Scientists have set a new record for creating the most square-shaped ice cubes possible.
International researchers say they have made “a near-perfect cubic arrangement of water molecules”, which is a form of ice that exists in the coldest areas of high-altitude clouds.
The researchers say these frozen water droplets – which were nearly 80% cubic – are extremely hard to achieve on Earth.
“While 80% might not sound ‘near perfect’, most researchers no longer believe that 100% pure cubic ice is attainable in the lab or in nature,” said Barbara Wyslouzil, project leader and professor at Ohio State University.
“So the question is, how cubic can we make it with current technology?
“Previous experiments and computer simulations observed ice that is about 75% cubic, but we’ve exceeded that.”
While all this sounds intriguing, the scientists say their main purpose is not to achieve geometric perfection for the sake of it, but to use the study as a key to understand climate change.
Wyslouzil believes studying cubic ice could help us understand more about the properties of water and design computer models of how clouds interact with sunlight and the atmosphere.
From the ice we see occurring naturally in frozen ponds and snow to the ice we make at home, all crystals are formed with hexagonal symmetry.
Wyslouzil says that by rearranging the water molecules slightly, the crystals can take on a more cubic shape.
For many years, scientists have struggled to make the perfect cubic ice in the laboratory, primarily because this cubic form is essentially unstable.
Until now, the closest anyone has come is to making hybrid crystals are ones that are 70% cubic and 30% hexagonal.
To make their near-perfect cubes, the researchers passed nitrogen and water vapour through nozzles at supersonic speeds.
The gas was cooled to form droplets that were 100,000 times smaller than the average raindrop, and after additional supercooling, they remained liquid until about minus 48C (minus 54F) and then froze in about a millionth of a second.
The scientists measured the cubicity of the ice crystals using a device known as the Linac Coherent Light Source, in California, which calculated the “squareness” with X-ray lasers and X-ray cameras.
The research is published in the Journal of Physical Chemistry Letters.
