Today the students undertook their first competitive task of
the week – the experimental examination that was ratified in Monday’s international
board meeting. The practical examination was based around two applications of diffraction.
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| "Photo 51" (Source 1) |
The first application was inspired by the work of noted British
scientist Rosalind Franklin. Franklin oversaw the use of X-ray diffraction to
investigate the structural properties of DNA and the findings, shown here
through the famous image “Photo 51”, were the basis that led Crick and Watson
to discover its characteristic double helix shape. In the examination the students
modelled this approach by determining parameters of two helical samples (a
small, thin spring and a double helix cross-section), using diffraction of
visible light from a laser source.
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| Diffraction of visible light (Source 2) |
The second application used a phenomenon where a diffraction
pattern can be obtained from waves on the surface of a liquid. In the second
experiment students used a loudspeaker attached to a plastic plate to set up regular
waves on sample of water and then, by again diffracting visible light from a laser
source, were able to determine the surface tension and viscosity of the water
in the sample.
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| Monsoon season in Mumbai |
Whilst the students were sitting their experimental
examination, the team leaders, observers and visitors were treated to a tour of
South Mumbai, which included notable sights including the Gateway of India and
the University of Mumbai, and also included a monsoon season downpour. It felt
quite like being back in the UK with the torrential rain, although admittedly with
considerably higher humidity. Following this, we the visited the Chhatrapati
Shivaji Maharaj Vastu Museum, which contains over 50,000 exhibits on art, archaeology
and natural history relevant to the region, such as artefacts from the Indus
Valley civilisation.
Source 1: www.wikipedia.com (Photo 51)
Source 2: www.flickr.com (Dragonlasers)
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