Talk:Plum pudding model

Example of damaging false and misleading information
"Obsolete theories in physics" -- English words have meaning

A quick review of the items listed on the Wikipedia Category page of "Obsolete theories in physics," one finds more scientific models, concepts, and ideas than actual theories. These words have specific meaning. As scientific terms, those meanings are both unique and well-defined.

In this particular instance, a scientific model is not a theory, and the false categorization of this page under "obsolete theories in physics" is disingenuous, misleading and damaging to Wikipedia as an "encyclopedia" (i.e. a "reference work...providing summaries of knowledge".

1. The plum pudding model is not a theory.

2. The plum pudding model is not an obsolete model.

3. The plum pudding model is not exclusively used today in physics.

4. The plum pudding model (1904) is in fact used today in many forms, and its publication history has accelerated since at least the 1980s.

To keep this false categorization in place on a commonly used platform of scientific information by everyday people, is an example of intentional disinformation.

Looking through the edits history, the last two contributors to reinstate the false categorization of this page had these remarks to substantiate their edits:

"The defining term here is obsolete physical thing, whether a theory, model or law" -StarryGrandma "it definitely is obsolete" - Headbomb

As I noted in my corrective edit, theories, models and scientific laws are not physical things. They are ideas, abstractions, math. The category label says nothing of obsolete physical things. And to merely state that something is obsolete as reason for an edit is disingenuous and intentionally misleading. A colleague had similarly removed this categorization some time ago. As a source widely cited by everyday users, Wikipedia is not a place for false information.

Words have meaning. Incorrectly used and placed on a platform such as Wikipedia only contributes to a growing culture of disinformation that damages the integrity of the online community. Wikipedia is a platform for science communicators. if science communicators place false information here, it leads to confusion and damages the integrity of scientific knowledge. We have more than enough growing problems with conspiracy theories, and other pseudoscience gibberish in the real world to contend with that even "little" things like this can have significant consequences.

Let's look at some definitions relevant to this page and its incorrect categorization. (In fact, most items on the category page shouldn't be listed there)

Definition obsolete | no longer produced or used; out of date.

The plum pudding model is the direct orgin of the Thomson problem, which is a benchmark computational problem for every reputable electromagnetics simulation package/app today. It is certainly used today and not out of date. The plum pudding model is definitely not obsolete.

Definition: theory | a set of principles on which the practice of an activity is based.

The Thomson problem is premised on the set of principles of the plum pudidng model and is practiced today. In fact, most literature on the subject has been produced from the mid 1980s through today with applications including golf ball design, geodesic dome design, fullerenes modeling, spherical virus modeling, global weather modeling, and atomic phenomena. The plum pudding model doesn't fit the definition of a theory.

Definition Italicmodel (science) | a physical and/or mathematical and/or conceptual representation of a system of ideas, events or processes

The plum pudding model was proposed as a conceptual representation of atomic structure and a framework in which the periodic table of elements could be better understood in the early 20th century. Thomson's own related later work in the 1920s, alongside the work of chemists Lewis and Langmuir for example, led to many foundational principles in chemistry including the octet rule and covalent bonding. These principles are used today. As a model, the plum pudding model is certainly not obsolete as it is the premise of numerous fundamental principles in physics, chemistry and biology -- not just physics.

This page should not be categorized in "obsolete theories in physics" ...and the list on the category page should be reviewed with an eye toward scientific and informational integrity.

. TJ LaFave (talk) 21:05, 8 February 2023 (UTC)


