Charge of an Electron: Millikan's Oil Drop Experiment

To see all my Chemistry videos, check out http://socratic.org/chemistry How did scientists discover how much negative charge an electron had? Robert Millikan and Harvey Fletcher used the oil drop experiment. They looked an tiny droplets of oil, and balanced the downward gravitational (gravity) force with an upward electrical force. At this point, they knew the forces had to equal, and they calculate the charge on the oil drops.