Difference between revisions of "Cockcroft and Walton Experiment"
(But in fact the overall energy expended to attain this transmutation is greater than the energy produced by it.) |
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Critics maintain that such verification is impossible due to the utter lack of any logical justification for that science fiction formula. | Critics maintain that such verification is impossible due to the utter lack of any logical justification for that science fiction formula. | ||
| + | Cockcroft and Walton "''did not see their experiments as a ''test'' of Einstein's mass-energy relationship; rather, they simply used that relationship in their analysis, assuming it to be valid ''"<ref>Roger H. Stuewer: ''Mass-Energy'' in ''Einstein in Context'', Cambridge University Press</ref> The first to stress this aspect of the experiment was the eminent physicist Kenneth Bainbridge in 1933: | ||
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| + | |The gain in energy in the reaction is 16.97×10<sup><small>6</small></sup> e-volts, an energy equivalent to 0.0182 mass units on the O<sup><small>16</small></sup> scale if ΔE =C²Δm. Taking Aston's values for the mass of helium and hydrogen and the author's value, 7.0146±0.0006 for Li<sup><small>7</small></sup>, the mass change is 0.0181 ± 0.0006 in the reaction which may be represented as Li<sup><small>7</small></sup> + p → 2α . Within the probable error of the measurements the equivalence of mass and energy is satisfied.'' --Kenneth Bainbridge | ||
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Neither the Nobel Prize committee nor the prize recipients made the claim that their experiment verified of [[Albert Einstein]]'s famous ''[[E=mc2|E=mc<sup>2</sup>]]'' formula,<ref>[http://www.aip.org/history/einstein/emc1.htm The Center for History of Physics: ''Einstein: Image and Impact], © 1996-2004 - American Institute of Physics</ref><ref>[http://homepage.eircom.net/~louiseboylan/Pages/Cockroft_walton.htm Louise Boylan:] ''Cockroft and Walton Experiment: Converting Mass into Energy''</ref> for which no logical derivation has ever been forthcoming. | Neither the Nobel Prize committee nor the prize recipients made the claim that their experiment verified of [[Albert Einstein]]'s famous ''[[E=mc2|E=mc<sup>2</sup>]]'' formula,<ref>[http://www.aip.org/history/einstein/emc1.htm The Center for History of Physics: ''Einstein: Image and Impact], © 1996-2004 - American Institute of Physics</ref><ref>[http://homepage.eircom.net/~louiseboylan/Pages/Cockroft_walton.htm Louise Boylan:] ''Cockroft and Walton Experiment: Converting Mass into Energy''</ref> for which no logical derivation has ever been forthcoming. | ||
Revision as of 17:51, January 24, 2013
This experiment by John Cockcroft and Ernest Walton is claimed by some[Citation Needed] physicists as demonstrating that E=mc2.[1]
Conducted in April 1932 at the University of Cambridge's Cavendish Laboratory in England, the physicists Cockroft and Walton successfully split lithium atom nuclei by colliding them with artificially accelerated protons. This experiment is general hailed as being the first transmutation of an element using artificially accelerated particles, for which they were honored with the Nobel Prize in 1951.[2]
Critics maintain that such verification is impossible due to the utter lack of any logical justification for that science fiction formula.
Cockcroft and Walton "did not see their experiments as a test of Einstein's mass-energy relationship; rather, they simply used that relationship in their analysis, assuming it to be valid "[3] The first to stress this aspect of the experiment was the eminent physicist Kenneth Bainbridge in 1933:
| The gain in energy in the reaction is 16.97×106 e-volts, an energy equivalent to 0.0182 mass units on the O16 scale if ΔE =C²Δm. Taking Aston's values for the mass of helium and hydrogen and the author's value, 7.0146±0.0006 for Li7, the mass change is 0.0181 ± 0.0006 in the reaction which may be represented as Li7 + p → 2α . Within the probable error of the measurements the equivalence of mass and energy is satisfied. --Kenneth Bainbridge |
Neither the Nobel Prize committee nor the prize recipients made the claim that their experiment verified of Albert Einstein's famous E=mc2 formula,[4][5] for which no logical derivation has ever been forthcoming.
Instead, a hand-waving claim was made that an excess in kinetic energy of the resultant helium nuclei, which is greater than the energy of the original nuclei, must be attributable to a loss in mass. But in fact the overall energy expended to attain this transmutation is greater than the energy produced by it.
References
- ↑ Mike Poole Cockcroft's subatomic legacy: splitting the atom, Cern Courier, Nov 20, 2007
- ↑ The Nobel Prize in Physics 1951, Nobelprize.org, 23 Jan 2013
- ↑ Roger H. Stuewer: Mass-Energy in Einstein in Context, Cambridge University Press
- ↑ The Center for History of Physics: Einstein: Image and Impact, © 1996-2004 - American Institute of Physics
- ↑ Louise Boylan: Cockroft and Walton Experiment: Converting Mass into Energy
