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The experiment starts with a single spinning disk. The student then drops
a second disk on the first (effectively doubling the moment of inertia).
Here's the rub. The variance on the mean should properly be calculated as
sigma/sqrt(n) for a selected set of random samples. But I don't think that
is valid in this case because the samples are correlated. Vernier's
software may even be doing some smoothing and approximation for angular
positions that fall between the position encoder's discrete digitization
After removing the copper from the neutron bath we measure the
activity of the sample with a simple geiger counter. Within the
undergraduate lab period we can take data for most of the short half
life decays. Students have to come back every day to take another data
set each of the next few days to get data to find the longer half
Traditionally we have them fit a double exponential function to this
data. But this is fraught with problems and subtle choices in the
analysis which will change the result. And it's not how these half
lives are really measured. Though, obviously in a precision
measurement you'd want to have continuous data collection.
You'd really enjoy David MacKay's lecture 10 on Information theory.