Liquid water comes in two forms — low density and high density, scientists have found.
The findings add to the anomalous properties of this ubiquitous, life-giving liquid, which is like no other on Earth.
“The new remarkable property is that we find that water can exist as two different liquids at low temperatures where ice crystallization is slow,” Anders Nilsson, a chemical physicist at Stockholm University in Sweden, said in a statement. [The Mysterious Physics of 7 Everyday Things]
Essential element for life
Water is essential for life (at least on Earth). And wherever liquid water exists — whether it’s in icebound lakes or scalding hydrothermal vents — tiny microbes have been found. That is why scientists have been excited by the possibility of salty water flows and other evidence of ancient water on Mars — it means there may well have been life early on in the Red Planet’s history.
It turns out that water has strange physical properties found in no other liquids known to scientists. For one, it can exist in all three phases at Earth-like temperatures and pressures. For another, its molecular configuration — two hydrogens mated to an oxygen molecule — creates strong polarity, or a highly positively charged region and a highly negatively charged region. That, in turn, allows almost any substance to be dissolved in it; in that way, substances such as calcium ions can travel (dissolved) within…