Dropping ice cubes in water (and liquid nitrogen) produce interesting results. Differential expansion. More slow motion from periodic videos: http://bit.ly/chemslomo Follow us on Facebook at http://www.facebook.com/periodicvideos More chemistry at http://www.periodicvideos.com/ And on Twitter at http://twitter.com/periodicvideos From the School of Chemistry at The University of Nottingham: http://bit.ly/NottChem Periodic Videos films are by video journalist Brady Haran: http://www.bradyharan.com/ Some sound design courtesy of Alan Stewart. A run-down of Brady's channels: http://bit.ly/bradychannels