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The Water Cycle for Kids
All Earth's Water

Sphere representing all of Earth's water

When you look at a picture of the Earth from space you notice all the blue—the oceans. The oceans cover most of the surface of the Earth, about 70 percent. And even though the oceans are miles deep, in comparison to the total volume of the Earth, all the water only occupies a thin layer on the surface of the planet. So, if we rolled up all water into one big ball, how big would that ball be?

The blue sphere represents all of Earth's water, and its diameter (distance across) is about 860 miles (the distance from Salt Lake City, Utah, to Topeka, Kansas). It would have a volume of about 332,500,000 cubic miles (mi³) (1,386,000,000 cubic kilometers (km³)). The sphere includes all the water in the oceans, ice caps, lakes, and rivers, as well as groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant.

Credit: Howard Perlman, USGS; globe illustration by Jack Cook, Woods Hole Oceanographic Institution (©); Adam Nieman.
Data source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York).