Talk:Discovery of nuclear fission

Discovery of nuclear fission is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so.

This article appeared on Wikipedia's Main Page as Today's featured article on June 22, 2021.

Article milestones
Date	Process	Result
August 7, 2020	Good article nominee	Listed
October 13, 2020	Featured article candidate	Promoted

A fact from this article appeared on Wikipedia's Main Page in the "Did you know?" column on August 30, 2020.

The text of the entry was: Did you know ... that Otto Hahn was the sole recipient of the 1944 Nobel Prize in Chemistry, awarded for the discovery of nuclear fission?

Current status: Featured article

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Add notation for what actually happened in Eureka[edit]

There's notation of what was falsely thought to happen in the Eureka section (²³⁸
₉₂U + n → α + ²³⁵
₉₀Th → α + ²³⁵
₈₈Ra) but not what actually happened, which was the production of barium and krypton. It is probably similar to what was on this stamp. --Blemby (talk) 06:02, 29 June 2020 (UTC)[reply]

Otto Hahn on a stamp of the German Democratic Republic, 1979

It is in the text though: "Logically, if barium was formed, the other element must be krypton". The problem with adding a notation is in the one you displayed: ²³⁵
₉₂U + n →
₅₆Ba +
₃₆Kr + einige n. Added anyway. Hawkeye7 (discuss) 06:20, 29 June 2020 (UTC)[reply]

The phenomenon was a new type of nuclear disintegration[edit]

Without a proper definition of nuclear fission in the first sentence, it's unclear how the phenomenon "was discovered in December 1938..." when it appears that it had already been known for 40 years: "The phenomenon was a new type of nuclear disintegration, one more powerful than any seen before." How is "nuclear disintegration" ≠ "nuclear fission"? What phenomenon did Fermi study in 1932? Was it only given a name in 1938, and not discovered? Ponor (talk) 19:08, 10 July 2020 (UTC)[reply]

Added a definition of fission from the article on "nuclear fission" to the first paragraph. The meaning of "discovery" is the subtext of the article. Known forms of radioactive decay were alpha, beta and gamma; known nuclear reactions were fusion, spallation and neutron capture. Fermi's team in Rome observed fission for the first time, but did not know what they were looking at. So too, for four years, did Lise Meitner's team in Berlin, and Irene Curie's team in Paris, as they struggled to confirm or refute Fermi's claim. Hahn and Strassmann proved that barium had been produced from bombarding uranium with neutrons. This was chemistry; how or why it happened wasn't of concern to Hahn. Then came the physics. Confronted with these results, Meitner worked up a physical explanation, and then, based on her theory, an experiment to confirm it. The experiment was carried out by Frisch, who observed the energetic activity of the fission process for the first time. And he gave it a name—a privilege usually accorded to the discoverer. Niels Bohr and John Wheeler then reworked the liquid drop model of the nucleus to produce a mathematical model of the fission process. The Nobel Chemistry Committee was impressed by Hahn's chemistry, and saw fission as a discovery in chemistry, whereas Meitner and Frisch's experiment involved bringing uranium together with a neutron source and looking at the results with a Geiger counter—where's the chemistry in that? So they awarded Hahn the prize. To physicists like Albert Einstein, Hahn was like Christopher Columbus, who set out not knowing where he was going, got there and did not know where he was, and returned without understanding where he'd been. Hawkeye7 (discuss) 21:01, 10 July 2020 (UTC)[reply]

This looks much better, thanks Hawkeye7. As someone who doesn't know much about history of early nuclear research, I'm still missing some relevant context, especially when reading this as a standalone article, now a GAN. Something along these lines would, I believe, read a bit better (just a suggestion): "Nuclear fission, a reaction or spontaneous decay process in which the nucleus of an atom splits into smaller and lighter nuclei, was discovered in December 1938 by physicist Lise Meitner and chemists Otto Hahn and Fritz Strassmann at the Kaiser Wilhelm Institute for Chemistry in Berlin. Other known nuclear processes at the time were... and the fission <what made it so special?> was the first to produce much lighter nuclei and release much larger amounts of energy <when compared to...> Nuclear fission often produces gamma rays <this necessary here? does gamma emission make nuclear fission any special?>."Ponor (talk) 02:06, 11 July 2020 (UTC)[reply]

What makes fission special is the large amount of energy involved. The fission of a kilogram of uranium-235 (about the size of a cue ball) releases as much heat as burning 2,000 tons of coal. Hawkeye7 (discuss) 12:18, 14 July 2020 (UTC)[reply]

GA Review[edit]

This review is transcluded from Talk:Discovery of nuclear fission/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Ponor (talk · contribs) 16:08, 6 August 2020 (UTC)[reply]

Review notes[edit]

Happy to review. Stay tuned for my comments. I believe we can have a new GA in the next few days.

Intro

Q: Why is it "by physicist Lise Meitner", and not "by physicists Lise Meitner and Otto Frisch"?

