Particles defy gravity, float upstream

[Still Waters]

Rogue tea leaves have led physicists to the discovery of a counterintuitive phenomenon: Particles can float upstream in moving water.

Any kayaker, plumber or physicist would probably say that things always flow downstream. But that conventional wisdom started to unravel for Sebastian Bianchini one night in 2008 when he prepared some mate tea, a South American specialty, by pouring hot water over a cup of tea leaves. Bianchini, then an undergraduate at the University of Havana in Cuba, noticed that by the time he filled his cup, a handful of tea leaves had invaded the pristine water in the kettle.

http://www.sciencene..._float_upstream