Why does the water collect in what we call clouds? Why doesn't it disperse evenly in the air?
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As the sun heats the earth, a layer of warmer air forms right above it. Warm air is less dense and it rises. As it does, it cools down by the adiabatic effect of a lesser pressure aloft. This is exactly the same that happens in your fridge when a coolant is released through a nozzle; it takes heat energy.
When the air reaches a point called the dew point temperature, it cannot sustain its moisture as vapour and has to condense some of it as tiny water droplets. But the process of condensation requires to give away heat energy and the tiny water molecules have virtually no mass to do so. It is then when it encounters anything with a mass; a smoke particle or dust, that it forms a tiny droplet. When enough droplets are formed to scatter the sunlight, it appears like a cloud.
An interesting point is that a cloud - like any other body of water on earth - is constantly evaporating. A cloud that remains its size or a cloud that increases in size is, actually, a cloud that keep rising. Then when the droplets are big enough to overcome the rising, it falls down as rain. But it means that all precipitation of rain and snow occurs first upward! And sometimes, it "rains upward" so much that the droplets reach such an altitude that they turn into pellets of ice. When they finally come down, it is as hail.
The reason clouds doesn't disperse evenly in the air is that while the air rises at some places, forming cumulus clouds, it most go down at other places, otherwise the air pressure would fall dramatically. The air that sinks then evaporates and that is why we get a scattered layer of clouds; it rises at some place and sinks at other places. As the owner and pilot of a very light aircraft, I notice very much that vertical circulation of the air. Glider pilots even use it to gain altitude. When they meet such "thermal bubbles" they circle in it to gain altitude. This happens usually, right under such a cumulus cloud and if you look carefully, on a nice summer day, you can see soaring birds like eagles and seagulls, doing exactly the same!
When the air reaches a point called the dew point temperature, it cannot sustain its moisture as vapour and has to condense some of it as tiny water droplets. But the process of condensation requires to give away heat energy and the tiny water molecules have virtually no mass to do so. It is then when it encounters anything with a mass; a smoke particle or dust, that it forms a tiny droplet. When enough droplets are formed to scatter the sunlight, it appears like a cloud.
An interesting point is that a cloud - like any other body of water on earth - is constantly evaporating. A cloud that remains its size or a cloud that increases in size is, actually, a cloud that keep rising. Then when the droplets are big enough to overcome the rising, it falls down as rain. But it means that all precipitation of rain and snow occurs first upward! And sometimes, it "rains upward" so much that the droplets reach such an altitude that they turn into pellets of ice. When they finally come down, it is as hail.
The reason clouds doesn't disperse evenly in the air is that while the air rises at some places, forming cumulus clouds, it most go down at other places, otherwise the air pressure would fall dramatically. The air that sinks then evaporates and that is why we get a scattered layer of clouds; it rises at some place and sinks at other places. As the owner and pilot of a very light aircraft, I notice very much that vertical circulation of the air. Glider pilots even use it to gain altitude. When they meet such "thermal bubbles" they circle in it to gain altitude. This happens usually, right under such a cumulus cloud and if you look carefully, on a nice summer day, you can see soaring birds like eagles and seagulls, doing exactly the same!
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Because it clings to dust particles in the atmosphere, that's why it's so fluffy and truly LOOKS like dust.
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It clings to dust particles.