# Day 120: Practicals & Demos

AP Physics: Central Force Practical

I got out the record player and, as a class, we found where a mass starts to slip when the player is at 33 1/3 rpm. Students then calculated what radius they should place the same mass at when the record player is at 45 rpm. Since the velocity depends on the radius, the math got a little hairy, but students were pretty successful working through it and making sense of how all the variables were connected.

Physics: Projectile Practical

Students rolled a marble down a short ramp to turn it into a horizontal and predicted where it should hit the floor. Both my classes were able to complete it with less support than I expected. After each group managed to hit the target (an old carbon-copy referral form), I asked them to predict where, relative to their first marble, a lighter one should land.

Chemistry Essentials: Demos

Students balanced a few different chemical reactions, then I demonstrated those reactions. Most of the students seem to be getting pretty confident with both skills and enjoyed the demonstrations. The thing I struggled with is the demos felt very separate from the balancing since they did confirm or otherwise add to the work students had done. I’m wondering if there is something I could have done differently to connect those two pieces better.