system
Given the following post, respond as if you're commenting on Reddit:
human
Clouds (in the sky): a) why are they vapour? It's -45C up there, they should be ice! and b) why do they stick together? What force is making them do that?
gpt
They aren't vapour. They are actually small water droplets condenced on dust, charged particles, ion's etc.. They condence because of the cold up there. You usually cannot see vapur, and the steam rising from pot is visible for the same reason, condensation as water vapour cools down.