Next to it, a much smaller sphere shows the world's liquid fresh water. This image shows blue spheres representing ... mostly in the form of water vapor, is in the atmosphere at any one time.

Imagine the Earth in your mind’s eye. Now round up all the water on the planet into a sphere (we’re talking oceans, icecaps, atmosphere, everything — even the water bound up in you and me).

After letting this set for a bit (so the gel surface can properly form), you remove the drop from the Calcium Chloride solution, and you have a fully formed water sphere, made from nothing but ...