Days 20-24: Constant Acceleration & Forces

Physics: Constant Acceleration

Physics started constant acceleration this week. We used video analysis to get position vs. time and velocity vs. time graphs for a cart on a ramp, then worked on Kelly O’Shea’s CAPM card sort. This was my first time using video analysis to introduce constant acceleration, and I’m really happy with the results overall.

The big thing I’m thinking about right now is when students are in groups. The first week of school, students were almost timid and weren’t engaging with each other, but tended to stay at their tables, which made it easy for me to pull the full group in when I came to answer a question. Over the past few weeks, things have shifted in a few of my classes. Students are still not engaging much with their groups, but are also leaving their group to go see their friends, which is making it harder for me to gather the whole group when I’m answering a question. I think a lot of it is students are out of practice working with each other after last year and simply aren’t seeing value in staying with their group. I think I need to make much more use of group roles and spend much more time working with students on how to interact with each other and building community so students feel like they can connect with more people in the class.

I think these issues have been compounded by the fact that I have larger class sizes than usual, so I’m juggling 10 groups in each of my classes. That means that if I’m having meaningful conversations with each group, it can be a while between my visits to a given group. I’m realizing that many of my students don’t feel like there is much they can do besides wait for me when they are stuck, which I think is contributing to some of the behavior I’m seeing. I think part of what I need to address is helping students recognize the strategies they have to work through moments of confusion or challenge.

AP Physics: Forces

We started the week with the catch the loot practical, which is one of my favorites since it is a challenging calculation at this point in the year, but so satisfying. This class is only 12 students, so I’ve had a much easier time building a positive class culture and helping students with strategies for when they are stuck. One thing I loved is when the first group finished, they decided each of them should join one of the other groups to help their classmates with the lab practical.

We shifted into forces with some mallet ball followed by Brian Frank’s interaction stations. So far this year, I’ve been really intentional that when we show the shortcomings of a common preconception, I also ask students about what reasonable thinking might lead a person to that idea and explicitly validating that thinking. My goal is to make it so that adopting a new idea doesn’t mean you are wrong or don’t understand physics, it just means you didn’t have all of the information when you formulated your old idea. I saw some payoff with the mallet ball as my students were quicker than usual to let go of the idea that they needed to keep tapping the bowling ball to keep it moving with a constant velocity and talking about the useful aspects of that idea even once they’d adopted a new one. We’ll see next week how that carries over into drawing free-body diagrams.

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