Compton scattering contributes to color in any way?

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Discussion Overview

The discussion centers around the relationship between Compton scattering and the colors of substances, exploring whether Compton scattering contributes to the observed colors of materials. Participants examine the mechanisms behind color perception, including atomic energy transitions and the role of scattering processes.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • One participant questions if Compton scattering is responsible for the different colors of substances, suggesting that higher energy electrons might affect photon wavelength differently than lower energy electrons.
  • Another participant argues against the idea, pointing to the Compton formula and questioning the relevance of the substance in determining color.
  • A participant seeks to understand the atomic differences that cause substances to reflect different colors, suggesting that energy level transitions in atomic structures determine the emitted photon frequency.
  • Some participants note that Compton scattering involves "free" electrons and may not directly relate to color, with one suggesting that absorption processes are more relevant to color perception.
  • There is mention of the effective mass of electrons in the context of Compton scattering, with a request for clarification on its significance.
  • Another participant introduces the idea of different mechanisms of Compton scattering and their potential relationship to color, mentioning the photoelectric effect and pair production as related phenomena.
  • One participant expresses interest in the concept of energy-mass equivalence, reflecting on the implications of pair production.
  • A later reply references previous discussions about mass and energy, suggesting that the concept of "pure" energy is misleading.

Areas of Agreement / Disagreement

Participants express differing views on the role of Compton scattering in color perception, with no consensus reached on whether it contributes to the colors of substances. Some participants emphasize the importance of absorption and atomic transitions, while others explore the nuances of scattering processes.

Contextual Notes

The discussion includes various assumptions about the mechanisms of scattering and absorption, as well as the definitions of energy and mass, which remain unresolved.

Charlie G
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Is compton scattering the reason why different substance have different colors?

I was thinking along the lines of substanes with higher energy electrons around the atom wouldn't cause too much of a change in the photons wavelength and atoms with lower energy electrons will absorb more energy and would cause a more dramatic increase in wavelength.

I have thought of flaws in my thinking like why when shine a blue light on something the light doesn't comes back to my eyes green, which I have never known to happen. But I was really just wanting to know if Compton scattering contributes to color in any way? Most definitions only seem to talk of gamma quanta and x-rays, so maybe the effect only happens with such high energy photons so we could never see it with our own eyes, but I'm just curious.
 
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Charlie G said:
Is compton scattering the reason why different substance have different colors?

No. A quick proof: look at the Compton formula. Does the substance where you get the electron enter into it? If not, how can this determine the color?
 
Yea good point, but could anyone tell me why one substance reflects blue light while the next one reflects green, what's the difference between two substances at the atomic level that causes them to be different colors?
 
Charlie G said:
Yea good point, but could anyone tell me why one substance reflects blue light while the next one reflects green, what's the difference between two substances at the atomic level that causes them to be different colors?

It is the transitions between energy levels within the atomic electron structure that determine the energy (frequency - color) of the emitted photons.

Compton scattering is scattering by "free" electrons.
 
Oh I see, thanks for the reply mathman.
 
Vanadium 50 said:
No. A quick proof: look at the Compton formula. Does the substance where you get the electron enter into it? If not, how can this determine the color?
That's not a very good reason, since Compton scattering does depend on the effective mass of the electron.

Perhaps a better one is something like: red objects illuminated by blue light appear black (indicating the relevant process is absorption rather than colour shifting).
 
cesiumfrog said:
That's not a very good reason, since Compton scattering does depend on the effective mass of the electron.
Can you clarify this? What/how much is effective mass in this case?
Thanks.
 
Charlie...good question, not an obvious answer...some errors in posts above..
Suggest you read Compton scattering and Color via Wikipedia for an introduction...
color and selected types of Compton scattering do seem related.

Because there are different "Compton ccattering" mechanisms you probably want to specify what you mean...here is one qualification as an example:

If the photon is of lower energy, but still has sufficient energy (in general a few eV, right around the energy of visible light), it can eject an electron from its host atom entirely (a process known as the photoelectric effect), instead of undergoing Compton scattering. Higher energy photons (~MeV) may be able to bombard the nucleus and cause an electron and a positron to be formed, a process called pair production


and
Compton scattering is of prime importance to radiobiology, as it happens to be the most probable interaction of high energy X rays with atomic nuclei ...Compton scattering is an important effect in gamma spectroscopy which gives rise to the Compton edge...

http://en.wikipedia.org/wiki/Compton_scattering#Compton_scattering
 
Thx for the reply Naty1. The pair production sounds really interesting, I think its really cool to find situations where energy becomes matter, rather than matter becoming energy. It really emphasizes energy-mass equivalence. Though its also kind of disturbing, ever since learning of energy-mass equivalence, my entire concept of mass is now blurred. But that's what makes physics so interesting:)
 
  • #10
Well, we had some major discussion last month regarding mass/energy. And also in this quite new thread:

https://www.physicsforums.com/showthread.php?t=289508

The results of these discussions is that there are no such thing as "pure" energy, hence talking about "mass becoming energy" is inaccurate :-)
 

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