Usha Devi K.S.

Source: britannica.com

Her name may now be forgotten by most people and only remembered as a reference in text books of nuclear physics. Chien Shiung Wu (May 31, 1912 – February 16, 1997) was a Chinese scientist who immigrated to USA, and was associated with the Manhattan Project for the development of the atomic bomb.

She helped develop the process for separating uranium metal into the uranium-235 and uranium-238 isotopes using gaseous diffusion. Her biggest contribution to science however was in proving a scientific law wrong. Her work overturned a widely accepted law in particle physics known as ‘The Principle of Conservation of Parity’, expounding ‘the idea of symmetry, where particles that are mirror images of each other will act in identical ways’.

In the mid 1950s, theoretical physicists, Chen Ning Yang and Tsung Dao Lee, had approached Wu to help them disprove the ‘law of parity’.  Wu carried out several significant experiments in ‘beta decay’ using cobalt-60 showing that one particle was more likely to eject an electron than the other and they were therefore not symmetrical. Her observations overturned the 30-year ‘conservation of parity’ law. 

However, Yang and Lee neglected to record her experimental observation in their paper proving the law was invalid. They were awarded the Nobel Prize in 1957 for their “discovery” that the conservation of parity was incorrect.  Though Wu had painstakingly carried out the actual experiments at the National Bureau of Standards, sadly her contribution was not mentioned in the Nobel citation…Read more on NOPR