In the 1600's, the English scientist and mathematician Sir Isaac Newton proposed three laws of motion. Newton's laws concern the ideal motion of objects and do not take into account air resistance or other friction. However, these laws have enabled scientists to describe a wide variety of motions.
The third law of motion states that for each action there is an equal and opposite reaction. For example, when hot gases escape from a rocket engine during take-off, the rocket is propelled upward. The downward motion of the gases from the rocket generates a reaction of the rocket upward. This reaction helps the rocket overcome air resistance and fly into space. There are many other examples of Newton's third law. When a rifle fires a bullet, the firing of the bullet is the action and the recoil of the rifle is the reaction. Both are caused by the expanding gas of the exploding gunpowder. Rotating lawn sprinklers propel a spray of water in one direction while rotating in the other direction.
Sometimes the reaction is such that it cannot be easily seen. When you throw a ball against a wall and the ball bounces back, you do not see the wall moving in the opposite direction. But there is a small motion of the area of the wall that was hit. If the ball bounces from the ground, the earth also draws back, but the mass of the earth is so great that we cannot see its motion.