Chien-Shiung Wu

WU, Chien-Shiung, Chinese/American physicist, 1912-1997. Her undergraduate work was in China, then the postgraduate study in the USA from 1936, she and her husband became naturalised Americans in 1954. During WW2  worked at Princeton U.,  the first woman instructor there, but was separating radioisotopes in connection with the atomic bomb preparations (Manhattan Project). A professor at Columbia U. from 1972-81. She experimentally confirmed Fermi’s theory that in beta decay most electrons ejected from the nucleus would be travelling at very high-speeds. In 1956 her experiments on beta rays emitted from Cobalt60 indicated non-conservation of parity in weak interactions. This shook the scientific world. Parity assumes symmetry of real physics events in their mirror images. In 1957 she used radioactive films of even thickness, and confirmed that more electrons were emitted opposite the magnetic field than along it. The parity concept was then dead. Highly honoured, including doctorates from many institutions. Serious and demanding of her students, but very humane. Called the Dragon Lady by some of the staff, but not by her students, some media reports have referred to her as the ‘Queen of Physics’. She created several inventions in experimental atomic physics, mainly for radiation-detection and wavelength separation during radioactive decay. Her colleagues Dao Li and Chen Ning Yang won the Nobel Prize in 1957 for proving that the Parity Principle does not hold universally. However her earlier experimental work had been the vital component.

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