WAVE BEHAVIOUR

All waves can be reflected, refracted and diffracted, and these behaviours can easily be observed with water waves.

Reflection: When waves strike an interface between materials, they be reflected. A ripple tank can be used to demonstrate the reflection of water waves. When a flat metal barrier is placed in a ripple tank, straight ripples are reflected when they strike the flat surface of the barrier. The metal barrier acts like a mirror, and the ripples bounce off it. The ripples are reflected by the metal barrier so that the angle of incidence is equal to the angle of reflection.

Refraction: When waves cross an interface between two materials they may change direction which is called refraction. A ripple tank is used to demonstrate refraction due to a change in speed. A glass plate is immerged in the water, to make the water shallower in that

part of the tank. There the ripples move more slowly because they drag on the bottom of the tank (which is actually the upper surface of the submerged glass plate).