Tyndall effect

Tyndall Effect: The scattering of light by Colloidal particles is called Tyndall effect. This effect is an optical property of colloids and can be used to distinguish a colloidal solution from a true solution.

Since the particles of a colloid distribute in a solvent non-uniformly, so the light rays show collision with these particles and get scattered. But the particles of a true solution are so small and homogeneously distributed that the light rays do not collide with them and hence, no scattering of light rays takes place.

Example: When sunlight passes through canopy of forest shows Tyndall effect as tiny droplets of water in mist acts as particles of colloid dispersed in air.