Chien - Shiung Wu

Provided the first experimental proof that parity is violated in weak nuclear interactions - fundamentally changed understanding of symmetry in physics.

Chien - Shiung Wu was a Chinese - American experimental physicist whose 1956 "Wu experiment" definitively showed that weak interactions violate parity symmetry - a breakthrough that reshaped particle physics. She also contributed to the uranium - enrichment process during the Manhattan Project.

Chien - Shiung Wu was born on May 31, 1912, in Liuhe, in Taicang (Jiangsu province), China. From early on, she grew up in a family supportive of education - something uncommon for girls in her time. She studied physics at National Central University in Nanjing (graduating 1934) before moving to the United States in 1936 for graduate study at the University of California, Berkeley. In 1940 she earned her Ph.D. in physics at Berkeley under the mentoring of prominent physicists. After her doctorate, Wu worked briefly as lecturer and then - with World War II underway - became involved in critical wartime research. She joined the Columbia University team (as part of the Manhattan Project) and helped develop the gaseous - diffusion process for separating uranium isotopes (U - 235 and U - 238), a key step in nuclear physics and atomic research. In 1956, acting on theoretical work by her colleagues Tsung - Dao Lee and Chen - Ning Yang, Wu conducted a decisive experiment with radioactive cobalt - 60 ("Wu experiment") and observed that beta particles emitted in weak nuclear decay had a preferred direction - thus demonstrating that the law of parity conservation fails in those interactions.This result upended a core assumption in physics and laid groundwork for modern particle theory. After the war, Wu continued her academic career at Columbia University. In 1957 she became Dupin Professor of Physics, later in 1972 Michael I. Pupin Professor, and remained there until her retirement in 1981. Her achievements brought many honors: she received the National Medal of Science (1975), and in 1978 she became the first recipient of the Wolf Prize in Physics for her experimental work. Chien - Shiung Wu died on February 16, 1997, in New York City. Her legacy lives on: she remains one of the most influential experimental physicists of the 20th century, celebrated for combining technical mastery with bold challenges to established scientific orthodoxy.