Wikipedia:Featured article candidates/James Chadwick/archive1

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The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by GrahamColm via Hawkeye7 (talk) 21:01, 29 September 2014 (UTC) [1].[reply]

James Chadwick[edit]

Nominator(s): Hawkeye7 (talk) 11:53, 15 July 2014 (UTC) and Nobeljeff (talk)[reply]

This article is about yet another scientist, James Chadwick is the man who discovered the neutron. In 1932, with a laboratory instrument literally made from string and sealing wax. The group photo of the Cavendish Lab staff that year had eight Nobel Prize winners sitting in the front row. Rutherford. Thomson. Kapitza. Cockcroft. Blackett. And then there was the neutron. Chadwick found it, measured it, weighed it. Within just a few years neutrons would be the key ingredient in a scientific endeavour on an unprecedented scale. And Chadwick played a key part in all of this. Hawkeye7 (talk) 11:53, 15 July 2014 (UTC)[reply]

Comment: I copyedited the article at A-class per my standard disclaimer. These are my edits. - Dank (push to talk) 12:16, 15 July 2014 (UTC)[reply]

Source review - spotchecks not done

  • Some of the details in the infobox, for example Pollard being his student, do not appear to be sourced in the text
  • Why bold Chadwick's name in Notes?
  • FN46: page?
  • Don't repeat cited sources in External links. Nikkimaria (talk) 12:32, 19 July 2014 (UTC)[reply]

With regard to the emboldened names in the papers. Someone has been going around creating DOI templates for famous papers. So the links to Chadwick appear bold in his own article. I like to have the original papers linked in the scientific articles so readers can see them for themselves. Hawkeye7 (talk) 22:42, 19 July 2014 (UTC)[reply]

Comments by Cwmhiraeth[edit]

This looks to be a well-written, well laid out article. I particularly like the fact that it is low on jargon and is understandable to a non-physicist like me. A few points on the prose:

  • What was the occupation of his father?
  • "He was named after his paternal grandfather" - It would be helpful if the name "James" was mentioned somewhere in this paragraph.
  • "At the age of 16, he sat for two university scholarship examinations, and was offered both." - Was he really offered two university scholarship examinations?
    • Two scholarships. At the age of 16, he sat two examinations for university scholarships, and won both of them. Hawkeye7 (talk) 22:21, 28 July 2014 (UTC)[reply]
  • "This time the resulting paper was published under his name only." - I don't care for the "only" at the end of this sentence.
  • "The reason for this would remain unexplained for many years." - This is an ambiguous remark.
    • The continuous spectrum would remain an unexplained phenomenon for many years. Hawkeye7 (talk) 22:21, 28 July 2014 (UTC)[reply]
  • "At a conference at Cambridge on beta particles and gamma rays in 1928, Chadwick met Geiger again, who brought with him a new model of his Geiger counter, which had been improved by his post-doctoral student Walther Müller." - This sentence is rather long and convoluted.
    • Split. At a conference at Cambridge on beta particles and gamma rays in 1928, Chadwick met Geiger again. Geiger had brought with him a new model of his Geiger counter, which had been improved by his post-doctoral student Walther Müller. Hawkeye7 (talk) 22:21, 28 July 2014 (UTC)[reply]
  • "... used polonium to bombard beryllium" - I think you mean particles emitted by polonium rather than the stuff itself?
    • Yes, but I've spent so much time writing about polonium that hadn't occurred to me.
  • "Chadwick had his Australian 1851 Exhibition scholar, Hugh Webster, duplicate their results." - "had" is not ideal here, perhaps "asked" or "directed" or somesuch.
    • No, that won't do. Have to think of something else. Hawkeye7 (talk) 22:21, 28 July 2014 (UTC)[reply]
  • "His research into such matters were complicated by ..." - Perhaps "was" rather than "were".
  • "Observing the work on the K-25 gaseous diffusion facility at Oak Ridge, Tennessee, he realised how wrong he had been about building the plant in wartime Britain." - This needs some explanation, - which of his ideas was wrong?
  • "... the Hungarian-born economist Peter Bauer. Bauer was subsequently involved in what became known as the Peasants' Revolt, in which fellows led by Patrick Hadley voted an old friend of Chadwick's off the council and replaced him with the younger Bauer." - Too many Bauers.
    • In what became known as the Peasants' Revolt, fellows led by Patrick Hadley voted an old friend of Chadwick's off the council and replaced him with Bauer. Hawkeye7 (talk) 22:21, 28 July 2014 (UTC)[reply]
  • "He anticipated that neutrons would become a major weapon in the fight against cancer." - This fact from the lead is not mentioned again in the body of the article as far as I can see. Cwmhiraeth (talk) 09:28, 28 July 2014 (UTC)[reply]
    • Added this. Chadwick anticipated that neutrons and radioactive isotopes produced with them could be used to study biochemical processes, and might become a weapon in the fight against cancer.
Thanks for your review! Hawkeye7 (talk) 22:21, 28 July 2014 (UTC)[reply]
  • I am happy with the changes you have made and now support this candidacy on the grounds of prose and comprehensiveness. An interesting article about an interesting man! Cwmhiraeth (talk) 09:45, 29 July 2014 (UTC)[reply]

