According to Newton's third law of motion, for every action, there is an equal and opposite reaction. This law explains how a rocket takes off.

- Action: The rocket's engines expel hot gases downwards with great force.

- Reaction: In response to the downward force of the exhaust gases, the rocket experiences an equal and opposite upward force, propelling it upwards.

Therefore, the reaction (upward force) is directed in the opposite direction of the action (downward force of the exhaust gases). As a result, the rocket rises off the ground and into the sky. This principle demonstrates how rockets defy Earth's gravity and achieve space travel.