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A further point about error analysis which I rarely see presented to students.
Most of us are familiar with the old linear expansion apparatus?
Where you heat up a metal rod, measure the expansion and calculate
the coefficient of expansion. Two of the measurements made are delta
L (change in length of the rod) and L (total length of the rod).
Rhetorical question (which I ask my students): Why is it you can get
away with measuring L with a meter stick but delta L has to be
measured with a micrometer? My point is: No measurement ever made in
science is perfect but some measurements are more important than
others.
Students ought to be able to do an error analysis which answers questions like:
1. Of all the measurements made in this experiment, improving which
measurement(s) (if any) would lead to the biggest improvement in the
accuracy of the answer?
2. Given this particular equipment with its inherent limitations
(which all instruments have), what is the smallest error you could
possibly get in your answer? The biggest (if all instruments are at
their maximum error)?
3. Is there any way to change the procedure to get a more accurate answer?
4. Can any error in one place be offset by another error somewhere
else? (For example starting a calorimeter experiment below room temp
and ending above room temp by the same amount to cancle heat
exchange.)