What makes it rain? Rain falls from clouds for the same reason anything falls to Earth.
The Earth's gravity pulls it. But every cloud is made of water UropteS or ice crystals. Why doesn't rain
or snow fall constantly from all clouds? The droplets or ice crystals in clouds are exceedingly, small.
The effect of gravity on them is minute. Air currents move and lift droplets so that the net downward
displacement
is zero, even though the droplets are in constant motioj}.
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Droplets and ice crystals i
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somewhat like dust in the air made ^^Bin a shaft of sunlight.
To the casual observer, dust seems to act in a totally random fashion, moving about chaotically without
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fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The
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cloud droplet ofareragB size is only 1/2500 inchSnlinMB. It is so small that it would take sixteen
hours to fall half a mile in perfectly still air, and it does not fall out of moving air at all. Only when the
droplet grows to a diameter of 1/125 inch or larger it can fall from the cloud. The average raindrop
contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size
large enough to fall out is the cause of rain and other forms of.KggjpjtatJQC. This important growth
process is called "coalescence.