Physics307L F09:People/sosa/Millikan

=Millikan Oil Experiment Summary=

For this experiment Manuel and I attempted to replicate the famous Millikan Oil Drop Experiment. The idea of this experiment is very simple, I think. We just compare the electric and gravitational forces that act on the oil drops to obtain a multiple of the charge of the electron. The derivation of the formulas to achieve this, is not so simple, but is not so hard to follow it in the Pasco Manual. The most important data that we had to get for this experiment were the rise and fall velocities of the oil drop with and without the electric field respectively. Once we have this data, it is easy to use the formulas derived in the manual and get the charge multiples for each droplet. It is important to mention that I had to change the viscosity of the air for the second day since the temperatures were different.I also had to look for the two values of the barometric pressure for each day. These changes didn't alter the result very much, but I think it is important to take them into account, since Millikan himself made his measurements on a period of 60 days. In such a long period of time, these little changes would have made a big difference.

Results
All the details and procedures can be found in my My Lab Notebook

Using the least squares method I was able to obtain the value $$(1.63\pm 0.02)\times 10^{-19}\;C$$ with a difference of $$2.14%\;$$ with the accepted value of $$1.602\times 10^{-19}\;C$$.