Water flows uphill

The 'Physikshow' is a regular exhibition held by students at the University of Bonn to demostrate the fun side of physics to members of the public. Videos from the most recent event have been put on YouTube and have been a big hit. My favourite is of a boat floating in the air:



The tank it floats over is filled with Sulphur Hexafluoride gas which is significantly denser than air and will therefore support light objects. You can see the effect when the students try to fill the boat with the gas and it sinks down. Brilliant!

The best of the rest include a cigarette burning through metal, a nuclear reaction shown with ping pong balls and water flowing uphill!