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Note the Wikipedia article for 'Atomic nucleus' was awkward here because first they depict the old concept with protons and neutrons as a bunch of spheres touching each other and in the sub-text explain how it’s outdated, which is fine for the historical context...but then further below in the "Nuclear makeup" section they depict a modern conceptual visualization of the electron cloud wave function, but still depict the protons and neutrons as separate spherical bodies (albeit each now a cloud gradient body, but still as distinct spheres touching each other). And again, the written sub-text is an explanation of how the visualization is not at all correct...why not just actually visually depict as correct as possible since they are able to do that for electrons?

So, wondering if this is just a weakness of the Wikpedia articles, or if it extends to a deeper matter. Such as, on the one hand, claiming the categorial distinction of protons and neutrons as separate particles as the main defining paradigm for understanding an atomic nucleus to begin with, yet on the other hand having no clear way to visually depict them as distinct wave/probability distributions in a visual spatial depiction of an atomic nucleus.

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  • $\begingroup$ I don't think this answers your question but you can read about the Nuclear Shell Model and it's similarities to the electron orbitals. Don't know about visualization though. $\endgroup$
    – Triatticus
    Commented Nov 14, 2023 at 18:03
  • $\begingroup$ It's not possible to visualize psi function for two or more particles. All visualizations of multidimensional functions ($d>3$) are a simplification/distortion of the actual thing, and are thus incorrect. $\endgroup$ Commented Nov 14, 2023 at 22:45
  • $\begingroup$ What can be visualized is probability density in 3D space. But this is a representation of one aspect of the psi function, namely probability of finding any particle at certain point of space; it is not the psi function itself, which is much more rich and complicated. $\endgroup$ Commented Nov 14, 2023 at 22:54

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I can't speak for Wikipedia, but this is the usual way of representing the atomic nucleus in all nuclear physics books.

I think the main reason is the energies involved. The typical energy used in nuclear physics is around ten MeV per nucleon. At these energies, nucleons effectively behave like spheres (more or less rigid). Models such as the nuclear shell model or the liquid drop model consider nucleons as spheres.

It is only when the energy increases that the nucleons will exhibit their 'cloudy' nature by revealing their internal structure.

If we keep the analogy with atomic physics, if we are only interested in chemistry for example, then atoms appear as spheres; the nucleus and the electron cloud form a single object.

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