Marie Curie

Marie Curie discovered two new chemical elements – radium and polonium. She carried out the first research into the treatment of tumors with radiation, and she founded of the Curie Institutes, which are important medical research centers.

She is the only person who has ever won Nobel Prizes in both physics and chemistry.

Marie Curie’s Early Life and Education

Maria Salomea Sklodowska was born in Warsaw, Poland on November 7, 1867. At that time, Warsaw lay within the borders of the Russian Empire. Maria’s family wanted Poland to be an independent country.

Marie’s mother and father – Bronislawa and Wladyslaw – were both teachers and encouraged her interest in science.

When Marie was aged 10, her mother died. Marie started attending a boarding school, then moved to a gymnasium – a selective school for academically strong children. Aged 15, Marie graduated from high school, winning the gold medal for top student. She was passionate about science and wanted to continue learning about it.

Problems

Two obstacles stood in Marie’s way:

• her father had too little money to support her ambition to go to university
• higher education was not available for girls in Poland

Marie’s sister Bronya faced exactly the same problems.

To overcome the obstacles they faced, Marie agreed to work as a tutor and children’s governess to support Bronya financially. This allowed Bronya to go to France and study medicine in Paris.

For the next few years of her life, Marie worked to earn money for herself and Bronya. In the evenings, if she had time, she studied chemistry, physics, and mathematics textbooks. She also attended lectures and laboratory practicals at an illegal free “university” where Poles learned about Polish culture and practical science, both of which had been suppressed by the Russian Tsarist authorities.

In November 1891, aged 24, Marie followed Bronya to Paris. There she studied chemistry, mathematics, and physics at the Sorbonne, Paris’s most prestigious university. The course was, of course, taught in French, which Marie had to reach top speed in very quickly.

At first she shared an apartment with Bronya and Bronya’s husband, but the apartment lay an hour away from the university. Marie decided to rent a room in the Latin Quarter, closer to the Sorbonne.

This was a time of hardship for the young scientist; winters in her unheated apartment chilled her to the bone.

Top Student Again

In summer 1893, aged 26, Marie finished as top student in her master’s physics degree course. She was then awarded industrial funding to investigate how the composition of steel affected its magnetic properties. The idea was to find ways of making stronger magnets.

Her thirst for knowledge pushed her to continue with her education: she completed a master’s degree in chemistry in 1894, aged 27.

Homesick

For a long time, Marie had been homesick. She dearly wished to return to live in Poland. After working in Paris on steel magnets for a year, she vacationed in Poland, hoping to find work, but were no jobs for her.

A few years earlier she had been unable to study for a degree in her homeland because she was a woman. Now, for the same reason, she found she could not get a position at a university.

Back to Paris and Pierre

Marie decided to return to Paris and begin a Ph.D. degree in physics.

Back in Paris, in the year 1895, aged 28, she married Pierre Curie. Pierre had proposed to her before her journey back to Poland. Aged 36, he had only recently completed a Ph.D. in physics himself and had become a professor. He had written his Ph.D. thesis after years of delay, because Marie had encouraged him to.

Pierre was already a highly respected industrial scientist and inventor who, at the age of 21, had discovered piezoelectricity with his brother Jacques.

Pierre was also an expert in magnetism: he discovered the effect now called the Curie Point where a change of temperature has a large effect on a magnet’s properties.

Marie Curie’s Scientific Discoveries

The Ph.D. degree is a research based degree, and Marie Curie now began investigating the chemical element uranium.

Why Uranium?

In 1895, Wilhelm Roentgen had discovered mysterious X-rays, which could capture photographs of human bones beneath skin and muscle.

The following year, Henri Becquerel had discovered that rays emitted by uranium could pass through metal, but Becquerel’s rays were not X-rays.

Marie decided to investigate the rays from uranium – this was a new and very exciting field to work in. Discoveries came to her thick and fast. She discovered that:

• Uranium rays electrically charge the air they pass through. Such air can conduct electricity. Marie detected this using an electrometer Pierre and his brother invented.
• The number of rays coming from uranium depends only on the amount of uranium present – not the chemical form of the uranium. From this she theorized correctly that the rays came from within the uranium atoms and not from a chemical reaction.
• The uranium minerals pitchblende and torbernite have more of an effect on the conductivity of air than pure uranium does. She theorized correctly that these minerals must contain another chemical element, more active than uranium.
• The chemical element thorium emits rays in the same way as uranium. (Gerhard Carl Schmidt in Germany actually discovered this a few weeks before Marie Curie in 1898: she discovered it independently.)

By the summer of 1898, Marie’s husband Pierre had become as excited about her discoveries as Marie herself. He asked Marie if he could cooperate with her scientifically, and she welcomed him. By this time, they had a one-year old daughter Irene. Amazingly, 37 years later, Irene Curie herself would win the Nobel Prize in Chemistry.

Discovery of Polonium and Radium, and Coining a New Word

Marie and Pierre decided to hunt for the new element they suspected might be present in pitchblende. By the end of 1898, after laboriously processing tons of pitchblende, they announced the discovery of two new chemical elements which would soon take their place in Dmitri Mendeleev’s periodic table.

The first element they discovered was polonium, named by Marie to honor her homeland. They found polonium was 300 times more radioactive that uranium. They wrote:

“We thus believe that the substance that we have extracted from pitchblende contains a metal never known before, akin to bismuth in its analytic properties. If the existence of this new metal is confirmed, we suggest that it should be called polonium after the name of the country of origin of one of us.”

The second element the couple discovered was radium, which they named after the Latin word for ray. The Curies found radium is several million times more radioactive than uranium! They also found radium’s compounds are luminous and that radium is a source of heat, which it produces continuously without any chemical reaction taking place. Radium is always hotter than its surroundings.

Together they came up with a new word for the phenomenon they were observing: radioactivity. Radioactivity is produced by radioactive elements such as uranium, thorium, polonium and radium.

A Ph.D. and a Nobel Prize in Physics!

In June 1903, Marie Curie was awarded her Ph.D. by the Sorbonne.

Her examiners were of the view that she had made the greatest contribution to science ever found in a Ph.D. thesis.

Six months later, the newly qualified researcher was awarded the Nobel Prize in Physics!

She shared the prize with Pierre Curie and Henri Becquerel, the original discover of radioactivity.

The Nobel Committee were at first only going to give prizes to Pierre Curie and Henri Becquerel.

However, Pierre insisted that Marie must be honored.

So three people shared the prize for discoveries in the scientific field of radiation.

Marie Curie was the first woman to be awarded a Nobel Prize.