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The Plates Weren't on the Windowsill
The section describing Becquerel's method to the French Academy must be in error. The entire point was to demonstrate that the uranium salts absorb xrays and re-emit them, thus shadowing the photographic plate. If Becquerel put the entire package on the windowsill, then the xrays from the sun would darken the photographic plate along with the "absorbed" xrays in the uranium salts and his experiment would be entirely black, proving nothing. I think the reality is that he put the uranium on the windowsill, then sat the uranium salt slab on the photographic plate where it would, supposedly, re-emit the suns xrays and darken the plate. Yes? http://www.practicalphysics.org/go/Resources_12.html
Becquerel's papers read before the French Academy on 24 Feb and 2 March 1896 explain better what he did and how his ideas developed. In the earlier experiments he wrapped the photographic plate in black paper and put the uranium salt on top of it in bright sunlight, outside the black paper. He believed his results showed that, when exposed to sunlight, uranium salts, in addition to their well known visible phosphorescence, also emitted a new and more penetrating kind of phosphorescent radiation, similar to X-rays. His subsequent experiments, reported on March 2, after a period of cloudy weather, showed that the penetrating radiation was emitted even without exposing the uranium to the sun, indeed even if it was kept next to the photographic plate in total darkness. He found this surprising and said that, although it was consistent with a very long-lived penetrating phosphorescence, it did not warrant such a conclusion. In the 2 March paper Becquerel was evidently not quite ready to accept the explanation, which we now know is true, that uranium compounds, without any external energy source at all, steadily emit penetrating radiation for billions of years. This would have seemed very implausible at a time when thermodynamics was well understood but radioactivity hadn't yet been discovered. I will revise the paragraph and add a quote from his second article to show how the ideas changed.CharlesHBennett (talk) 13:05, 23 January 2012 (UTC)
I have uploaded a higher-resolution version of the Becquerel plate, and included its attribution. Would someone be kind enough to make the swap the old one out? (Technically the author of the image died 98 years ago as of 2006, not 100, but that should be good enough for the spirit of the law, no?)
Thangalin 02:37, 29 December 2006 (UTC)
At the centuary of the discovery and shortly after several overview papers have been published:
- E. Buncel, E. A. Evans, J. R. Jones, L. Pichat, A. Wolf (2222). "Radioactivity - Henri Becquerel's discovery". Journal of Labelled Compounds and Radiopharmaceuticals 38 (10): 873 – 874. doi:10.1002/(SICI)1099-1344(199610)38:10<873::AID-JLCR928>3.0.CO;2-G. Check date values in:
- C. Détraz (1999). "The discovery of radioactivity: A one-hundred year heritage". Nuclear Physics A 654 (1-2): C12–C18. doi:10.1016/S0375-9474(99)00244-4.
- N. S. Kipnis (2000). "The Window of Opportunity: Logic and Chance in Becquerel's Discovery of Radioactivity". Physics in Perspective 2 (1): 63–99. doi:10.1007/s000160050037.
- R. de Andrade Martins (1997). "Becquerel and the choice of uranium compounds". Archive for History of Exact Sciences 1 (51): 67–81. doi:10.1007/BF00376452.
- A. Allisy (1996). "Henri Becquerel: The Discovery of Radioactivity". Radiation Protection Dosimetry 68: 3–10.
- M. Genet (1995). "The discovery of uranic rays: A short step for Henri Becquerel but a giant step for science". Radichimica Acta 70 (1): 3–12.
- J. Dutreix, A. Dutreix (1995). "Becquerel, Henri (1852-1908)". Medical Physics 22 (11): 1869–1875.
- L. Badash (1996). "History of science: Henri Becquerel and a diverted discovery". Recherche 288: 78–82.
- M Genet (1998). "The discovery of uranic rays: A short step for Henri Becquerel but a giant step for science". Actualite Chimique 1: 34–41.
--Stone 16:23, 20 March 2007 (UTC)
An audience member named Stephen Rhodes comments on a BBC In Our Time program that: 'In Einstein's reliance on the work of Maxwell, I am reminded of Isaac Newton's quotation "If I have seen further it is by standing on the shoulders of giants". He was,incidentally, also standing on the shoulders of Henri Becquerel who published the famous e=mc2 in Nature in 1900.' (http://www.bbc.co.uk/radio4/history/inourtime/inourtime_comments_maxwell.shtml). I don't know if this is true but, if it is, it should obviously be added to both this and the Albert Einstein page.
Zoe Ocean 01:36, 28 May 2007 (UTC)
I'm a professional physicist, but I've never heard of Becquerel pre-empting E=mc2. Although I can't be sure, I'd be surprised as Becquerel seems to have been mainly an experimentalist, not a theorist. Incidentally although E=mc2 gets all the glory, it's not really the "core" of relativity. It's an interesting and very important result, but there is an awfull lot more to relativity. Baska436 (talk) 09:04, 1 March 2014 (UTC)
Dating in text.
On the main page the date 24 January appears, this is possibly a mistake, as the first report on X-rays were given on 20 January in The French academy of Sciences. Becquerel presented a paper on 24 February, which is the correct date to use. —Preceding unsigned comment added by 184.108.40.206 (talk) 08:06, 17 October 2007 (UTC)
In this article "École Polytechnique", "École des Ponts et Chaussées", and "Muséum National d'Histoire Naturelle" are all italicized. Is this correct? I did not think names of places were supposed to be italicized, but only names of works. –02:52, 21 October 2007 (UTC)
- I am quite sure that I am right, so I changed it. Wikipedia:Manual of Style#Institutions seems to support this. – 02:59, 21 October 2007 (UTC)
WikiProject class rating
This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:44, 10 November 2007 (UTC)
Cause of death
What did M. Becquerel die of? Relating to his 1903 Nobel prize in physics, was it as prosaic as M Curie's street accident, or closer to Mme Curie's radiation-induced disease? 220.127.116.11 (talk) 09:10, 7 March 2010 (UTC)
Circumstances of his death
Initial confusion as to uranium radiation properties
The radioactivity emissions of uranium were initially confused with infrared light emissions. And in Dr. Gustave Le Bon's book "The evolution of matter" he says that after the discovery of the radioactivity phenomenon Dr Becquerel spent 3 years trying to prove that the radiation of uranium could be "polarized, refracted, and reflected". This was later determined not to be the case, which Dr Becquerel later acknowledged in 1900.WFPM (talk) 01:58, 28 November 2012 (UTC) A controversy over this matter evidently occurred prior to the determination of the alpha particle and beta ray (electron) emission phenomena by Ernest Rutherford in 1900.WFPM (talk) 09:13, 28 November 2012 (UTC)