I know it's probably the most stupid question there is, but why do they fly are the clouds lighter than air? What's keeping those tiny ice structures floating miles about the ground? I've been looking all over the internet and I can't find acceptable answer to this basic physical question. Can you please help me?
This question was marked as answered - but I don't believe it has been explained satisfactory. Please bare with me on this one.
Have you ever walked through fog? What is it made of?
Lots of very small water droplets. They are so small that their weight is negligible compared to the motion of air molecules, so they fall too slowly to ever notice.
Next time you boil water, and you see "steam", what is it? Same thing.
The only difference between fog and a cloud is that fog is a cloud that happens to be on the ground.
This is easier to picture with a particular example. Have you seen clouds with flat bottoms, like a lot of small clouds that all have flat bottoms at the same level? These clouds are blobs of air with more moisture than the surrounding air. The flat bottom type are from rising air from heat convection. This is what pilots call "thermals". The air cools as it rises both from the surrounding air being cooler and because the air is expanding.
The flat bottom you see is the altitude at which the temperature equals the dew point for the humid air rising up and there is condensation. If you watch you can often see that the cloud grows as more humid air rises. It only becomes visible as it passes the dew point. The types of birds that soar will be under these clouds getting a lift.
