Robert Andrews Millikan
Born: 22 March 1868, Morrison, IL, USA
Died: 19 December 1953, San Marino, CA, USA
Affiliation at the time of the award: California Institute of Technology (Caltech), Pasadena, CA, USA
Prize motivation: "for his work on the elementary charge of electricity and on the photoelectric effect"
Field: electromagnetism, particle physics
Prize share: 1/1
During the 1890s the theory that electricity was conveyed by a miniscule unit, the electron, gained acceptance. In 1910 Robert Millikan succeeded in precisely determining the magnitude of the electron's charge. Small electrically charged drops of oil were suspended between two metal plates where they were subjected to the downward force of gravity and the upward attraction of an electrical field. By measuring how the various drops of oil moved about, Robert Millikan showed that their charge always was a multiple of a precisely determined charge - the electron's charge.