List of famous experiments
The following is a list of historically important scientific
experiments and observations.
See also:
timeline of scientific experiments,
list of famous discoveries,
thought experiment.
*
Eratosthenes measures the earth's circumference (
240 BC)
*
Galileo Galilei uses a
telescope to observe that the
moons of Jupiter appear to circle
Jupiter. This evidence supports the
heliocentric model, and weakens the
geocentric model of the cosmos (
1609)
*
Ole Rømer makes the first quantitative estimate of the
speed of light in
1676 by timing the motions of Jupiter's satellite
Io with a telescope
*
Arno Penzias and
Robert Wilson detect the
cosmic microwave background radiation, giving support to the theory of the
Big Bang (
1964)
* Researchers at the
Lawrence Berkeley National Laboratory in
California discover, by observing
Type 1a supernovae, that the
expansion of the Universe is accelerating (
1998)
*
Robert Hooke, using a
microscope, observes
cells (
1665)
*
Anton van Leeuwenhoek discovers
microorganisms (1674-1676)
*
James Lind, publishes 'A Treatise of the Scurvy' which describes a controlled ship board 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 lead him to surmise many of the fundamental laws of genetics (
dominant vs
recessive genes, the 1-2-1 ratio, see
Mendelian inheritance) (
1856-
1863)
*
Louis Pasteur uses S-shaped flasks to prevent
spores from contaminating broth. Disproves the theory of
Spontaneous generation (also known as
abiogenesis). (
1861) An extension of the rancid meat experiment of
Francesco Redi to the micro scale.
*
Charles Darwin and his son
Frances, 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).
*
Frederick Griffith demonstrates (
Griffith's experiment) that living cells can be transformed via a
transforming principle, later discovered to be
DNA (
1928)
*
Alexander Fleming demonstrates that the zone of inhibition around a growth of
Penicillium mold on a culture dish of bacteria is caused by a diffusable substance secreted by the mold. (1928)
*
Karl von Frisch decodes the "dance"
honeybees use to communicate the location of flowers (
1940)
*
George Wells Beadle and
Edward Lawrie Tatum prove the "one gene, one enzyme" hypothesis using induced mutations in bread mold,
Neurospora crassa (
1941)
*
Luria-Delbruck 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
jumping genes. (
1944)
*
Linus Pauling and colleagues show 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)
*
Miller-Urey experiment demonstrates that
organic compounds can arise spontaneously from
inorganic ones (
1953)
*
Meselson-Stahl experiment proves that
DNA replication is
semiconservative (
1958)
*
Crick, Brenner et al. experiment using frameshift mutations to support the triplet nature of the genetic code (
1961)
*
Nirenberg and Matthaei experiment with
in vitro protein synthesis using synthetic RNA as to substitute for
messenger RNA (
1961).
*
John Gurdon clones an animal, a
frog tadpole, from an
egg cell using the nucleus from an
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 transcriptases in tumor
viruses, independently by
Howard Temin and
David Baltimore,
1970*
Herbert Boyer and
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).
*
Kary Mullis demonstrates the
polymerase chain reaction, a method for amplifying specific bits of DNA (
1983).
* Napoli, Lemieux and Jorgensen discover
RNA interference (
1990)
*
Blaise Pascal caries a
barometer up a church tower and a mountain to determine that atmospheric pressure is due to a column of air (
1648).
*
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, Count Rumford demonstrates that the
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 studies very small partices in water under the microscope and observes
Brownian motion which was later named in his honor (
1827).
*
Friedrich Wöhler synthesizes the
organic compound urea using
inorganic reactants, disproving the application of
vitalism to chemical processes (
1828).
*
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
heat generated by mechanical work. This establishes the principle of
conservation of energy and the
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 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).
*
Henri Louis Le Chatelier performs several experiments to disturb a
chemical equilibrium before formulating
Le Chatelier's Principle (
1884).
*
Svante Arrhenius studies the
conductivity of
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
Lord Rayleigh (John Strutt) isolate the
noble gases (
1894-
1898).
*
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).
*
Lise Meitner,
Otto Hahn and
Fritz Strassmann observe
nuclear fission (
1938).
*
Glenn Theodore Seaborg creates and isolates five
transuranium elements. He reorganizes the
periodic table to its current form. (
1941-
1950).
