School project Hope someone can help me, it is for a Junior school Car disks Material:  30 x 30 cm paperboard  2 old CD or DVD disks  2 skewer sticks  Plastic card  1 bead  3 rubber bands  Hot silicone  Coin Procedure: Cut three 5 cm wide paperboard strips, it must have the same rubber band length, then cut and paste them on the disks. Use the coin to cut a circle in the plastic card with a little hole in the center, then stick it on a disk, cut the skewer sticks, one must be longer than the disk radio and the other one must be shorter, after that take the rubber band trough the bead hole, fasten it to the longer stick and take the other band end trough the CD hole and fasten using the shorter stick, finally use some silicone on it. It works circling the long stick. Explanation: Circling the stick we accumulate elastic potential energy because it pulls over the rubber band so it accumulates energy and it is liberated when the floor keeps off the stick’s turning.