Question

Explain the following:

Colloidal dust is sprayed on clouds to compel them to rain.

Answer 1

Colloidal dust is sprayed on clouds to induce artificial rain because clouds are colloidal systems containing water vapor mixed with tiny dust particles. The water molecules in clouds carry an electrical charge, which keeps them dispersed and prevents precipitation. When oppositely charged colloidal dust or sand particles are sprayed onto these clouds, they neutralize the charges on the water molecules. This neutralization reduces the repulsive forces between water droplets, causing them to coagulate or combine. Consequently, the larger droplets gain sufficient weight to precipitate as rain. Thus, spraying colloidal dust helps compel clouds to rain by promoting the coagulation of charged water particles in the cloud.