 * has been edit warring  to keep this uncited category. He's argued elsewhere that this categorization is patently obvious, but the burden is on  to provide reliable sources.      &mdash;&hairsp; Freoh 12:54, 9 February 2023 (UTC)
 * It is cited. See Refs 24, 25 amongst others. And quite frankly, if you don't know that the plum pudding model is obsolete, you have no business editing this article. &#32; Headbomb {t · c · p · b} 13:23, 9 February 2023 (UTC)
 * It's as obsolete as a model of the atom can get. It has been outdated since the discovery of the nucleus. It has been further outdated since the discovery of quantum mechanics. The Thomson problem is a question that arose from it and has been studied for other reasons, but that doesn't make the plum pudding model anything other than an obsolete model of the atom. XOR&#39;easter (talk) 14:17, 9 February 2023 (UTC)
 * For analogy: somebody figured out how to draw Homer Simpson with epicycles, but epicycles are still an obsolete way of understanding the solar system. XOR&#39;easter (talk) 14:20, 9 February 2023 (UTC)
 * The analogy to epicycles is without merit here even with an assumption that my intent is to use the Thomson problem as a stand-in for the plum pudding model.
 * Models ≠ theories. Scientific and grammatical fact. The category does not apply here. Categories about chickens do not apply to oranges. 2 + 2 ≠ 5. Certainly not if we're being serious, professional, or sane. TJ LaFave (talk) 21:09, 24 March 2023 (UTC)
 * I'm a little bemused by the intensity of this challenge. Though the article may be a bit inaccurate in describing Thomson's corpuscular theory of matter, challenging the category makes no sense.  —Quondum 23:09, 9 February 2023 (UTC)
 * @Tjlafave, you appear to be the author of the paper "Correspondences between the classical electrostatic Thomson problem and atomic electronic structure". By categorizing this atomic model as obsolete we are not saying the Thomson problem is obsolete, or that papers on it are not valuable. StarryGrandma (talk) 19:20, 13 February 2023 (UTC)
 * This isn't about whether or not the Thomson problem is obsolete nor whether papers about it are of any value.
 * In as plain English as possible, the "plum pudding model" is not a "scientific theory." Categorizing the "plum pudding model" as a "theory" is scientifically and grammatically incorrect. Further categorizing the "plum pudding model" as "obsolete" is both disingenuous and scientifically incorrect for a variety of reasons I gave earlier and many more that have impacts in many branches of science.
 * Ipso facto, by multiple metrics, categorizing the Wikipedia page on the "plum pudding model" as an "obsolete theory(ies) in physics" is a error. Continuing to reinstate that error is intentional disinformation.
 * 2+2 does not equal 5. Stating this on a mathematics page would be intentional disinformation.
 * At least half of the linked pages from the category page in question are errors. TJ LaFave (talk) 20:54, 24 March 2023 (UTC)
 * , it seems that there is widespread disagreement over the precise criteria for inclusion in Category:Obsolete scientific theories. This was also an issue at . I do not have strong opinions about what the inclusion criteria should be, but I think that Category:Obsolete scientific theories should document them clearly and precisely. It would probably make sense for you to open an RfC at Category talk:Obsolete scientific theories, and I could help you with that process if you are interested. &emsp;&mdash;&hairsp; Freoh 02:01, 26 March 2023 (UTC)
 * "the "plum pudding model" is not a "scientific theory."
 * Not anymore no. At the time, however, it was so. Now it's obsolete, and no one uses it to describe the atom anymore. &#32; Headbomb {t · c · p · b} 01:57, 6 April 2023 (UTC)
 * I am also surprised at the heat of the initial query in this thread. I think it is misplaced. The plum pudding model is clearly a scientific theory, and it is clearly obsolete. I say these things with at least some authority, as I am a retired professor of history of science who specialized over my 40+ year career in the close study of theories in the physical sciences of the 19th and 20th centuries, particularly atomic theory. The definitions given at the top of the thread are deficient. Throughout the history of science, models can definitely fulfill the definition of theories. In fact, the definition given above of a model can also serve as an excellent definition of a theory: "a physical and/or mathematical and/or conceptual representation of a system of ideas, events or processes"; we speak (for instance) of the geocentric or heliocentric model of the solar system. The plum pudding model (his theory of the composition of the atom) died with advent the Rutherford-Bohr nuclear atom, as Thomson well recognized. "Damaging"? "False"? "Misleading"? No, none of these.Ajrocke (talk) 18:17, 30 April 2024 (UTC)

My diagram
I drew this diagram of the plum pudding model based on a 1905 diagram by JJ Thomson. The electrons are arranged in a pentagonal dipyramid, equidistant from the center. Is this a good diagram or misleading? Kurzon (talk) 19:15, 28 April 2024 (UTC)


 * As a re-drawing of a historical diagram I think it is fine. I will tweak the caption. Johnjbarton (talk) 15:24, 29 April 2024 (UTC)
 * Should all the electrons be the same distance from the center of the sphere? I wonder if the peaks of the pyramids should be a different distance. Kurzon (talk) 08:48, 12 July 2024 (UTC)
 * The diagram looks like the ones in Thomson's paper. Johnjbarton (talk) 00:37, 13 July 2024 (UTC)
 * Have you seen one that shows multi-shell electrons? I have heard of the "Thomson problem" in mathematics but all the diagrams I find constrain the electrons to the surface of the sphere. Kurzon (talk) 06:52, 13 July 2024 (UTC)
 * I have not see such a diagram. Thomson's analysis of the multi-ring case was very limited. Above 6 electrons he finds that stability requires adding electrons in the center of the atom. Above 9 electrons the number of electrons in the center increase until at 15 he needs 15 in the center. (Recall that as more electrons are added the positive sphere also increases in strength). The electrons in the center then repel, leading to an inner ring. By this analysis he gets multi-rings. But he cannot do stability calculations on multiple rings, he's just guessing at this point.
 * Bohr later said the equivalent of "he's making stuff up". Pais notes that Thomson generally considered physical models to be stories useful for generating ideas rather than the basis of quantitative analysis. (I can something about this to the article if you think it useful). And note that the great success of Bohr's later shell model follows the idea of rings of special stability. Johnjbarton (talk) 16:25, 13 July 2024 (UTC)
 * Nobody has tried a computer simulation? Kurzon (talk) 18:20, 13 July 2024 (UTC)
 * Perhaps if we expand the section on the Thomson problem one will come up. Johnjbarton (talk) 02:25, 14 July 2024 (UTC)
 * It looks fine to me.Ajrocke (talk) 17:56, 30 April 2024 (UTC)



