The idea of energy has to be explored as much as possible because life on earth much depends on the vital use of energy. It is the transfer of energy that gets things done. In this unit we will investigate an important way of transferring energy. One way of transferring energy is by wave motion. All waves transfer energy. The idea of waves is important in understanding sound. Sound plays so important role in our lives that we communicate each other using it.

Periodic vibrations can cause disturbances that move through a medium in the form of waves. Many kinds of waves occur in nature, such as sound waves, water waves and electromagnetic waves. As a wave propagates, it carries e