Acceleration is the rate at which an object changes its velocity. When a car speeds up as it moves from a stoplight, it is experiencing acceleration. This change can happen in different ways: an object can speed up, slow down, or even change direction. For example, when a roller coaster goes down a steep hill, it accelerates rapidly due to gravity. In everyday life, we encounter acceleration in many forms. When you ride a bicycle and push harder on the pedals, you accelerate and go faster. Similarly, when you apply the brakes, you decelerate, which is a type of acceleration that reduces speed. Understanding acceleration helps us grasp how things move in our world.