Monday, November 13, 2017 at 4:00pm to 5:00pm
Rockefeller Hall, Schwartz Auditorium
General Physics Colloquium and Henley Lecture, Professor Heinrich Jaeger, University of Chicago.
Refreshments from 3:30-3:50 pm
Title: Granular Streams
Host: Itai Cohen
Abstract: Streams of accelerated particles are important tools for probing atomic or molecular collision processes. In this talk I will show how particle streams also offer unique opportunities to investigate interactions in granular media, where the particles are much more macroscopic. Motivated by experiments on dense jets of particles that exhibit liquid-like breakup into droplets, we developed an experiment to investigate the evolution of a stream of granular media accelerated by gravity. This has opened up possibilities to resolve minute inter-particle forces and gain direct access to dynamic collision processes at the single particle level. The results have provided a host of new insights into the fundamental processes by which athermal particle aggregates break apart, they have revised our understanding of the origin of collisional charging in dielectrics, and they have provided a first glimpse at the creation of ‘granular molecules’ from individual particles via collide-and-capture events.