Big Nuts, Center of Mass, and Potential Energy
When opening a can of mixed nuts, why are the
largest and heaviest always on top?
At first, this inversion of the larger components "rising" to the
top seems counter-intuitive. The reason for this is a factor that is
not so important in fluids, but is important in granular media. The
large "chunks" form an open cell rigid structure. The smaller
components can "rattle around" and fall through the spaces in the
open cells between the larger immobilized components. Eventually
with shaking it is the smaller particles that "sink" to the bottom,
in between the spaces formed by the larger granules.
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Update: June 2012