Events - GC Physics Department

Science Speakers series

3:20 PM, Thursday
October 23, 2025
Science Building, Room 106

Science on the Edge: Avalanches in Granular Systems

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Susan Lehman is the Victor J. Andrew Professor of Physics at the College of Wooster, OH and a graduate of Goshen College ('93). Much of the research described here was in collaboration with undergraduate students at the College of Wooster.

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.

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.