Comments by Headbomb[edit]

Lead
Resolved issues
  • A graduate of the University of Manchester, he studied under Ernest Rutherford, known as the "father of nuclear physics". I'm a bit worried that some people will have to parse this a few times before realizign that the "father of nuclear physics" is Rutherford, and I'm unsure it's necessary to mention that he's the father of nuclear physics. Also, it seems to implied that as a graduate, he studied under Rutherford. And for which degree is unclear. This is further compounded/confused by the next bit "After the war, Chadwick followed Rutherford to the Cavendish Laboratory at the University of Cambridge, where Chadwick earned his Doctor of Philosophy degree at Gonville and Caius College, Cambridge." I'm having a hard time making sense of the timeline here. I'm sure I could if I sat down and re-read things 20 times, but prose isn't clear if I have to do that to make sense of it. I would try a rephrasing similar to "In <YEAR>, he obtained his <DEGREE> under the supervision of Ernest Rutherford at the University of Manchester." or some such (if this is what is meant). In all cases, I would at the very least mention specific years, and specific degrees and specific supervisions. It's nice that Chadwick followed Rutherford at Gonville/Caius, but he could very well have had a different supervisor there.
  • Tried to make it clearer, but I think your real problem is confusion over what Gonville and Caius College is. Hawkeye7 (talk) 10:30, 1 August 2014 (UTC)[reply]
  • My problem was mostly the unclear timeline and degrees obtained in the second paragraph. I put dates and degrees from the nobel biography. Tweak as needed. Headbomb {talk / contribs / physics / books} 15:00, 5 August 2014 (UTC)[reply]
  • Not sure that it needs to be mentioned that he paid for the cyclotron with his Nobel money in the lead. This seems superflous to the core of his achievements.
Education/Life
Resolved issues
  • ... first child of John Joseph" John Joseph Chadwick? Or John Joseph?
  • When were his sibling born exactly? At least the years.
  • Sorry. Do not have that information. Hawkeye7 (talk) 10:30, 1 August 2014 (UTC)[reply]
  • Out of curiousity, who/when was the continuous spectrum of radiation explained? Is that how Pauli came to postulate the existence of neutrinos? If so, this should be mentionned!
  • ...within an error of less than 1.5 percent. A citation needs to be provided for this.
  • left the genius perplexed Who? Einstein or Chadwick? Also I don't like that kind of flowery language. It's very WP:WEASEL.
  • The only thing I had a problem with in this passage [2] was the ambiguity of the word "genius". The language of the explanation also seems a bit irrelevant. The quote itself was a really nice addition to the article. Consider something like A perplexed Chadwick wrote to Einstein "I can explain either of these things, but I can't explain them both at the same time." or something different if it was Einstein that said those words. Maybe with a note containing the original German quote if that's important. Headbomb {talk / contribs / physics / books} 15:00, 5 August 2014 (UTC)[reply]
Research
Resolved issues
  • Chadwick's Clerk Maxwell studentship expired in 1923 He had one? Should have been mentioned in the previous section then.
  • It is. Chadwick was awarded a Clerk-Maxwell studentship in 1920,
  • In 1925, Chadwick met Aileen Stewart-Brown, the daughter of a Liverpool stockbroker. The two were married in August 1925,[18] with Kapitza as Best Man. The couple had twin daughters, Joanna and Judy, who were born in February 1927.[19] This is not research. Rename the section, or put this elsewhere.
  • christened the neutrino "christened" is a fancy word for fanciness' sake. Keep it simple please, not everyone reads at this level.
  • In the Liverpool section, we go back to 1930 (last section ended in 1932), before jumping to 1935. I'd keep things chronologically if possible.
  • Lyon Jones Chair link?
  • Nope. But I can tell you who they were:
  • 1881-1900: [Sir] Oliver Joseph Lodge
    1900-1935: Lionel Robert Wilberforce
    1935-1948: (Sir) James Chadwick
    1949-1960: Herbert Wakefield Banks Skinner
    1960-1982: James Macdonald Cassels
    1987-1995: Charles Edward Johnson
    1997-2001: Peter John Twin
  • The university was something of a backwater What's a backwater? A backwater town? Backwater location? there's a word missing there. Also according to whom? And the backwater seems very negative. Rephrase to be more neutral/less flowery.
  • A remote place; somewhere that remains unaffected by new events, progresses, ideas, etc. (wikt:backwater) Hawkeye7 (talk) 12:16, 1 August 2014 (UTC)[reply]
  • He therefore chafed under Rutherford, again flowery for no reason. Keep it simple.
  • £700 in today's money, what would that be? Same for the other amounts.
  • No. Per Template:Inflation: This template is incapable of inflating Capital expenses, government expenses, or the personal wealth and expenditure of the rich. Incorrect use of this template would constitute original research. Hawkeye7 (talk) 12:16, 1 August 2014 (UTC)[reply]
  • Bernard Kinsey and Harold Walke links?
  • so Chadwick paid the rest from his Nobel Prize money the amount he received should be mentioned somewhere, although not necessarily here. He seems to have overspent by some £484, which could or could not be a significant chunk of the prize.
  • The Prize was 159,917 kr in 1935. I don't know what the exchange rate was then, but this is about 4.8 million kr today, which is about £413,000. Whereas £484 = £35744 today. So he probably had some change. Hawkeye7 (talk) 12:16, 1 August 2014 (UTC)[reply]
  • and might become a weapon in the fight against cancer How exactly did Chadwick suspect this? A random guess? Why cancer specifically, and not other biological diseases? I would expand on this if possible.
  • I have no proof, but I think it is because of the Liverpool Radium Institute and Hospital for Cancer, which opened in 1931.