*
Melvin Calvin and
Andrew Benson delineate the path of carbon in
photosynthesis using
Chlorella and
carbon dioxide labeled with
carbon-14 (
14CO
2) (
1945) - (
1954).
*
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 to the discovery of 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.
*
Harold Kroto,
James Heath,
Sean O'Brien,
Robert Curl and
Richard Smalley isolate buckyballs and other
fullerenes (
1985).
*
Archimedes, while sitting in a bathtub, notices that his body becomes lighter as it pushes the water aside. This leads to the first true theory of
buoyancy. (c.
250 BC)
*
Eratosthenes evaluates the diameter of the
Earth by comparing the length of the longest shadow of the day with the distance between that location and a place where the sun shines to the bottom of the well at midday (
240 BC)
*
Galileo Galilei uses rolling balls to disprove the
Aristotelian theory of motion (
1602 -
1607)
*
Isaac Newton decomposes sunlight with a
prism.
*
Ole Rømer uses the timing of the eclipses of the moons of Jupiter with respect their distance from earth to estimate the
speed of light for the first time. He yields a value of 225,000 km/s (actual value of 299,792 km/s) (
1672)
*
Henry Cavendish's
torsion bar experiment (
1798)
*
Thomas Young's
double-slit experiment (c
1805)
*
Hans Christian Ørsted discovers the connection of
electricity and
magnetism by experiments involving a
compass and
electric circuits (
1820)
*
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 (
1845)
*
Léon Foucault's namesake
Foucault pendulum is first exhibited. It demonstrates the
Coriolis effect and the rotation of the
earth (
1851)
*
Michelson-Morley experiment exposes weaknesses of the prevailing variant of the theory of
luminiferous aether. (
1887)
*
Guglielmo Marconi demonstrates that
radio signals can travel between two points separated by an obstacle. Marconi's servant is behind a hill 3
kilometers away and fires his rifle upon receiving the signals (
1895).
*
Henri Becquerel,
Marie Curie, and
Pierre Curie discover
radioactivity and describe its properties. (
1896)
*
Joseph John Thomson's cathode ray tube experiments (discovers the
electron and its negative charge) (
1897)
*
Robert Millikan's
oil-drop experiment, which suggests that
electric charge occurs as
quanta (whole units), (
1909)
*
Heike Kamerlingh Onnes demonstrates
superconductivity (
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 (
1911)
*
Arthur Eddington leads an expedition to the island of
Principe to observe a total solar eclipse (
gravitational lensing). 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) (
1919)
*
Otto Stern and
Walter Gerlach conduct the
Stern-Gerlach experiment, which demonstrates particle
spin (
1920)
*
Enrico Fermi splits the atom (
1934, although the results were not fully understood until
1939, by
Otto Hahn and
Fritz Strassmann)
*
Enrico Fermi builds the first critical nuclear reactor (
1942)
*
John Bardeen and
Walter Brattain fabricate the first working
transistor (
1947)
*
Clyde L. Cowan and
Frederick Reines confirm the existence of the
neutrino in the
neutrino experiment (
1955)
*The
Scout rocket experiment confirms the
time dilation effect of
gravity. (
1976)
*A team at
CERN discovered the W and Z bosons, providing direct experimental evidence for the
Electroweak theory, and adding further weight to the
Standard Model of Particle Physics (
1983)
*
Eric A. Cornell and
Carl E. Wieman synthesize
Bose-Einstein condensate at the
University of Colorado at Boulder (
1995)
|
Pavlov's Dog, 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)
*
Solomon Asch's
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
experiments on human obedience (
1963)
*
Philip Zimbardo's
Stanford prison experiment (
1971)
*
Allan and
Beatrice Gardner' attempts to teach
American Sign Language to the
chimpanzee Washoe (
1970s)
*
Martin Seligman studies
learned helplessness in dogs (
1970s)
*
Rosenhan experiment (
1972)
*
Kansas City preventive patrol experiment (1972-1973)
*
Elizabeth Loftus' and
John C. Palmer's car crash experiment shows that
leading questions can produce
false memories (
1974)
*
Robert Axelrod's
Prisoner's Dilemma computer tournaments, later documented in
The Evolution of Cooperation
