Scientists shed light on the 'dance of water'

Washington, August 12 (ANI): A team of scientists is shedding new light on water's molecular idiosyncrasies, like the 'dance of water', offering insight into its strange bulk properties.

In all, water exhibits 66 known anomalies, including a strangely varying density, large heat capacity and high surface tension.

Contrary to other "normal" liquids, which become denser as they get colder, water reaches its maximum density at about 4 degrees Celsius.

Above and below this temperature, water is less dense; this is why, for example, lakes freeze from the surface down.

Water also has an unusually large capacity to store heat, which stabilizes the temperature of the oceans, and a high surface tension, which allows insects to walk on water, droplets to form and trees to transport water to great heights.

"Understanding these anomalies is very important because water is the ultimate basis for our existence: no water, no life," said SLAC scientist Anders Nilsson, who is leading the experimental efforts.

"Our work helps explain these anomalies on the molecular level at temperatures which are relevant to life," he added.

Experiments suggested that the textbook model of water at ambient conditions was incorrect and that, unexpectedly, two distinct structures, either very disordered or very tetrahedral, exist no matter the temperature.

Researchers revealed the additional discovery that the two types of structure are spatially separated, with the tetrahedral structures existing in "clumps" made of up to about 100 molecules surrounded by disordered regions.

The liquid is a fluctuating mix of the two structures at temperatures ranging from ambient to all the way up near the boiling point.

As the temperature of water increases, fewer and fewer of these clumps exist; but they are always there to some degree, in clumps of a similar size.

The researchers also discovered that the disordered regions themselves become more disordered as the temperature rises.

"One can visualize this as a crowded dance restaurant, with some people sitting at large tables, taking up quite a bit of room-like the tetrahedral component in water-and other people on the dance floor, standing close together and moving slower or faster depending on the mood or 'temperature' of the restaurant-like the molecules in the disordered regions can be excited by heat, the dancers can be excited and move faster with the music," Nilsson said. (ANI)