Question: if the clouds are solid how can we see them

Ciarán O'Brien answered on 14 Nov 2014:

The clouds aren’t particularly solid. They’re mostly water vapor and tiny droplets of liquid water that formed around dust floating about in the wind.

You know how your breath fogs up when it’s cold outside? That’s pretty much what a cloud is. Same thing with the steam coming out of a kettle. You don’t actually see the water as a gas because it’s invisible. what you DO see is tiny water drops that are so light they can stay in the air for ages.

You get clouds at ground level too when it’s foggy. In weather it happens when warmer air with more water vapor in it meets colder, drier air, and the water vapor turns into tiny liquid particles. They scatter light that passes through them a lot, and they end up looking white and fluffy (or darker and darker grey, depending on how thick the cloud is and how much water is condensing in them.

When the water droplets bump into each other they join up and get bigger, and they’re not so good at floating any more. When a bunch of them get so big they can’t float at all, they fall to the ground as rain.