Jamming and Flow in Granular Matter: A Physics Lab Course Experiment

TL;DR

This paper presents a light scattering experiment using diffusing wave spectroscopy to study jamming in granular materials, linking it to glass transition phenomena and involving undergraduate education.

Contribution

It introduces a DWS-based experimental setup for undergraduate labs to explore granular jamming and its relation to glass transition, including theoretical background and preliminary results.

Findings

Demonstrates similarity between granular jamming and glass transition.

Provides a practical DWS setup for educational purposes.

Shows potential for microgravity experiments in space environments.

Abstract

We describe a dynamic light scattering setup that uses diffusing wave spectroscopy (DWS) to investigate the dynamics in sand grains subjected to periodic vertical shaking by a loudspeaker. Along with the setup that is used in the undergraduate physics lab course at TU Darmstadt, the necessary DWS theory is introduced, including the proper treatment of the oscillatory excitation. Some exemplary results are presented that demonstrate the similarity of jamming in an athermal granular medium with the glass transition in thermally driven molecular systems, a relation that has frequently been pointed out but still is poorly understood. Similar, albeit more sophisticated experiments are currently conducted in microgravity environments such as the international space station ISS and the experiment may serve as an introduction to an exciting field of current research.