High Quality Content by WIKIPEDIA articles! 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 Bragg) of the Nobel Prize for Physics in 1915. He was knighted in 1941. To date, Lawrence Bragg is the youngest Nobel Laureate. He was the director of the Cavendish Laboratory, Cambridge, when the epochal discovery of the structure of DNA was made by James D. Watson and Francis Crick in February 1953.