He also made important contribution to American science as an educator, administrator and popular writer.
He was perhaps the most renowned and influential scientist in the United States.
Born in Illinois, the son of Congregational minister, Millikan studied at Oberlin College and Columbia University where he received his PhD in 1895. He spent a year in Europe at Gottingen and Berlin before taking up an appointment in 1896 at the University of Chicago.
Millikan left Chicago in 1921 to become director of Northern Bridge Laboratory of the California Institute of Technology post he held until his retirement in 1945.
Although J.J Thompson had identified the electron in 1897, the magnitude of its charge was still uncertain when Millikan carried out a series of classic experiments in 1909.
In a paper published in 1913, based on 58 observations with charged of the oil drops. Millikan’s most famous experiment is the so-called oil drop experiment, by which he measured in 1929, the electrical charge of an electron.
The research represented the first accurate determination of the charge on the electron.
For all these achievements, as well as for his measurement of Plank’s constant, he was awarded the 1923 Nobel Prize for Physics.
He also investigated cosmic rays, a term he coined in 1925. Millikan worked for many years on the nature of the cosmic rays first identified in 1912 by Vector Hess. In a series of ingenious observations begins in the 1920s Millikan conclusively demonstrated that they originated beyond the earth’s atmosphere.
Millikan was author or co-author of the following books: A College Course in Physics, with S.W. Stratton (1898); Mechanics, Molecular Physics, and Heat (1902); The Theory of Optics, with C.R. Mann translated from the German (1903); A First Course in Physics, with H.G. Gale (1906); A Laboratory Course in Physics for Secondary Schools, with H.G. Gale (1907); Electricity, Sound, and Light, with J. Mills (1908); Practical Physics - revision of A First Course(1920); The Electron(1917; rev. eds. 1924, 1935).
He died in 1953 in Pasadena, California.
Millikan, Robert Andrews (1868-1953)
