# Day 20: Droppin’ Eggs and Terminalin’ Velocity

Physics: Air Resistance day! Gotta talk about terminal velocity and how acceleration changes as objects fall. Charlie uses a story about a man being thrown out of a helicopter. I like Kelly’s scenario of throwing a worthless lab partner off a cliff.

Ended up using the throwing a worthless lab partner off a cliff story, but I really felt like they were able to start putting the ideas together and making sense of how air resistance affects motion and causes a changing acceleration. It was harder to explain without using the math as a back-up, but they were working very hard to understand. Watching the ideas swirl around in their brains and coalesce is so amazing. The difference between speed and acceleration is slowly starting to happen in their brains. It’s nice.

Honors Physics: Egg drop! It’s the momentum-impulse lab, and we don’t have sensor technology, so I figured tried and true. G bought 5 dozen eggs for me at CostCo, so them baker’s dozen a kids gotta go through ’em. I have a ton of random crap I have picked up over the years at RAFT thinking, “Oh, I could do something with this!” but never actually did the something and just accumulated piles and piles of things. Since these kids don’t all go home to parents who can run to the store to buy them stuff, I’m providing all the things. The restrictions I’ll give them are still a little vague. Maybe I shouldn’t give them any restrictions at all considering they have 80 minutes to build, test, and rebuild. I could have them do whatever and see how it works. The strictest limit is that they only get one strip of masking tape that’s ~1m long to hold it all together.

I should have given them significantly more restrictions, because there was very little creativity in their devices. It was mostly just put soft things around the egg. I used to make a requirement be no parachutes and no streamers so that the whole idea had to be impact prevention rather than slowing it down in the air, but I wanted to see how things went. They went way too easy. Also, the place where I was planning to throw them up in the air had an overhang I hadn’t taken into account, so there were some silly things that happened. Their requirement to process the activity was to write a one-page double-spaced paper explaining the physics of how their device worked or didn’t work, and if it didn’t work, what could they do to improve it.

AP Physics: Multiple Choice Practice for Kinematics. We’ve learned everything we need for basic kinematics. The only topic left is drag/air resistance/differential equations, and I need to brush up on that tonight to teach tomorrow. I’ve never taught differential equations, but I know how they work and I’m sure I can put it all together.