Working in the Becquerel lab, Marie Curie and her husband, Pierre, beganwhat became a life long study of radioactivity. It took fresh and openminds, along with much dedicated work, for these scientists to establishthe properties of radioactive matter. Marie Curie wrote, "The subject seemedto us very attractive and all the more so because the question was entirelynew and nothing yet had been written upon it." Becquerel had already noted that uranium emanations could turn air intoa conductor of electricity. Using sensitive instruments invented by PierreCurie and his brother, Pierre and Marie Curie measured the ability of emanationsfrom various elements to induce conductivity. On February 17, 1898, theCuries tested an ore of uranium, pitchblende, for its ability to turn airinto a conductor of electricity. The Curies found that the pitchblendeproduced a current 300 times stronger than that produced by pure uranium.They tested and recalibrated their instruments, and yet they still foundthe same puzzling results. The Curies reasoned that a very active unknownsubstance in addition to the uranium must exist within the pitchblende.In the title of a paper describing this hypothesized element (which theynamed polonium after Marie's native Poland), they introduced the new term:"radio-active." After much grueling work, the Curies were able to extract enough poloniumand another radioactive element, radium, to establish the chemical propertiesof these elements. Marie Curie, with her husband and continuing after hisdeath, established the first quantitative standards by which the rate ofradioactive emission of charged particles from elements could be measuredand compared. In addition, she found that there was a decrease in the rateof radioactive emissions over time and that this decrease could be calculatedand predicted. But perhaps Marie Curie's greatest and most unique achievementwas her realization that radiation is an atomic property of matter ratherthan a separate independent emanation.
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