 | the Michelson-Morley experiment |
 | early tests of relativity |
 | Millikan's oil-drop experiment |
 | the discovery of the electron |
 | Rutherford's nuclear scattering experiments |
 | the discovery of the neutron |
 | early attempts to understand the photoelectric effect |
 | early attempts to overcome "ultraviolet catastrophe" |
 | Roentgen's early work with x-rays |
 | Sommerfeld's relativistic extensions to Bohr theory |
 | the first maser or laser |
 | London's connection between superfluidity and Bose condensation |
 | the discovery of the transistor |
 | the discovery of fission |