Why do suspended particles settle in muddy water over time but not in milk? [Pg. No. 72]

Suspended particles settle in muddy water because it is a suspension. The mud particles are comparatively large and heavy, so they settle down under the effect of gravity when left undisturbed. Milk, however, is a colloid in which tiny fat droplets and protein particles are dispersed in water. These particles are very small and remain suspended due to continuous random motion and stabilising substances present in milk. Therefore, particles in milk do not settle easily on standing, unlike mud particles in muddy water.