Why water clouds don't fall when there is strong wind and no updraft?
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First, a cloud is not an object like a snowball or a raindrop. It is a grouping of microdroplets which have formed in a region of air where the temperature is at the dew point (the temperature at which the air cannot hold any more water vapor), or below the freezing point and ice microcrystals have formed. The droplets and crystals are of such a size that the mass-to-area ratio is so small that very small air currents will keep them suspended, much like fine dust. Where you believe that there are no updrafts, there may actually be moderate updrafts of moist air, continually refreshing the cloud.
You should investigate the ideas of aerosols and colloidal suspensions if you want to know more about the behavior of very small particles.
Large cumulus clouds that seem to be floating and stable are actually losing and gaining droplets continually. The regions around clouds which are "empty" actually may have the same water vapor presence (or not), but the local temperature is above the dew point, so none of it condenses. If you look carefully at cumulus clouds you will notice that the lower parts of them are flat. That's the boundary line when the temperature drops to the local dew point.
When winds are blowing but clouds seem stationary, again it's because the cloud forms where the local temperature is low enough. You don't see the droplets forming or evaporating because the boundaries of the temperature region aren't moving.
Moving clouds are simply the transport of droplets or ice crystals along with the cold air and surrounding water vapor that resulted in their formation in the first place, but again, the cloud is continually changing. It is not a static entity.
Because of gravity, air is pushed together more at lower heights (since the air above it is sitting on top of it). This makes the air near the earth have move friction than air above. This effect is called the wind gradient, and it what you are seeing is likely seeing. Since friction is different air higher up will be slowed down less than air below. So if you are observing almost no wind near you, that does not guarantee that the air above you is moving at the same speed.
If you've ever tried flying a kite, you'd know this effect. It's tricky to get a kite up in the air, but once you can get it high enough it'll be up there for good!
You should investigate the ideas of aerosols and colloidal suspensions if you want to know more about the behavior of very small particles.
Large cumulus clouds that seem to be floating and stable are actually losing and gaining droplets continually. The regions around clouds which are "empty" actually may have the same water vapor presence (or not), but the local temperature is above the dew point, so none of it condenses. If you look carefully at cumulus clouds you will notice that the lower parts of them are flat. That's the boundary line when the temperature drops to the local dew point.
When winds are blowing but clouds seem stationary, again it's because the cloud forms where the local temperature is low enough. You don't see the droplets forming or evaporating because the boundaries of the temperature region aren't moving.
Moving clouds are simply the transport of droplets or ice crystals along with the cold air and surrounding water vapor that resulted in their formation in the first place, but again, the cloud is continually changing. It is not a static entity.
Because of gravity, air is pushed together more at lower heights (since the air above it is sitting on top of it). This makes the air near the earth have move friction than air above. This effect is called the wind gradient, and it what you are seeing is likely seeing. Since friction is different air higher up will be slowed down less than air below. So if you are observing almost no wind near you, that does not guarantee that the air above you is moving at the same speed.
If you've ever tried flying a kite, you'd know this effect. It's tricky to get a kite up in the air, but once you can get it high enough it'll be up there for good!
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Eventually, the droplets in the clouds are heavy enough to be pulled down by gravity — and that's rain! Well, it's sometimes rain. If the air is cold near the surface, we might get sleet or snow instead. And if the air is too dry, the water might evaporate before it even hits the ground.
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