Looking Back: The Birth of Nuclear Physics

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Looking Back: The Birth of Nuclear Physics


Brittany Maynard, SPS Member, Hampton University

Brittany Maynard. Photo courtesy of the author.Nuclear physics is a startlingly young science, especially considering the advances it has led to in medicine and energy.

The first hints of this new science came with—of all things— a glowing piece of paper. In 1895, in a laboratory at the University of Wurzburg, Germany, physicist Wilhelm Röntgen was experimenting with an electric tube. Upon turning it on, a piece of chemically coated paper near him began to glow. This astonished Röntgen. He turned the electric tube off and the glow disappeared. He turned the tube on and off several times before realizing that the tube produced something invisible that was interacting with the paper. He called this effect “x-ray radiation.” For his discovery Röntgen received the first Nobel Prize in Physics, awarded in 1901. Physicists sprang into action. If this tube could cause radiation, what else could?

One physicist intrigued by Röntgen’s work was French scientist Antoine Henri Becquerel. A colleague suggested that the “glowing” uranium salts he owned could be giving off radiation, so Becquerel set out to see if this was true. After one long day of experimenting in 1896, Becquerel had plans to take photographs outside, a hobby of his. However, the weather turned sour so he threw the photographic plates into a drawer—the same one that contained the uranium salts. When the weather improved he used the plates, but upon developing them found they were corrupted. Was this the evidence of radiation Becquerel was looking for? Further work revealed that uranium was indeed a source of radiation and had corrupted the plates.

After learning of Becquerel’s discovery, a young woman made it her mission to study radiation. Marie Curie was Polish but had immigrated to France to study physics because women in Poland were unable to study at universities at that time.

Marie Skłodowska-Curie. Public domain.Curie showed that the intensity of radiation in a uranium compound correlated only with the concentration of uranium, proving that uranium atoms, not molecular interactions, were responsible for radioactivity. This was important because at the time, many scientists thought that atoms were indivisible objects. Later, when studying the uranium mineral known as pitchblende, Curie came to the startling conclusion that there was something much more radioactive than uranium hidden in the pitchblende.

Working with her husband, Pierre, Curie isolated a tiny amount of a new element, more radioactive than uranium, and heavier too. They named this element polonium after Poland, the country which gave birth to Marie Curie yet denied her a higher education. Later that year the Curies found a second element, radium. Becquerel and the Curies shared the 1903 Nobel Prize in Physics for their work on radiation. The following year the Curies began perhaps their most important work, discovering that tumors shrink when injected with radium. This “Curie therapy” is the basis of a cancer treatment still being perfected today.

Over the next several years, the quest to understand radiation led scientists to further investigate the structure of the atom and eventually to the discovery of the nucleus in 1911. Trying to break apart the nucleus became something of a sport in the early part of the 20th century, and eventually a new device called a particle accelerator was created for that express purpose. Nuclear science is a growing field even today, leading to significant advancements in medicine, clean energy, and our understanding of the universe. To think it all started with a rainy day....

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