Sir William Bragg

Sir William Lawrence Bragg CH OBE MC FRS (31 March 1890 – 1 July 1971) was an Australian-born British physicist and X-ray crystallographer, discoverer (1912) of the Bragg law of X-ray diffraction, which is basic for the determination of crystal structure. He was joint winner (with his father, Sir William Henry Bragg) of the Nobel Prize for Physics in 1915: "For their services in the analysis of crystal structure by means of X-ray" an important step in the development of X-ray crystallography. He was knighted in 1941. To date, Lawrence Bragg is the youngest Nobel Laureate, having received the award at the age of 25. He was the director of the Cavendish Laboratory, Cambridge, when the epochal discovery of the structure of DNA was reported by James D. Watson and Francis Crick in February 1953.

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.

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 this work he was aided by William Sansome Tucker, Harold Roper Robinson and Henry Harold Hemming. For his work during WWI he was awarded the Military Cross and appointed Officer of the Order of the British Empire. He was also Mentioned in Despatches on 16 June 1916, 4 January 1917 and 7 July 1919.

On 2 September 1915 his brother was killed during the Gallipoli Campaign. Shortly afterwards, William Lawrence Bragg received the news that he had been awarded the Nobel Prize in Physics, aged 25, making him the youngest ever winner of a Nobel Prize.

Between the wars, from 1919 to 1937, he worked at the Victoria University of Manchester as Langworthy Professor of Physics. 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".

Honours and awards:

He was elected an FRS in 1921—"a qualification that makes other ones irrelevant". He was knighted by King George VI in the 1941 New Year Honours, and received both the Copley Medal and the Royal Medal of the Royal Society. Although Hunter, in his book on Bragg Light is a Messenger, argued that he was more a crystallographer than a physicist, Bragg's lifelong activity showed otherwise—he was more of a physicist than anything else. Thus, from 1939 to 1943, he served as President of the Institute of Physics, London. In the 1967 New Year Honours he was appointed Companion of Honour by Queen Elizabeth II.

Since 1992, the Australian Institute of Physics has awarded the Bragg Gold Medal for Excellence in Physics to commemorate Sir Lawrence Bragg (in front on the medal) and his father, Sir William Bragg, for the best PhD thesis by a student at an Australian university.

Nobel Prize (1915)

Matteucci Medal (1915)

Hughes Medal (1931)

Royal Medal (1946)

Guthrie Lecture (1952)

Copley Medal (1966)