William Lawrence Bragg

William Lawrence Bragg
File:William Lawrence Bragg.jpg William Lawrence Bragg
Born	31 March 1890 North Adelaide, South Australia
Died	1 July 1971 Ipswich, Suffolk, England
Residence	Australia, UK
Nationality	Australian- English
Institutions	Victoria University Cambridge University
Alma mater	University of Adelaide Cambridge University
Academic advisor	J.J. Thompson W.H. Bragg 20px
Notable students	John Crank Ronald Wilfried Gurney
Known for	X-ray diffraction
Notable prizes	Nobel Prize in Physics (1915)
Youngest person to ever receive a Nobel Prize. He is the son of W.H. Bragg. Note that the PhD did not exist at Cambridge until 1919, and so J.J. Thompson and W.H. Bragg were his Master's advisors.

Sir William Lawrence Bragg CH, FRS, (31 March 1890 – 1 July 1971) was an Australian physicist who shared the Nobel Prize in Physics in 1915 with his father Sir William Henry Bragg. He was the director of the Cavendish Laboratory, Cambridge when the discovery of the structure of DNA was made by James Watson and Francis Crick in February 1953. Together with King's College London's Maurice Wilkins, Watson and Crick were awarded the Nobel Prize for Physiology or Medicine in 1962.

Biography

Bragg was born in North Adelaide, South Australia. He was an impressionable boy and showed an early interest in science and mathematics. His father, William Henry Bragg, was Professor of Mathematics and Physics at the University of Adelaide. Shortly after starting school aged 5, William Lawrence Bragg fell from his tricycle and broke his arm. His father had read about Röntgen's experiments in Europe of only a year earlier, and used the newly discovered X-rays to examine the broken arm. This combined with a program of rehabilitation enabled Bragg to salvage the use of his arm almost completely. This is the first recorded surgical use of X-rays in Australia.

Bragg was a very able student. At age 9, he was sent to Queens preparatory school in North Adelaide. Two years later he was sent to [[St Peter's College, Adelaide, where he found his intellectual accomplishments better rewarded, and was honored for being the top student of his class. In 1906 he went to the University of Adelaide at age 15 to study mathematics, chemistry and physics. He later blamed a lack of interaction with his peers during this period with his failure to develop adequate social skills. His father was domineering, compellling Bragg to study with him in his office. But in spite of these discomforts, Bragg graduated in 1908. In the same year his father accepted a job at Leeds University, and brought the family back to England. Bragg entered Trinity College, Cambridge in the autumn of 1909 and received a major scholarship in mathematics, despite taking the exam while in bed with pneumonia. After initially excelling in mathematics, he transferred to the physics course in the later years of his studies, and graduated in 1911. Among his fellow students during this period was Niels Bohr. Bragg considered Wilson, who invented the cloud chamber for the visual detection of subatomic particles, his most inspiring teacher.

Bragg is most famous for his law on the diffraction of X-rays by crystals. Bragg's law makes it possible to calculate the positions of the atoms within a crystal from the way in which an X-ray beam is diffracted by the crystal lattice. He made this discovery in 1912, during his first year as a research student in Cambridge. He discussed his ideas with his father, who developed the X-ray spectrometer in Leeds. This tool allowed many different types of crystals to be analysed. The collaboration between father and son led many people to believe that the father had initiated the research, a fact that upset the son.

Bragg's research work was interrupted by both World War I and World War II. During both wars he worked on sound ranging methods for locating enemy guns. In autumn 1915, his brother Robert was killed. At about the same time William Lawrence Bragg received the news that he had become the youngest person ever to receive the Nobel Prize in Physics, aged 25. Between the wars, from 1919 to 1937, he worked at the Victoria University of Manchester as Langworthy Professor of Physics. He married in 1921, to Alice Grace Jenny. He was knighted in 1941.

After World War II, he returned to Cambridge, splitting the Cavendish Laboratory into research groups. He believed that 'the ideal research unit is one of six to twelve scientists and a few assistants'. In 1948 Bragg became interested in the structure of proteins and was partly responsible for creating a group that used physics to solve biological problems. He played a major part in the 1953 discovery of the structure of DNA, in that he provided support to Francis Crick and James D. Watson who worked under his aegis at the Cavendish. Bragg was gratified to see that the X-ray method that he developed forty years before was at the heart of this profound insight into the nature of life itself. At the same time at the Cavendish Max Perutz was also doing his Nobel Prize winning work on the structure of haemoglobin. Bragg subsequently successfully lobbied for and nominated Crick, Watson and Wilkins for the 1962 Nobel Prize in Physiology or Medicine; Wilkins' share recognised the contribution made by King's College London, under Sir John Randall, to the determination of the structure of DNA and its subsequent validation by the KCL staff.

