Day 5: All Classes are Different (when they talk about CVPM)

I teach two sections of AP Physics 1. They're both in the morning. They both have the exact same number of kids. They both had the exact same amount of time to do a lab with motion detectors. As two classes, though, the vibe couldn't be different.

One period talked about all the different situations with the motion detector pretty quickly. All the students basically agreed, and the questions seemed mostly limited to questions about the conventions of the representations. (Do the axes have arrows on them? When do the arrows go on the dots in the motion map?) When I was done, I was uneasy that they had not yet made their intuitions explicit. So we made a class consensus focused around two questions: how we show the direction of motion and how we show if the object is moving fast or slow in these different representations.

The other period, when going over the different situations, got into it. Some students seemed to want to represent what they actually saw in lab, while others were more willing to idealize it (use their "physics goggles"). Students could reason between the representations and give arguments for their answers. Not all of them, though, saw the situation the same way. It got a little hot. All the answers they whiteboarded were reasoned and not intuited. Even if their reasoning was not the same reasoning I would use, it was consistent and intelligent. By the time we did the class consensus, which I felt I should do, partially because I did it in the previous class and partially because I wanted to make sure we all ended up in the same place, every student was articulate about how to answer the two questions. The arguments were productive, but a bit too critical.

When we moved on to the next activity with the second class, I knew it was time to pull out Kelly O'Shea's Fun-Time Super-Cool Mistake Game™. (That's not what she calls it, but that what I call it in my head.) The mistake game is great; I learn more every time I read Kelly's post. I'm introducing it here because students were passionate about their answers, which is good, but were phrasing everything in terms of "right" and "wrong." I contributed to that; they started to echo my language about what I like and don't like by exclusively talked about what they don't like, meaning what they thought the whiteboard got wrong. This is a trap I fall in all the time, and Kelly O'Shea's Fun-Time Super-Cool Mistake Game helps me get out of that trap. I need to shift the conversation to questions like "According to the motion map, where does your object start? How does your motion map show that?"