Question 1

Who was He Zehui and why is she important in the history of science?

Accepted Answer

He Zehui (1914–2011) was a Chinese nuclear physicist often nicknamed the “Marie Curie of China.” What makes her pivotal is that, together with her husband Qian Sanqiang, she discovered in 1947 the ternary and quaternary fission of uranium – a rare phenomenon in which the nucleus splits into three or four fragments instead of two. This work, carried out at the Joliot-Curie laboratory in Paris, profoundly enriched the understanding of nuclear fission. The key takeaway is that she then helped found nuclear research in China, training a generation of physicists and developing nuclear emulsions that freed China from its reliance on foreign supplies.

Question 2

How did He Zehui overcome gender prejudice to become a physicist?

Accepted Answer

To understand this, you have to remember that in 1932 the head of the physics department at Tsinghua University believed physics was unsuitable for women and tried to steer them into other programs. He Zehui refused to give in and graduated top of her class in 1936, proving him wrong. What is striking here is her determination: during the Sino-Japanese War, she deliberately chose to study ballistics in Berlin to help her country defend itself, becoming the first woman admitted to this German military specialty. She thus broke two glass ceilings – in China and in Germany.

Question 3

What was He Zehui's role in the development of nuclear physics in China?

Accepted Answer

What makes He Zehui important to China is that, on her return in 1948, she co-founded the Institute of Modern Physics and trained the first Chinese researchers in nuclear physics. In the 1950s she also developed Chinese nuclear emulsions, enabling the country to detect particles without depending on foreign suppliers. Less famous than China's atomic bomb of 1964, her contribution was nonetheless essential in equipping China with an independent research infrastructure. What is often forgotten is that she later turned her work toward cosmic rays and high-energy astrophysics, opening a new field in the 1970s–1990s.

Question 4

What did a typical day for He Zehui look like in the laboratory?

Accepted Answer

Picture a physicist who begins her morning early by preparing radium-beryllium neutron sources and emulsion plates, then launches uranium bombardment experiments. In the afternoon she spends hours hunched over an analysis microscope, measuring one by one the tiny tracks left by the fission fragments – long and painstaking observation work. In the evening she reads scientific journals and discusses physics with her husband Qian Sanqiang. The key takeaway is that her entire life was devoted to research, with remarkable frugality: she wore old patched clothes and lived in modest housing, despite her fame.

Question 5

What objects did He Zehui commonly use in her experiments?

Accepted Answer

He Zehui's tools were those of nuclear physics in the 1940s–1950s. The most emblematic is the photographic nuclear emulsion: plates coated with a sensitive gelatin in which particles leave tracks visible under the microscope – it was with these that she observed ternary fission. She also used a cloud chamber (Wilson chamber) to visualize trajectories, a Geiger-Müller counter to measure radioactivity, and a radium-beryllium neutron source to bombard uranium. What is striking is the simplicity of these instruments compared with modern accelerators: precision and patience were her true tools.

Question 6

What does the term “ternary fission” mean and why was its discovery important?

Accepted Answer

Ternary fission is a rare case in which the nucleus of a heavy atom, such as uranium, splits into three fragments instead of two. He Zehui and her husband discovered it in 1946–1947 by bombarding uranium with neutrons. What makes this discovery important is that it showed fission was not a simple binary process but could produce lighter fragments, opening a new understanding of nuclear physics. The key takeaway is that this observation was hailed by the Joliot-Curies as the greatest advance in their laboratory since the war.

Question 7

What is the most famous anecdote about He Zehui during the Second World War?

Accepted Answer

During the war, international mail was limited to 25 words. It was through these tiny letters that Qian Sanqiang, who had stayed in Paris, proposed marriage to He Zehui, who had remained in Germany. She accepted, and they married in Paris in 1946. What is striking here is that this story illustrates both the constraints of the time and the strength of their bond, which became a legendary scientific partnership. Less romantic but equally remarkable: in 1946–1947, in the Joliot-Curie laboratory, they observed a uranium nucleus splitting into three and then four fragments – the Western press grew enthusiastic and nicknamed her “the Marie Curie of China.”

Question 8

In what global context did He Zehui make her discoveries?

Accepted Answer

To understand this, you have to remember that her career unfolded during a period marked by the rise of nuclear physics: in 1939, Hahn, Strassmann and Meitner explained the fission of uranium; in 1945, the atomic bombs of Hiroshima and Nagasaki changed the world. He Zehui arrived in Paris in 1946, just after the war, in the Joliot-Curie laboratory – committed communist scientists. What makes her work singular is that it took place while China was in the midst of civil war, before becoming the People's Republic of China in 1949. She chose to return in 1948 to contribute to the scientific rebuilding of her country, in the context of a nascent Cold War.

Question 9

What are the key places in He Zehui's life?

Accepted Answer

The landmark places of her life are: Suzhou, her birthplace in China; Tsinghua University in Beijing, where she studied physics; the Berlin Institute of Technology, where she earned her doctorate in ballistics in 1940; the Joliot-Curie laboratory in Paris, where she discovered ternary fission; and finally the Institute of Atomic Energy in Beijing, where she founded Chinese nuclear research. The key takeaway is that each of these places corresponds to a decisive stage: training, major discovery, and then the building of a national science.

Question 10

What primary sources attest to He Zehui's discoveries?

Accepted Answer

He Zehui's discoveries are documented by several primary sources. The most important is a communication to the Academy of Sciences in 1946–1947, signed by Tsien San-Tsiang, Ho Zah-Wei, R. Chastel and L. Vigneron, describing the observation of the tripartition and quadripartition of uranium. A detailed article then appeared in the Journal de Physique et le Radium in 1947, measuring the trajectories of the fragments. Finally, the Joliot-Curies publicly praised this work as the most important carried out in their laboratory since the war. What is often forgotten is that these publications were written in French, testifying to the international collaboration of the time.

Question 11

What scientific vocabulary is associated with He Zehui's era?

Accepted Answer

To understand He Zehui's work, you need to master a few key terms: nuclear fission, the phenomenon in which a heavy nucleus splits; ternary fission, discovered by He Zehui; the neutron, the particle that triggers fission; the nuclear emulsion, a sensitive plate where particles leave tracks; the cloud chamber, a device that visualizes trajectories; and radioactivity, the property of unstable atoms. What is striking is that these words are still used today in high-school physics textbooks, proof that the discoveries of that era remain fundamental.

Question 12

What would have happened if He Zehui had lived today?

Accepted Answer

If He Zehui were a 21st-century physicist, she would probably work at CERN or in a major Chinese laboratory such as the Institute of High Energy Physics in Beijing. With modern accelerators, she would study exotic particles or dark matter rather than fission. What would still set her apart is her determination to break down prejudice: in a world where women are still underrepresented in physics, she would be an activist figure for equality. Less a revolutionary than a pioneer, she would embody perseverance and excellence, just as she did in the 20th century.

He Zehui(1914 — 2011)

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