Ripple tank
The concept of reflection and refraction of light waves can be understood by the study of reflection and refraction of waves on water. The water waves travel as crests and troughs and can be treated as transverse waves like light waves for practical purposes. This can be demonstrated with the help of ripple tank.
- The ripple tank consists of a rectangular shaped trough (tank) made of transparent glass material .
- This tank containing water is held at a height with the support from four legs.
- Below the tank, a white paper is spread on the floor (which act as screen)
- Above the tank, a partially covered electric bulb is fixed to illuminate the tank.
- A small needle (N) is fixed at one end of a metallic strip connected to an electric vibrator.
- The tip of the needle is kept vertically in contact with the water surface in the ripple tank.
- When the strip vibrates, the needle also vibrates and produces disturbance.
- This disturbance travels in the water in the form of circular waves with the tip as the centre.