Illustration of Radium

1898 Radium

The book of science

Tom Sharp

ParisMarie Curie, Pierre Curie elements Illustration of Radium


Pierre and Marie Curie analyzed pitchblende which they knew contained radioactive uranium. They removed the uranium, and separated the residue into salts of bismuth and salts of barium. From the barium fraction they isolated a substance that was three million times more radioactive than uranium. They identified it as a new element from its carmine lines in their spectroscope and named it radium because it radiates radioactive rays.

Atomic number 88

Isotopes were not yet understood. Scientists isolated similar elements later shown to be isotopes of radium, or radioactive isotopes of other elements, polonium, lead, thallium, and bismuth.

Fun with science

It used to be fun and useful. Spooky glow-in-the-dark Halloween costumes. Luminous dials of my Timex, my Big Ben Westclox. It used to be healthy. Pots to infuse drinking water with radium. Radium toothpaste to make teeth shine white. It used to be medically approved. Radium chloride to treat cancer. Radium capsules sewn into tumors during surgery. It used to be “scientific” but scientific claims motivated by profit were not always scientifically justified.

The natural decay of uranium and thorium produces radium. The natural decay of radium produces radon gas, which is also radioactive and dangerous.

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