Newton's idea spotted in reflected neutrons

Discussion in 'Current Events' started by obeygiant, Jan 16, 2010.

  1. obeygiant macrumors 68040

    obeygiant

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    #1
    physicsworld.com

    The whole dual nature of light as waves and particles has always fascinated me. I believe you can observe light acting as waves if you hold your hand up to a light and look between your fingers, fingers close enough but not touching, you'll see parallel lines which are wave nodes.
     
  2. Abstract macrumors Penryn

    Abstract

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  3. RedTomato macrumors 68040

    RedTomato

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    #3
    Nice find, OP. The stuff about holding your finger / thumb close together, I don't think the optical effect is due to wave/particle duality.

    You'd need a far finer slit than that. There's many fascinating optical edge effects sure, but I think they're due to other reasons.
     
  4. obeygiant thread starter macrumors 68040

    obeygiant

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    I was looking around I found a NASA article on it:

    NASA

    I just thought that if the light was acting as particles it wouldn't do that.
     
  5. RedTomato macrumors 68040

    RedTomato

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    Well explained sir. Now I'm looking between my fingers and thumb and trying to work out which of the optical effects I'm seeing are the ones you mean.

    While reading up on the double slit experiment, I also found that the interference fringes are seen even if you fire one single electron at a time, recording its location of landing on a photographic slide. The location of the next landing can't be predicted, even given previous landings, yet even with a time gap between firings, a coherent image is built up. That wasn't in the books when I was studying physics ...

    [​IMG]

    Even more oddly, it's been done with large molecules and just recently with a 1mm droplet of oil. Somehow they managed to make it interfere with itself while passing through a two slits apparatus.

    http://www.physorg.com/news78650511.html

    I won't pretend to understand that. Just have to remember that we are not actually dealing with 'waves' and 'particles' here - they're just interpretions or rationalisations of extremely, extremely strange things.
     
  6. Abstract macrumors Penryn

    Abstract

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    WhatEhat you guys are talking about is pretty much correct. To make it even more interesting, take a strand of hair and somehow straighten it out while it's in the air. This is easy to do with your fingers, but don't use them. If possible, ask someone else to hold it.

    Next, take a red laser pointer and shine it at the hair. Do it in a dark room, and against a white wall so that the red laser has somehing clear to hit.

    Using the power of Google, do a search for an experiment of this type. There should be much better instructions for his experiment there, but he point is that by measuring the space between points in the pattern, and relating this spacing with those of other small things/particles of known size, you can actually figure out how thick your hair is. :)
     

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