Over 2.5 million viewers, including many physicists, have been astonished by Steve Mould's videos of a chain flowing along its own length from a pot to the floor below. Apparently defying gravity, the chain rises above the pot as a fountain before falling down. Proceedings A has published a paper which explains why this fountain occurs by considering the forces bringing successive links into motion. In this podcast, authors Mark Warner and John Biggins explain what is going on. For more information see: http://rspa.royalsocietypublishing.org/content/470/2163/20130689 For a collection of related problems to work through go to http://www.rutherford-physics.org.uk/