The law of conservation of energy states that energy can neither be created nor destroyed, but it can be transformed from one form to another. Here are some examples of the conservation of energy:
A roller coaster moving up and down a track: As the roller coaster climbs up a hill, it gains potential energy. When it reaches the top and starts to descend, this potential energy is converted into kinetic energy. At the bottom of the hill, the kinetic energy is at its maximum and the potential energy is at its minimum.
A pendulum swinging back and forth: As a pendulum swings, it moves between two points of maximum potential energy, where it is momentarily at rest, and two points of maximum kinetic energy, where it is moving the fastest.
A light bulb converting electrical energy into light: When a light bulb is turned on, electrical energy is converted into light energy and heat energy. The total amount of energy is conserved, but some of it is lost as heat.
A car braking to a stop: When a car brakes, the kinetic energy of the moving car is converted into thermal energy due to friction between the brake pads and the wheels. The total amount of energy is conserved, but the kinetic energy is transformed into a less useful form.
A battery powering a device: When a battery is used to power a device, chemical energy is converted into electrical energy. The electrical energy is then used to perform work, such as lighting a bulb or spinning a motor.
These are just a few examples of the conservation of energy in action. In each case, energy is transformed from one form to another, but the total amount of energy remains constant.