In the formation of droplets in a stream of falling sand, scientists have witnessed a dynamic that points beyond the boundaries of traditional physics, and may represent one aspect of a fifth state of matter.
The droplets formed because of instabilities in the subtle atomic forces that attract sand grains to each other. Something similar happens to water falling from a faucet, but the forces acting on those molecules are 100,000 times stronger.
Measurements of this phenomena
overturn the previous explanation for sand droplets — that grains stick to each other after colliding — and quantify what’s called an “ultralow-surface-tension regime.”
It’s entirely new territory for researchers, and just one of many dynamics governing the behavior of granular materials, which for reasons unknown to science act sometimes as solids, or liquids, or gases — or something in-between
You walk on the beach, and the sand supports your weight. Pick up a handful, and it runs through your fingers, like a liquid
clipped from: www.wired.com