Ice Block
© Wikimedia CommonsIce block at beach near Jökulsárlón, Iceland.
Besides vapor, ice and liquid, a fourth form of water may exist, but don't worry, Kurt Vonnegut fans, it's not ice-nine, the dangerous, solid at room temperature substance from the book Cat's Cradle. Unlike the fictional ice-nine, which melted at 114 degrees Fahrenheit, this new form of H2O likes it cold, about 54 degrees below zero Fahrenheit.

Liquid water usually freezes into ice at 32 Fahrenheit, but under the right conditions, like the high pressure at the bottom of the ocean, water stays liquid below 32 Fahrenheit.

Water's fourth form, or phase, may be a liquid with some of the properties of both ice and regular liquid water. But laboratory equipment isn't sensitive enough to observe the rapid transformation from regular liquid water to the fourth form.

Researchers Pradeep Kumar and H. Eugene Stanley used a computer simulation to model the elusive liquid. They found that at about 54 degrees below zero Fahrenheit, the local structure of water seems to become extremely ordered, like ice, while undergoing sharp but continuous structural changes and remaining liquid.

Oddly, at this temperature the water also became more conductive of heat, the opposite of what happens with regular liquid water and ice, as anyone living in an igloo will tell you.

The strange behavior of water at low temperatures is what led Stanley and Kumar to believe that their results support the idea that water has a fourth phase.