When air is cooled below its dew point, the water vapor it contains tends to condense as droplets of water or tiny ice crystals. Condensation may not occur, however, in the absence of tiny particles on which the water or ice can form. These particles...

Cloud condensation nuclei or CCNs (also known as cloud seeds) are small particles (typically 0.0002 mm, or 1/100 th the size of a cloud droplet [1]) about which cloud droplets coalesce. Water requires a non-gaseous surface to make the transition from a...