Millikan, Robert Andrews
Millikan, Robert Andrews (1868-1953), a United States physicist. In 1909 Millikan became the first to measure the electrical charge of a single electron, by means of an experiment with oil droplets. In 1916 he verified Albert Einstein's photoelectric equation, an application of quantum theory which deals with the transformation of light energy into mechanical energy. Millikan made another valuable contribution to the quantum theory at the same time by determining Planck's constant (h) with great accuracy. He received the 1923 Nobel Prize in physics.
Most of Millikan's later work was devoted to the then little-known radiations that he named cosmic rays in 1927. He and his collaborators proved definitely during 1922-26 that the rays reach the earth from outer space. He traveled to Bolivia, Tasmania, and India to investigate the intensity and penetrating power of cosmic rays.
Millikan was born in Morrison, Illinois. He received his B.A. in 1891 and M.A. in 1893 from Oberlin College, and his Ph.D. from Columbia University in 1895. During 1895-96 he studied at the universities of Berlin and Göttingen. Millikan became an assistant in physics at the University of Chicago in 1896 and advanced to a full professorship in 1910. During World War I he headed the science and research division of the U.S. Army's Signal Corps.
In 1921 Millikan was made chairman of the executive council (equivalent to president) of the California Institute of Technology. He also became director of the school's Norman Bridge Laboratory of Physics. He retired in 1945. During World War II Millikan did research in rocket and jet aeronautics, for which he received the Medal of Merit in 1947.
Among his books are: The Electron (1917); Evolution of Science and Religion (1927); Electrons, Protons, Photons, Neutrons, and Cosmic Rays (1935); Cosmic Rays (1939); The Autobiography of Robert A. Millikan (1950).