How to Build a Catapult

Remove bark from a "Y"-shaped piece of wood.

Sand off bumps or sharp edges from the wood so it becomes smooth.

Dry the wood. Cut two big rubber bands to have two lengths of strong elastic material. Each of these lengths forms side-band of the catapult.

Use smaller rubber bands to secure one end of the cut rubber band to an arm of the Y-shaped wood. Use multiple rubber bands to secure it properly. Do the same for other side of the catapult.

Make a sling or a pocket in which to hold the projectile. Cut the piece of soft leather. The sling should taper down the ends and be widest in the middle.

Take smaller rubber bands to connect one end of the sling with loose end of one of the catapult bands. Use multiple rubber bands, if required.

Attach the other end of the sling to the second end of the catapult. Use smaller rubber bands to do so.

Test your catapult. Hold the handle of the catapult in front of you, load a pebble or a small object in the sling. Pull the sling back as far as possible, aim and release it to see the projectile being hurled away.