In 1910 he published his first work on 38 charge measurements on single droplets, which met with great interest and criticism. With these measurements he succeeded in determining the unit of the smallest electric charge, which he called “e”. Millikan’s original oil-drop apparatus, circa 1909–1910įirst he used the droplet method for his experiments, which was common at that time, later the oil droplet method, which was better suited for the determination of the elementary charge, because oil droplets proved to be much more stable compared to water droplets. Millikan and his then graduate student Harvey Fletcher used the oil-drop experiment to measure the charge of the electron as well as the electron mass, and Avogadro’s number, since their relation to the electron charge was known. Therefore, if one of these two values were to be discovered, the other could easily be calculated. However, the actual charge and mass values were unknown. Thomson had already discovered the charge-to-mass ratio of the electron. ![]() Starting in 1908, while a professor at the University of Chicago, Millikan worked on an oil-drop experiment in which he measured the charge on a single electron. Michelson, to become assistant at the newly established Ryerson Laboratory at the University of Chicago in 1896. Here he investigated the radioactivity of uranium and the electric discharges in gases. On the instigation of his professors, Millikan spent a year (1895-1896) in Germany, at the Universities of Berlin and Göttingen. from Columbia University in 1895 with a thesis “ On the polarization of light emitted from the surfaces of incandescent solids and liquids“. In 1893, after obtaining his mastership in physics, he was appointed Fellow in Physics at Columbia University. Millikan received a bachelor’s degree in the classics from Oberlin College in 1891 and for two years he took a teaching post in elementary physics. After working for a short time as a court reporter, he entered Oberlin College (Ohio) in 1886. Millikan went to high school in Maquoketa, Iowa. Robert Andrews Millikan was born in Morrison, Illinois, as the second son of the Reverend Silas Franklin Millikan and Mary Jane Andrews. Robert Andrews Millikan, Robert Millikan – Youth and Education “Fullness of knowledge always means some understanding of the depths of our ignorance and that is always conducive to humility and reverence.” In later work, Millikan coined the term “ cosmic rays” in 1925 during his study of the radiation from outer space. Millikan‘s famous oil-drop experiment ( 1911) was far superior to previous determinations of the charge of an electron, and further showed that the electron was a fundamental, discrete particle. Millikan was honored with the Nobel Prize for Physics in 1923 for his measurement of the elementary electronic charge and for his work on the photoelectric effect. On December 19, 1953, US-American physicist and Nobel laureate Robert Andrews Millikan passed away.
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