An American Physicist
Robert A. Millikan was an American experimental physicist. He received a PhD in physics from Columbia University in 1985, for research on the polarization of light emitted by incandescent surfaces - using for this purpose molten gold and silver at the U.S. Mint.
Millikan won the Nobel Prize for physics for his work on the photoelectric effect and measuring the charge of the electron in 1923.
After his graduation from Oberlin College (Ohio) in 1891, he took, for two years, a teaching post in elementary physics. It was during this time that he developed his interest in the subject in which he was later to excel in.
The “Millikan Oil Drop Experiment”, an experiment performed by Millikan, in 1909, determined the size of the charge on an electron. He also determined that there was a smallest 'unit' charge.