CONCLUSIONS and ERROR

The measurement of the electric charge was good. The accepted value was inside the range provided by the standard deviation. There were several problems in measuring the charge. One was becoming familiar with the apparatus. Clusters and fragments of spheres were in the viewing area as well as single spheres. Clusters and fragments give different measurements because their mass would be different. Because of the small size of the spheres it was impossible to distinguish between the clusters, fragments, and uniform spheres. Knowing the expected values for the voltage helped to find the single spheres, and with practice technique got better. Keeping the sphere in the viewing area was also a problem, because the microscope would lose focus on a sphere as it moved forward or backward in the viewing chamber.

The mass was checked to see that the given radius and density of the spheres were acceptable to use as the mass in determining the charge. The experimental value showed that the mass determined from the given units was acceptable. The difference between the experimental mass and the calculated mass was not very large. This meant that the calculated mass used in the first part was acceptable. One problem was that I ran out of spheres of the size used for the charge measurement, so the spheres used for to find the mass experimentally were different. This prevented the experimental mass being used to compare with as a measurement of charge. The measuring of the mass had the same problems as measuring the charge because the clusters would fall faster than the single spheres. The fragments would fall slower than the single spheres. The given radius was also used in the calculation. One set of data was taken with predominately clusters in free fall because the times were too fast. This set was discarded when the error was found and a second run was done with spheres that better fit the expected times.

In estimating the Boltzmann constant an initial error is made when the equation used here is used. This equation assumes that Brownian motion is the only thing that affects the spheres and that is not true. This causes error in the estimation of the constant. The same problems with the measurement of the mass carry over to this estimation, because the times used here were the same as were used in measuring the mass.