AP Physics: Elevators

I showed students a video I made riding the elevator with a balance and asked them to determine whether the elevator was going up or going down and support their answer with free-body diagrams. I was pleased with how many groups started their conversation with “What’s our system?” I could tell from the conversations that a lot of students are still not entirely solid on the idea that an acceleration can be in the opposite direction of the motion, but thinking about the bowling ball lab from a few days ago seems to be helping. Next year, I want to do a better job of using the change in velocity arrows that show up in Etkina to help solidify the direction of acceleration.

Earth Science: Turbine Interference

In the next step towards designing a wind farm, students experimented with several turbines, comparing the amperage produced with different arrangements. This lab got my students asking some great questions that had me wishing that the trimester on physics came first rather than second this year. A lot wanted to know why the last turbine in a line wasn’t spinning, which is easy to explain with conservation of energy. A few others wanted to know what’s inside the turbine, which fits great with the build-a-motor lab we do in 9th grade physics. When we work on next year’s schedule, I’ll make sure to advocate for physics-earth-earth rather than this year’s earth-physics-earth sequence.