The Cycle of Energy
The Law of Conservation of Energy tells us that energy cannot be created or destroyed. It can only be converted into other types of energy. In the picture at the left we see a baseball moving upwards and then downwards. When it is high in the air it has gravitational potential energy. It has the potential to fall. So, when the ball begins to move upwards it has kinetic energy. That kinetic energy turns into gravitational potential energy as it moves upwards. The kinetic energy decreases because the ball is slowing down. When the ball starts to fall, the kinetic energy increases because the ball is speeding up. The gravitational potential energy decreases because the ball is lower to the ground.