A crossbow is a medieval type of weapon based on a bow and arrow, in which the bow is mounted horizontally on a stock. Build and experiment with five different types of crossbows. The projectile, called the bolt, has a safe foam tip and a special cross-section that prevents other projectiles from being launched. When the bolt is loaded into the crossbow, a rubber band is pulled backward and energy is stored in the stretched rubber band. A trigger releases the bolt and the rubber band launches it through the air toward its target.
A catapult is another medieval ballistic device that uses mechanical rubber bands and counterweights to fling projectiles into the air. The 32-page, full-color manual has illustrated step-by-step instructions.