AP Physics: Board Meeting
We had a board meeting on this week’s impulse lab. I had one section where about half of the groups changed the mass of their cart for each trial, so I need to make sure I revisit experimental design concepts, like how to tell what variables should remain constant. Students still recognized all of the relevant patterns and we were able to get to the impulse equation nicely.
Students finished collecting data for distance and time down a ramp to see a quadratic relationship. The results weren’t as clean as I hoped, largely because a lot of groups started their cart a fair distance behind the first photogate. It takes some background knowledge to understand why that matters, and with the cognitive load required to learn to use the photogates and set up the dynamics track, they lost track of that detail. If I do a graphing unit next year, I might give more traditional written directions rather than relying on discussion and expecting students to make the notes they need to help ease them in a little more.
Chemistry Essentials: Mass of a Gas
Earlier this week, a student asked what would have happened with the dissolving Alka Seltzer if we had a way to trap the gas and the rest of the class was very excited to discuss their ideas. Today, to answer that question, I had them mix calcium chloride and sodium bicarbonate, along with some indicator, in a Ziploc bag. Things were chaotic enough that I didn’t get much chance to listen to students reason about the reaction, but part of the chaos was a lot of groups were excited to tell me about their observations, which was a great kind of chaos to have.