Robert Andrews Millikan
1868–1953, Morrison, Illinois, United States, San Marino, California, United States
American physicist known for the oil-drop measurement of the electron's charge and measurements of the photoelectric effect; he received the 1923 Nobel Prize in Physics.
Millikan was born in Morrison, Illinois, studied at Oberlin College, and received his doctorate from Columbia University in 1895. After teaching at Chicago, he moved to Caltech and led the institute for decades. His measurements of the electron's charge and Planck's constant strengthened the experimental foundations of atomic and quantum physics.
In the oil-drop experiment reported in 1910, he measured the elementary charge by balancing electric and gravitational forces on tiny oil drops; the results showed that charge is quantized. His photoelectric studies tested the relation between electron energy and light frequency and helped determine Planck's constant. He received the 1923 Nobel Prize in Physics.
Nobel-winning work
Millikan received the 1923 Nobel Prize in Physics 'for his work on the elementary charge of electricity and on the photoelectric effect'. His oil-drop experiments (1909–1913) measured the electron charge e = 1.592×10⁻¹⁹ C to high precision and proved charge is quantized. His meticulous 1914–1916 photoelectric measurements verified Einstein's equation E = hν − W and produced a precise value of Planck's constant.
Workplaces: University of Chicago, California Institute of Technology
United States