large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_01_asimov_64kb_108
large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_01_asimov_64kb
English
12904
As chemists learned to work out the atomic weights of the various elements, they found, however, that, of the elements then known, uranium had the highest atomic weight of all—238. Once uranium was discovered to be an endless source of radiation, it gained interest that has risen ever since. Madame Curie gave the name "radioactivity" to this phenomenon of continuously giving off rays. AS CHEMISTS LEARNED TO WORK OUT THE ATOMIC WEIGHTS OF THE VARIOUS ELEMENTS THEY FOUND HOWEVER THAT OF THE ELEMENTS THEN KNOWN URANIUM HAD THE HIGHEST ATOMIC WEIGHT OF ALL TWO HUNDRED THIRTY EIGHT ONCE URANIUM WAS DISCOVERED TO BE AN ENDLESS SOURCE OF RADIATION IT GAINED INTEREST THAT HAS RISEN EVER SINCE MADAME CURI GAVE THE NAME RADIOA ACTIVITY TO THIS PHENOMENON OF CONTINUOUSLY GIVING OFF RAYS
 while investigating the problem in 1896, Becquerel found that the compound was giving off invisible penetrating X-ray-like radiation continually, whether it was exposed to sunlight or not. The radiation was detected because it would fog a photographic plate just as light would. What’s more, the radiation would fog the plate, even if the plate were wrapped in black paper, so that it could penetrate matter just as X rays could. Others, in addition to Becquerel, were soon investigating the new phenomenon. In 1898 the Polish (later French) physicist Marie Sklodowska Curie (1867-1934) showed that it was the uranium atom that was the source of the radiation, and that any compound containing the uranium atom would give off these penetrating rays. Until then, uranium had not been of much interest to chemists. It was a comparatively rare metal that was first discovered in 1789 by the German chemist Martin Heinrich Klaproth (1743-1817). It had no particular uses and remained an obscure element. UND WAS GIVING OFF INVISIBLE PENETRATING X RAY LIKE RADIATION CONTINUALLY WHETHER IT WAS EXPOSED TO SUNLIGHT OR NOT THE RADIATION WAS DETECTED BECAUSE IT WOULD FOG A PHOTOGRAPHIC PLATE JUST AS LIGHT WOOD WHAT'S MORE THE RADIATION WOULD FOG THE PLATE EVEN IF THE PLATE WERE WRAPPED IN BLACK PAPER SO THAT IT COULD PENETRATE MATTER JUST AS X RAYS COULD OTHERS IN ADDITION TO BECAREL WERE SOON INVESTIGATING THE NEW PHENOMENON IN EIGHTEEN NINETY EIGHT THE POLISH LATER FRENCH PHYSICIST MARIE SKWARDOWSKA CURI EIGHTEEN SIXTY SEVEN NINETEEN THIRTY FOUR SHOWED THAT IT WAS THE URANIUM ATOM THAT WAS THE SOURCE OF THE RADIATION AND THAT ANY COMPOUND CONTAINING THE URANIUM ATOM WOULD GIVE OFF THESE PENETRATING RAYS UNTIL THEN URANIUM HAD NOT BEEN OF MUCH INTEREST TO CHEMISTS IT WAS A COMPARATIVELY RARE METAL THAT WAS FIRST DISCOVERED IN SEVENTEEN EIGHTY NINE BY THE GERMAN CHEMIST MARTIN HEINRICH CLAPROTH SEVENTEEN FORTY THREE EIGHTEEN SEVENTEEN IT HAD NO PARTICULAR USES AND REMAINED AN OBSCURE ELEMENT
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