The standard rubber band car features a rubber band wrapped around an axle, which propels the axle forward, thereby spinning the wheels when snapped. The more the band is twisted around the axle, the more momentum is built up to propel the car.
All rubber band cars follow the same basic structure. A chassis, or car body, is at the core. This can be made from wood or any other desired material. At the back of this chassis is an empty nook cut away to make room for the rubber band to wrap around the back axle. Two thin, cylindrical objects, such as pens, are placed at either end beneath the chassis and four wheels are attached. These can be made out of anything from Life Savers to CDs.
Generally, three rubber bands are formed into a chain, wrapped around the back axle and then taped or glued to the front end of the car. When the axle is twisted, it tightens the rubber band, making the car spring forward upon release.
In order to make sure the rubber band car works properly, the axles must be exactly the same length. Otherwise, the car does not go in a straight line. Likewise, the wheels must be tight to the axles. If they are loose, the builder can hot glue them in place, or the rubber band car does not move far.