The earth’* atmosphere is a heterogeneous mixture of minute particles. These particles include smoke, tiny water droplets, suspended particles of dust and molecules of air. When beam of light strikes such air particles, the path of the beam becomes visible. Similarly the path of a beam of light passing through a true solution is not visible. However, its path becomes visible through a colloidal solution where the size of the particles is relatively larger. The phenomenon of scattering of light by the colloidal particles gives rise to Tyndall effect.
Tyndall effect is the visible scattering effect of light on particles path of a beam of light passing through a colloid system.
