The Millikan Oil experiment was an experiment that was performed by Robert Millikan in 1909 to find the size of the charge on an electron. He also found out that there was a small unit charge/that charge is quantized. Millikan set up a pair of plates horizontally parallel to each other, one on top of the other, with a large electric field between them that can be adjusted. He charged the plates by connecting each to opposite terminals of a large bank of storage batteries where its potential difference could be wide-ranging. He then used something called an electrical microbalance. He used the electrical microbalance to isolate and give off charged oil drops to measure the total charge on each. Fine mists of Oil is sprayed using an atomizer