large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_02_asimov_64kb_18
large/12904/worldswithinworlds_v1-3_1904_librivox_64kb_mp3/worldswithinworlds_02_asimov_64kb
English
12904
To physicists the concept of "work" is that of exerting a force on a body and making it move through some distance. To lift a weight against the pull of gravity is work. To drive a nail into wood against the friction of its fibers is work. TO PHYSICISTS THE CONCEPT OF WORK IS THAT OF EXERTING A FORCE ON A BODY AND MAKING IT MOVE THROUGH SOME DISTANCE TO LIFT A WEIGHT AGAINST THE PULL OF GRAVITY IS WORK TO DRIVE A NAIL INTO WOOD AGAINST THE FRICTION OF ITS FIBRES IS WORK
ements did not escape this new view either. The atomic weight of uranium (chemical symbol U) is just about 238 and, indeed, most of its atoms are ²³⁸U. In 1935, however, the Canadian-American physicist, Arthur Jeffrey Dempster (1886-1950), found that 0.7% of its atoms were a lighter isotope, ²³⁵U. These differed considerably in radioactive properties. The common uranium isotope, ²³⁸U, had a half-life of 4500 million years, while ²³⁵U had a half-life of only 700 million years. Furthermore ²³⁵U broke down in three stages to actinium. It was ²³⁵U, not actinium itself, that was the beginning of the actinium radioactive series. As for thorium (atomic symbol Th) with an atomic weight of 232, it did indeed turn out that in the naturally occurring element virtually all the atoms were ²³²Th. ENERGY The Law of Conservation of Energy We have now gone as far as we conveniently can in considering the intertwining strands of the atom and of electricity. It is time to turn to the third strand—energy.  SECTION NUMBER TWO OF WORLDS WITHIN WORLDS THE STORY OF NUCLEAR ENERGY BY ISAAC ASAM THIS IS A LIBERVOX RECORDING ALL LIBERVOX RECORDINGS ARE IN THE PUBLIC DOMAIN FOR MORE INFORMATION OR TO VOLUNTEER PLEASE VISIT LIBERVOX DOT O R G RECORDING BY BLAINE ADEN MAC COY RIVERSIDE CALIFORNIA TWO THOUSAND NINETEEN ENERGY THE LAW OF CONSERVATION OF ENERGY WE HAVE NOW GONE AS FAR AS WE CONVENIENTLY CAN IN CONSIDERING THE INTERTWINING STRANDS OF THE ATOM AND OF ELECTRICITY IT IS TIME TO TURN TO THE THIRD STRAND ENERGY
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