9. Marie Curie - Radioactivity (1867 1934)
Marie Curie was a pioneer in the field of radioactivity, and the first woman to ever win a Nobel Prize, and the first person to ever win twice! Marie grew up in Poland whilst it was part of the Russian Empire. When Russian authorities eliminated laboratory instruction from Polish schools, Maries father, a mathematics and physics teacher, brought much of the equipment home and taught his children how to use it. She saved up for eight years so she could attend the University of Paris, from which she graduated in Physics and Mathematics. During her studies, Marie had heard of the discovery of invisible rays emitting from uranium salts, and she decided to investigate the phenomenon for her thesis. These rays could pass through solids, fogs and photographic film, and caused air to conduct electricity. She showed that radioactivity as she named it, is an atomic property, as the intensity of rays from uranium was in direct proportion to the uranium within a sample, and nothing she did affected the rays. She also discovered two minerals pitchblende and chalcite were even more radioactive than uranium, and must contain a new radioactive element. Marie and her husband Pierre searched for this element, starting by grinding pitchblende in a pestle and mortar, not knowing she would need to grind over a tonne of the mineral before being able to extract 0.1 grammes of the element. Eventually, they succeeded by extracting a black powder 330 times more radioactive than uranium, and they named it polonium after Maries home country. They had discovered a new chemical element, atomic number 84. There are only about one hundred natural elements in the universe, and Marie Curie had discovered one. However, she then realised that the liquid left behind from the extraction of polonium was still extremely radioactive and must contain yet another element, far more radioactive than polonium. After further study, they named this second element radium, atomic number 225.93. Marie initially refrained from patenting the process in which radium was isolated, so that studies could continue unhindered. Further studies of radium led to the advancement of radiation techniques to help battle cancer at the time. During their work, the Curies processed large batches of radioactive materials constantly grinding, dissolving, filtering, crystallising. At the time, the negative effects of radioactivity were not so well known, and both of the Curies suffered from what we now know to be radiation sickness. Marie died reasonably young, at just 66, from pernicious anaemia, now attributed to her exposure to radiation.