Scientists continue to explore the differences and similarities between granular materials (such as sugar, salt, marbles, and sand) and conventional solids and liquids. Jeffrey Olafsen and Jeffrey Urbach at Georgetown University place steel balls on a table which is shaken vertically. The "temperature" of the excited balls can be lowered by slowly decreasing the agitation. At a certain point some of the balls "crystallize" into a condensate which is at rest, even as other balls continue to move about. See http://www.physics.georgetown.edu:80/~granular/collapse.html.

This research is reported by Jeffrey Olafsen in the 16 November 1998 issue of Physical Review Letters.