Overview is too long and detailed.
The Overview is too dense. I'm not even sure why it exists. Seems like what we need is "Background". The intro should be the overview. Johnjbarton (talk) 03:00, 27 June 2024 (UTC)


 * Ok I moved content out of Overview, and deleted some of it. In its place I added a Background section with four ingredients essential for the Thomson story: atomic model, electrons, radiation, and spectral lines. Thomson uses electrons to build a model of the atom, radiation to probe matter in support of his model, but ultimately fails to describe spectral lines. Johnjbarton (talk) 18:48, 27 June 2024 (UTC)

Need a section on the experimental evidence.
Thomson and his colleague Crowther published work on the scattering of beta particles by metal foils that they used to support Thomson's model. This work should be discussed. Johnjbarton (talk) 03:09, 27 June 2024 (UTC)

Development
Unfortunately at least some of content of the Development section is wrong, and now I suspect it all. It appears to be a synopsis of self-selected contributions of Thomson by date, created by reading the original papers. It's a good example of why Wikipedia prefers secondary sources.

For example the 1905 lecture was an overview of previous work, esp. a 1903 paper where the magnetic analogy was introduced based on previous work by Alfred Marshall Mayer. Johnjbarton (talk) 21:48, 27 June 2024 (UTC)


 * In my experience working on many history projects on Wikipedia, secondary sources are often unreliable. They often present a distorted summarization of what came before. That's why I use both. Kurzon (talk) 22:04, 27 June 2024 (UTC)
 * Well I agree that many pages use web sites as if they were secondary sources or sensationalized pop-science articles that aren't historical analysis. Johnjbarton (talk) 00:50, 28 June 2024 (UTC)
 * Also secondary sources might contradict each other and we end up having to pick and choose and interpret anyway . Kurzon (talk) 22:17, 27 June 2024 (UTC)

Lead sentence is inappropriate.
The lead sentence is currently This incorrectly makes "obsolete" the most significant characteristic of the Thomson model. That does not, for example, distinguish it among other articles on atomic models: or models without their own page, including Joseph Larmor's Solar System model (1897), Jean Perrin's model (1901), Hantaro Nagaoka's Saturnian model (1904), Arthur Haas's quantum model (1910), and John William Nicholson's nuclear quantum model (1912). The distinguishing feature of the Thomson model was the first use of internal structure. In addition the concept of "obsolete" is not a major point of discussion in the article as an aspect of the model, making "obsolete" a secondary point.
 * The plum pudding model is an obsolete scientific model of the atom.

I changed the first sentence to one that matches the subject, but @Kurzon changed it back. I disagree and want a sentence that describes this model more clearly. Johnjbarton (talk) 17:00, 28 June 2024 (UTC)


 * The point you want to make is just a few sentences further. It's ok. Kurzon (talk) 17:01, 28 June 2024 (UTC)
 * I disagree. If a later sentence is adequate for the most important characteristic of the model (being the first with internal structure), then it certainly is adequate for the least important characteristic (being obsolete). Johnjbarton (talk) 17:53, 28 June 2024 (UTC)
 * I like it because it signals to students "You don't have to know any of this for the exam. You can take a nap instead of reading this if you want.". Kurzon (talk) 21:14, 28 June 2024 (UTC)
 * That's not a Wikipedia goal. Plus any student who can't figure this out is probably napping already. Johnjbarton (talk) 00:52, 29 June 2024 (UTC)
 * Alternatives include:
 * The plum pudding model was the first modern scientific model of the atom.
 * Per
 * Kragh, Helge. "Before Bohr: Theories of atomic structure 1850-1913." RePoSS: Research Publications on Science Studies 10 (2010). https://css.au.dk/fileadmin/reposs/reposs-010.pdf
 * "The atomic model developed by the famous Cavendish physicist Joseph John Thomson in the early years of the twentieth century can with some justification be called the first modern model of the atom".
 * or
 * The plum pudding model was the first scientific model of the internal structure of the atom.
 * Per
 * "J. J. Thomson's plum-pudding atomic model: The making of a scientific myth" Giora Hon, Bernard R. Goldstein 06 September 2013 https://doi.org/10.1002/andp.201300732
 * "What distinguishes Thomson's theory is his assignment of a specific inner structure to the atom as well as a set of dynamical assumptions."
 * Johnjbarton (talk) 18:27, 28 June 2024 (UTC)
 * I have incorporated these references and an additional secondary history ref in a new section called "Significance". Johnjbarton (talk) 03:50, 14 July 2024 (UTC)

