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, then why doesn't the rain water contain salt and
other pollutants that exist in rivers and surface waters?