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Light decomposing when moving your eyes

  1. Dec 1, 2012 #1
    last night i was in a bar, and i noticed that when i moved my head fast from left to right and right to left, i could see the reflection of white light in the beer barrels decompose in three colors. why does that happen?
     
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  3. Dec 1, 2012 #2

    Drakkith

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    What were the beer barrels made out of? Glass?
     
  4. Dec 2, 2012 #3

    A.T.

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    What kind of light source was it? If white light is generated by mixing colored light pulses that have a slight time offset (like CRT color TV), such effects can occur.
     
  5. Dec 2, 2012 #4

    sophiecentaur

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    Can you repeat the experiment sober? :wink:
    Could you find the bar?

    Sorry - that was a very 'drinkist' reply.
     
  6. Dec 2, 2012 #5

    Ibix

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    I've seen the effect with a projector that produced images by flashing coloured LEDs in sequence at a mirror array. The flickering was fast enough that you saw mixed colours, but if you moved your head fast you could offset the R, G and B images on your retina slightly. This sounds similar. White LEDs don't work this way, do they?
     
  7. Dec 2, 2012 #6

    sophiecentaur

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    When the three coloured images flicker and are not produced at the same time (when they are multiplexed sequentially) and you scan in some way - either by moving your eyes or the display - then they will appear in different positions in space.
    That could explain it. It would depend upon the particular display. You could experiment by waggling a hand held mirror to stretch the effect more. Girlies often have these in their handbags so you could, perhaps borrow one next time you're there. (Original chat-up line!)
     
  8. Dec 2, 2012 #7

    haruspex

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    This effect is sometimes used intentionally. What appears to be a narrow strip of steady white light is actually a rapid sequence of consecutive multicoloured strips out of a complete picture. By scanning your eyes across the strip the original picture becomes visible. There's an example at MONA in Tasmania, and another at Mont Orgueil Castle in Jersey.
     
  9. Dec 2, 2012 #8
    Drakkith: the barrels were made of bright steel
    A.T.: there where multiple lights around, there was a projector, light bulbs, light of cars driving by the street... i would say the reflection in the beer barrels wasbeing produced by the light bulbs
    Ibix: It does indeed sound similar. But I don't think that the reflection was coming from some electronic device, I think it was just coming from the light bulbs, even though it might well be the case that I got the wrong impression. I believe white leds just produce 'pure' white light.....
    sophiecentaur: hahahah!! that would indeed be an original chat-up line!
    haruspex: yes, I understand. but i was wondering if i could decompose the reflection of an actual white light by moving my head very fast?¿
     
  10. Dec 2, 2012 #9

    haruspex

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    No. There needs to be some time separation of hues in the original light.
     
  11. Dec 3, 2012 #10
    I would like to repeat this experiment for myself. What were you drinking?

    What is "pure white light"?
     
  12. Dec 3, 2012 #11

    sophiecentaur

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    It's a new cocktail. You haven't tried it?
     
  13. Dec 20, 2012 #12

    A.T.

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    It was the projector. I observed the same thing today. Look at the lens from the side, so it doesn't blind you. Then perform some rapid eye movement. In my case it was this model:

    316W4gXQTcL._SL500_AA300_.jpg
     
    Last edited: Dec 21, 2012
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