Building an elastic-powered car can be a fun project for children, and can be done with adult supervision. The craft project can be used to teach about potential and kinetic energy. When the car is constructed and the rubber band is wrapped around the car's axle, the potential energy is stored in the rubber band. When you let it go, and the rubber band unravels and propels the car forward, it turns into kinetic energy.
Cut a 2-inch wide and 1 1/2-inch deep notch in the centre of the short side of the cardboard.
Slide the skewer through the cardboard on the same edge of the notch. The skewer will pass through the cardboard, through the notch and then through the cardboard to the other side.
Wrap a small piece of tape in the centre of the skewer, to make a catch for the rubber band. Twist the tape to make it thick enough to hold the rubber band.
Hold a washer in the centre hole of a CD and slide both onto the skewer, without pushing it too close to the cardboard. Use poster putty to stick the CD, washer and skewer together. Repeat with the other side.
Tape the rubber band to the cardboard at the end opposite the skewer and wrap the other end on the skewer's catch. It is now ready for you to wrap the rubber band around the axle several times and let it drive.
Always supervise children when they're using scissors.