Question

what do you understand by condensation nuclei

Answer 1

Cloud condensation nuclei or CCNs (also known as cloud seeds) are small particles typically 0.2 µm, or 1/100th the size of a cloud droplet on which water vapor condenses. Water requires a non-gaseous surface to make the transition from a vapour to a liquid; this process is called condensation.

Answer 2

Condensation nuclei are tiny particles in the air on which water vapour condenses and they are the key to making clouds, fog, haze and other forms of precipitation.