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1775 Coulomb proposed Coulomb's law of electrostatic forces
1814 Fraunhofer dicovers absorption spectra in sunlight
1820 Oersted discovered that an electric current can affect a magnet (first indication that e & m are related
1827 Ohm proposed Ohm's law relating current to voltage
1831 Faraday proved that electric currents could be induced by magnetic fields
1843 Joule discovered the mechanical equivalent of heat - thus conservation of energy
1864 Maxwell integraed electromagnetic equations into the Maxwell equations & predicted em radiation
1869 Mendeleev periodic chart
1881 Michelson Morley verified that the speed of light was a constant in a vacuum
1884 Boltzman discovered entropy - a measure of disorder in statistical mechanics
1886 Becquerel observed radioactivity
1887 Hertz confirmed electromagnitic waves predicted by Maxwell
1895 Roentgen dicovers X Rays
1895 Balmer finds a formula for visible series of spectra of hydrogen
1897 Thompson discovers the electron
1900 Plank proposes  quantization of energy to explain black body radiation
1905 Einstein proposes quantized EM unit of photon
1905 Einstein proposes special relativity - four dimensional space-time
1908 Perrin determines Avagadro's number
1909 Rutherford proposes the model of the atom with nucleus
1913 Bohr proposes first quantum model of hydrogen atom - explains spectra
1914 Moseley uses X ray spectroscopy to relate atomic number to charge on nucleus
1916 Einstein proposes general relativity - integrates acceleration & gravity theory w curved space-time
1923 Compton shows photons scatter like particles
1924 de Broglie proposes all particles have wave nature
1925 Pauli exclusion principle - no two electrons can be in the same state at the same time
1926 Schrodinger Formulates wave equation for quantum theory
1926 Goudsmit & Uhlenbeck proposed electron spin
1927 Heisenberg formulates uncertainy principle (and matrix theory of quantum mechanics)
1927 Davissson & Germer observe electron diffraction confinrming wave nature of particles
1930 Dirac formulated relativistic equation for quantum mechanics & predicted the positron (antimatter)
1932 Chadwick confirms Rutherfords hypothesis that the neucleus contains a neutral particle (neutron)
1932 Anderson discovered Dirac's predicted particle, the positron, in cosmic rays
1934 Pauli predicted the neutrino
1932 Yukawa predicted the pion
1942 Fermi theory of beta decay of nucleus & first atomic reactor (chain reaction) - also fermions
1943 von Neuman invented the stored program computer (also foundations of quantum theory)
1947 Powell discovered the pion as predicted by Yukawa
1948 Feynman, Schwinger, Tomonaga theory of quantum electrodynamics
1948 Shannon discovered concept of information (negative entropy) in computer systems
1954 Reines discovered the neutrino
1955 Segre & Chamberlain discover anti proton
1955 Yang proposed non-conservation of parity
1967 Glashow, Salam, Weinberg integrate electromagnetic and weak interactions