    Chadwick arrived in Liverpool in September 1935 and took up the post of Lyon Jones Professor and Head of the Department of Physics. There was close cooperation between the Faculties of Science and Medicine at that time and Chadwick was automatically a committee member of both faculties... The somewhat ad hoc arrangements for the treatment for cancer in Liverpool and elsewhere were, however, clearly recognised as unsatisfactory and in 1938 Lord Derby led a Commission to look at this problem and report on the work. Chadwick was made a member of this Commission. Sir James Chadwick and his Medical Plans

  • I would add a mention of Chadwick being a member of that commission and of the collaboration between Science and Medicine. It gives a bit more context, IMO.Headbomb {talk / contribs / physics / books} 15:00, 5 August 2014 (UTC)[reply]
  • ... sent Chadwick about 2 millicuries curies are a unit of radiation, not an amount of mass/substance. Rephrase.
  • No, Curies is what is used then and today. Polonium is 4490 curies/g, so 2 millicuries is 445 ng. Added. Hawkeye7 (talk) 10:57, 1 August 2014 (UTC)[reply]
  • This had a bit of false precision in the conversion. I put 0.5 μg instead. However, this assumes that the polonium sent to Chadwick was pure Po-210. Was this the case? Headbomb {talk / contribs / physics / books} 15:00, 5 August 2014 (UTC)[reply]
  • Given the short half life of Polonium, that would be impossible. But she made it from lead oxide. The amount of polonium is measured from the alpha emission. So 2 mCu means you have 500 ng. Hawkeye7 (talk) 02:36, 6 August 2014 (UTC)[reply]
  • Hmm... Do you know in what form this polonium was sent then? "... Meitner sent Chadwick about 2 millicuries (about 0.5 µg) from Germany, in the form of a <type of sample>." This is a minor point, but if you know/if it can be found, it would be good to add it IMO. Headbomb {talk / contribs / physics / books} 13:34, 7 August 2014 (UTC)[reply]
  • the mass of the neutron experimentally, and found that it was greater than that of the proton thereby confirming this theory. This makes it look like the mass of the neutron being greater than the proton is a key feature of the theory, and the reason why the theory is right. I'm very doubtful that in the 1930s you could measure the mass of protons and neutron with enough resolution to measure a significant difference between the two. And I'm also pretty sure that expectations were that the neutron and protons had about the same mass. This passage, and those surrounding it, need to be reworked to give a better and more accurate explanation of this.
  • Measuring the mass of a proton is something we did in high school, so the readers will know how. As for the neutron, you sadly underestimate the genius of Chadwick. Hawkeye7 (talk) 10:57, 1 August 2014 (UTC)[reply]
  • Decided to include this in the article.
  • The expanded section is clearer, but it still makes the point that the mass of the neutron being greater than the mass of the proton is what confirms the theory to be right. This claim will be very puzzling to most, given that Chadwick predicted the mass of the neutron to be less than that of the proton, contradicting the experimental findings. What confirms the theory to be right is that the masses of the neutron and protons are very similar (which is why changing the model of nitrogen nucleus from 14p+7e to 7p+7n still gave the right mass). I don't know how Chadwick estimated the mass of the neutron, but I'm pretty sure he was happy to predict the mass within 0.2% of experimental results. Headbomb {talk / contribs / physics / books} 15:00, 5 August 2014 (UTC)[reply]
  • How Chadwick calculated the mass of the neutron is now in the article!
In his paper, Chadwick estimated that a neutron weighed about 1.0067 u. As a proton and an electron together weighed 1.0078 u, this implied a binding force of about 2 MeV, which sounded reasonable. Then Maurice Goldhaber, a refugee from Nazi Germany and a graduate student at the Cavendish Laboratory, suggested that deuterons could be photodisintegrated by gamma rays:
