How can the clouds float but we can not

Question: How can the clouds float but we can not
- Keywords:
  clouds
Asked by KUNG FU TIGER to Jake, James, Pete, Senga, Simonne on 13 Nov 2017.
- Jake Langham answered on 13 Nov 2017:
  
  This might be a bit tricky, so I split my answer into two. Let me know if you don’t understand and I’ll try to help.
  
  *****
  
  Short answer: Clouds have a density which is the same as the air around them, allowing them to float. Our bodies are much too dense for this. ‘Density’ means how heavy they are per amount of space that they take up.
  
  *****
  
  Proper answer: Objects float or sink in the air (or water) according to something called ‘Archimedes principle’. Suppose you have a balloon in the air. Archimedes principle says that there is a force pushing the balloon upwards that is equal to the weight of the air displaced by the balloon. (‘Air displaced’ means all the air that would be where the balloon is if it wasn’t there.) In order to float upwards, this force has to be bigger than the weight of the balloon, which pulls it down to Earth due to gravity. If the balloon is filled with lots of helium, its total weight is less than an amount of air which takes up the same space. So a helium balloon floats upwards from the ground. I think you would agree that an amount of air that takes up the same amount of space as a human weighs much less than a human does. Therefore, humans do not float. Clouds on the other hand are about as dense as the air around them so they do float because the force pushing them up is the same as their weight pulling them down. Different clouds float at different heights depending on how dense they are. Fog is basically a cloud that is so dense it only floats close to the ground.
- Pete Gwynne answered on 13 Nov 2017:
  
  if something is small enough and spread out enough, it gets held up by the air. clouds are made of tiny droplets of water and they are spread out really wide, even though they look quite solid. a cup full of cloud would only have a few drops of liquid water in it. the clouds only fall as rain when the tiny droplets start joining together (normally when they get colder) and become too big to be held up by the air.
  ——
  so clouds float because they are much more spread out than we are. you could make yourself float by becoming really small (maybe half the width of a hair) or by spreading yourself out. you’d need to spread yourself out to the size of a cube 50 kilometers on each side, which is about the same size as a pretty big lake.
- Senga Robertson answered on 14 Nov 2017:
  
  Hi Kung Fu Tiger
  
  Jake and Pete have given you brilliant answers. I explain clouds to people like this:
  
  Clouds are made of water but the water droplets are so tiny that gravity doesn’t affect them so they can float.
  
  Unfortunately we are big enough to be affected by gravity so we can’t float….that would be pretty cool.
  
  Senga 🙂

Question: How can the clouds float but we can not

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