Cloud condensation nuclei

Cloud condensation nuclei or CCNs are small particles (typically 0.00002 mm, or 1/100 th the size of a cloud droplet http://apollo.lsc.vsc.edu/classes/met130/notes/chapter6/ccn.html) about which cloud droplets coalesce. Water requires a solid surface to make the transition from a vapour to a liquid. In the atmosphere, this surface presents itself as tiny solid particles called CCNs. When no CCNs are present, water vapour can be supercooled below 0 °C (32 °F) before droplets spontaneously form (this is the basis of the cloud chamber for detecting subatomic particles).

Related Topics:
Cloud - Coalesce - Vapour - Liquid - Water vapour - C - F - Cloud chamber

~ ~ ~ ~ ~ ~ ~ ~ ~ ~