Why does the sun looks red at the time of setting ? Explain on the basis of colloidal properties.

Explanation

Air contains dust particles along with water suspended in it. As such it behaves as a colloidal solution. Those dust particles and water suspended in air scatter light. The colour of a colloidal solution changes with the manner in which the observer receives the light. Therefore due to the change in angle of viewing sky appear blue at noon and red in the morning and evening.