Ice cubes float in water because they’re less dense than the liquid. But a newfound type of ice has a density nearly equal to what’s in your water glass, researchers report in the Feb. 3 Science. If you could plop this ice in your cup without it melting immediately, it would bob around, neither floating nor sinking.
The new ice is a special type called an amorphous ice. That means the water molecules within it aren’t arranged in a neat pattern, as in normal, crystalline ice. Other types of amorphous ice are already known, but they have densities either lower or higher than water’s density under standard conditions. Some scientists hope this newly made amorphous ice could help solve the scientific mysteries that swirl around water.
To generate the new ice, scientists used a surprisingly simple technique. Called ball milling, it involves shaking a container of ice and stainless steel balls, cooled to 77 kelvins (nearly –200° Celsius). The researchers were motivated by curiosity; they didn’t expect the technique to produce a new amorphous ice. “It was a sort of Friday-afternoon idea we had, to just give it a go and see what happens,” says physical chemist Christoph Salzmann of University College London.
An analysis of how X-rays scattered from the frosty stuff suggested they’d created an amorphous ice. And computer simulations that mimicked the effects of ball milling revealed that a disordered structure could be produced by layers of ice sliding past one another in random directions, in response to the forces exerted by the balls.
“You have to be open, as a scientist, for the unexpected,” says chemical physicist Anders Nilsson of Stockholm University, who was not involved with the research. The ball milling technique, he says, “was quite innovative to do.”
2023-02-02 14:00:00
Article from www.sciencenews.org
Water is one of the most abundant molecules on Earth. With two hydrogen atoms and one oxygen atom, it is also one of the simplest molecules in the universe. However, despite its simplicity, water has unique properties that have long baffled scientists. Now, researchers have found a new form of ice – ice XVIII – that could help us better understand why water behaves so strangely.
Ice XVIII is an extremely cold form of ice, made up of densely packed water molecules coated in a layer of oxygen and hydrogen. This particular ice is incredibly difficult to form, as heat needs to be taken away from water more quickly than ever before. It is created at temperatures as low as -263 degrees Celsius, equivalent to just 10 degrees above absolute zero.
While that might sound straightforward, ice XVIII’s properties explain why water behaves so strangely. The ice floats to the top of the container when it is formed, meaning it is less dense than the liquid it is formed from. This is the opposite of other forms of ice, which sink to the bottom. The water in ice XVIII is also held together more loosely than in other forms of ice. This falls in line with water’s overall behavior, as high temperatures cause the hydrogen bonds between water molecules to weaken, allowing the molecules to move around more freely.
In addition to that, the unique structure of its molecules allows liquid water to hold on to heat for a longer period of time than any other liquid. This phenomenon can be seen across our planet, as water’s higher boiling point explains why the ocean is relatively slow to change its temperature.
Overall, ice XVIII has helped researchers understand more about why water behaves the way it does. While more research needs to be done, it is clear that this unusual molecule has some weird and wonderful properties that can be studied to gain a deeper understanding of the role water plays in our world.
