Day 35: Toothbrushes and Friction

College-Prep Physics: Today will likely be our last round of voting for while. As per Preconceptions in Mechanics, we started this round of discussion on friction with a Pre-Instruction quiz. I set up a toy buggy (without the tire treads) connected to a friction sled by a rubber band to help visualize the scenario:


In previous years, I’ve used a pair of hair bushes to model friction between surfaces. But the black bristles made it hard for everyone to see. So I took PiM’s advice and bought a class set of toothbrushes.


And gave everyone a toothbrush so they could interlock brushes with a partner and observe.

oprah car

“And you get a toothbrush! And you get a toothbrush! Everybody gets a toothbrush!”

Much better!



NGSS Science and Engineering Practice #2: Developing Models
NGSS Science and Engineering Practice #6: Constructing Explanations


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About Frank Noschese

HS Physics Teacher constantly questioning my teaching.

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