Day 44: Practical, Spring Force, & Vocab Review

AP Physics: CAPM Practical

Students figured out where to start a buggy so that a marble rolling down a ramp would land in it. Some groups had some trouble translating their strategies for yesterday’s problems to this lab practical, which has been pretty common this year. However, once students got going, there was a lot of success!

Physics: Spring Force

Students worked through the spring force lab I’d previously done with my AP Physics classes. We used force sensors to stretch the spring instead of spring scales or hanging masses so that students could pick one of their springs to also stretch horizontally. From what I saw in notebooks, results are coming out pretty nicely.

Chemistry Essentials: Vocab Review

This unit has had more vocabulary and factual knowledge than many of the others, so we took some time to review key terms and reinforce connections between the different ideas.

6 thoughts on “Day 44: Practical, Spring Force, & Vocab Review”

1. I love the cup and the slo-mo video!
What were your inputs for this practical? Just get the ball in the cup given that the ball starts at certain point on the ramp? And let them model the buggy and ball/ramp separately?

I’m always interested in the different ways this practical can be done.
thanks
Doug

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• I also like to follow up by asking students how they’d need to change their answer for a lighter marble.

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2. Thanks! That group was very satisfied đź™‚

As a class, we used photogates to measure the time it took the marble to get between two photogates 100 cm apart, which the students used to calculate the marble’s acceleration. Then, we timed the buggy going 3 m to calculate its velocity.

Once they have those two values, I give each group a starting position for one object. The calculation with a starting position for the marble is trickier, so that’s what I gave them in AP. In regular Physics, I usually give at least some groups a starting position for the buggy.

Once they have a starting position, I leave it up to the students to figure out how to solve it. They typically model the buggy and the marble separately, using the same time for both, then figure out the unknown distance. A few groups will try to come up with a graphical solution (i.e. make x vs. t graphs and look for the intersection), but I haven’t seen that work yet.

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• About how long did it take your regular physics class? 40 min? 60 min?

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• AP, I usually have every group done within 40 minutes, including the whole-class data collection. In regular, I usually have some groups who need up to 75 minutes.

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