Robert Millikan

American experimental physicist

About Robert

Born March 22, 1868 in Morrison, Illinois and died on December 19, 1953 in San Marino, California. He was an American experimental physicist honored with the Nobel prize in physics in 1923 for his measurement of the elementary electronic charge and for his work on the photo-electric effect. He studied at Columbia University and received a Ph.D for research on the polarization of light.

Oil droplets experiment

In 1909, Robert performed an experiment to determine the charge of an electron. The charge to the mass of the ratio of the electron had already been calculated by J.J. Tompson in 1897. But until Robert experiment neither the mass nor charge was known, only the ratio. By examining the motion of the oil droplets falling between two highly charged plates, he found the charge to be -1.6x10^-19 C. The charged plates were similar to a parrellel plate capacitor.
Robert Andrews Millikan
Millikan Oil Drop Experiment