I would like a rigorous explanation: a theory and model which describes glass as well as iron, and see why one of them is transparent; a detailed mathematical computation or a detailed reference.

And, from this model, trivially one has to be able to calculate the intensity of the partial reflection of light from the glass as a function of its thickness.

Richard Feynman has answered a somehow popular answer to this question in his little QED book. I would like to see detailed mathematical calculations which conclude this fact from rigorous QED theory.


closed as too broad by Jon Custer, my2cts, ZeroTheHero, GiorgioP, John Rennie Mar 20 at 6:02

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Wood (cellulose) is transparent. It just has lots of surfaces. Like snow. $\endgroup$ – Pieter Mar 19 at 21:36
  • $\begingroup$ I changed wood by iron and having less information about materials I hope it does not transparent. $\endgroup$ – moshtaba Mar 19 at 21:43
  • 4
    $\begingroup$ This isn't a question. This is a work request, with significant deliverables. $\endgroup$ – J... Mar 19 at 22:31
  • 1
    $\begingroup$ @moshtaba How much do you know about QED? $\endgroup$ – GiorgioP Mar 19 at 22:41
  • 1
    $\begingroup$ The question is too broad and there is a clear lack of research. You need solid state physics, such as band theory, local density approximation, Drude model, Hubbard model. $\endgroup$ – my2cts Mar 19 at 22:45

While the theory that explains all of this is quantum mechanics, the derivations you want are not trivial at all. The examples you gave are completely different types of materials with completely different approaches being used in solid state physics to describe them via QM. You should be able to find descriptions in every good book on solid state physics.

A few hints at a better understanding of the topic: Glass is transparent in the visible part of the spectrum. However: UV light has a hard time passing glass. That's why one can't get a sunburn below glass. This means that glass is only transparent from our perspective. At the same time radio waves can easily penetrate walls that visible light cannot. So glass just happens to be transparent to us, while e.g. muscle tissue would be transparent to some hypothetical creature being sensible to x-rays. If you look at the complete spectrum, every material is transparent at some wavelengths and not at others. Using QM you can compute which material is transparent at which wavelengths.

EDIT: While QED may be more fundamental than QM, as well as somewhat more suitable b/c one has to work w/ many particle systems, the QM derivations are enough for qualitative descriptions as relativistic effects aren't of much interest here and in the non-relativistic limit QED gives QM w/ minimal substitution.


Not the answer you're looking for? Browse other questions tagged or ask your own question.