Einstein's Tea Leaves and Pressure Systems in the Atmosphere

Abstract

Tea leaves gather in the center of the cup when the tea is stirred. In 1926 Einstein explained the phenomenon in terms of a secondary, rim‐to‐center circulation caused by the fluid rubbing against the bottom of the cup. This explanation can be connected to air movement in atmospheric pressure systems to explore, for example, why low‐pressure systems tend to be stormy and high‐pressure systems are fair weather. Here, following Einstein's lead, we revisit the tea leaf phenomenon, make the connection with atmospheric pressure systems, and describe an illustrative laboratory experiment.