Dynamics of Granular Materials Arshad Kudrolli Associate Professor Department of Physics Clark University Abstract: Granular media is a paradigm for complex materials which are out of equilibrium. Although each granular particle is obviously solid, a collection of these particles show distinctly non-solid behavior when subjected to external forces. For example, grains in a container will avalanche and thus appearing liquid-like when tilted beyond a critical angle. We will discuss a series of experiments which show self-organization of granular materials exploiting size, shape anisotropy and surface interactions. Anisotropy driven vortex patterns are observed in granular rods. Magnetized particles are observed to self-assemble in to form chains, rings and other clusters depending on applied conditions. The segregation and stability properties of granular materials are dramatic affected by addition of small amounts of liquids. High speed-imaging and processing is extensively used to obtain quantitative measurements of these properties and develop models. Implications for geophysical and industrial systems will be discussed. Refreshments will be served during the Physics Coffee Hour, in Rm. N201 at 2:30 PM.