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.
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