A: A cloud will not be a large pool of liquid water however consists of minuscule droplets (~10 microns every) and generally ice crystals. These particles are so small and light-weight that they’re simply suspended by rising air currents and turbulence in the environment.
Each droplet is topic to gravity however as a result of it’s so small, air resistance virtually completely balances its weight. The falling pace of a 10-micron droplet is just round 1 cm/s, so it might take hours to fall by 1 km of air. Updrafts in clouds are sometimes stronger than this.
As droplets collide and coalesce into bigger drops or as ice crystals develop and soften, their mass will increase a lot quicker than air drag. A 2-mm-wide raindrop can fall at round 7 m/s, which is quicker than updrafts. So as soon as droplets attain that dimension, gravity wins and the droplets fall as rain.
A bucket of water is a steady physique. Surface pressure holds all of the molecules collectively, so if you happen to overturn it, the water pours out in a sheet. A cloud has no such cohesion: it’s simply a diffuse suspension of impartial droplets scattered by kilometres of air.
