Chien-Shiung Wu, the First Lady of Physics

By Jaime Seltzer

“It is the courage to doubt what has long been established and the incessant search for its verification and proof that pushes the wheel of science forward.”

Chien-Shiung Wu was born in 1912 in Liuhe, China. She was born at a felicitous time: the year before, the new Republic of China was established, overthrowing the last Chinese dynasty and creating an atmosphere of reform and social change in China. Her parents named her Chien-Shiung, which means ‘courageous hero’.

Her father, Zhongyi Wu, was an engineer and a fierce proponent of women’s rights in China. He opened the Mingde School for Girls, and his wife, Fan Fuhua, helped persuade other families to send their girls as well.

The Mingde School had been designed to teach small children the basics of reading, writing, and mathematics, and soon the brilliant Chien-Shiung soon far outstripped her peers. Her parents sent her to the Suzhou Girls’ School to board, which might have been very difficult for the ten-year old Chien-Shiung. But on the advice of her father, she ignored all obstacles and pushed forward.

Chien-Shiung persevered for seven years, discovering her passion for mathematics and physics along the way. Her studies (and a recommendation from Hu Shi, who invented and popularized phonetic Chinese writing) made it possible for her to enter the National Central University in Nanjing, earning her degree in physics in 1934 with top honors. Afterwards, she lived and worked in Shanghai, teaching classes in x-ray crystallography at the National Academy of Sciences.

The experiment she designed clearly and elegantly disproved that parity existed for all particles in all circumstances, which had dramatic influence on the way in which physicists understood the universe and how it worked.

But Chien-Shiung wasn’t satisfied with being one of the first little girls to attend school in her province, or being amongst a handful of women who held a physics degree worldwide. Instead, she set her sights higher, on a physics doctorate. At the time, no such thing existed in Shanghai; so, with funds from a kindly uncle, she packed her bags and moved to the United States to learn about the universe hidden within the atom.

Once again, a strange confluence of events conspired to dramatically shape Chien-Shiung’s life. She arrived in California and made the decision to talk to the physicists at Berkeley before she made her way to Michigan, where she planned on earning her degree. Berkeley’s stellar physics department had her wandering around for hours, speaking to such well-known nuclear scientists as Oppenheimer and Lawrence, and touring the facilities until she was practically petting the machinery. Of course she had to stay, and she began classes at Berkeley immediately.

Wu developed the reputation for being incredibly devoted to her work, staying in the lab until the wee hours, and for noting the tiny flaws that could invalidate the results of an experiment. Her dedication was the most noticeable thing about her, after her brilliance.

Less than a year after she arrived in California, Japan invaded China and Chien-Shiung abruptly and devastatingly lost contact with her close-knit family.

Chien-Shiung remembered her father’s advice to push forward and devoted ever-more of her time to her work on the atom, earning her doctorate in a mere four years. She served as a research assistant and then taught briefly at Smith College and at Princeton, where she was the first female professor, ever.

Chien Shiung Wu

Dr Chien Shiung Wu and her Women in Science card.

Then she was snatched up for – I’m sure you could see this coming a mile off – the Manhattan Project, which was already underway. Enrico Fermi was struggling with producing a viable reactor when someone suggested he “ask Miss Wu” for advice. Not only did Wu join, she immediately saw the problem with the reactor – a buildup of the inert gas, xenon – and suggested a workaround.

While working at the Manhattan Project, Wu improved on uranium enrichment methods and made significant improvements to the Geiger counter; and when World War II ended, she received the incredibly happy news that her family was alive and well after eight years without contact.

In 1946, she began research on beta-decay, a type of radioactive decay of an element in which a proton can become a neutron, or a neutron can become a proton, allowing an element to become more stable. A beta particle is emitted during this process, either an electron or a positron.

In 1956 she and two other scientists began studying something called ‘Parity Law’ that states that if two objects are mirror images of one another, they will have the same properties and behave the same way. Wu suggested which type of particle to use in the experiment and performed it at the National Bureau of Standards in Washington, D.C. to ensure the experiment could be performed at the low temperatures the experimental setup required. Wu used cobalt-60 was able to observe the particles it emitted while caught in a magnetic field. If parity were preserved, the radioactive particles would travel equally towards and away from the field. Instead, 60% of the gamma rays pointed in one direction, and only 40% pointed in the other direction.

The experiment she designed clearly and elegantly disproved that parity existed for all particles in all circumstances, which had dramatic influence on the way in which physicists understood the universe and how it worked. It was such a dramatic turn of events that Wu’s two male colleagues were awarded the Nobel Prize; however, Wu herself was not named. Wu’s nationality and gender may have co-conspired to keep her from the honor; but even at the time, the decision to leave Wu out was considered outrageous by fellow scientists.

Immediately, other committees heaped awards on Wu’s head, as if to make up for the stinging slight. She won the Comstock Award of the National Academy of Sciences shortly after being passed over for the Nobel, and numerous other prizes as her career continued. She was the first female president of the American Physics Society in 1975 and, that same year, she won the National Medal of Science.

When Wu passed away in 1997, she was remembered for her brilliance and kindness, but also for the qualities exemplified in her name: her determination and the bravery it took to go up against a central maxim of science: the woman who overturned a law of physics and helped to build the hydrogen bomb.

References:
Garwin, R.L. and Lee, T-D. (1997, October). Obituaries Chien-Shiung Wu. Physics Today. Retrieved from http://scitation.aip.org/docserver/fulltext/aip/magazine/physicstoday/50/10/1.2806727.pdf?expires=1442265336&id=id&accname=guest&checksum=332ED4A936BC8398317EC7C1A35BFEAE
Gould, S. (2013, September 11). This Brilliant Female Physicist Was Overlooked for a Nobel Prize. In The American Association of University Women (AAUW). Retrieved September 15, 2015, from http://www.aauw.org/2013/09/11/overlooked-for-nobel-prize/
Liu, T. (2012, November 27). Inside Story: C S Wu – First Lady of physics research. CERN Courier (International Journal of High-Energy Physics). Retrieved from http://cerncourier.com/cws/article/cern/51556
Weinstock, M. (2013, October 15). Channeling Ada Lovelace: Chien-Shiung Wu, Courageous Hero of Physics. In Scientific American Blogs. Retrieved October 14, 2015, from http://blogs.scientificamerican.com/guest-blog/channeling-ada-lovelace-chien-shiung-wu-courageous-hero-of-physics/

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