Introduction
and
Theory
The first experiment to try an obtain the charge of the electron was carried out by Townsend in the late 1890's by observing electrolysis. This experiment was based on many assumptions that were only partially true, and the results weren't all too close to what is now accepted now accepted (37.5% error). Townsend=3.0*10^-10 e.s.u. Today=4.803*10^-10 e.s.u.
Wilson improved upon Townsend's experiment by adding parallel plates to creat a charge-field. Using a zero electric field and an electric field when the potential across the plates was 2000 volts, Wilson found a value of e to within 35.5%. Wilson=3.1*10^-10 e.s.u. Today=4.803*10^-10 e.s.u.
Both of these experiments treated clouds of suspended particles. There was no way of isolating an individual particle and examining it closely. That is, there was no way of isolating an individual particle until Millikan devised his experiment.
Millikan, using much higher potentials that Wilson used, could force droplets of water to move up--against gravity. Millikan could capture a single droplet of water and by releasing it and capturing it multiple times, figure out a value of e. Millikan was then within 28.9% of accepted. Millikan=3.422*10^-10 e.s.u. Today=4.803*10^-10 e.s.u.
Changing particles from water to oil allowed longer observational periods (the oil wouldn't evaporate). Using long observations and much patience, Millikan found e to within 0.6%. Millikan=4.774*10^-10 e.s.u. Today=4.803*10^-10 e.s.u.
Today's value of e was found using X-ray diffraction measurements on crystals to determine Avagadro's number, which could then be used to precisely calibrate e to be 4.803*10^-10 e.s.u.
Our theory is based on the nature of balanced forces. Balance the force of gravity with the force a charged particle feels in within a potential field.
This expected voltage was used as a "starting place" for finding n=1 particles.
In our experiment, we used small latex particles in a suspension that were atomized into the space between two aluminum plates attached to a variable voltage source and volt meter. We used 184 volts as a starting point of where we expected n=1 particles to be trapped. Our data show otherwise, suggesting a 151.36 volt n=1.