On Sunday the 9th July X-ray crystallographers from the Asthma and Allergy group in the Randall department gathered alongside artist Dr Shelley James to present an exciting exhibition at the Royal Society’s Summer Science Exhibition. This family-friendly event introduced children and adults alike to the fundamentals of symmetry and ‘forbidden symmetry’. Symmetry operators form the basis of crystallography and were explained using colourful tiles which members of the public arranged in patterns as seen below.

IMG_20170719_121950IMG_20170719_122012

With periodic patterns understood, the public were introduced to ‘forbidden-symmetry’ in the form of Penrose tiling that has 5-fold symmetry not found in nature. This beautiful form of symmetry contains local symmetrical patterns; however, the overall pattern is infinite and the arrangement of the tiles never repeats but can tile a room without leaving gaps – a feature usually assigned to 2, 3, 4 and 6 fold symmetry only.

1200px-Penrose_Tiling_(Rhombi).svg.png

 

The biggest hit of the day with the adults were these special hexagonal tiles (shown below) which were designed by Prof. Brian Sutton and Dr Shelly James to illustrate a newly discovered form of symmetry. There are only two-different types of tile in total which are mirror images of each other. Placement of tiles followed two main rules: the cut-away lines in the tiles had to match and the density of lines crossing the whole tile had to contrast with a tile opposite it. This fiendish task had audiences captivated and motivated attendees completed the tile patterning to create this large pattern below. Despite the periodic triangular pattern, the position of the tiles (pale and dark) is unique and never repeats itself.

 

IMG_20170719_122906

IMG_20170719_123039

written by Veronica I