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Water Cycle
2009-07-06 17:58:20

The water cycle (or hydrologic cycle) describes the continuous movement of water above, below, and on the planet. Since the water cycle is in fact a "cycle", there is no beginning or end. Water exists in three states: liquid, vapor, and ice. Although the balance of water on our planet is fairly constant, individual water molecules may come and go. The water cycle is driven by the sun. The sun...