Results of physics teaching survey
For each of the nine questions, we show:
- The fraction of students choosing each answer (sideways bar graphs).
The correct answer (answers) is (are) have shaded bars.
Each bar contains two horizontal bars:
- the top bar shows how certain
students were of the choice: the "!" subbar means "Yes! I am certain,"
and the "?" subbar means "I was not certain." The answersheet shows how we asked about certainty.
- The bottom bar shows whether students remembered seeing the question
before (most of the IB students had seen them in lecture): "y" for
"yes", "n" for "no", and "?" for "not sure".
- A thumbnail image
of the question, to remind you what the question is. You can
also see the full-size
gifs of the questions.)
- The fraction choosing the correct answer, as a function of year in
the course; as well as the fraction over all students.
Caveats
1. Bouncing pingpong ball on top of golf ball
The question
did not tell students to assume that the golf ball was infinitely
massive compared to the pingpong ball. A few students wrote on their
answersheet that the answer depends on the mass.
One student thought that the golf ball and pingpong balls were held
next to each other (instead of one atop the other) before being
dropped.
3. Pendulum period versus amplitude
We counted the flat curve as a correct answer, even though the period
increases as the amplitude increases. But how much it increases was
not obvious, and students may have had trouble with the scales on the
graph not being obvious. The correct `up curve' graph should have
been generated from the analytic solution.
4. Merry-go-round
Students who said `neither' may have been worried about the rotation
of the earth. The phrase `when viewed from above' was designed to
make the vertical falling irrelevant, but it may have confused
students into using the earth frame only (it is easier to imagine an
earth-frame view from above than a merry-go-round-frame view from
above).
8. Wood block
While demonstrating the tapping tone, I
(Sanjoy) held the wood block at the end instead of nearer to the
middle, where the node is. So the resulting note was not pure. This
mistake may have prevented students from understanding how the wood
block makes a sound. On the other hand, almost everyone
misunderstands this point, even with a proper demonstration (most
people think that the note is generated by internal sound waves in the
wood block).