Researchers reveal secrets of supercooled water
water_SLAC
Image: Gregory Stewart/SLAC National Accelerator Laboratory

Getting water to its supercooled state at between -43 to -48 degrees Celsius is no easy task, and scientists have dubbed this state ‘no-man’s land’. A new study, published in the journal Nature, however, explains how scientists managed to get to water’s no-man’s land by cooling water to -46 degrees Celsius. The results of the study will help further understand our knowledge of water in all conditions.

Physicist Anders Nilsson and his team from the Standford University National Accelerator Laboratory in the US managed to make 10-micron-sized water droplets in a vacuum. The droplets evaporated really fast, but they were able to keep them at -46 degrees Celsius for enough milliseconds to take x-rays to study the structural makeup of the droplets. 

The images revealed that water's molecular structure transforms continuously as it enters this mysterious zone, and with further cooling the changes accelerate even more than previously thought.

The study has provided the first structural measurements of liquid water in no-man's land, but we’ll have to wait a bit more to get a full picture of the amazing properties of water at even lower temperatures. "Our dream is to follow these dynamics as far as we can,” said Nilsson in a release. “Eventually our understanding of what’s happening here in no-man’s land will help us fundamentally understand water in all conditions.”

Water, however, has many other interesting features. “Upon cooling below 4 degrees Celsius water expands instead of contracting,” told Anders Nielsson to ABC’s Stuart Gary.

This, as Gary explained, is why bottles of water in the freezer don’t crack, and why ice forms in the surface of lakes, rivers and seas in cold climates, while the water below remains in a liquid state and keeps warm.

Ice doesn’t conduct heat that well, so it delays the energy transfer from the liquid water below the ice, preventing the water from freezing and allowing fish and other marine creatures to survive.

“Without the density maximum [the highest attainable density under given conditions] all the oceans would have frozen to the bottom, but since water is getting lighter if it cools below 4 degrees Celsius it will rise upwards,” said Nilsson.

Sources: Discover and ABC