Dr. Marie Curie is a Polish-born physicist and mathematician. She worked for the Sorbonne University in Paris. She read physics and mathematics – she had naturally discovered a love of the subjects through her insatiable appetite for learning. It was in Paris, in 1894, that she met Pierre Curie – a scientist working in the city – and who she married a year later.
The Curies began their pioneering work into invisible rays given off by uranium at the School of Chemistry and Physics in Paris, where Professor Henri Becquerel had recently discovered a new phenomenon.
He demonstrated that the rays could pass through solid matter, fog, and photographic film, causing air to conduct electricity.
Marie also discovered that samples of pitchblende, a mineral containing uranium ore, were far more radioactive than pure uranium. Further research convinced her that the extremely high readings she was getting could not be attributed to uranium alone; there was something else in the pitchblende. Because it had never been discovered before, it could only be present in trace amounts, and it appeared to be highly radioactive. Marie was convinced she had discovered a new chemical element, but other scientists questioned her findings.
Pierre and Marie Curie began their search for the unknown element. They ground up pitchblende samples, dissolved them in acid, and began separating the various elements present using standard analytical chemistry techniques of the time. They eventually extracted polonium, a black powder 330 times more radioactive than uranium. Polonium, with the atomic number 84, was a new chemical element.
When the Curies looked into it further, they discovered that the liquid left behind after extracting polonium was still extremely radioactive. They discovered that pitchblende contained a new element that was far more radioactive than polonium but was present in much smaller quantities.
The Curies published strong evidence supporting the existence of the new element, which they named radium, in 1898, but they still did not have a sample of it. Pitchblende is a costly mineral because it contains valuable uranium, and Marie requires a large amount of it.
She contacted an Austrian factory that extracted uranium from pitchblende for industrial use and purchased several tonnes of the worthless waste product, which was even more radioactive than the original pitchblende but much cheaper. Marie began processing the pitchblende to extract the trace amounts of radium. This required grinding, dissolving, filtering, precipitating, collecting, redissolving, crystallization, and recrystallization on a much larger scale than before, with 20 kg batches of the mineral.
The work was heavy and physically demanding, with risks that the Curies did not appreciate. They began to feel sick and physically exhausted during this time, which we can now attribute to the early symptoms of radiation sickness. They persisted in their ignorance of the risks, often with raw and inflamed hands as a result of their constant handling of highly radioactive material.
Marie finally isolated radium (as radium chloride) in 1902, determining its atomic weight to be 225.93. The road to the discovery had been long and difficult.
In 1903, Marie Curie, Pierre Curie, and Henri Becquerel received the Nobel Peace Prize in Physics for their work in radioactivity. Curie was the first woman to be awarded this honour. Curie established 18 mobile x-ray stations during World War I. They were known as the Petites Curies, or little Curies, because they were used on the front lines. The technology Marie Curie developed for the "Petites Curies'' is similar to that used today in our Hampstead hospice's fluoroscopy machine. It is a powerful X-ray machine that allows doctors to examine moving images in the body, such as the heart's pumping action or the motion of swallowing.
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