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Primary sourceArtifact1911

International Radium Standard

Marie Curie · 1911

The sealed radium sample Marie Curie prepared in 1911 to serve as the world's reference standard for measuring radioactivity.

This is the radium standard Marie Curie herself prepared, which gave rise to the unit named after her and Pierre.

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A museum display case showing a wooden mahogany box with its lid open and a round metal radium container inside, beside a separate lidded metal canister with a brass knob, a key on a chain, and a small cluster of tubes on the glass base.
Radium sample prepared by Marie Curie as the international standard, 1911. Bureau International des Poids et Mesures, Sèvres.

About this source

What it is

This is the radium sample Marie Curie prepared in 1911 to act as the international standard for radioactive emissions. It is kept at the Bureau International des Poids et Mesures in Sèvres, France.

Why it matters

After isolating radium, Curie defined this standard so that scientists everywhere could measure radioactivity consistently. The unit of radioactivity, the curie, was later named after her and Pierre Curie because of this work. It shows how her discoveries moved from the laboratory into international science as shared, measurable knowledge.

Look closer

  • Why would scientists around the world need a shared standard like this?
  • What does naming a unit after Marie and Pierre Curie suggest about how their work was valued?
  • What risks might have come with handling radioactive material like this in 1911?

This artifact is part of the curated material that grounds the AI version of Marie Curie on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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Cover of the January 1904 issue of the magazine Le Radium, showing a printed masthead and a photograph captioned Le Laboratoire de la Rue Lhomond. The photo shows two men and a seated woman among laboratory equipment and glassware, with the caption M. & Mme Curie below.Photograph

Primary source

Photograph of Pierre and Marie Curie in their Laboratory, rue Lhomond

c. 1898-1904

Title page of the 1904 second edition of Recherches sur les substances radioactives by Madame Sklodowska Curie, a thesis presented at the Faculté des Sciences de Paris. Published in Paris by Gauthier-Villars. Handwritten number 5 and a note appear in the top right corner.Book

Primary source

Recherches sur les substances radioactives

Marie Curie · 1904

Document

Primary source

Rayons émis par les composés de l'uranium et du thorium

Marie Curie · 12 April 1898

Black-and-white photograph of a clear glass vessel with a flared conical bowl, a pouring spout on the left rim, and a short stem on a flat circular foot, set against a plain light background.Artifact

Primary source

Glass beaker used for the first radium salt solution

Black-and-white photograph of a woman with hair pinned up, wearing a long dark dress with a high lace-trimmed collar, standing beside laboratory apparatus in a room with a wooden table, a wall clock, and glass equipment. A blurred figure stands in the background.Photograph

Primary source

Marie Curie, Portrait Photograph

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