00:03Sand is a solid, but it will flow if poured. However, it can sometimes stop flowing suddenly,
00:09getting caught as if it has become a solid once again. This is something we've all likely
00:13encountered at some point or another, but it has massive implications for industrial processes.
00:18Yet scientists have never really been able to explain why it happens until now. Researchers
00:22used data from myriad previous studies to run a computer simulation in conjunction with random
00:27matrix theory, a type of mathematics developed in the 1950s which allows many physical systems with
00:32random variables to be outlined mathematically. The researchers were looking specifically at
00:36bead vibration frequencies. All matter has the capacity to vibrate, and different materials
00:41only vibrate at specific frequencies. What they found was a particular distribution of statistical
00:46probabilities, one that already exists, called the Wishart-Laguerre Ensemble. Using this probability,
00:52the researchers found they were able to correctly reproduce the universal statistical properties
00:56of jammed granular matter, finding that when the beads come into contact, they actually compress
01:01and recoil much like a spring. This creates a much greater force than expected, and is the
01:06first step in solving the sand-jamming conundrum.
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