Robert Millikan

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Andrew Millikan Biography

Robert A. Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist who won the Nobel Prize for Physics in 1923 for his measurement of the elementary electronic charge and for his work on the photoelectric effect.In 1916 Millikan took up with similar skill the experimental verification of the equation introduced by Albert Einstein in 1905 to describe the photoelectric effect. He used this same research to obtain an accurate value of Planck's constant. In 1921 Millikan left the University of Chicago to become director of the Norman Bridge Laboratory of Physics at the California Institute of Technology in Pasadena,California. There he undertook a major study of the radiation that the physicist Victor Hess had detected coming from outer space. Millikan proved that this radiation is indeed of extraterrestrial origin, and he named it “cosmic rays.”

Oil Drop Experiment

In 1908, at the University of Chicago, Millikan began to work on an oil drop experiment where he measured the charge of one single electron. The mass to charge ratio had previously been discovered, but the actual change and mass were not known. He used this experiment to figure out the actual charge and mass of an electron.As chairman of the Executive Council of Cal-tech,Millikan helped to turn the school into one of the leading research institutions in the United States.The oil drop experiment was one of the major factors in Millikan winning the Nobel Prize.
Robert Millikan's Oil Drop Experiment - The Charge of an Electron
Millikan's Oil Drop Experiment