Science on the Edge: Critical Phenomena in Granular Systems
Date: Thursday, February 16th, 2017
Speaker: Susan Lehman, Claire Booth Luce Associate Professor of Physics at The College of Wooster in Wooster, Ohio
Abstract: A granular system behaves in some ways like a liquid with an ability to flow, and in some ways like a solid with a stable fixed structure if undisturbed. A tiny stimulus to the pile most often results in only a small response, but the same small stimulus can also create an unpredictable and catastrophic collapse of the pile. These collapses occur both in natural settings, with hazards such as landslides and snow avalanches, and in industrial situations, where granular materials like sand or agricultural grains need to flow freely. We use a simple experimental system – a 3D conical pile of uniform beads – in order to model these real-world physical systems. We investigate the dynamic response of the pile by recording avalanches from the pile over the course of tens of thousands of bead drops. The resulting behavior is well-characterized by universal power laws and scaling functions, relating this work to the broader study of critical systems.
All of these results were obtained at The College of Wooster, a liberal arts college with a particular focus on mentored undergraduate research. As part of the talk, I will discuss how work at a liberal arts college differs from work at a large research university, and suggest ways to prepare for alternative academic careers.
Host: Ray Frey
Location: 100 Willamette Hall