Our hunt for intriguing new tech research recently turned up a mini-buzz about some so-called “magic powder” freezing water droplets. Following are some cool high-speed photographic sequences in a video from King Abdullah University in Saudi Arabia. Liquid droplets impact a bed of powder, are coated, and hold their shape after rebounding.
Admittedly, the droplets on high-speed are cool-looking. (Not much on high-speed isn’t cool-looking.) But there’s more to this story. Nothing, in fact, freezes (i.e., there’s no phase change) and the study of these “liquid marbles” isn’t new at all. Rather, it’s a small contribution to at least a decade of research.
Curious, we dug up a bit more about liquid marbles and their potential applications.
Liquid marbles are small spherical water reservoirs encased in a shell of hydrophobic powder. They are formed when a droplet of solution (not always pure water) is “bounced” off a bed of hydrophobic powder. The powder coats the droplet and causes it to rebound, powder in tow. As the water reforms into a droplet, it is encased in powder, holding its spherical shape even after it falls back to Earth. The newly formed liquid marble can be rolled across a surface without leaving behind a trail of water.
The earliest mention of liquid marbles we found was June 2001 when a study in the Journal Nature spawned a Scientific American write-up. (Notably, one commenter mentions the research is much older than even 2001.) The study was conducted by two scientists, Pascale Aussillous and David Quere, at the the College of France in Paris. They hoped “liquid marbles [would] find uses in technological applications that need small amounts of liquid moved quickly across a solid surface."
Since that early study, researchers have focused on determining the best technique for creating liquid marbles and discovering the optimal hydrophobic powder and solution that creates the sturdiest marbles.
A central finding of all that research is that marble creation depends almost entirely on kinetic energy and angle of impact. A lower and upper kinetic threshold had already been established before the King Abdullah University study. On the lower end the water droplet is not fully covered in powder, while at the upper boundary, powder and solution coalesce to form a “mousse.”
The King Abdullah University researchers seem to have further refined the upper bound, where a marble forms but is not the ideal spherical shape—it is a deformed liquid marble. Presumably, the findings will help more precisely control the formation of liquid marbles for future testing and even manufacturing.
A recent MIT study notes liquid marbles “show promise for high-value applications in the medical, biotechnology, chemical, and pharmaceutical industries.” The tech is already in use in the cosmetics industry, but is yet far from widespread.
So there you have it. Liquid marbles. Pretty obscure stuff, you may be thinking. And yes, we’d agree. But stick with us a moment more. Obscure is a great thing.
This shows we have more researchers working on more problems than ever before. Research is no longer constrained by geography and no longer the domain of a handful of developed countries. From China to Brazil to Saudi Arabia, detailed scientific study is going global—has been for years.
As humans become more educated on average and more linked than ever, curious minds are pressed into more specialized research and able to engage in small back-and-forth developments and discoveries like this one. The multitudes of small discoveries sum to bigger breakthroughs and add to the pace of technology—and they make for some cool photos from time to time too.