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Does this make sense

  1. Sep 26, 2011 #1
    hi there, im currently working on a photography zine, i am by no means a physicist my any stretch of the imagination, but i was reading about how particles and waves are subjective? any way i wanted to accompany a photograph with this annotation:

    "physicists suggest that all things are made of particles and waves, depending on how you see them effects how they manifest themselves. All fences are waves, walk right through them."

    but obviously before i publish this i would like to know if it makes any sense!!

    thanks in advance for your time!

  2. jcsd
  3. Sep 26, 2011 #2

    Ken G

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    Gold Member

    It sounds like you are referring to what is known as "wave-particle duality." In the days of classical physics, it was thought that motion came in two distinctly different versions, the trajectory of a particle and the propagation of a wave. These two forms we so completely different that not only did no one dream they could be unified, no one seemed to even have a desire to try. A particle had a definite location at any given time, and its motion was somehow "hidden in the particle" itself (they might have said the particle "had a momentum", perhaps in its back pocket). A wave was spatially spread out, even at a given moment, and its motion was not contained in any of its parts, but rather was a kind of sum over all the coherently interfering things that all the pieces of the wave were doing (everywhere on a wave acts like a source for the future behavior of that wave, and the behavior involves constructive and destructive interference of all those parts).

    But when light was recognized to be a particle, and we knew that light diffracted, the need to unify the wave and the particle versions of motion was thrust upon us unexpectedly. Then it was quickly recognized what we really could have figured out a long time ago-- wave mechanics and particle trajectories can be unified, the latter is just the short-wavelength limit of the former.

    So you can walk through a fence, but only in the limit of a long-wavelength fence-- you need enough space between the posts to fit through! In the short-wavelength limit, fences act like walls, and particles have trajectories.
  4. Sep 26, 2011 #3


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    Staff Emeritus
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    You and I and also fences and everything else is made up of tiny objects, or subatomic particles. When we do experiments and observe them, very often they seem to "act" like a wave. They can interfere with themselves (as in the Double Slit Experiment) and the math we use to predict how they will behave is all based on waves and wavefunctions.

    HOWEVER, they DO act like particles at the same time if that makes any sense. An electron, even though it can act like a wave, still has a negative electric charge and will repel anything else that is negative if it gets to close. The distance that this happens at is larger than the "size" of the electron, so we generally aren't able to walk through walls and fences as all these electrons in our bodies and the fences and walls repel each other if they get too close. We can use a "wavefunction" to tell the probability of where an electron will be found, however when obseved the electron is always found in one spot in this area.

    In my opinion, stating that all fences are waves and to walk right through is simply incorrect and will only spread false information.
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