Place the three inch diver in a full plastic bottle of water (follow directions included with diver). Squeeze and hold the sides of the bottle and watch as the diver dives down. Release the bottle and watch the diver float back to the top. This experiment is based on water pressure and will bring hours of enjoyment to you and your children. One and two liter plastic pop bottles work the best with the catch and hook diver. Bottle and water not included.