Working in a converted shed at the School of Physics and Chemistry in Paris, Marie Curie and her husband Pierre set out in the late 1890s to investigate a strange property Henri Becquerel had noticed in uranium salts, the ability to fog a photographic plate through paper without any external source of energy. Marie Curie coined the word radioactivity for the phenomenon and showed, through careful measurement, that it was a property of the atom itself rather than of any chemical reaction. Processing tons of a uranium ore called pitchblende by hand, the Curies isolated two new elements far more radioactive than uranium: polonium, which Marie named for her native Poland, and radium, in 1898.
In 1903 the Curies shared the Nobel Prize in Physics with Becquerel for their work on radioactivity, the Nobel committee's initial shortlist did not include Marie at all, she was added only after Pierre insisted, in writing, that the recognition belonged to both of them. She became the first woman to win a Nobel Prize. Pierre died in a street accident in 1906, and Marie took over his professorship at the Sorbonne, becoming its first female professor. In 1911 she won a second Nobel Prize, this time in Chemistry, for isolating pure radium metal and determining its atomic weight, the first person of either sex to win two Nobel Prizes and, to date, the only person to win them in two different sciences.