Conservation of Energy

Energy comes in many different forms – for example, heat, light and sound. We often can, and do, change energy from one form to another. When you turn on a light, electrical energy changes to light energy and heat energy. When this change or conversion takes place, there is some waste heat produced but no energy is lost. It has simply changed, even though some may have left the system. Energy therefore can neither be created nor destroyed, simply changed from one form to another, hence it is conserved.