Why Do Ice Trees Grow on Frozen Droplets?
Today, another beauty from this year’s Gallery of Fluid Motion, which examines an interesting puzzle associated with frozen water droplets on a flat surface.
Oscar Enriquez and pals at the University of Twente in the Netherlands placed a liquid water dropleton a plate cooled to -20 degrees C and watched as the drop froze.
In liquid form, the drops have a spherical shape. But the frozen drops are angular, with a point at the top, like Mount Fuji. How come?
The video clearly shows what’s going on. “The process of solidification can be observed very clearly due to the change in refraction when water turns into ice,” say Enriquez and co.
This shows that the drop freezes from the bottom up, where it is in contact with the cold plate. As the freezing occurs, the drop remains more or less spherical while the water at the top is still liquid.
But as the final part of the liquid freezes, the surface is pushed up by the water as it expands to form ice. It is this expansion that causes a point to form at the top of the ‘mountain’.
But then something unexpected happens: a tiny ‘tree’ of ice begins to grow from the tip of the ice mountain.
That’s a little more difficult to explain but Enriquez and co eventually settle on an explanation. I won’t spoil the fun. If you want to find out why the tree grows, take a look at the video (link below). It’s a gem.
Ref: arxiv.org/abs/1110.3698: Freezing Singularities In Water Drops
Hi-res video
Lo-res video
Keep Reading
Most Popular
Large language models can do jaw-dropping things. But nobody knows exactly why.
And that's a problem. Figuring it out is one of the biggest scientific puzzles of our time and a crucial step towards controlling more powerful future models.
The problem with plug-in hybrids? Their drivers.
Plug-in hybrids are often sold as a transition to EVs, but new data from Europe shows we’re still underestimating the emissions they produce.
How scientists traced a mysterious covid case back to six toilets
When wastewater surveillance turns into a hunt for a single infected individual, the ethics get tricky.
Google DeepMind’s new generative model makes Super Mario–like games from scratch
Genie learns how to control games by watching hours and hours of video. It could help train next-gen robots too.
Stay connected
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.