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How cereal settles in a shaking box

Saturday, February 1, 2020 - 9:30am
"How cereal settles in a shaking box"

Around 1960 Bernal and Scott did experiments on the settling of ball bearings in a large box as the box was shaken, and discovered the curious phenomenon of random close packing. Recent experimental advances on this phenomenon now show that when shaken gently enough, and long enough, the balls spontaneously begin to reorganize into a global crystalline configuration. Theoretical explanation requires the same stochastic reasoning invented by Boltzmann and used to model the freezing of water molecules into crystalline ice. It is here applied to the deterministic evolution of ball bearings (or cereal) in a precisely shaken box. This offers an accessible but physically realistic setting to mathematically study the entry of probability into macroscopic physical laws.