Question

why is milk white in colour

Answer 1

Milk contains 87% water and 13% of fats and proteins. Among the proteins, casein protein is the largest in milk that amounts 82 per cent. Milk is a natural emulsion with the percentage of disperse phase in milk is very low. The whiteness is due to the scattering of light by the colloidal particles (casein proteins and some of the fats in the milk) of the milk emulsion. These proteins and some of the fats in the milk scatter and deflect light somewhat uniformly throughout the visual spectrum without absorption. This results in milk being fairly opaque and appearing white to our eyes.