Adventures in Fluid Flow: Generating Interesting Dendritic Patterns

Electrical discharge patterns produced by dielectric breakdown in transparent plastic blocks provide insights into the phenomenon that causes a gush of rain after a lightning flash. In simulations of thunderclouds, aluminum pigment particles dispersed in kerosene make visible thermal convection patterns. In the course of repairing a damaged Kalliroscope used to demonstrate convection, the author discovered that a variety of decorative, dendritic designs can be formed by first squeezing wet paint between two flat, smooth surfaces and then pulling the surfaces apart. The patterns produced by these very different physical processes satisfy the eye and challenge the mind.