Wednesday, 30 March 2016

Stinks and bangs

It's two years since my gaffer from grad school left us bereft. As a child he had a couple of near-death experiences doing daft boy-things: crushed pelvis when he fell off the running board of a running truck and fell under the rear wheel; left hand blown to ribbons when one of his bombs exploded prematurely.  That sort of thing happens much less rarely nowadays because kids are glued to their devices rather than out testing the reality of the world.  No matter how graphic the graphics, nobody dies in Grand Kill Zombie Apocalypse IV.  I suggest that this is a Bad Thing; early experimentation teaches care and attention and a handiness with physical things. We need 'a good pair of hands'; we need a lot of them indeed if we're to have a future as a technological nation.  It's not going to happen if we protect children too much from making mistakes. Robin McKie has a passionate polemic about this quoting from his own experience of blowing up his bedroom and Alec "DNA fingerprinting" Jeffries growing a beard to hide the burns on his face.

Today is also the birthday of Robert "Burner" Bunsen, unless it isn't: he was definitely born in March 1811 but not even he was sure if it was the 30th or 31st.  No matter, he grew up when Chemistry was at its most exciting. The first synthesis of an organic compound (urea) was carried out in 1828 and Bunsen grew up into a world where everything was waiting to be discovered.  Nowadays 500 new compounds are being developed described and named every week; but it's not possible for a teenager to make a wholly novel contribution; the frontiers have moved away from a cupboard in a bedroom. Wolfram maintains that the frontier is present for youngsters in the world of big data. But that's not direct 'good pair of hands' reality. Bunsen's career was notably peripatetic: born a son of the chief librarian at Georg-August-Universität Göttingen, he held faculty positions in Göttingen, Kassel, Marburg, Breslau, and Heidelberg. Nobody doubted that he was smart - he was awarded his PhD at the age of 19! - but he was also notable for the rich network of collaborators and correspondents that he built up.  He was famous for the quality of his teaching and his students, including the dreadful Fritz Haber, loved him.

His earliest work was assisting at the birth of organo-metal chemistry, especially compound of arsenic which were notoriously smelly, toxic and in some cases unstable.  His position at Kassel was inherited from Friedrich Wöhler, the chap who carried out the laboratory synthesis of of urea. Bunsen continued the great man's work on compounds of  tetramethyldiarsine [L] which had been named cacodyl [foul-smelling oil] by the great Swedish chemist Jöns Jacob Berzelius. Bunsen noted "the smell produces instantaneous tingling of the hands and feet, and even giddiness and insensibility. It is remarkable that when one is exposed to the smell of these compounds the tongue becomes covered with a black coating, even when no further evil effects are noticeable". He spent years living in a miasma of garlicky pongs which might have prevented him getting married.  More importantly, one of his cacodyl experiments exploded [I did mention 'unstable'] on him and destroyed the sight of one eye.  One of the developments of all this basic science was an effective antidote to arsenic poisoning.

He's known now for his eponymous Bunsen Burner which was the first widely available, controllable, safe, clear, hot, flame for use in laboratories.  But in his day, in collaboration with Gustav Kirchhoff, he was known for his work in spectroscopy - the analysis of the wavelengths of light absorbed and emitted by different compounds. They appreciated that you could only get good crisp results if their samples were of high purity, which they had the determination and application to achieve. Bunsen knocked off the distinctive spectral lines of lithium, sodium and potassium.  Afterwards he noted that mineral water from a spa at Dürkheim produced spectral lines in the blue range of the visible spectrum.  In a monster analysis worthy of Marie Curie discovering radium, Bunsen reduced 40 tonnes of this water to 17g of a pure new element that he named caesium.  The following year, he completed the alkali metal column in the periodic table by isolating rubidium.  That's what it was like in those heady far-off days, you could discover a new element.  It wasn't easy, you had to work hard, you had to have creative solutions to intermediate problems, but new frontiers were on every side.  In 1877, Bunsen and Kirchhoff were awarded the first Davy Medal by the British Royal Society for their work on spectroscopy. Their investigations opened up the world of astronomy by noting that spectral decomposition of the light of stars could be replicated in the flame of a Bunsen burner in a laboratory.  So elements could be identified in places that were far beyond the reach of human hands. Bunsen never became rich, because he had no desire for money or for 'stuff', he refused to patent any of his inventions because that seemed to inhibit the progress of science. Hats off!

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