An Everyday Scientific Mystery: New Study Reveals Universal Secrets of Granular Matter

Coffee beans in a jar and piles of rice or sand are examples of granular matter: materials composed of large numbers of macroscopic—rather than atomic scale—particles. Although granular matter is extremely familiar in everyday life, it represents an unexpected frontier in fundamental physics: Very little is understood about it.

In a new study published recently in the European Physical Journal E, Onuttom Narayan and Harsh Mathur, theoretical physicists at the University of California at Santa Cruz and Case Western Reserve University, respectively, shed some light on the propagation of sound through granular materials particularly close to what is called “the jamming transition.”