Here is an interesting question/answer from the U.S. Geological Survey (USGS).
Q: If you were to take all of the Earth's water and put it into a sphere, how big would the sphere be?
Hmmm, when I read this I really was hard pressed to come up with an answer. We know that the oceans cover 75% or so of the planet, but how much water is that, and how much comes from streams, groundwater, ice caps, etc?
A: A sphere that is 860 miles across, or as described by USGS, "reaching from about Salt Lake City, Utah to Topeka, Kansas".
When you see the water sphere set against the planet, it is quite a comparison and shows us in a different perspective how valuable and precious water is.
Conserve water when and wherever you can....remember the small blue sphere.
Read More About It: http://ga.water.usgs.gov/edu/2010/gallery/global-water-volume.html
Sky Guy in VA