It takes some heat to form ice

The study results of Anton Tamtögl et al lead to a completely new understanding of ice formation: Water molecules require additional energy before they freeze into ice. Lunghammer - TU Graz By Susanne Eigner - Researchers from TU Graz in Austria and the Universities of Cambridge and Surrey succeeded to track down the first step in ice formation at a surface, revealing that additional energy is needed for water before ice can start to form. Picture material for download at the end of the message Water freezes and turns to ice when brought in contact with a cold surface - a well-known fact. However, the exact process and its microscopic details remained elusive up to know. Anton Tamtögl from the Institute of Experimental Physics at TU Graz explains: "The first step in ice formation is called 'nucleation' and happens in an incredibly short length of time, a fraction of a billionth of a second, when highly mobile individual water molecules 'find each other' and coalesce." Conventional microscopes are far too slow to follow the motion of water molecules and so it is impossible to use them to 'watch' how molecules combine on top of solid surfaces. Findings turn previous understanding of ice formation upside down. With the help of a new experimental technique and computational simulations, Tamtögl and a group of researchers from the Universities of Cambridge and Surrey were able to track down the first step in ice formation on a graphene surface.