Lesson Summary

Image courtesy of ahisgett/Flickr.

What makes our planet so unique? What key resource helps make our planet habitable? The answer is water!

All living things require water to survive. The hydrologic (water) cycle is composed of the interconnections between Earth's reservoirs, living organisms, and the physical processes (e.g. evaporation, condensation, transpiration) involved in the movement of water between those reservoirs. The sun's energy is the mechanism responsible for driving the water cycle.

Only a relatively small amount of the water found on our planet is available for consumption by living organisms. The majority of Earth's water is stored in the oceans. Most of the freshwater resources of our planet are contained in glaciers and ice sheets, and therefore not available for use. Surface water sources such as lakes & rivers, as well as groundwater, are the primary water resources used by humans to satisfy their daily water needs.
Last modified: Tuesday, 7 December 2010, 5:34 PM