2
1D
 		 + 
γ
 		 →  1
1H
 		 + 
n
Chadwick tried this and found that it worked. They measured the kinetic energy of the protons produced as 1.05 MeV, leaving the mass of the neutron as the only unknown in the equation. He then calculated that it was between 1.0077 and 1.0086 atomic units.
You can read about it in Chadwick's notebook, in his own hand. Hawkeye7 (talk) 02:36, 6 August 2014 (UTC)[reply]
That's all fine and dandy, but that doesn't resolve the core of the problem mentioned in my previous post in this thread. Headbomb {talk / contribs / physics / books} 03:44, 6 August 2014 (UTC)[reply]
The prevailing theory was that the neutron was a composite particle like an alpha particle, but consisting of an electron and a proton. (The mass of an electron is negligible compare to a proton or neutron.) By determining that the neutron actually weighed more, Chadwick demonstrated that this could not be the case. So it had to be a new kind of particle. Hawkeye7 (talk) 02:46, 7 August 2014 (UTC)[reply]
When you rewrite this section, could you also add the original articles by Bohr/Chadwick/Heisenberg/Goldhaber/others? I don't have access to Brown, but I would have access to those (as I suspect many others). Headbomb {talk / contribs / physics / books} 13:46, 7 August 2014 (UTC)[reply]
Added the original articles by Heisenberg. Hawkeye7 (talk) 21:23, 7 August 2014 (UTC)[reply]
WWII
Resolved issues
  • He also endeavoured to place British scientists in as many parts of the project as possible in order to facilitate a post-war British project that Chadwick was committed to. Which project?
  • Changed to "a post-war British nuclear weapons project" Hawkeye7 (talk) 12:16, 1 August 2014 (UTC)[reply]
  • In the tube alloy section, the timeline seems to be Meitner & Frisch explained fission, Hahn & Strassman noted the possibility of chain reactions, then Joliot et al. confirmed it. There are a few ommissions in this make it seem to contradict the timeline in Nuclear fission#History/Otto Hahn#Discovery of nuclear fission. Hahn & Strassman discovered fission first (missing), communicated with Meitner & Frisch who explained it, and Frisch later confirmed it (missing). Then Hanh & Strassman hypothesizes chain reactions, which were confirmed by Joliot et al.Headbomb {talk / contribs / physics / books} 06:38, 8 August 2014 (UTC)[reply]
  • Well, I didn't want to stray too far from Chadwick. Added a bit. Hawkeye7 (talk) 00:36, 9 August 2014 (UTC)[reply]
Additional comments
Resolved issues
  • The contributions of Wang Ganchang to the discovery of the neutron seems to be overlooked (if his Wikipedia article is to be believed.) 15:17, 5 August 2014 (UTC)
  • The use of polonium and beryllium a a radiation source was discovered by Bothe and Becker in 1930. Irene and Frédéric Joliot-Curie used it, but did not interpret the results as indicating the existence of neutrons. Given that Meitner was skeptical about the neutrons, I don't think that Wang Ganchang would have found them either had he built his cloud chamber. The fact is that he didn't do or find anything. Hawkeye7 (talk) 21:15, 5 August 2014 (UTC)[reply]
  • Fair enough. I thought it might have been documented somewhere that he gave the idea to Meitner, and Meitner gave it to Chadwick or something, but I was going off a a badly-referenced Wikipedia entry more than anything reliable. Headbomb {talk / contribs / physics / books} 23:32, 5 August 2014 (UTC)[reply]
  • I don't get the point of this edit. Nothing broke... and re-introduced a bunch of long-form citations that really should have been in {{sfn}} format. 15:17, 5 August 2014 (UTC)
  • Violates WP:CITEVAR: As with spelling differences, unless there is consensus to change, defer to the style used by the first major contributor. I dislike reducing all the author's names to initials. The doi templates that an editor added have been stripped. OCLCs have gone missing. Worst of all, the source review now has to be completely redone. If retained, I would have to withdraw the article. So I'm putting it back. Hawkeye7 (talk) 21:15, 5 August 2014 (UTC)[reply]
