# Day 32

Oct 18, 2017

Physics: Simple machines and a pulley lab. We started by talking about levers and inclined planes, although the Hewitt book uses the distance from the fulcrum as a proxy rather than the actual distance the end moves, which drives me nuts. Work is the force times the distance the object MOVES, and a lever doesn’t move an object closer to or farther away from the fulcrum. Yes, it works out in terms of torque, but it does NOT in terms of work and energy. My colleague spent an entire class talking about simple machines, where I spent 15 minutes before the lab going over the ideas super quickly. We’ll definitely review that heavily, but they did great with the lab. We had set-ups with 1, 2, 3, and 4 pulleys. Each group got one set-up, and tomorrow I’ll do something like have the students compare their results with someone from a different group with a different number of pulleys and see if they can find a pattern.

Honors Physics: Pendula! We’re continuing the Pendulum Study. Before break we did a bit of conservation of energy with a pendulum. Today was the ballistic pendulum and basic “how fast is a pendulum going at this point” problems. The goal is still helping students figure out when to use momentum and when to use energy, similar to the goals of today’s AP class. We basically got through two problems, which I am A-OK with. They have two practice problems as homework, as well, to try out this process, and we’ll keep practicing. Tomorrow my plan is to have them swing some things around and figure out when the force feels like it’s the greatest and then start on circular motion force diagrams.

AP Physics: Continuing energy and momentum. Today we practiced some problems where the first task was to decide whether the ideas to use were energy or momentum, and then the students attempted them, and then we went over them. I had another set of questions with some T/F that led to good discussions, after which we looked at the math involved with change in energy of a swinging pendulum very quickly before sending them off with a few practice problems and the admonishment that I care way, way, way more about the work and the process than getting the final answer.