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Double slit experiment for school

  1. Dec 15, 2013 #1
    I have to do an experiment for my physics class and I was thinking of doing the double slit experiment. Ideally I'd like to do the single photon version if its possible but I realize that's probably too ambitious. If I used neutral density filters to reduce the output from a laser pointer how would I detect the photons? Would it be possible to use a digital camera? Also since I have to do this in my physics class another problem is getting the room dark enough. Could I use a box and cover any openings or would it not be big enough? Thanks for any help.
  2. jcsd
  3. Dec 15, 2013 #2

    Simon Bridge

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    Welcome to PF;
    single-photon experiments will be beyond your means - even if you could afford the equipment (no - a digital camera is not sensitive enough, you can't just put a box over it etc) a typical experiment takes more than an hour to run so you cannot do it in just one class.

    Why not do a normal diffraction experiment?
    You can use a known width slit to get the wavelength of the light from the laser pointer and then use the pointer to find the width of a single hair.
  4. Dec 16, 2013 #3


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    Would you really expect a class of School kids to catch onto the intricacies of the statistics of single photon behaviour? Just catching onto the basics of how path difference affects the resulting vector addition of waves is quite enough. Believe me, I have spent a to of one-to-one time with A-level students, trying to get them to make sense of this and to be able to reproduce the derivation of the simple formulae for where you find the fringe max and mins.

    How would you imagine that you could detect these single photons, in any case, and how long would you have for the experiment? A lesson in School is unlikely to last more than two hours. This is one of those situations where, if you have to ask about basic practical details, (as you have done,) then you can't rely having enough experimental knowledge or equipment to do the work.
    Set up a convincing Young's Fringes demonstration and you will impress the class. Try any more and you will lose them. If you really want to relate this to photons then look around for a simulation app on the web,
  5. Dec 16, 2013 #4
    I figured it would be much too advanced for me. I guess i'll just show the interference pattern then. Thanks for your help.
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