There are different forms of energy, such as:

• kinetic - moving energy
• heat
• light
• sound
• electrical
• chemical
• nuclear
• potential

Energy cannot be created or destroyed, though it can be transferred from one form to another. This is rather like money which, when spent, does not vanish but goes somewhere else!

For example, energy is changed from one form to another every time your climb the stairs of hit a tennis ball or dig the garden...