Results of physics teaching survey

For each of the nine questions, we show:
  1. 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:
    1. 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.
    2. 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".
  2. A thumbnail image of the question, to remind you what the question is. You can also see the full-size gifs of the questions.)
  3. The fraction choosing the correct answer, as a function of year in the course; as well as the fraction over all students.

1. Bouncing pingpong ball on top of golf ball

2. Disc and hoop rolling down the plane

3. Pendulum period versus amplitude

4. Merry-go-round

5. Slinky

6. Sliding bead on a rotating wire

7. Satellite in orbit

8. Wood block

9. Spinning light rod


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).