15th May 1953. The Braggs: Father and Son.

Matter started as an inorganic structure and will revert to it quicker than we think (Author).

Today in 1953 the News Chronicle the headline recorded: ‘Why You Are You. Nearer Secret of Life.’ (1)

The article referred to William Lawrence Bragg who had given a talk at Guy’s Hospital Medical School in London yesterday on Thursday 14th May.(2)

W.L.Bragg was the son and collaborator with his his equally brilliant father William Henry, both of whom had used X-Rays to determine the arrangement of atoms in molecular structures

The article recognised the work that father and son by the use of X-rays which was at the heart of the work on DNA.

Bragg dressed for experimentation.

William Henry Bragg, son of  William Lawrence, dressed for experimentation!

This contribution was remarked on by James Watson on the 1953 discovery of the DNA structure who said the X-Ray method developed 40 years before was at the heart of this profound insight into the nature of life itself.

The Braggs used the recent discovery of X-Rays to show how these mysterious rays reacted strangely when exposed to crystals, produced patterns of spots on a photographic plate.

Bragg (senior) William Henry, had sought the help of an instrument maker, as he wanted to construct the best spectrometer which was better than the one at Cambridge University. W.H.Bragg’s expertise was in perfecting the instrument and in his experimental work.

 

The Braggs worked on a formula that linked X-Ray diffraction with crystalline atomic structure and in 1912/1913 when diffraction was largely unexplained, at Leeds University they used their spectrometer to produce molecular analysis of diamonds and common salt, along with what the miners called zinc blende, which comes from the main zinc mineral, Sphalerite.

William Lawrence, the son, suggested that when a narrow beam of X-Rays is passed through a crystal, the beam behaves as though it had been reflected by a regular arrangement of atoms, as light is reflected by a mirror. This behaviour generates a pattern of spots on photographic film placed behind the crystal.

William Henry Bragg with the first spectrometer. Image courtesy of Royal Institution.

William Henry Bragg with the first spectrometer. Image courtesy of Royal Institution.

Their discovery of X-Ray crystallography is still today the most accurate technique to determine the structure of materials at the atomic level.

Remarkably, the Braggs, father and son, received the Nobel Prize for physics in 1915. Lawrence was and is the youngest to win the prize, being only 25.

From understanding the properties of the crystals diamonds and salt, development came with complex organic compounds and proteins which was to result in great advances in science and medicine.

Before the Braggs, it was known about the theory of molecules and atoms, but there was no way of knowing how atoms were arranged in space.

Answers could now start to be given to fundamental questions as to why water boils at 100(c) and methane -161; why is blood red?; grass green?; wax soft; diamonds hard and sunlight essential to growth, all using structural analysis of atoms.

(1) Article by science writer Ritchie Calder. His grandson is the travel writer.

(2) W.L. Bragg: 31st March 1890-1st July 1971.

Ref: chemistryexperiments.com/william Lawrence Bragg.

Ref: William Henry Bragg (1862-1942), English physicist with spectrometer c1910s Science Museum /Science and Society Picture Library shows Bragg posing by his instrument and typical of the great scientists of the time wearing a three-piece suit. Pic Ref: diamond.ac.uk.

Ref: Leeds.ac.uk/ Birth of Crystallography Celebrations Bragg Centenary 1913-2013.

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About colindunkerley

My name is Colin Dunkerley who having spent two years in the Royal Army Pay Corps ploughed many a barren industrial furrow until drawn to the 'chalk-face' as a teacher, now retired. I have spent the last 15 years researching all aspects of life in Britain since Roman times.

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