William Lawrence Bragg

William Lawrence Bragg was born in Adelaide, Australia, on 31st March 1890. He was an impressionable boy and showed an early interest in science.

His father, William Henry Bragg, was Professor of Mathematics and Physics at the University of Adelaide. Shortly after starting school at age 5, Bragg fell from his tricycle and broke his arm. His father, having recently read about Röntgen's experiments in Europe, used the newly discovered X-rays to examine Bragg's arm. This is the first recorded surgical use of X-rays in Australia.

Bragg was a very able student, and from the age of 11 studied at St Peter's College. He was in a class of older boys who saw him as 'an amusing freak', but did not tease or bully him. In 1904, aged 15, Bragg entered Adelaide University to read mathematics, chemistry and physics. He graduated in 1908, aged 18.

In 1908 Bragg's father accepted the Chair of Physics at Leeds University, and took the family back to England on the Waratah, a ship that sank on her next voyage!

Bragg entered Trinity College, Cambridge in the autumn of 1909. He received a major scholarship in mathematics, despite taking the exam while in bed with pneumonia. After gaining first class honours in Part I mathematics, Bragg transferred to the Part II Physics course, and graduated with first class honours in 1911.

Bragg is most famous for his law on the diffraction of X-rays by crystals, a 'theory which makes it possible to calculate the positions of [the X-ray beams] for all dispositions of crystal and photographic plates'. He made this discovery in 1912, during his first year as a research student in Cambridge. To make the discovery Bragg drew together results published by Laue in Germany and concepts from lectures by J.J. Thomson and C.T.R. Wilson. He presented his theory to the Cambridge Philosophical Society on 11th November 1912.

Bragg 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, work which Bragg could not perform in the over-crowded Cavendish Laboratory. The collaboration between father and son led many people to believe that Bragg's father had initiated the research, a fact that upset William Lawrence.

In 1914 Bragg was elected to a Fellowship at Trinity College, but the First World War interrupted his work. Bragg was commissioned as a 2nd Lieutenant in the Leicester Royal Horse Artillery, and in August 1915 began working on sound ranging methods for locating enemy guns. He supervised this work between 1917 and 1919, rising to the rank of Major.

In autumn 1915, Bragg's brother Robert was killed in the War. At about the same time Bragg received the news that he had won the Nobel Prize in Physics.

Bragg returned to Cambridge early in 1919, but later that year became Langworthy Professor of Physics at Manchester, in succession to Ernest Rutherford. Bragg was elected as a Fellow of the Royal Society on 12th May 1921, and in December married Alice Hopkinson, a historian from Cambridge with whom he had four children.

In 1930 Bragg suffered a breakdown, but recovered quickly after the birth of his third child in June 1931. In November 1937 Bragg became Director of the National Physical Laboratory, but found the work disappointing. On 17th October 1937 Rutherford died. The following year Bragg was appointed as his successor at the Cavendish.

Bragg moved to Cambridge with his family in October 1938, but the Laboratory was rapidly emptying as research staff left for service in the Second World War. Bragg again worked on sound ranging, and on improving a form of sonar. In 1941 he was knighted a 'Sir Lawrence', and spent six months as Scientific Liaison Officer in Canada. Between 1939 and 1943 he was President of the Institute of Physics.

After the War, Bragg returned to Cambridge, splitting the Cavendish into research groups. 'The ideal research unit is one of six to twelve scientists and a few assistants'. Bragg was keen that no single research group should dominate, as nuclear physics had dominated in the past. The groups were nuclear, radio and low-temperature physics, crystallography, metal physics and mathematical physics.

In 1948 Bragg became interested in the structure of proteins. Although he played no direct part in the 1953 discovery of DNA's structure, James Watson admits that 'the X-ray method [Bragg] developed forty years before was at the heart of this profound insight into the nature of life itself.'

In April 1953 Bragg accepted the post of Resident Professor at the Royal Institution in London. Bragg proposed that the Royal Institution should perform some form of public service, and suggested 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.

Some of Bragg's lectures were televised by the BBC. Bragg became a popular communicator of science, admired and recognised by the public. He worked at the Royal Institution until his retirement in September 1966.

Bragg's hobbies included painting, literature and a life-long intereset in gardening. He 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.

William Lawrence Bragg died at a hospital near his home at Waldringfield, Suffolk on 1st July 1971.