Scientists Marie and Pierre Curie were working with pitchblende, a heavy mineral known to contain the radioactive element uranium, when they noticed something unusual. Somehow, the pitchblende was more radioactive than the uranium it contained. The culprit was radium, a previously unknown element present in pitchblende only in trace amounts—yet more than a million times more radioactive than uranium. What common household products contained radium until it was discovered to be dangerous? Discussfrom This Day in History http://ift.tt/2kw1Iu9
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