To end our unit on force and motion, we had a box car derby. We sent a note home before Thanksgiving Break asking the students to make a box car with a box no bigger than a shoe box and they had to create their own wheels. On the day of the derby we used a piece of wood and the stage to create a ramp for the cars to roll down. The idea was to see whose car could push a wooden block the farthest. The kids had a lot of fun rolling their cars down the ramp even if their car did not push the block the farthest.