TEMPE, Ariz. -- Water has some amazing properties. It is the only natural substance found in all three states solid, liquid and gas within the range of natural Earth temperatures. Its solid form is less dense than its liquid form, which is why ice floats. It can absorb a great deal of heat without getting hot, has very high surface tension (helping it move through roots and capillaries vital to maintaining life on Earth) and is virtually incompressible.
A less commonly known distinction of water, but one of great interest to physical chemists, is its odd behavior at its transition to the glassy phase. The glassy state is a sub-state of matter glassy water and ice, for example, are chemically identical and have the same state (solid), but have a different structure. Put another way, ice is crystalline, whereas glass is, well, chunky. As water makes the transition to its glassy state, it behaves very oddly, a fact that has baffled scientists.
Arizona State University Regents Professor C. Austen Angell has found a vital clue that helps explain waters bizarre behavior at the glass transition and, along the way, gained important insights into phases of liquid water as well. His research is published in the Feb. 1, 2008 issue of the journal Science.
We know a lot about glasses that form from ordinary silicates, sugars and metals, Angell says. Theyre making golf clubs out of glassy metals these days. But how important is the glassy state of water" And what can it tell us about ordinary water, which is such an anomalous liquid"
Most glassy forms of matter experience a gradual increase in heat capacity the amount of energy it takes to heat a sample by one degree Kelvin until a key transition point is reached. At that point (called the glass temperature), these materials suddenly up-jump to a new, 100 percent higher, heat capacity zone and change from a solid to very viscous liquid phase as if a solid brick of cold honey were h
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Arizona State University