Robert Millikan is credited with accurately determining the charge of an electron through his famous oil drop experiment.
Robert Millikan and the Oil Drop Experiment
While J.J. Thomson discovered the electron itself, it was Robert Millikan who precisely measured the elementary electric charge (the charge of a single electron). He performed his groundbreaking experiments between 1909 and 1913. This work earned him the Nobel Prize in Physics in 1923.
Millikan's "oil drop experiment" involved observing tiny electrically charged droplets of oil between two parallel metal electrodes. By carefully adjusting the electric field, he could suspend the oil droplets and calculate their charge.
Significance of Millikan's Discovery
Millikan's determination of the electron's charge was a significant step forward in physics. It confirmed that electric charge is quantized, meaning it exists only in discrete units (multiples of the elementary charge). His precise measurement allowed scientists to calculate other fundamental constants, such as Avogadro's number. The currently accepted value for the elementary charge is approximately 1.602 x 10-19 coulombs, a testament to Millikan's accurate work.
