Ice ice maybe
11 Jul 2007 by Evoluted New Media
Scientists have begun to unravel how individual water molecules come together to form ice crystals and in doing so hope to have made a crucial breakthrough in predicting the weather.
Scientists have begun to unravel how individual water molecules come together to form ice crystals and in doing so hope to have made a crucial breakthrough in predicting the weather.
Collaborative research between scientists in the UK and Germany has started to reveal the process of ice nucleation at a molecular level and take them a step closer to understanding the mysterious process through which ice forms around microscopic dust particles in the upper atmosphere.
Dr Angelos Michaelides of the London Centre for Nanotechnology said: “We are all familiar with the freezing of water. It features prominently in our daily lives, from fridge freezers to winter snow. Despite all this, the question of how individual water molecules come together and give birth to ice crystals remains mysterious. Our research provides an insight into the most important and ubiquitous type of ice nucleation event, namely heterogeneous nucleation.”
State-of-the-art experimental and theoretical techniques allowed the researchers to watch and accurately model what happens to water molecules at very low temperatures.
The researchers cooled down a metallic surface to 5?C above absolute zero (-268?C) at which temperature it was possible to trap and obtain images of the smallest possible pieces (hexamers) of ice using a scanning tunnelling microscope (STM). The hexamer - the simplest and most basic snow flake - is composed of just six water molecules. Other ice nanoclusters containing seven, eight and nine molecules were also imaged.
Professor Karina Morgenstern of the Leibniz University Hannover in Germany said: “Scientists have long struggled to resolve single water molecules within ice clusters, because they are so vulnerable to damage induced by electrons - the very thing that creates the image. The high resolution could only be achieved by reducing the current to the smallest value technically possible.”
The researchers hope that the study will take us a step closer to understanding how water interacts with different aerosols and dust particles in the atmosphere - processes which drive cloud formation and have a large impact on the planet’s climate.
