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1898 CEPrimary source · 2 sourcesWell documented

Marie and Pierre Curie Discover Radioactivity

A mineral more radioactive than the uranium inside it points to two entirely new elements

On the timeline · around 1898 CE · Classical PhysicsClassical PhysicsThe Quantum and Relativity RevolutionMarie and Pierre Curie Discover Radioactivity18301850187018901910

Quick facts

New elements isolated
Polonium and radium, 1898
Built on
Henri Becquerel's 1896 discovery of uranium radiation
Term coined
"Radioactivity"
Nobel recognition
Physics, 1903 (shared); Chemistry, 1911 (Marie Curie alone)

What happened

Building on Henri Becquerel's 1896 discovery that uranium salts emitted radiation on their own, Marie Curie set out to measure this radiation systematically in ores containing uranium and thorium. She and her husband Pierre found that pitchblende, a uranium ore, was far more radioactive than its uranium content alone could explain, and the U.S. National Park Service records that this discovery led her to deduce that radiation emitted directly from atoms, not from how they are arranged within molecules, a genuinely new idea at the time. Pursuing that extra radioactivity through the arduous chemical separation of tons of ore, the Curies isolated two previously unknown elements in 1898: polonium, named for Marie's native Poland, and radium. In the course of this work Marie Curie coined the term radioactivity itself.

Why it matters

The Curies' work showed that radioactivity was a property of individual atoms rather than of chemical bonds, undermining the 19th-century assumption that atoms were permanent and unchangeable, a discovery that fed directly into 20th-century nuclear physics and, decades later, into the discovery of nuclear fission. Marie Curie shared the 1903 Nobel Prize in Physics with Pierre Curie and Becquerel, and won a second, unshared Nobel Prize in Chemistry in 1911, the first person ever to win two Nobel Prizes in different sciences.

How we know

The Curies published their results in papers to the French Academy of Sciences in 1898, and their claimed new elements were confirmed through the physical isolation of measurable quantities of polonium and radium salts, work independently replicated and extended by other chemists in the years that followed.

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Marie and Pierre Curie Discover Radioactivity · History of Physics · SourcedStory