A: Read the article, and then you tell me who discovered fission. Bear in mind that Otto Hahn alone won the Nobel Prize for the discovery. The article explores what we mean by "discovery". Added Otto Robert Frisch. Hawkeye7 (discuss) 20:57, 6 August 2020 (UTC)[reply]

I think this is fine. Check the Deutsches Museum figure caption.

Q: This is a standalone article, so it would be nice to know from the beginning what other nuclear reactions and radioactive decay processes were known at the time and how this one was different.

A: Added to the first paragraph: "Scientists already knew about alpha decay and beta decay" and moved "the discovery that a nuclear chain reaction was possible led to the development of nuclear power and nuclear weapons" up to the top. Hawkeye7 (discuss) 20:57, 6 August 2020 (UTC)[reply]

Radioactivity

Q: Pls try to clarify: "had a screen coated with barium platinocyanide that would fluoresce when exposed to cathode rays" (from what I understand, this screen was outside of the vacuum tube, where electrons could not reach it) & 2 "he noticed that even though his cathode ray tube was not pointed at his screen, and it was covered in black cardboard, it still fluoresced" (he probably had a sample inside the tube and was shooting electrons onto it; I don't understand what they were observing with the outside screen because electrons cannot go through glass, was it there for some other reason?; "it still fluoresced" - "it" refers to black cardboard, screen (✓), or the tube?

A: The fluoresce is caused by X-ray photons emitted from the CRT, not electrons. They easily penetrate glass. Hawkeye7 (discuss) 03:28, 7 August 2020 (UTC)[reply]

What I meant is: 1 we have "screen would fluoresce when exposed to cathode rays", and cathode rays are electrons; I wonder what he used the external screen for (not knowing about X-rays).

2 "tube was not pointed at the screen"..."it still fluoresced"? the tube? I didn't want to touch this because I don't know the details. X-ray article is a bit more clear.

Tried to clarify. A cathode ray tube produces X-rays as well as electrons. One thing that bothering me is that fission produces X-rays too; the article refers to them as gamma rays, which is sort of correct. Hawkeye7 (discuss) 05:57, 7 August 2020 (UTC)[reply]

Transmutation

Q: Why is the nitrogen to oxygen transmutation written like this - isn't there an electron missing? Conventions vary, so it might be a good idea (for those who add As and Zs) to say the reaction is written for the nuclei only.

A: Possibly because Blackett didn't mention it. But because we're using the modern notation anyway, added the electron. Hawkeye7 (discuss) 20:57, 6 August 2020 (UTC)[reply]

Forgive me, I am going to revert this edit. I did some research, and it seems that writing the reaction for the whole atoms might be confusing. I'm adding that the formula is valid for the nuclei. No electron is emitted from the nucleus, and we don't really know when and how the electrons find their new nuclei.

Forgiven. Hawkeye7 (discuss) 03:28, 7 August 2020 (UTC)[reply]

Q: Explanation why this wasn't fission would be nice: "known as 'splitting the atom', but was not nuclear fission"

A: Added: as it was not the result of initiating an internal radioactive decay process. It may have also contributed to throwing Fermi, Meitner and Curie off the scent, as nuclear reactions were supposed to just chip fragments off nuclei. (Aside: The names of the scientists in the article are as they appear in their scientific papers.) Hawkeye7 (discuss) 03:28, 7 August 2020 (UTC)[reply]

Discovery

Q: "Bohr's liquid drop model had not yet been formulated, so there was no theoretical way to calculate whether it was physically possible for the uranium atoms to break into large pieces." The model was introduced in the previous section as Gamov's liquid drop model. When did Bohr formulate his model?

A: The previous section said: The current model of the nucleus was the liquid drop model first proposed by George Gamov in 1930. His simple and elegant model was refined and developed by Carl Friedrich von Weizsäcker and, after the discovery of the neutron, by Werner Heisenberg and Niels Bohr Hawkeye7 (discuss) 03:28, 7 August 2020 (UTC)[reply]

Still, it kind of appears out of the blue because we, at that point, don't know when Bohr developed his own model. How about "and Niels Bohr (in 193x)."

Added "in 1936". Hawkeye7 (discuss) 05:57, 7 August 2020 (UTC)[reply]

Q: Last two paragraphs of "Objections" (why this title?) don't seem too relevant, should they be rather be in their respective biographies? The story is interesting, for sure, but the article is already too long.

A: It tells the reader how this team came together, and why Meitner and Hahn were engaged in digging in to this mystery instead of running the KWI for Chemistry. Meitner's later departure is also foreshadowed. (The title refers to objections to Fermi's claim to have discovered Hawkeye7 (discuss) 03:28, 7 August 2020 (UTC)[reply]

It's a biographic digression that I found a bit too long. Interesting, but long. No reason to fail GAN, though.

Q: Last few sentences in "Eureka" - it's unclear if all these dates were in 1939. Frisch conducted exp. in February, but mailed papers (about what?) in January.

