by Xiaomeng Han

Chien-Shiung Wu

In the spring of 1912, a baby girl was born to a family in China. It was the family’s tradition that all the boys in the generation have the character “Chien” in their first names, followed by characters from the phrase “Ying-Shiung-Hao-Jie”, which means “heroes”. The parents believed their daughter should be treated equally, so they named her “Chien-Shiung”. They were determined to raise their daughter to become a hero, although at that time they didn’t know that Chien-Shiung would become one of the most distinguished experimental physicists in the 20th century and a true hero for many generations of women scientists.

Both strong proponents of gender equality, Chien-Shiung’s parents founded the Ming De School for girls, where Chien-Shiung began her education. In 1934, she earned her Bachelor of Science degree from National Central University. Inspired by Marie Curie’s story and impressed by the rapid progress in modern physics, she decided to pursue a PhD in physics in California. In 1936, Chien-Shiung waved goodbye to her parents on a ship to the US; this was the last time she saw them.

At UC Berkeley, Chien-Shiung became the student of Ernest Lawrence, a Nobel laureate in nuclear physics. Her extreme and meticulous attitude as an experimental physicist won her a reputation of excellence from fellow physicists, who said of her “If the experiment was done by Wu, it must be correct.” She completed her PhD in 1940 and married fellow physicist Luke C.L. Yuan. In 1944, she became the only Chinese-American person invited to join the top-secret Manhattan Project, an initiative begun during WWII to develop the atomic bomb. After the war, the couple soon welcomed a son who would ultimately follow in his parents’ footsteps to become a nuclear physicist. Chien-Shiung also accepted a faculty position at Columbia University, where she would eventually become the first tenured female professor in physics.

At Columbia, Chien-Shiung focused her research on beta decay, a process in which unstable,  radioactive atoms release small particles (like electrons) in an attempt to become more stable. Her sophisticated experimental design made her a top authority in this field. In 1956, two of her colleagues developed a theory to challenge a longstanding law in physics. Physicists used to believe that symmetry governs every process in nature, which is called conservation of parity, but it seemed not to be the case for beta decay. Chien-Shiung designed and carried out the famous “Wu Experiment” based on the beta-decay of the radioactive atom cobalt-60. She precisely measured the small particles released from the atom, and found that they were jettisoned in an asymmetrical manner. This proved her colleagues’ theory that parity is not conserved for beta decay, leading to them winning the Nobel Prize in 1957. Although Chien-Shiung’s contribution was unacknowledged, she was later awarded with the Wolf Prize in Physics and elected to be the first female president of the American Physical Society.

In her later life, Chien-Shiung devoted much of her time to educational programs for girls in the STEM fields both in the US and in China. Her inspirational story made her a hero for many young women scientists, just as her name “Chien-Shiung” implies.

Xiaomeng Han is a graduate student in the Harvard Ph.D. Program in Neuroscience. She uses electron microscopy to study neuronal connectivity.

Cover image by Gerd Altmann from Pixabay

Photograph of Chien-Shiung Wu courtesy of the Smithsonian Institution from United States via Wikimedia Commons

This biography is part of our “Picture a Scientist” initiative. To learn more about the amazing men and women who paved the way for modern scientific discovery, check out our homepage.

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