Proposal for new organization of Development section.
Currently the Development section has chronological year-named subsections corresponding to some of Thomson publications or lectures. Several secondary references discuss this work as having two phases, one culminating in Thomson's 1904 paper and related lectures and a second phase triggered by his discovery that the number of electrons per atom is similar to the atomic weight ratio to hydrogen in 1906. Here is what A. Pais writes in Inward Bound: I propose an organization like: Johnjbarton (talk) 16:23, 29 June 2024 (UTC)
 * The period 1897-1913 consists of two distinct parts. In the first, it was believed that the number of electrons in the atom is large. In the second, it was realized that this number is of the order of the atomic number. This change was wrought by Thomson, in 1906.
 * Development (or Models?)
 * Polyelectron atomic model
 * Magnet analog, mechanical stability, comparison to periodic chart and chemistry.
 * Revised model
 * Discovery of the number of electrons per atom, consequences for the model.
 * Beta scattering theory and experiment.
 * First efforts to directly test atomic model. Initial success.


 * Eventually maybe. In writing history a good approach is to begin with a chronological approach, because timing is everything in history. Then as the information matures, it could perhaps be reorganized into something else. First, add the stuff you want to add with the chronological system. Kurzon (talk) 17:03, 29 June 2024 (UTC)

Removing incorrect reference.
The reference is very short. It claims The proton was not properly identified until at least 1917. Thomson's models had no protons. The reference appears in support of "as was the fact that atoms were neutral in charge". However this is not needed in the article because the reason Thomson needed positive charge was stability, not neutrality. Johnjbarton (talk) 23:23, 30 June 2024 (UTC)
 * "The electron was discovered by J. J. Thomson in 1897. The existence of protons was also known, as was the fact that atoms were neutral in charge. Since the intact atom had no net charge and the electron and proton had opposite charges, the next step after the discovery of subatomic particles was to figure out how these particles were arranged in the atom."


 * Also the ref says:
 * "In Thomson's plum pudding model of the atom, the electrons were embedded in a uniform sphere of positive charge like blueberries stuck into a muffin."
 * which is complete baloney. Johnjbarton (talk) 23:25, 30 June 2024 (UTC)

J. Arnold Crowther
One of the main protagonists in the atomic theory of 1905-1910 is James Arnold Crowther. Given so many dubiously notable biographies on Wikipedia I was surprised to discover nothing about him here. In addition to his publications on beta scattering, consider published books: His obitutary: Johnjbarton (talk) 18:02, 6 July 2024 (UTC)
 * Crowther, James Arnold. Ions, electrons, and ionizing radiations. Longmans, Green, 1924.
 * "Many have owed their first acquainance with modern physics to this excellent intermediate text, which reached its eigth and final edition in 1949, the year before Crowther's death." Heilbron, 1968, footnote on page 296.
 * Crowther, James Arnold. A manual of Physics. H. Frowde, 1919.
 * Crowther, James Arnold. Molecular Physics. J. & A. Churchill, 1923.
 * Crowther, James Arnold. The life and discoveries of Michael Faraday. Society for promoting Christian knowledge, 1920.
 * Whiddington, R. "Prof. JA Crowther." Nature 165.4202 (1950): 750-751.


 * I created a page for James Arnold Crowther. ✅ Johnjbarton (talk) 16:06, 12 July 2024 (UTC)

Thomson problem
Has anyone ever done a computer simulation of a Thomson atom with 100 or so atoms, arranged in shells like Thomson imagined? The Thomson problem solutions I found online constrain the electrons to the surface of the sphere. Kurzon (talk) 16:45, 11 July 2024 (UTC)


 * Thomson's 1906 paper discusses analytic stability of his shells in detail. Johnjbarton (talk) 16:59, 11 July 2024 (UTC)
 * I am looking for a diagram. Kurzon (talk) 08:44, 12 July 2024 (UTC)

Dalton's was the first
I don't want to be pedantic, but Dalton's model of the atom was the first. It had atomic weights, which is not much but something. Kurzon (talk) 21:44, 13 July 2024 (UTC)


 * I have previously discussed this issue under Lead_sentence_is_inappropriate. Johnjbarton (talk) 03:48, 14 July 2024 (UTC)