Pedagogical simplification is a tricky subject. Wikipedia's take on it is here. The last two or three paragraphs before "See also" are provocative. Nuclear

Pedagogical simplification is a tricky subject. Wikipedia's take on it is here. The last two or three paragraphs before "See also" are provocative. Nuclear physics are enormously complicated and the simplified picture usually presented of the Standard Model (in charts showing 3-quark particles) is a compromise between getting across the idea of a composite particle like a proton and digging into why a proton is an extremely messy thing filled with pions and gluons. The latter is where the symmetry groups of the Standard Model lead you, and down that path lies enormous many-body problems. Those are almost always irrelevant at the scale of chemistry, nuclear engineering, or even most of astrophysics, where the simplification is good enough. Indeed, most of the time quarks and gluons don't even arise in the solutions to problems in those fields. Additionally, at that scale one starts running into some problems in the Standard Model which are essentially irrelevant in useful effective field theories, and which are simply not well enough understood by working scientists in the field to boil down to something useful for teaching except at the graduate level. (Well, as long as you believe in the principle that to explain something to a child, or even an adult non-specialist, you have to understand it extremely well or sacrifice accuracy.) https://en.wikipedia.org/wiki/Lie-to-children https://en.wikipedia.org/wiki/Lie-to-children