How to Build a Rubber Band Powered Car

Learn how to turn recycled materials into a fast-moving car powered by the energy stored in a rubber band. HowTo: Family Edition: family how-tos that actually help.

1. Prepare the chassis. Cut your cardboard into a rectangle about 4 inches by 6 inches. Tape your two straws across the width of the cardboard, one near the front and one near the back, so they are parallel to each other.
2. Make the wheels. Ask a grown-up to poke a hole exactly in the center of each of the four bottle caps. Slide one skewer through the front straw and one through the back straw. Press the bottle caps onto the ends of the skewers to act as wheels.
3. Add the engine. Cut a small notch into the center of your back axle (the skewer). Hook one end of your rubber band to the notch, then stretch the other end toward the front of the car and tape it securely to the cardboard base.
4. Launch your car. Roll the car backward on the floor to wind the rubber band around the back axle. When you let go, the energy in the rubber band will spin the axle and send your car forward.