Snow - how does rain turn into snow? what's the difference between snow and ice?
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Snow in China

About two and a half billion years ago, the Earth finally cooled down enough for it to snow for the first time. Most of the time since then, the Earth has been warm enough that it didn't snow at all. But from time to time, the Earth becomes cooler, entering an Ice Age. We are in one of these Ice Ages now, though not at the coldest part of an Ice Age, and so it snows sometimes, in some places, but not as much as it would in the coldest part of an Ice Age.

When water evaporates into the sky and forms clouds, usually the clouds soon form into tiny balls of ice and fall, melting into raindrops as they come down to the ground.

Snowflakes, because they are made of ice, are really

Snow usually falls either in the winter (if you are in the Northern Hemisphere) or in the summer (if you are in the Southern Hemisphere) or on top of high mountains, where snow often lasts all year round. Near the Equator, it doesn't snow at all.

Learn by Doing - Snow
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Learn by doing - Seasons

Bibliography and further reading about weather:

Learn by Doing - Clouds
More about clouds
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Copyright 2012-2015 Karen Carr, Portland State University. This page last updated September 2015.

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