Re: Millikan Apparatus- best one ?

[stenton@phastf.phys.uvic.ca (Don Stenton)]

On Wed, 9 Oct 1996, Leigh Palmer wrote:
> Has anyone in this group ever had a student who succeeded in
> demonstrating the quantization of charge doing this experiment?
> How many one-pass datasets were taken? how many different drops
> were measured?

One way to demonstrate the quantized nature of charge concentration on the
oil drop is to plot a graph. We ask our students to 'fit' an n-value to the
ratio of the speed of rise to the speed of fall (actually [1 + v(r)/v(f)]
using a Spreadsheet program. Occasionally, students find a data point that
does not fit.  Having captured their data on video tape, they can once
again review the measurements to verify that there may have been a change
of charge on the drop during its time of rise. I suspect that this method
helps re-enforce the concept of quantization of charge.

PS. On Monday, this week, one student managed to identify 11 charges on one
drop.
....Don

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Don Stenton                        voice: (604) 721-7709
Dept. of Physics and Astronomy     fax:  (604)  721-7715
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