Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
_______________________________________________
As an aside, I do have this same problem with juniors and seniors in my
experimental
physics course for physics majors at our university. They think that
their only
discussion in the lab report should be about "error" and often ignore the
physics of the
experiment. They do have this belief that there is always some "accepted
value" and
that there is no way they can make a measurement without "human error."
In one
recent report, a student claimed, "The error in this case cannot be human
error because
all of the data was measured using a computer."
The experiment in question is the Kater pendulum, where our objective is
to measure
the local value of the acceleration due to gravity to the fourth decimal
place. We get
this accuaracy by measuring over 125 periods at each of 32 bob positions;
and by
measuring the distance between the two fulcrums to within 100 microns
using a
precision cathetometer. Even though it is communicated to the students
that our goal is
a precise measurement of g, some of them still want to compare it with the
book value
of 9.81 m/s^2 and calculate a percent error, even though it is clearly
stated not to
compare the measured result with any other number. They are asked to do
an
uncertainty propagation to prove the precision of the measurement. Almost
none of the
students attempt this, even though they were given practice problems at
the beginning
of the semester on how to do it.