Sixty Symbols regulars Roger and James are part of a team investigating surface tension in granular systems. Their new paper is published at prl.aps.org/abstract/PRL/v109/i22/e228002 Featuring Roger Bowley and James Clewett. Special thanks also to Mike Swift. Visit our website at www.sixtysymbols.com/ We're on Facebook at www.facebook.com/sixtysymbols And Twitter at twitter.com/#!/periodicvideos This project features scientists from The University of Nottingham www.nottingham.ac.uk/physics/index.aspx Sixty Symbols videos by Brady Haran A run-down of Brady's channels: periodicvideos.blogspot.co.uk/2012/06/here-are-my-channels.html