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Pick up a handful of sand, and it flows through your fingers like a liquid. But when you walk on the beach, the sand supports your weight like a solid. What happens to the forces between the jumbled sand grains when you step on them to keep you from sinking? An international team of researchers have developed a new way to measure the forces inside materials such as sand, soil or snow under pressure.
The technique uses lasers coupled with force sensors, digital cameras and advanced computer algorithms to peer inside and measure the forces between neighboring particles in 3-D. This new approach will allow researchers to better understand phenomena like the jamming of grain hoppers or the early warning signs of earthquakes and avalanches.Image credit: Photo by Felice Frankel and Joshua Dijksman