A: Added "1939". Hawkeye7 (discuss) 05:57, 7 August 2020 (UTC)[reply]

Eureka

Q: At first I thought this was the name of a project or a new element. Adding exclamation mark, Archimedes style, hope you're ok with that.

A: Sure. Hawkeye7 (discuss) 05:57, 7 August 2020 (UTC)[reply]

Assessment[edit]

GA review – see WP:WIAGA for criteria

Is it well written?
A. The prose is clear and concise, and the spelling and grammar are correct:

B. It complies with the manual of style guidelines for lead sections, layout, words to watch, fiction, and list incorporation:
Is it verifiable with no original research?
A. It contains a list of all references (sources of information), presented in accordance with the layout style guideline:

B. All in-line citations are from reliable sources, including those for direct quotations, statistics, published opinion, counter-intuitive or controversial statements that are challenged or likely to be challenged, and contentious material relating to living persons—science-based articles should follow the scientific citation guidelines:

C. It contains no original research:

D. It contains no copyright violations nor plagiarism:
Is it broad in its coverage?
A. It addresses the main aspects of the topic:

B. It stays focused on the topic without going into unnecessary detail (see summary style):
Is it neutral?
It represents viewpoints fairly and without editorial bias, giving due weight to each:
Is it stable?
It does not change significantly from day to day because of an ongoing edit war or content dispute:
Is it illustrated, if possible, by images?
A. Images are tagged with their copyright status, and valid fair use rationales are provided for non-free content:
all CC or public domain

B. Images are relevant to the topic, and have suitable captions:
Overall:
Pass or Fail:

Did you know nomination[edit]

The following is an archived discussion of the DYK nomination of the article below. Please do not modify this page. Subsequent comments should be made on the appropriate discussion page (such as this nomination's talk page, the article's talk page or Wikipedia talk:Did you know), unless there is consensus to re-open the discussion at this page. No further edits should be made to this page.

The result was: promoted by The Squirrel Conspiracy (talk) 01:50, 19 August 2020 (UTC)[reply]

(

Comment or view
Article history

)

... that Otto Hahn was the sole recipient of the 1944 Nobel Prize in Chemistry for the discovery of nuclear fission? Source: [1]

Reviewed: Template:Did you know nominations/Flight Pattern, Template:Did you know nominations/Aurora: Beyond Equality
Comment: If Otto Hahn gets through GA, this could become a double hook

Improved to Good Article status by Hawkeye7 (talk). Self-nominated at 06:17, 7 August 2020 (UTC).[reply]

Article - Promoted to GA within 5 days, long enough and within policy Y
Hook - Meets formatting requirements, interesting and neutral Y
QPQ - Checked Y

Would you like this to be passed now, or would you rather wait for Otto Hahn's GA review?

Adding Otto Hahn specifics to this review, since it came up at WT:DYK. Most of the DYK review has already been checked above, but I went ahead and fully checked it anyway. It passed GA on August 28, 2020. It's certainly long enough, and detailed enough, with every paragraph sourced - some of them multiple times. The images are on Commons and appropriately licensed. The care and detail with which this was edited and upgraded even before it passed GA, is really evident. The work on Otto Hahn is excellent. I ran it through Earwig's copyvio tool, and the only thing that came up was some oddball jewelry site that, when I opened it, had nothing about Otto Hahn. Every paragraph is sourced as they should be. Images are appropriate. QPQ supplied, and the GA passing makes it eligible. Eveyything is fine for DYk here. — Maile (talk) 00:42, 29 August 2020 (UTC)[reply]

Pass it now. The review of Otto Hahn could be months away. Hawkeye7 (discuss) 20:06, 7 August 2020 (UTC)[reply]

Good to go Pi (Talk to me!) 21:45, 7 August 2020 (UTC)[reply]

Szilard and the nuclear chain reaction[edit]

Szilard came up with the idea of a nuclear chain reaction in 1934. This was analogous to a chemical chain reaction. He wasn't thinking about nuclear fission at all. The idea came in the wake of Ernest Walton and John Cockcroft "splitting the atom" (in this case lithium) and James Chadwick's discovery of the neutron in 1932, and Mark Oliphant's discovery of nuclear fusion in 1933. Szilard's idea was that he could create a chain reaction with the neutrons produced by a fusion reaction. So he experimented with the light elements, attempting to get a chain reaction going. (Fusing elements heavier than iron would have required more neutrons to be input.) Another path to a nuclear chain reaction showed up after Hahn, Strassmann, Meitner and Frisch discovered nuclear fission in 1938. Only then did Szilard then switched his attention to uranium. Fermi was unsure about this; it required that Bohr's hypothesis about the fissile part of uranium being the uranium-235 isotope (which had not been verified), fission reactions producing more than one neutron per fission on average (which had not been demonstrated), and the neutrons having the right energy (which was uncertain). Fermi, Szilard and others were able to solve these issues and get a chain reaction to actually occur. Hawkeye7 (discuss) 06:43, 18 April 2023 (UTC)[reply]