Measuring the Coefficient of Friction
Posted March 18, 2009on:
I developed this lab for my physical science classes, but I wish I had thought of it for my physics classes. Since we do more with the coefficient of friction in physics, I will be upgrading and adding this lab to my course for next year.
In this lab, the students pull various objects across different surfaces. The objects pulled were what I could get my hands on in a very short amount of time. I had wooden blocks, plastic coated weights, steel weights, aluminum ringstand rings, and I asked the students to also use their sneakers.
They pulled these objects across a whole range of surfaces. They used the top of the desk, the floor tiles, cardboard, plywood, tile board (white board), a rubber coated lab apron, cork board, and Styrofoam sheets. I asked them to get creative and find objects and surfaces in the room. I didn’t have sandpaper out, but many of them asked for it in their write-up. The plan was to pick an object, pull it across as many surfaces as possible, then move on to another object.
They were surprised at the stickiness of the aluminum ring on the shop apron. I was too, it had a coefficient of friction greater than 0.5.
When I do this with my physics students, I will probably add a component where they have to predict the maximum angle of incline for an object on a surface before it starts slipping. I like that.
Here’s my lab paper: measuring-the-coefficient-of-friction1