How does the pendulum conserve energy?
A pendulum moves with harmonic motion. It is a good device for illustrating the conservation of energy. When lifted up to one side we give it gravitational energy, when released this turns into movement energy as the pendulum swings downwards. After reaching its lowest point the pendulum slows down as it moves upwards again – movement is now being turned back into gravitational energy, and so on. This would continue forever if the pendulum was swinging in a vacuum. However, most of the time the pendulum swings in air and so it slowly loses energy due to air resistance. This lost energy is in the form of heat. This means the swings get smaller, but importantly, the period stays constant. This is shown by the two graphs. Notice that they always reach the midpoint of their swing at the same time even though one is being damped. Putting the pendulum to work Galileo was the first person to think of using a pendulum to make a clock. However, he was unable to get it working properly. It wasn’