Building a car propelled by a rubber band is a fun and educational project for kids of all ages. After it is built, the vehicle can be raced and kids can calculate how far they can make their car go. Rubber bands hold potential energy in tension stored through wrapping the band around the axle. When you let the car go, it speeds off. The distance the car will go largely depends on the amount of energy stored in the rubber band.
Cut the cardboard into a 5-by-6 inch piece, with the corrugation visible from the 6-inch sides.
Cut a notch in one 5-inch side of the cardboard piece, 2 inches wide and 1 1/2 inches deep. Center this notch on that side.
Poke the skewer between the corrugation as close to the edge with the notch as possible. The middle of the skewer will be visible in between the two non-notched pieces of cardboard.
Cut a piece of duct tape 1/2 inch wide and 1 1/2 inches long. Pinch the duct tape in the centre of the skewer so that 1/2 inch touches another 1/2 inch of the tape. Roll up the remaining 1/2 inch to create a stopper on the tab.
Slide a CD and washer onto each end of the skewer and secure on both sides with poster putty
Tape a rubber band to the surface of the cardboard so that the band fits loosely over the tab.