In April 1953 Bragg accepted the job of Resident Professor at the Royal Institution in London. He proposed that the Royal Institution should perform some form of public service, and suggested a series of lectures to show experiments to schoolchildren. This idea was met with an enthusiastic response, and by 1965 20,000 schoolchildren were attending these lectures each year. He worked at the Royal Institution until his retirement in September 1966.

William Lawrence Bragg's hobbies included painting, literature and a life-long interest in gardening. When he moved to London, he missed having a garden and so worked as a part-time gardener, unrecognised by his employer, until a guest at the house expressed surprise at seeing him there.

Bragg received both the Copley Medal and the Royal Medal of the Royal Society, and in 1967 was made a Companion of Honour by the Queen. He died at a hospital near his home at Waldringford on 1 July 1971.

Since 1992 the Australian Institute of Physics has awarded the Bragg Gold Medal for Excellence in Physics for the best PhD thesis by a student at an Australian university.

• spouse = Alice Hopkinson (m. 1921)
• children = Stephen Lawrence, David William, Margaret Alice, Patience Mary

X-ray crystallography

Max von Laue, a German physicist, passed x-rays through a crystal, and by the use of photographic film, demonstrated that the rays produced a diffraction pattern similar to that shown by light passing through parallel slits. He was not, however, able to explain the pattern by a clear theory of the atomic architecture of the crystals. Bragg successfully interpreted the diffraction patterns in terms of atomic crystal structure by assuming that the crystals effectively formed parallel planes that were responsible for the diffraction. He also corrected Laue's interpretation by suggesting a different type of atomic packing in the crystal structure. Through both of these assumptions, he was able to clearly explain the diffraction pattern, and also draw conclusions about the structure of crystals. Bragg was only 22 at the time of his discovery, and but a year out of graduate school. Bragg's father, William Henry Bragg, later developed a laboratory apparatus called the x-ray spectromemter, which simplifed and systematized the analyses of crystals through x-ray diffraction. The two were awarded the Nobel Prize in 1915 for their accomplishments.

Legacy

William Lawrence Bragg could have been easily overshadowed by his father. In fact, when his son, in his teens, found s sea shell that represented a new species, the elder Bragg interfered and prevented the species from being named after him. In spite of this tendency to be overbearing and perhaps antagonistic to his son's achievements, the two were able to work together productively. Each was inspired and instructed by the other, and both produced independently their own discoveries in the same field. Their relationship demonstrates the mutual support that scientists provide one another in their investigations.

The use of x-ray spectroscopy was eventually applied to organic molecules, and was crucial to deciphering of the complex double-helix structure of deoxyribonucleic acid (DNA), the fundamental molecule of heredity. The latter occured some 40 years after Bragg and his father received the Nobel Prize for his accomplishments.

Timeline

• Victoria University of Manchester (1919–37)
• Cambridge University (1938–53)

Prizes

• Nobel Prize (1915
• Matteucci Medal (1915)
• Royal Medal (1946)
• Copley Medal (1966)

See also

• Crystal
• William Henry Bragg
• X-ray

References

ISBN links support NWE through referral fees

<<We need at least 3 reliable references here, properly formatted.>>

• Biography: "Light Is A Messenger, the life and science of William Lawrence Bragg" by Graeme Hunter, ISBN 0-19-852921-X; Oxford University Press, 2004.

• Ridley, Matt; "Francis Crick: Discoverer of the Genetic Code (Eminent Lives)" first published in July 2006 in the USA and then in the UK. September 2006, by HarperCollins Publishers; 192 pp, ISBN 0-06-082333-X; [This short book is in the publisher's "Eminent Lives" series.]

External links

• 'Death' of D.N.A. Helix (Crystaline) joke funeral card.
• [1] First press stories on D.N.A.
• Nobelprize.org - The Nobel Prize for Physics in 1915

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