Talk:Nuclear fission

"Output" wrong or at least hard to understand

In "Output" it is shown two different values for how much energy is released from uranium fission.

Currently it is says that:

"Thus, in any fission event of an isotope in the actinide mass range, roughly 0.9 MeV are released per nucleon of the starting element."

Two paragraphs further down it says:

"When a uranium nucleus fissions into two daughter nuclei fragments, about 0.1 percent of the mass of the uranium nucleus appears as the fission energy of ~200 MeV. "

What does the second sentence mean? I can read it that each nuclei release 200 MeV but that can´t be correct. What is the original text wanting to say and is there a better way to reframe it? Is that entire paragraph even correct? Keleyr (talk) 18:39, 22 April 2023 (UTC)

Without looking it up, it sounds about right, since 235 x 0.9 = 211.5 Hawkeye7 (discuss) 20:15, 22 April 2023 (UTC)

I haven't thought about this in so much detail. Should the energy release be linear in nuclide mass? Gah4 (talk) 23:09, 1 July 2024 (UTC)

Lise Meitner

Lise Meitner is perhaps the most outstanding physicist not to have obtained a Nobel Prize. She is widely recognized as the codiscoverer of nuclear fission with Otto Hahn. Only Hahn received the Nobel for the discovery. Probably the biggest travesty in the history of science. 206.146.91.223 (talk) 02:21, 23 July 2023 (UTC)

Factual error

"Nuclear fission was discovered on 19 December 1938 in Berlin by German chemists Otto Hahn and Fritz Strassmann." This is an incorrect statement, even though, for obvious reasons, it has been widely accepted.

Based on the chronology of the published works and the work methodology, the order of priority of the discovery of fission, which has been officially established, is as follows: Fermi, I. Joliot-Curie and P. Savić, Hahn and Strassman, and that corresponds to the facts. In the Palace of Discovery in Paris, on the panel where the history of the discovery of fission is displayed, the order was later changed: Fermi, Hahn-Strassmann, I. J. Curie and P. Savić, which does not agree with either the chronology or Hahn's letter to F. Jolie.

That the credit for the discovery of nuclear fission belongs to Irène Curie and Pavle Savić is also confirmed by the fact that at the beginning of the same year, 1939, they were nominated for the Nobel Prize.

In the third paper by Curie and Savić, published in the fall of 1938, they showed that "uranium under neutron bombardment was converted into an element similar to lanthanum."

At the end of that same year, Hahn sent a letter to Frédéric Joly asking him to influence his wife and Savić so that they would retract their results, because otherwise the professional public will have to point out that they are in error. So Hahn was actually convinced at first that they were wrong.

(This will not help rectify this intentional injustice, but here it is for the record anyway.) 85.165.131.21 (talk) 09:58, 1 October 2023 (UTC)

The statement is correct. Like Fermi, Curie bombarded uranium with neutrons but believed that a heavier element had been created. Hawkeye7 (discuss) 11:24, 1 October 2023 (UTC)

It is accepted as correct, but incorrect otherwise, as the order is deliberately changed. Hahn and Strassmann' work is based on Curie and Savić discoveries, not the other way around. It is not the first or last time of such inversion. There are worse cases than that. On the other hand Wikipedis is not the place where such accepted statement can be changed.

Therefore, I added a note for those who are interested in history on the subject. Nothing else. 85.165.131.21 (talk) 15:22, 1 October 2023 (UTC)

Fermi hit uranium with neutrons, and found new radioactivity. He was expecting beta decay to produce new, transuranic elements. Maybe not surprising, he got the Nobel prize for discovering them. (And they didn't take it back, later.) So, yes, it was Hahn being sure that he found barium that made the discovery. And Meitner believing he was sure. Gah4 (talk) 23:14, 1 July 2024 (UTC)