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If light is waves

  1. Feb 12, 2005 #1
    :uhh: If light is a wave of photonic particles wouldn't that mean that when light hit a bolck of lead that it would compress and ultimatly nutalize it self? Due to the fact, that lead is extremly dense, so eventualy if a wave of photonic particles came incontact lead at a 180* angle that it they would eventually come into contact with some molocule and all the photonic wave particles would all bounce back and colide into the on coming photonic waves? :frown:
  2. jcsd
  3. Feb 12, 2005 #2
    I'm an engineering major so this isn't my forte and maybe my reasoning is wrong but here are my opinions on the questions you posed. This might have been a more apt question for the physics or even chemistry forums:

    If I got your question right, "if light is a wave" shouldn't photons interfere with themselves if two happened to collide? I could hardly explain why it happens in the double-slit experiment but yeah light does "neutralize" itself I guess when certain conditions are met like in the experiment mentioned above, but simply shining 2 lights at each other won't cause a lot if any visible destructive interference.

    Diamond is much more dense than lead. I think that absorption of the light depends more on the chemical makeup of the molecules inside the substance.

    Did you mean normal to the lead? (90 degrees). As far as I know, there are no macroscopic effets of light bouncing back through itself, although I've seen calculations of photon-photon collisions that appear to change the energy (and therefore color) of both. Even in substances that have the property of being transparent/translucent, photons don't miraculously go through without being touched: They're constantly being absorbed and re-emitted by molecules as they pass through.

    I'll leave it to one of the many physics gurus on this board to 1. fill in the gaps of my explanations and/or 2. tell me I'm completely wrong.
    Last edited by a moderator: Feb 12, 2005
  4. Feb 12, 2005 #3


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    I believe any engineer ought to know better... :wink: The mass volumic density of lead is roughly 11900Kg m^{-3},while for diamond approx.3500Kg m^{-3}... :rolleyes:

    No...Just look again in the density table...If you didn't do it while studying engineering.:wink:

  5. Feb 12, 2005 #4
    Alright I guess I was wrong, but maybe I should mention although I'm an engineering major I haven't actually taken any engineering courses yet (1st yr) but I suppose I shouldn't have spoken like I knew what I was talking about. I guess my argument holds just my example was crap. Thanks for pointing that out dextercioby :)
  6. Feb 13, 2005 #5
    I still don't understan why, if light is waves why doesn't it do the following
    Lead |
    Box | <<</\/\/\/\/\/\(Light waves)/\/\/\/\

    Lead |
    Box | /\/\/\(Light)/\/\/\/>>>||||<<<</\/\/\(Waves)/\/\/\/\/\/\<

    ||||=The two wave coliding into on another causng the wave to nutralize it's self by it's deflected(refleced Counter part)

    And wouldnt that say a mirror is more dense than lead (FYI: I know a mirror isn't) since it reflects the light waves exactly the same?

    If not, or if so, why?
  7. Feb 13, 2005 #6


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    "Light" ,that is EM radiation in the visible range. does not "see" lead it sees electron shells. When a photon encounters the electron shell of an atom it is either adsorbed or passes on by. Clearly, because we cannot see through it, the lead atom adsorbs photons of the visible spectrum. Once a photon is adsorbed, after a short delay, there is a photon reemtted. The frequency (color) of this photon may, or may not be the same as the adsorbed photon. The color of lead (or any material) is determined by the reemitted photons.

    The fundamental problem with your analysis is assuming that photons of light see lead as a solid block. They do not, they see electron shells and have no idea what a solid is.
  8. Feb 13, 2005 #7
    then how is it that they interact with our eyes so that we "see" light and everything wraped in it if they do not see any particles as solids?
  9. Feb 13, 2005 #8


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    They interact with the electrons in the atomic structure of your eyes. Your nervous system has developed to react to these electronic transions. Just like they do with ALL material objects.
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