30. Rockets

Water Rocket — A toy rocket is loaded with water and compressed air and shot across the room. It can also be fired with air only (no water in it) to show the difference.

C02 rocket — A rod mounted on the end of a shaft is free to turn about the shaft's axis. At the end of the rod is a C02 cartridge. When the cartridge is punctured, the escaping gasses propel the rod with considerable speed.

Hero's engine — spins by the reaction force of escaping steam.