115 The conceptual classes have been doing a pretty good job measuring and calculating, and releasing their ball bearings from the same height on a ramp every time. Some groups are really close to the red line!
Modeling Instruction and Standards-Based Grading, plus some AP Physics too
72 Starting off the new year with a lab. This is a coffee filter drop lab, in which students model the motion of a coffee filter from data they take in class, then they predict how high they would have to drop it from in order for the filter to take a given amount of time to hit the floor. The tricky bit is the room is less than 3 meters tall, and invariably they calculate a height greater than 3 meters (I’m sneaky about how I pick the “given” times). We have to go out to one of the stairwells to test the prediction. A good model results in a drop time within 0.1 s of the given time.
66 Today some conceptual students did their first “practicum.” They timed how long it took the slow-acceleration disk to roll one meter down its ramp. Then they had to determine how fast it had been going when it passed the 1-m mark. While they timed it, I took video. While they debated how to find the answer, I did video analysis. They told me the answer was 0.16 m/s and then Tracker told me the answer was 0.164 m/s. So I told them that they got it right. They were a little stunned, I think, and I hope they were also proud of themselves for doing it. Next step: more complicated questions.