Understanding the Speed and Behavior of Light in Different Mediums

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Discussion Overview

The discussion revolves around the behavior of light as it travels through different mediums, particularly focusing on the phenomenon of light slowing down in denser materials and then speeding up again upon exiting. Participants explore the implications of these behaviors on classical physics, particularly in relation to Newton's laws.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants question why light appears to speed up when leaving a dense medium without an external force acting on it.
  • One participant suggests that the apparent increase in velocity is due to the refraction of light, asking for examples to clarify this concept.
  • Another participant describes the behavior of photons in a medium as akin to a game of pinball, where photons are absorbed and re-emitted by atoms, affecting their average speed.
  • A different analogy compares photons to cars at stoplights, where the average speed drops due to interruptions but returns to the original speed once clear.
  • Concerns are raised about the potential for photons to be refracted in multiple directions, questioning the visibility of laser beams over long distances.
  • One participant proposes a theoretical model involving a bipartite system of a positron and electron to explain the behavior of photons in different mediums.
  • Another participant clarifies that the net velocity of light is affected by the medium, while instantaneous velocity remains constant.
  • Some participants express confusion about how light can appear to travel in a straight line through glass while still being affected by the medium.

Areas of Agreement / Disagreement

Participants express various viewpoints and analogies regarding the behavior of light in different mediums, with no consensus reached on the underlying mechanisms or implications. The discussion remains unresolved with multiple competing explanations and interpretations.

Contextual Notes

Participants note the complexity of light's behavior in mediums and the potential for misunderstandings regarding concepts like refraction and net velocity. There are also references to classical physics concepts that may not fully apply to the behavior of light.

  • #31
Hey Blacksheepdork

look what you started! the world is full of questions and answers! Boy does the physics teacher have a thing or two to learn also.
 
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  • #32
Actually, that's an interesting question, Integral.

I had been implicitly presuming the same thing; I was talking about how "easy" it is to reemit the energy in a particular direction, but kept tacit the law of large numbers which (kinda sorta) states that the net result is predominately the easiest one.


But... some of the interesting QM experiments seem to say otherwise. For instance, in the famous experiments involving half-silvered mirrors, photons are said to either be transmitted through the mirror, or to be perfectly reflected via incidence = reflection...


I guess (I think) it falls down to the fact that the photon is really the center of probability for a wave packet, so by definition it follows perfectly the expected behavior.

Hurkyl
 
  • #33
Well, in a vacuum a photon isn't following that random a path, right? Obviously, it's not following a simple angle of incidence, since it's actually a complex wavefunction, but each imaginary particle in the wavefunction I would expect reflects the way you expect it. That's how it seems to me anyway. Not that I wouldn't be interested in reading that book, but it doesn't feel to me like this entire thread is on shaky ground...'course that's me

Take care.
 

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