Professor Katz investigates the rheology of suspensions. Starch suspensions show the striking phenomenon of discontinuous shear thickening, familiar to school children. His group has studied hysteresis in shear thickening and the phenomenon of stick- slip friction at the thickening threshold. They also study starch suspensions in oil that do not shear thicken but show the ubiquitous phenomenon of shear thinning.
Professor Katz has also been studying trends in storminess and drought, phenomena that climate models cannot calculate well. Historic data show an increase in storminess in regions in which storms are rare.