Why do suspended particles settle in muddy water over time but not in milk? Class 9

Why do suspended particles settle in muddy water over time but not in milk? Class 9

Think It Over (Page 72)

Question 1.

Why do suspended particles settle in muddy water over time but not in milk? Class 9

Answer:

Suspended particles in muddy water are large and heavy, so they settle down due to gravity when left undisturbed. Milk is a colloid, and its particles are very small and remain uniformly dispersed, so they do not settle.

Question 2.

How is evaporation different from boiling? Class 9

Answer:

Evaporation is a slow process that occurs at the surface of a liquid at any temperature, whereas boiling is a rapid process that occurs throughout the liquid at a fixed temperature (boiling point)>

Question 3.

Why do you see bright rays of sunlight when it passes through small gaps between the leaves of a dense tree? Class 9

Answer:

This happens due to the scattering of light by tiny particles like dust and water droplets present in air (Tyndall effect), which makes the path of light visible.