|Rain and snow are the
main sources of fresh water for people living on earth. Both
rain and snow come from the clouds; but, where do the clouds
come from? It often seems that clouds appear from nowhere.
One minute the sky is clear and then a few minutes later clouds
form. Sometimes clouds come from far places. Wind moves the
clouds from one area to another.
If you live near a lake, ocean or
forest, you may have seen water vapors rising from wet surfaces and
disappearing in the air. Is it possible that the same vapors become
visible again when they get to higher elevations? If the clouds come from oceans, forests and other surface waters,
doesn't the rain
water contain salt and other pollutants that exist in rivers
and surface waters?