Manomay Shravage

The Tyndall effect is the scattering of light as a light beam passes through a colloid. The individual suspension particles scatter and reflect light, making the beam visible.

The amount of scattering depends on the frequency of the light and density of the particles. As with Rayleigh scattering, blue light is scattered more strongly than red light by the Tyndall effect. Another way to look at it is that longer wavelength light is transmitted, while shorter wavelength light is reflected by scattering.

The size of the particles is what distinguishes a colloid from a true solution. For a mixture to be a colloid, the particles must be in the range of 1-1000 nanometers in diameter.