  • If the point of contention is the name of authors, that's a very easy thing to fix. OCLC adds nothing over the ISBN, especially since the OCLC record is incomplete and generally in bad state, but they could easily be added back. Using {{cite doi}} however, just makes things harder to edit and maintain, and in fact makes the article inconsistent, as cite doi templates must not use full names, but rather "Smith, J." format. And I've got no idea what you mean by "source review", given it's all the same sources (except [3], and the expanded further reading section). Headbomb {talk / contribs / physics / books} 23:11, 5 August 2014 (UTC)[reply]
  • The point of contention is a clear cut violation of WP:CITEVAR. I don't want to spend all my Wikipedia time fighting Wiki Gnomes. Hawkeye7 (talk) 08:17, 7 August 2014 (UTC)[reply]
  • My citation style is consistent, and has passed FAC many times. ANI has already supported the mix of {{cite doi}} and {{cite journal}} (which I opposed). Hawkeye7 (talk) 20:38, 7 August 2014 (UTC)[reply]
  • It was not and I would fail the FAC on these grounds alone. ANI is clueless when it comes to consistent citations if it allows a mixed Smith, J. (2009) next to Jones, James (2013).Headbomb {talk / contribs / physics / books} 01:16, 8 August 2014 (UTC)[reply]
  • Chadwick was a critic of the American approach to science. He refuted Lawrence's claims, which he correctly considered due to contamination. Rutherford and Oliphant then found that deuterium fuses to form helium-3, discovering nuclear fusion. Hawkeye7 (talk) 21:22, 5 August 2014 (UTC)[reply]
  • Added a bit. I wrote that article too. Hawkeye7 (talk) 08:17, 7 August 2014 (UTC)[reply]
  • The expanded version hits the nail on the head, but it needs original sources for Lawrence/Rutherford/Oliphant's claims. Also, in which he considered careless should that be which (Big Science), or whom (Lawrence)? Or is my grammar off here? Headbomb {talk / contribs / physics / books} 06:03, 8 August 2014 (UTC)[reply]
Re-worded. Not sure what you mean by original sources. The paragraph is footnoted. Hawkeye7 (talk) 03:32, 12 August 2014 (UTC)[reply]
The rewording is fine. And by original sources I mean the original articles/proceedings/letters/etc... where Lawrence/Rutherford/Oliphant's made those claims. I.e. in what publication did Lawrence postulate the new particle? (Is this the "light neutron" in Heilbron & Seidel? doi:10.1103/PhysRev.44.313?) Where did Chadwick expressed that the results were likely due to contamination? Where did Lawrence rechecked his results? Where did Rutherford & Oliphant found deuterium fusion? Etc... I don't doubt that Heilbron & Seidel and Herken support the paragraph (Heilbron & Seidel gives a an impressively detailed history of this whole paragraph actually), but having the primary sources alongside Heilbron & Seidel add a lot for those who want to see the nitty gritty details of it all. Headbomb {talk / contribs / physics / books} 18:02, 12 August 2014 (UTC)[reply]
  1. Heilbron & Seidel cite the appropriate sources, mostly letters, but since most of they are not online, it makes little point to cite the primary sources. Heilbron & Seidel give a good account. There's no requirement to fill the article with primary sources. The gritty details can be found in the subarticles.
  2. It is the light neutron, but Lawrence didn't publish a lot of papers, preferring to make announcements at conferences and in the newspapers. I don't see the value of including an erroneous paper. The Americans generally presumed that they were the most technologically advanced nation on Earth, but in the 1930s Britain was ahead. Chadwick was one of those Britons that Americans found a staunch ally, but prone to being snooty, patronising and condescending.
  3. The other point is about Big Science. Chadwick was one of its progenitors, but did not like it.
  4. As the article says, Chadwick expressed his opinions at the Solvay Conference
  5. As the article says, Rutherford & Oliphant worked at the Cavendish. Hawkeye7 (talk) 21:12, 14 August 2014 (UTC)[reply]
Final thoughts

