Activity 1: Spool Racers

Materials needed (for each student):

• one spool
• one rubber band
• toothpick
• pencil or dowel
• two metal washers
• masking tape

Procedure:

1. Begin by asking the students if they have ever wound up a swing and then let it go. What happens? The swing unwinds and then begins to wind up again going the other direction. This continues until it stops. Explain to the students that this is called "elastic potential energy." The swing is wound up and stores potential energy. When you let go, kinetic energy results and the inertia of the swing makes it keep going and start winding up again. The swing then has elastic potential energy again. This continues until all the energy has been exhausted.
2. Both activities today will explore elastic potential energy, kinetic energy, and inertia.
3. Give the students the materials to make a spool racer. See the copy of the Spool Racer activity sheet for step-by-step instructions. You may copy this for each student if you wish.
4. Let the students make the spool racers and then try them out on the floor. (Discuss: What happens if you change the number of twists in the rubber band? Let them try this.)
5. Add a strip of tape around the outside rims of the spool? Does this change the behavior of the spool?