22 Jun '10 21:48>
A thundercloud (cumulonimbus) can weigh as much as thousands of elephants.
How come it doesn't come crashing to earth?
How come it doesn't come crashing to earth?
Originally posted by uzlessIt's pretty simple, cumulonimbus clouds are less dense than the air underneath, like oil floating to the top of a pond. If you captured exactly say, a cubic meter of the thundercloud and a cubic meter of air closer to ground level, the ground level air would have more mass so it would naturally be at the bottom of a gravity well.
A thundercloud (cumulonimbus) can weigh as much as thousands of elephants.
How come it doesn't come crashing to earth?
Originally posted by uzlessIts not mass but density that counts. If you burnt an elephant, all its mass could go into the air and float away.
A thundercloud (cumulonimbus) can weigh as much as thousands of elephants.
How come it doesn't come crashing to earth?
Originally posted by uzlessThink of how much Hindenburg, the Zeppeline, weighted. It didn't crach (because it was heavy).
A thundercloud (cumulonimbus) can weigh as much as thousands of elephants.
How come it doesn't come crashing to earth?
Originally posted by FabianFnasNo, that's really not it, at all. The air below the cloud is still lower density. Water is still higher density.
Think of how much Hindenburg, the Zeppeline, weighted. It didn't crach (because it was heavy).
Think of the difference between mass and weight...
Originally posted by joneschrHindenburg in equibrilium is the same as the watercloud. It finds its place where the mean density under it is higher and above it is lower compare to the mean density of the ship.
No, that's really not it, at all. The air below the cloud is still lower density. Water is still higher density.
Originally posted by FabianFnasThat about sums it up. Why is there such a debate over such a mundane issue?
Hindenburg in equibrilium is the same as the watercloud. It finds its place where the mean density under it is higher and above it is lower compare to the mean density of the ship.
Originally posted by joneschrnow, we're gettin somewhere
Because clouds still float when the mean density of the cloud is higher than the mean density of the air underneath the cloud. And that's the principle that addresses the OP's question.
The issues is why water droplets (which are more dense than air) don't crash to the ground. To address that point, you need to understand drag - (not density and not pressure).
Originally posted by joneschrBut is it? (the mean density of the cloud higher). If so, it would only be marginal or there would be a downdraft (the cloud would fall).
Because clouds still float when the mean density of the cloud is higher than the mean density of the air underneath the cloud.
Originally posted by joneschrIf it was just drag, then air would fall to the surface, eventually. It doesn't, because of pressure.
Yes, the cloud would fall. But at an extremely slow rate - as I posted earlier, a cloud will naturally fall from gravity. But again, because of drag, it would take a couple of years to reach the ground.