Robert Andrews Millikan

Robert Andrews Millikan was an American <a href="/facts/Physicist/cQcgvSIm">physicist</a> who received the <a href="/facts/Nobel_Prize_in_Physics/o6w1nCbr">Nobel Prize in Physics</a> in 1923 "for his work on the <a href="/facts/Elementary_charge/lPcj6CoQ">elementary charge</a> of <a href="/facts/Electricity/hNC8D65W">electricity</a> and on the <a href="/facts/Photoelectric_effect/gIDcdm5U">photoelectric effect</a>".
Millikan graduated from <a href="/facts/Oberlin_College/oXrCnwWv">Oberlin College</a> in 1891 and obtained his doctorate at <a href="/facts/Columbia_University/Hlf1gw53">Columbia University</a> in 1895. In 1896, he became an assistant at the <a href="/facts/University_of_Chicago/z6zRMUmV">University of Chicago</a>, where he became a full professor in 1910. In 1909, Millikan began a series of experiments to determine the <a href="/facts/Electric_charge/xxsBfmlB">electric charge</a> carried by a single electron. He began by measuring the course of charged <a href="/facts/Water/0lkXnJPK">water</a> droplets in an <a href="/facts/Electric_field/tt4MooBs">electric field</a>. The results suggested that the charge on the droplets is a multiple of the elementary electric charge, but the experiment was not accurate enough to be convincing. He obtained more precise results in 1910 with his <a href="/facts/Oil_drop_experiment/C2BBYkKh">oil-drop experiment</a> in which he replaced water (which tended to evaporate too quickly) with <a href="/facts/Oil/GP0Jk7YL">oil</a>.
In 1914 Millikan took up with similar skill the experimental verification of the equation introduced by <a href="/facts/Albert_Einstein/CNTet8qu">Albert Einstein</a> in 1905 to describe the photoelectric effect. He used this same research to obtain an accurate value of the <a href="/facts/Planck_constant/qGHAe3qq">Planck constant</a>. In 1921 Millikan left the University of Chicago to become director of the Norman Bridge Laboratory of Physics at the <a href="/facts/California_Institute_of_Technology/3FPcp7BL">California Institute of Technology</a> (Caltech) in <a href="/facts/Pasadena%2c_California/Y6AEEI03">Pasadena, California</a>. There he undertook a major study of the radiation that the physicist <a href="/facts/Victor_Hess/8FxbP6zg">Victor Hess</a> had detected coming from outer space. Millikan proved that this radiation is indeed of <a href="/facts/Outer_space/R3LRKyFs">extraterrestrial</a> origin, and he named it "<a href="/facts/Cosmic_rays/uxCVdTKd">cosmic rays</a>." As chairman of the Executive Council of Caltech (the school's governing body at the time) from 1921 until his retirement in 1945, Millikan helped to turn the school into one of the leading research institutions in the United States. He also served on the board of trustees for Science Service, now known as <a href="/facts/Society_for_Science_%2526_the_Public/B047DeXP">Society for Science & the Public</a>, from 1921 to 1953.
Millikan was an elected member of the <a href="/facts/American_Philosophical_Society/auqTbV2C">American Philosophical Society</a>, the <a href="/facts/American_Academy_of_Arts_and_Sciences/KptWYgz4">American Academy of Arts and Sciences</a>, and the United States <a href="/facts/National_Academy_of_Sciences/M3oePVeG">National Academy of Sciences</a>. He was elected an Honorary Member of the <a href="/facts/Optica_(society)/9WkJwyhr">Optical Society of America</a> in 1950.

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Robert Andrews Millikan