Clearest signs yet that water is two liquids

摘要

SUPERCOOLING liquid water to record low temperatures has revealed new evidence that it can exist as two different liquids simultaneously. Supercooled water - liquid water chilled below its freezing point without being allowed to freeze - has been baffling chemists for decades. Previous studies found that the extent to which water molecules pack together, known as their density, starts to fluctuate as water is cooled to extremely low temperatures. Since then, evidence has been mounting that these fluctuations may indicate the presence of two different liquids in one, with some water molecules packed more closely together and others spaced further apart.