# Physics

### Chapter : 5. Sound

#### Introduction To Wave Motion

Most of us have seen the formation of ripples when a small stone (pebble) is dropped into a pond. The disturbances created by the stone in the water produces ripples which move outwards towards the shore of the pond.
If you examine the motion of a leaf floating near the disturbance for a short while on a steady day, you would see that the leaf moves up and down about its original position, but does not move away or towards the source of disturbance. This indicates that the disturbance (such as a water wave) moves from one place to another, but the water is not carried with it. The water particles simply move up and down their mean positions.
The formation of ripples on the surface of water is an example of wave motion.
Wave Motion :The movement of a disturbance produced in one part of a medium to another involving the transfer of energy but not the transfer of matter is called wave motion.
Examples :
(i) Formation of ripples on the water surface.
(ii) Propagation of sound waves through air or any other material medium.