Melody Lim (email): I am an experimental soft matter physicist. I am currently a graduate student at the University of Chicago, where I work in the research group of Heinrich Jaeger on experiments in soft matter that span acoustic levitation, granular self-assembly, the mechanics of active solids, and contact charging between dielectric materials. I received my undergraduate degree from Duke University, working with Bob Behringer on flows in dense suspensions and impact into granular materials.



Talk details: Acoustically Levitated Granular Matter
When a cavity is driven with ultrasonic sound waves, the resulting pressure standing wave can carry enough momentum to levitate small (sub-millimetre) particles. Scattered sound then establishes attractive forces between particles: six or seven particles cluster into shapes that resemble flowers and turtles, while hundreds of particles self-assemble into granular droplets with strikingly fluid-like behaviour. By driving the cavity slightly off-resonance, we generate additional forces that drive cluster rearrangements, droplet spinning and splitting, and soft hinge-like motions, creating a tunable active granular material.