Talk:Discovery of nuclear fission

Add notation for what actually happened in Eureka
There's notation of what was falsely thought to happen in the Eureka section ( + n → α + → α + ) 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)
 * 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: + n →  +  + einige n. Added anyway.  Hawkeye7   (discuss)  06:20, 29 June 2020 (UTC)

The phenomenon was a new type of nuclear disintegration
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)


 * 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)
 * 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  was the first to produce much lighter nuclei and release much larger amounts of energy  Nuclear fission often produces gamma rays ."Ponor (talk) 02:06, 11 July 2020 (UTC)
 * 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)

Szilard and the nuclear chain reaction
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)