In the second of his Tales from the Prep Room for the Royal Institution’s online RI Channel, technician Andrew Marmery uses wire and a laser pen to recreate the famous cross-shaped diffraction patterns observed by Rosalind Franklin in 1952 which captured “Photograph 51”, revealing the structure of DNA and later used by James D. Watson and Francis Crick as the basis for their famous model of the double helix.
By shining a laser through different configurations of wire, Andy is able to change the resulting diffraction pattern. Theoretically, he could then work backwards from each pattern to deduce the original position of each wire. It is this idea that forms the basis of X-ray crystallography, using x-rays instead of laser light, and atoms instead of wires.
Diffraction is being shown as part of the 2012 European Science TV and New Media Festival at 15:05 on Saturday 14th July 2012, as part of the New Media Session. A full festival programme can be found here.