Day 37: 3rd Law & Kepler

AP Physics: 3rd Law

On Friday, students predicted how the force on a pair of carts would compare for various collisions. Today, we got out a pair of carts and force sensors to test out their predictions. I got pretty excited when, after seeing the first couple collisions had the same force, one student took another look at her system schema and free-body diagrams, then pointed out both forces are measuring the same interaction, so the magnitude should be consistent. Afterward, we watched Veritasium’s excellent video on the 3rd Law.

Earth Science: Kepler’s Laws

Students drew ellipses and measured the distance between the foci and points on the ellipse to look for patterns. Students were pretty successful at finding the pattern in the distance to the focal points. I tweaked the lab as written to try to have students discover the equal areas law, but I did not account for the fact that the length of the string loops varies a lot. Tomorrow is slated for more time on this lab, so I think I’m going to try and find some data they can use to plot actual positions of one of the planets tomorrow.


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