This idea comes from a TED Talk from Frank Noschese. This was day 1 of our Forces Unit in AP Physics C. My goals were for students to learn how to draw detailed Free Body Diagrams and also to think about how to practically apply Newtons’s 2nd Law. The challenge was to “weight my car without picking it up.” I did this as a whole class challenge lab. I described the challenge, introduced the available materials, and answered questions (“no, you may not weigh the car with water displacement”, “yes, I bet that any of you are strong enough to push the car.”) Each team wrote a proposal for how the class would completed this challenge (What will you measure? How will you measure it? How will you use this to determine the mass of the car?). As a class, they shared these proposals and discussed one method to perform as a team. The discussion about friction was awesome! (“Can we just ignore friction?” “What’s the coefficient of friction for your tires, Mr. Randall?” How would we measure friction ourselves?”) After collecting data as a class, each team used the data they collected to calculate the mass of my car. In order to make this less “google-able” I loaded up my truck with textbooks and bowling balls. I plan to take my car to a scale to get it measured precisely before next class.
Randall Physics 