Marie Curie was born in Warsaw, Poland, to parents who were both teachers. In 1896, Henri Becquerel found that uranium gives off rays. Marie Curie set out to measure them. The rays create faint electric currents in air. To measure these currents, she used an electrometer. Pierre Curie and his older brother Jacques had invented it about 15 years earlier. Marie found that the strength of the rays depended only on how much uranium was present. She went beyond Becquerel with a crucial hypothesis. The rays from uranium compounds could be an atomic property of uranium, built into its atoms. In April 1898, she found that thorium compounds also give off rays.
Marie was born Maria, but when she registered at the Sorbonne in Paris, she began using the French name Marie. She and her husband, Pierre, worked together as scientists, and she invented the word radioactivity, based on the Latin word for ray, to describe this behavior. Radium is named after the same Latin word. Then came a puzzle. The mineral pitchblende was more radioactive than uranium. So the Curies concluded it must contain other radioactive elements. Pitchblende is made of combinations of up to 30 different elements. The unknown substances were present only in tiny amounts. To isolate them, the Curies were the first to use a new method of chemical analysis.
In July 1898, the Curies reported that the bismuth part of pitchblende held a new element. Chemically it acted almost exactly like bismuth. But it was radioactive, so it had to be something new. This element was 400 times more radioactive than uranium. In 1898, it was added to the Periodic Table as polonium. Marie named it after Poland, the country where she was born. The Curies announced radium in December. Radium gives off light and heat. Other scientists did not trust the announcement. The Curies did not have enough of either element to see and weigh. Their existence was known only from their radioactivity.
To prove radium was real, Marie had to treat very large amounts of pitchblende ore. Much of the Curies' work took place in a shed. In 1910, she produced radium as a pure metal. It is a silvery-white, shiny metal that decomposes water violently and chars paper. It melts at 700 degrees Celsius. In 1906, Lord Kelvin suggested that radium was not an element but a compound of lead and five helium atoms. This threatened the science of radioactivity, so Marie began lab work to disprove it. With the help of her colleague André Debierne, she confirmed that radium was an element.
The Curies published how they isolated radium and did not patent their methods. French academics first proposed only Pierre Curie and Henri Becquerel for the 1903 physics prize, but Pierre insisted that his wife share the honor. Marie became the first woman to win a Nobel Prize. In 1911, she won a second one, in chemistry, for her discovery of radium and polonium. In 1906, she became the first woman to hold a professor's post at the Sorbonne. On 5 November 1906, she gave her first lecture there. She made no introductory remarks. She began with the last sentence Pierre had spoken in that very place.
In 1913, Marie inaugurated the radioactivity pavilion in Warsaw, in her native Poland. During World War I, she organized mobile X-ray teams, and her daughter Irène, a scientist, worked with her. Marie learned to drive a car so she could operate the vehicles herself. The French government asked people to give gold and silver for the war. Marie offered her two Nobel medals, but the bank refused them. So she used most of her Nobel prize money to buy war bonds. At the Radium Institute, she prepared tiny glass tubes of radon, a radioactive gas given off by radium. Doctors inserted them into patients where the radiation would destroy diseased tissue.
Marie led a radioactivity laboratory in the Radium Institute in Paris. In 1921, the women of America gave her one gram of radium, presented by U.S. President Harding. Since 1922, she had served on the Committee of Intellectual Co-operation of the League of Nations. The Curies did not fully understand how dangerous the radioactive materials they handled were. Marie Curie died on 4 July 1934, of aplastic anemia, a blood disease that often results from exposure to large amounts of radiation. As of November 2026, the Curie Institute in Paris is a center for cancer treatment and research, and it has a hospital that treats cancer patients.
Words to know
- electrometer: a current gauge
- hypothesis: a testable idea
- pitchblende: a uranium ore
- radon: a radioactive gas
- bismuth: a metal element
