Hero's Engine

We use a Hero's engine model to show how equal and opposite forces can cause propulsion. Two holes are pierced in a metal bottle and some water is added. This is suspended above a Bunsen burner, and as the water boils and leaves the holes, the bottle begins to spin. Physics - Forces - Learning Points. Hero's engine is a very primitive heat engine. Newton's third law of motion states that for every force there is an equal and opposite reaction force. Steam is accelerated in two jets tangential to the aluminium water bottle. The two tangential reaction forces create a rotational force, or torque, that spins the bottle. A Twig Experiment Film. Let students experience real experiments in lab conditions anywhere, from setup, method all the way through to analysis and real-world application.