Overall enjoyable, most of the above should be easily fixable. The end of the article is somewhat abrupt however. I like a "Legacy" section of some type, like things named after Chadwick, selected works, etc.. Maybe a "See also" section. Ending with "and then he died" seems... uninspired. Also doi:10.1038/161964a0 and doi:10.1080/00107517208205684 should be explored. I cannot support FA in the current state, but it's close to being there. Headbomb {talk / contribs / physics / books} 20:20, 31 July 2014 (UTC)[reply]

Comments by Ian Rose[edit]

Recusing from coord duties to review, as I have a FAC open myself at the moment...

  • Tweaked prose as I generally do so pls let me know any issues. Few remaining concerns except:
    • I fully agree with Headbomb re. "which he considered careless should that be which (Big Science), or whom (Lawrence)?" -- needs clarification/rewording.
    • Although I took out a second mention of his daughters' names for reasons I explained in the edit summary, you called them Judy and Joanna initially but then Julie and Joanna -- better check that Judy (from the initial mention that I left in) is correct.
    • Under See also, if Chadwick crater is indeed named after the man, as seems to be the implication, why not move to and cite in the Legacy section and just drop the See also?
  • Structure and level of detail seem fine.
  • I'll happily defer to Nikki for the source review.
  • As far as images go, licensing looks good to me though I'd assume File:Solvay1933Large.jpg and File:Liverpool Blitz D 5984.jpg would have a US copyright tag in addition to those present.

Generally looks a worthy addition to your series of mad scientists (is there any other kind?)... ;-) Cheers, Ian Rose (talk) 02:18, 12 August 2014 (UTC)[reply]

  • Added a 1996 tag to File:Liverpool Blitz D 5984.jpg. Removed the Solvay picture. Cannot understand how Commons can tag an image as author unknown while stating who the author was. Hawkeye7 (talk) 02:56, 12 August 2014 (UTC)[reply]
    • Merged the crater into the Legacy section. Hadn't even noticed that one. Hawkeye7 (talk) 03:04, 12 August 2014 (UTC)[reply]
      • Chadwick's twin daughters are Joanna and Judith. (My favourites names were Granville Ryrie's twin daughters, Dee and Dar.) Hawkeye7 (talk) 03:14, 12 August 2014 (UTC)[reply]
Happy to support now. Cheers, Ian Rose (talk) 08:17, 12 August 2014 (UTC)[reply]
  • More on images -- Points re. initial check were resolved, have reviewed licensing for two recently added colour picture and both look okay. Cheers, Ian Rose (talk) 01:51, 17 August 2014 (UTC)[reply]

Comment - I came here with a view to making a closing decision but I am concerned about the accuracy of the physics. This phrase jumped out at me: "Chadwick was able to demonstrate that beta radiation produced a continuous electromagnetic spectrum, and not discrete lines as had been thought." I am a biologist and not a physicist, but I think photons and not electrons form the electromagnetic spectrum. Electrons produce a kinetic energy spectrum, which is different. The source used says "the beta ray emission from the radioactive deposit had a continuous range of energy practically from zero up to a certain limit on which was superimposed these peaks". Am I missing something? Graham Colm (talk) 06:49, 14 August 2014 (UTC)[reply]

Well, I'm a mathematician, not a physicist. I think the problem is in the clarity of the wording. From the article on Bremsstrahlung:

Bremsstrahlung "braking radiation" or "deceleration radiation") is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron... The moving particle loses kinetic energy, which is converted into a photon, thus satisfying the law of conservation of energy... Bremsstrahlung has a continuous spectrum, which becomes more intense and whose peak intensity shifts toward higher frequencies as the change of the energy of the accelerated particles increases. Hawkeye7 (talk) 12:20, 14 August 2014 (UTC)

