Rocket engine

A rocket engine is a device that produces a force by pushing gases at high speed out of a nozzle. Rocket engines usually burn chemicals such as petrochemicals and liquid oxygen at very high pressures and temperatures to turn their chemical energy into motion of the rocket. In some cases (such as the Rocketdyne F-1), the force created can be over 1,500,000 pounds-force (6,700,000 newtons).

A garden hose shows how moving fluid can create a force. When a hose is turned up, the hose will snake around unless it is held still. The water which is leaving the hose, is creating a force on the hose just like how the gases coming out of a rocket engine push on the rocket engine. This principle can be explained by Newton's third law.