Frasi di Joseph John Thomson (9 frasi) | Citazioni e frasi celebri

Joseph John Thomson: 9 citazioni0 Mi piace

Joseph John Thomson Frasi e Citazioni

“Una delle grandi conquiste, forse la più grande, nella storia del pensiero umano.”

Joseph John Thomson: Frasi in inglese

“The difficulties which would have to be overcome to make several of the preceding experiments conclusive are so great as to be almost insurmountable.”

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J. J. Thomson

Warning about the non-conclusiveness for the experimental foundation of electrostatic theory, in a footnote of the third edition of: [James Clerk Maxwell, A Treatise on Electricity and Magnetism, Vol.1, 3rd Edition, Oxford University Press, 1891, 37]
Quotes eat me

“The electron: may it never be of any use to anybody!”

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J. J. Thomson

A popular toast or slogan at J. J. Thomson's Cavendish Laboratory in the first years of the 1900s, as quoted in Proceedings of the Royal Institution of Great Britain, Volume 35 (1951), p. 251.
Attributed

“I can see no escape from the conclusion that they are charges of negative electricity carried by particles of matter.”

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J. J. Thomson

"Cathode rays" http://web.lemoyne.edu/~GIUNTA/thomson1897.html Philosophical Magazine, 44, 293 (1897). <br class="br">Quotes eat me <br class="br">Contesto: As the cathode rays carry a charge of negative electricity, are deflected by an electrostatic force as if they were negatively electrified, and are acted on by a magnetic force in just the way in which this force would act on a negatively electrified body moving along the path of these rays, I can see no escape from the conclusion that they are charges of negative electricity carried by particles of matter.

“We see from Lenard's table that a cathode ray can travel through air at atmospheric pressure a distance of about half a centimetre before the brightness of the phosphorescence falls to about half its original value. Now the mean free path of the molecules of air at this pressure is about 10-5 cm., and if a molecule of air were projected it would lose half its momentum in a space comparable with the mean free path. Even if we suppose that it is not the same molecule that is carried, the effect of the obliquity of the collisions would reduce the momentum to half in a short multiple of that path. Thus, from Lenard's experiments on the absorption of the rays outside the tube, it follows on the hypothesis that the cathode rays are charged particles moving with high velocities, that the size of the carriers must be small compared with the dimensions of ordinary atoms or molecules. The assumption of a state of matter more finely subdivided than the atom of an element is a somewhat startling one; but a hypothesis that would involve somewhat similar consequences—viz. that the so-called elements are compounds of some primordial element—has been put forward from time to time by various chemists.”

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J. J. Thomson

Royal Institution Lecture (April 30, 1897) as quoted by Edmund Taylor Whittaker, A History of the Theories of Aether and Electricity from the Age of Descartes to the Close of the Nineteenth Century http://books.google.com/books?id=CGJDAAAAIAAJ (1910). <br class="br">Quotes eat me

“I have described at some length the application of Positive Rays to chemical analysis; one of the main reasons for writing this book was the hope that it might induce others, and especially chemists, to try this method of analysis. I feel sure that there are many problems in chemistry, which could be solved with far greater ease by this than any other method. The method is surprisingly sensitive — more so than even that of spectrum analysis, requires an infinitesimal amount of material, and does not require this to be specially purified; the technique is not difficult if appliances for producing high vacua are available.”

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J. J. Thomson

Rays of Positive Electricity (1913).
Quotes eat me

“This example illustrates the differences in the effects which may be produced by research in pure or applied science. A research on the lines of applied science would doubtless have led to improvement and development of the older methods—the research in pure science has given us an entirely new and much more powerful method. In fact, research in applied science leads to reforms, research in pure science leads to revolutions, and revolutions, whether political or industrial, are exceedingly profitable things if you are on the winning side.”

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J. J. Thomson

Cited from Lord Rayleigh, The Life of Sir J. J. Thomson (1943), p. 199.
Attributed

“If, in the very intense electric field in the neighbourhood of the cathode, the molecules of the gas are dissociated and are split up, not into the ordinary chemical atoms, but into these primordial atoms, which we shall for brevity call corpuscles; and if these corpuscles are charged with electricity and projected from the cathode by the electric field, they would behave exactly like the cathode rays.”

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J. J. Thomson

"Cathode rays" http://web.lemoyne.edu/~GIUNTA/thomson1897.html Philosophical Magazine, 44, 293 (1897). <br class="br">Quotes eat me