eli5: How do (presumably very heavy) clouds stay suspended in the sky? More specifically how are they floating AND flat on the bottom?

Question

And what causes them to suddenly drop all of that water in the form of rain.

Judging by the amount of rain they must weigh a ton.

In: 337

Answer 1

Your main logical failing here is considering the weight of the cloud but dismissing the weight of the atmosphere.

If you pour oil on a pool of water, how does the oil float on the water, it’s heavy! Well the water is denser.

Dry air is denser than water vapour/humid/hot air. And that is why it floats above the ground (but not always, fog is a thing).

The reason that they are flat at the bottom, is that the water condenses out of the air at a given temperature based on the humidity (dew point). As you go up, the temperature drops, so at the height were the temp had dropped to the dew point, is where the clouds are. And since that’s a pretty sharp line, the clouds are flat at the bottom.