Quantum mechanics/Timelines

Founding experiments

c 1805: Thomas Young's double-slit experiment demonstrating the wave nature of light. 1896: Henri Becquerel discovers radioactivity. 1897: Joseph John Thomson's cathode ray tube experiments (discovers the electron and its negative charge). 1850 - 1900: The study of black body radiation, which could not be explained without quantum concepts. 1905: The photoelectric effect: Explained by Einstein (who later received a Nobel prize for it) using the concept of photons, particles of light with quantized energy. 1909: Robert Millikan's oil-drop experiment, which showed that electric charge occurs as quanta (whole units). 1911: Ernest Rutherford's gold foil experiment disproved the plum pudding model of the atom which suggested that the mass and positive charge of the atom are almost uniformly distributed. 1920: Otto Stern and Walther Gerlach conduct the Stern-Gerlach experiment, which demonstrates the quantized nature of particle spin. 1927: Clinton Davisson and Lester Germer demonstrate the wave nature of the electron in the Electron diffraction experiment. 1955: Clyde L. Cowan and Frederick Reines confirm the existence of the neutrino in the neutrino experiment. 1961: Claus Jönsson`s double-slit experiment with electrons. 1980: The Quantum Hall effect, discovered by Klaus von Klitzing. The quantized version of the Hall effect has allowed for the definition of a new practical standard for electrical resistance and for an extremely precise independent determination of the fine structure constant.