The Remains of Humpty Dumpty

From: Sam Wormley (swormley1_at_mchsi.com)
Date: 07/26/04 

Date: Mon, 26 Jul 2004 19:58:01 GMT

Ref: http://focus.aps.org/story/v14/st5
     Phys. Rev. Lett. 93, 035504 (issue of 16 July 2004)

  All the king's horses and all the king's men couldn't
  reassemble Humpty Dumpty, but they might have at least
  estimated the number of pieces they had based on results
  reported in the 16 July PRL. To learn how shells shatter--and
  compare them with solid objects--researchers hurled empty
  eggshells against the ground and exploded others. The
  fragment sizes from both types of destruction followed a
  similar pattern and matched that of a computer simulation,
  suggesting that all shell-like structures may fragment in a
  similar way. The researchers hope to use the results to
  estimate the amount of spacecraft debris in orbit and to
  analyze mass redistribution following a supernova.

  A better understanding of how materials fragment would help
  the military, miners, and demolition crews design explosions;
  it would also help forensic scientists reconstruct the
  details of an explosion from its aftermath. Researchers
  characterize the fragments of an explosion with a
  "distribution" plot showing the number of particles for each
  particle size. The plot is usually a "power law," which means
  that no particular fragment size is favored: An average chunk
  of the original object is just as likely to break into a few
  large pieces as it is to disintegrate into many small ones.
  Many studies--from examining moon craters to exploding
  coal--suggest that the exponent that describes the power law
  is "universal," depending only on the number of dimensions of
  the object and independent of its size, material, and
  explosion energy.

See: http://focus.aps.org/story/v14/st5