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 droplets 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 motion.Droplets and ice crystals behave somewhat like dust in the air made Visible in a shaft of sunlight.To the casual observer, dust seems to act in a totally randogn fashion, moving about chaotically without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The
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cloud droplet ofB0818§t size is only 1 /2500BB8l"U8i^- 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 droptet to a size is only 1 /2500BB8l"U8i^- It is so small that it would take sixteen
hours