American researchers claim that supercooled water is two liquids in one. They came to this conclusion by measuring water at temperatures well below its normal freezing point, according to the journal Science.
Despite its extremely widespread occurrence, water as a chemical is still not fully understood. Scientists sometimes call it the most mysterious substance on Earth.
Specialists from the Pacific Northwest National Laboratory (PNNL) of the US Department of Energy destroyed a thin ice film with a laser, creating supercooled liquid water, after which, using infrared spectroscopy, they tracked the stages of its transformations in the range from -138 to -28 degrees Celsius.
On the “freeze frames” of phase states, scientists saw that during supercooling, water condenses into a dense liquid phase, which continues to coexist with the usual liquid phase. In this case, the proportion of liquid with a high density decreases rapidly with an increase in temperature from 190 to 245 Kelvin.
We have shown that liquid water at very low temperatures is not only relatively stable but also exists in two structural forms. The findings help resolve a long-standing debate about whether deeply supercooled water always crystallizes before it equilibrates. The answer is no.
Greg Kimmel, one of the study authors
According to the data obtained, water does not always crystallize on hypothermia before equilibrating. Supercooled water can be in a stable two-phase liquid-liquid state, and the phase ratio varies depending on temperature.