Friday, Sept 29
Even more behind on grading, because every class had something to hand in today. Yeesh. I will get caught up this weekend. I WILL get caught up this weekend. I promised the students I would hand everything back on Monday and have study guides ready for the AP and Honors exams later in the week, which means it has to happen.
Physics: Reviewed for the exam. It’s on N2L and N3L, and I screwed up this week and never managed to debrief the lab that we did on Monday, so I had to change up the exam question that related to the lab to be more focused on what we did discuss. The students really, really have no concept of what forces are or how they work, which is horrifying to me. I didn’t realize how bad it was until today when we were reviewing for an exam on Monday and they were still super confused about how objects move and the difference between acceleration and velocity, much less the laws forces follow. I can’t go on this way. This super surface learning sans deep or even big picture understanding is driving me crazy.
The next unit is momentum and energy. Forget the textbook. We’re going to use the IF charts and SOS diagrams and then LOL diagrams to describe systems and understand how the motion changes and try to back-load the different representations in a useful way so students can begin putting different ideas together into a coherent story rather than these discrete topics that are never connected together.
Honors Physics: Reviewed momentum. First we did the system analysis goal-less quiz and then went over the center of mass homework, but the rest of the period we reviewed momentum and IF charts. The exam is next Wednesday, so I’ve got to get cracking on that study guide and have it ready by Monday. Thankfully Honors and AP are close enough to the same spot that one study guide will work for both with a few added problems for AP.
AP Physics: Reviewed differential equations with air resistance. Watching someone do extensive algebra on the whiteboard may not be the world’s most exciting class, but there were a lot of steps in the math where different students got lost, so I needed to go through the whole solution step by step, occasionally backing up and re-doing a step, and answering questions the entire time. There will definitely be a few of these on the study guide so they can practice on their own, but I really felt like today both classes needed direct instruction that could be interrupted in real time with questions and discussion that wouldn’t be possible with a screen cast or sending them to watch a video. I also wanted to make the point that while solving the DE involved 80% of the space when showing work on the board, it only counted for 20% of the points in the whole question. The free body diagram, graphing the acceleration, and writing the DE in the first place each counted for more points than all the algebra to solve it.
Next year I plan to do the coffee filter lab, but that doesn’t involve solving DEs, so it still can’t take the place of going through the algebra and helping the students see the process before trying it themselves. This is a tricky problem to bring the DE solving bit into something student-centered.
Monday we’re doing reference frames, so homework is to watch at least the first five minutes of “Frames of Reference” from 1960. I hope they continue to watch a little more, but the first five minutes are still pretty good.