href="/facts/Martin_Seligman/bqMTHV4X">Martin Seligman</a> studies <a href="/facts/Learned_helplessness/m7obuyPx">learned helplessness</a> in dogs (1970s)</li> <li><a href="/facts/Rosenhan_experiment/YsrHCvH4">Rosenhan experiment</a> (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.</li> <li><a href="/facts/Kansas_City_preventive_patrol_experiment/BwxP9h3s">Kansas City preventive patrol experiment</a> (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.</li> <li><a href="/facts/Elizabeth_Loftus/TqhMCdUX">Elizabeth Loftus</a>' and John C. Palmer's car crash experiment shows that <a href="/facts/Leading_question/3KswLw4M">leading questions</a> can produce <a href="/facts/False_memory/8LrcKItt">false memories</a> (1974)</li> <li><a href="/facts/Benjamin_Libet/Q9o4lInW">Benjamin Libet</a>'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)</li> <li><a href="/facts/Vilayanur_S._Ramachandran/Jnd4MAk3">Vilayanur S. Ramachandran</a>'s experiment on phantom limbs with the Mirror Box throw light on the nature of 'learned paralysis' (1998)</li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/List_of_thought_experiments/GXlr0lz9">List of thought experiments</a></li> <li><a href="/facts/Timeline_of_scientific_experiments/WFu6NREM">Timeline of scientific experiments</a></li></ul> <ul> <li>Science portal</li></ul>