I learned that theres more friction if you pull the block across fine sandpaper rather than coarse sandpaper. I learned that coarse sandpaper does go up steady with 2 blocks. I learned that there is more friction when theres more wieght in one spot.
We measured by taking a spring scale hooking it up to the block and pulling it 20 cent.Then we measure what the spring scale reads and we do three times and then get the average.This is measuring friction force.
3. We kept the surface Type the same because if we changed two variables we would have not good data.