“Dice Become Ordered When Stirred, Not Shaken” is a headline on a snappy summary of a new physics paper. The headline, and the summary, are published in Physics Focus. Their own summary of their summary: “A jumble of thousands of cubic dice, agitated by an oscillating rotation, can rapidly become completely ordered, a result that is hard to produce with more conventional shaking.”
The researchers produced an action video:
The study itself is “Experimental Study of Ordering of Hard Cubes by Shearing,” K. Asencio, M. Acevedo, I. Zuriguel, and D. Maza, Physical Review Letters, epub December 1, 2017. The authors, at Universidad de Navarra, Spain and Unidad Monterrey, Mexico report:
“We experimentally analyze the compaction dynamics of an ensemble of cubic particles submitted to a novel type of excitation. Instead of the standard tapping procedure used in granular materials we apply alternative twists to the cylindrical container. Under this agitation, the development of shear forces among the different layers of cubes leads to particle alignment. As a result, the packing fraction grows monotonically with the number of twists. If the intensity of the excitations is sufficiently large, an ordered final state is reached where the volume fraction is the densest possible compatible with the boundary condition.”
(Thanks to Mason Porter for bringing this to our attention.)