Energy

Work and heat energy

The energy mainly comes under two forms: work-energy and heat-energy. The former can be fully transformed into the latter, but not vice-versa because the heat tends to disperse. The energy that produces work can again be divided into potential and kinetic energy. Potential energy is connected to the respective positions of two bodies, for example the gravity pull increases insofar as the distance between a body and the centre of the Earth increases. Kinetic energy is the energy of the chaotic movement of molecules. By throwing a ball up into the air, its kinetic energy increases. While moving upwards, the ball looses kinetic energy and increases its potential energy. When the topmost point is reached, the potential energy reaches its peak and the kinetic energy is nil, and the ball starts falling down. During its downfall, the ball increases its kinetic energy while the potential energy decreases. By bouncing on the ground, the ball transfers part of its kinetic energy to the Earth as heat.