* 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)
* 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).
* 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).
* 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)
* 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 (14CO2) (1945) - (1954).
* Neil Bartlett mixes xenon and platinum hexafluoride leading to the first synthesis of a noble gas compound, xenon hexafluoroplatinate (1962).
* 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)
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