# Day 16: Systems, v-t Graphs, & Good Questions

AP Physics: Systems

Students did the mistakes game (pretty much my default mode of whiteboarding if you can’t tell yet) for a free-body diagram worksheet. Both classes had some great discussion about whether there should be an upward force for a projectile while it is in the air and it helped a lot to frame forces as interactions. I ended up wishing I’d taken some time to revisit Newton’s 1st Law from the momentum unit since some students were having trouble with the idea that forces are balanced on an object rising with a constant velocity. I’ll probably spend some time reinforcing that tomorrow.

I also took this opportunity to introduce students to the idea of defining their system. Both sections had debates about different problems where they were trying to decide what was causing an upward force. That lead nicely into discussing how we could define our system to make each possible answer correct.

Physics: v-t Graphs

Students worked on sketching velocity vs. time graphs based on motion maps and position vs. time graphs. The calculus class started v-t graphs at the end of last week, so I had some students who not only finished quickly, but were eager to exercise their new knowledge by helping their peers, which was great. I had a lot of students who struggled with the idea that the horizontal axis on the graph represents moving forward in time; I want to try getting out the motion detectors tomorrow so they can watch the graph form in real-time to see if that helps.

Chemistry Essentials: Good Questions

We spent some time working on asking good questions. I prepped a whiteboard with an intentional mistake, and asked students about what they saw. Some were able to use the question stems to immediately get to a good question. When a student had an observation or an idea of where to steer me next, I had them share it and we formed a question as a class. Then, we went back to the remaining student whiteboards and were much more successful and focused than yesterday.