it is shameful that there are so few women in science”*

Chien Shiung Wu - image via Smithsonian Institution

 吳健雄, Chien-Shung Wu, was born this day, May 31, in 1912. She is best remembered today for her work on parity breaking. The Wu Experiment analyzed the decay of Cobalt 60 and the gamma rays emitted. She established that the emission was non-isotropic, that is, that the emissions were biased in particular directions. This was the first firm experimental evidence that not all physical interactions at the quantum level were fully symmetric, leading to the development of the modern Standard Model and its understanding of symmetry and symmetry breaking. For this work, her male colleagues were awarded the Nobel Prize, but Dr. Wu was not.

Additionally, over the course of her career she studied beta decay, fission, medical physics, and quantum entanglement. She was a talented educator and an outspoken critic of sexism in science and society. She was the first woman to serve as president of the American Physical Society.


She was profiled last week on JSTOR:

To learn more about her work, you can read the 1957 paper “Experimental Test of Parity Conservation in Beta Decay” in Physical Review:

and check out The Fall of Parity on the NIST website



* quote published in Newsweek (20 May 1963)