I am not at all convinced by this argument and quoting another of our articles does not help. I think that there is a fundamental error here, which calls into question – at least in my mind – the accuracy of the rest of the physics in this article. I would not be confident in promoting this candidate without more reassurance from our physicists. Graham Colm (talk) 22:30, 14 August 2014 (UTC)[reply]
I would advise against closing until the concerns about the The mass of the neutron was indeed greater than that of the proton, thereby supporting Bohr and Heisenberg's theory. passage (and surrounding text) have been fully addressed. As it stands, the article is very misleading on that issue.
The mass of a neutron is greater than that of a proton. Hawkeye7 (talk) 21:12, 14 August 2014 (UTC)[reply]
That fact is not in dispute, it's the whole explanation that is confusing and misleading. Chadwick predicted a lesser mass, then it was discovered it was greater. If the core of the argument is that different mass implies a different particle than the proton, then what is important is that the mass of the neutron is different, not that it is greater, than that of the proton. Headbomb {talk / contribs / physics / books} 23:45, 19 August 2014 (UTC)[reply]
As for the continuous spectrum, I'll look into it. I didn't even notice EM spectrum, in there. The way I've seen those before was in terms of momentum spectrum [4] (which is more or less equivalent to presenting it in terms of an energy spectrum). I don't think Bremsstrahlung is involved at all, but I'll dig further to confirm. Headbomb {talk / contribs / physics / books} 14:13, 14 August 2014 (UTC)[reply]

Comments from Tim riley[edit]

I am to physics what whales are to rollerskating, so excuse any howlers in my comments. This, to the layman's eye, is a fine article. I don't understand some of the scientific bits, but I don't need to. The biographical stuff – which is most of the article – is first class. I offer these few comments for the nominators' consideration, and look forward to adding my support thereafter.

  • Education and early life
    • "physics" – perhaps move blue link to the first mention earlier in the para.
    • "within an error of less than 1.5 percent" – the Manual of Style thinks "percent" is American and "per cent" British, and so do I.
  • Cambridge
    • "You are inconsistent about whether or not to use the false title when labelling people: thus, you have "succeeded by the Russian physicist Pyotr Kapitza" with the definite article but "Theoretical physicists Niels Bohr and Werner Heisenberg" without it. The latter is undesirable in good British English, though good AmEng and beloved of our tabloid newspapers. There are other false titles later in the article, such as "Cosmologist Sir Hermann Bondi", "Prime Minister Winston Churchill" and "New York Times reporter William L. Laurence"
  • Liverpool
    • "the government became more parsimonious with funding for science" – a bit POV, perhaps, especially without a citation. Perhaps, "the government cut back funding for science"
    • "Chadwick responded condescendingly" – unless this is a quote from a source the adverb seems to me to fall foul of WP:EDITORIAL
    • "his 159,917 kr Nobel Prize money" – a Sterling translation would be useful here
    • "Lord Derby" – perhaps a piped link to Lord Derby?
  • Tube Alloys and the MAUD Report
    • "Meitner and her nephew Otto Frisch created an uproar" – this reads rather as though the scientific community was outraged rather than astonished, which I think you probably don't mean to suggest
  • References
    • "Some statements are given as many as four individual citations. To the layman's eye this looks like overkill, but I am quite prepared to be told I'm wrong.
    • "Your bibliographic style, though impeccably academic, is not what I usually expect in Wikipedia: I refer to your "— (1932)" style for second and later mentions of authors' names in your list of references. I thought the MoS disapproved of this style, but if it does I can't find it, and so I just mention it and leave it to you to agree or disagree with me.

I hope you can find some useful points in this little batch of quibbles. Tim riley talk 13:24, 30 August 2014 (UTC)[reply]

It's always good to meet an editor I haven't encountered before. Thanks very much for your review! I presume that Chadwick is a local hero in Liverpool. Well he out to be. I've addressed all your points.

  • "Percent" makes no sense to me, and my spell checker flags it as an error. The Commonwealth Style Guide says "per cent" is correct. I'm blaming the Wiki-Gnomes.
  • I'd never heard of "false title" before, but have removed them.
  • I did not have much hope of converting kroner to Sterling, but as luck might have it, the kroner was fixed to 19.40 to the pound at the time.
  • What happens with the multiple citations is that one is a secondary source that covers it, and the other three are scientific papers, so the readers can read the details for themselves.
  • By "parsimonious". I didn't mean that they actually cut funding per se; they tightened the eligibility rules. The whole article is cited.
  • If you can find the bit in the MoS that disapproves of the bibliographic style I'll change it.

