Rockets are propelled by Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. Here's how it works:

1. Burning Fuel: Rockets burn fuel, usually a combination of liquid hydrogen and oxygen, inside a combustion chamber. This burning creates hot, expanding gases.

2. Nozzle Expansion: The expanding gases are forced out of a nozzle at high speed. This creates a force in the opposite direction, propelling the rocket forward.

3. Action-Reaction: The action of pushing the hot gases out of the nozzle creates the reaction of the rocket being propelled forward.

In essence, rockets use the power of their own exhaust to propel themselves. The faster the exhaust gases are expelled, the more powerful the thrust and the faster the rocket accelerates.

There are different types of rockets, including solid-fuel and liquid-fuel rockets, but the fundamental principle of action-reaction remains the same.