Hawkeye7 (talk) 23:01, 30 August 2014 (UTC)[reply]

I too don't like the "--" in the citing style, if only because if you click on e.g. "Chadwick & Ellis, 1922, you're transported to a citation that doesn't explicitly contain Chadwick, and you have to backtrack to find who -- was, exactly. It also makes it more annoying to copy/paste the citation (e.g. in Google, or in another document). I like -- for lists of work by the same person (e.g. David_Malet_Armstrong#Bibliography), but I don't like it in reference sections such as this one. But this might be YMMV stuff. Headbomb {talk / contribs / physics / books} 19:02, 7 September 2014 (UTC)[reply]

Image check[edit]

Conclusion: Probably fails? It might be fine, but I have significant doubts on several images. Adam Cuerden (talk) 05:34, 16 September 2014 (UTC)[reply]

Closing comment - I have decided to break with tradition and promote this article without the usual level of explicit support. This is not to be taken as a precedent. In my view – thanks in part to the thorough reviews above – this article satisfies the FA criteria. Graham Colm (talk) 19:05, 27 September 2014 (UTC)[reply]


@GrahamColm: I'm sorry, but File:Chadwick.jpg claims its copyright in Sweden based on it being anonymous - but lists the photographer. That's kind of a nonsense copyright claim. Please actually resolve the image check issues before promotion. Adam Cuerden (talk) 19:18, 27 September 2014 (UTC)[reply]
I am satisfied that any remaining issues will be resolved post FAC as we have done in the past with other candidates. Graham Colm (talk) 19:23, 27 September 2014 (UTC)[reply]
Without actually flagging up such things as needing done post-FAC? The lead image is quite possibly a copyvio. And, given the lead image is liekly the one that will go onto the main.. screw it, I'll just nominate them for deletion at commons and be done with it, shall I? Good thing I actually noticed this was bpassed without resolving the issues, because I don't think anyone else was paying attention. Adam Cuerden (talk) 19:24, 27 September 2014 (UTC)[reply]
I also disagree with the closure, the issues with the mass of the neutron experimentally, and found that it was greater than that of the proton thereby confirming this theory still have not been resolved. The rest of my objections were addressed satisfactorily, but not this one. Headbomb {talk / contribs / physics / books} 19:33, 27 September 2014 (UTC)[reply]
The best I could do was: The mass of the neutron was too large to be a proton/electron pair, and so had to be something else, thereby supporting Bohr and Heisenberg's theory that it was a new nuclear particle. Hawkeye7 (talk) 20:07, 27 September 2014 (UTC)[reply]
It's bad to close things with unresolved image reviews. It's worse when the lead image is one of the ones that may be a copyright violation, because that gives a very high risk of copyvio on the main page. If you expect the things to be dealt with after closure, I'd ask how you expect that to happen, if you don't, say, put a message on the talk page of the article saying, in bold, all caps, "fix these issues now", but, instead, hope they read a closed FAC - which is meant to have had all issues dealt with - and notice that actually, no, that didn't happen, then it's likely the problems will not, in fact, be fixed. We're not in the habit of doing Image reviews on things that are already FAs, because FAC is meant to have dealt with that. Seriously, had I not noticed this had closed, and checked it, I have very little doubt we'd have copyvio on the main page in a few months. Adam Cuerden (talk) 19:43, 27 September 2014 (UTC)[reply]
I was here as a reviewer rather than a FAC delegate but I have to admit that if I was wearing my delegate hat on this one I might well have closed it too based on the image review as it stood. The way the most recent comments on the outstanding points were worded just didn't suggest to me the level of concern that's now apparent -- there was no oppose statement, and no use of the term "copyvio" until after promotion. Okay, the concern is quite apparent now so it should be addressed one way or another but, for the future, if anyone really thinks an article should not be promoted then the best way is to explicitly oppose it. There's nothing harsh about this, it simply acts as a red light until the issues are dealt with, at which point the reviewer can change it to support or at least strike it out. Cheers, Ian Rose (talk) 08:05, 28 September 2014 (UTC)[reply]
The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.
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