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Physics window experiment,please comment

  1. Jun 13, 2006 #1
    I have an idea for a physics demonstration, but i am unsure if it will work. Here it is.

    Aim: To change the refractive index of a small model window using electricity.

    Materials: 25g KPD (Kerr Medium) watered down and inserted between 2 glass panels.
    Electrodes placed above and below panels powered by upto 9V Car battery

    Diagram: See Website http://www.geocities.com/ctrl_alt_sam/HomePage.html?1148196883437

    I hope to beable to change the refractive index which should distort the light through the 16x8cm Window
    Please Tell me if you have spotted any problems or any suggestions that would make this experiment a success(As it is quite an expensive experiment, it would be ashame for it not to work)
    Thanks For your Suggestions
  2. jcsd
  3. Jun 13, 2006 #2


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    I'm afraid that I've never heard of KPD. The first 7 pages of Googling, in fact, turned up only one reference, which is an article that you have to pay for. There was one other possible hit, but it wasn't in English.
    My main concern here is that you'll need a voltage regulator; there aren't any 9V car batteries. Standard is 12V (charged at 13.5), and you might be able to find an old 6V one kicking around since VW used them in their older models. Do you really need that much current, though?
    If your proposal is all that expensive, could you not perhaps do your demonstration using a pre-fab LCD display?
  4. Jun 14, 2006 #3
    Sorry, Please Don't hate me, It's a typo it's actually KDP (not kurdish democratic party) Potassium dihydrogenphosphate

    I'm also unsure about the voltage I said car battery as it could supply a bit more energy
  5. Jun 14, 2006 #4


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    Believe me, buddy... nobody around here is ever going to hate you for a typo. Everybody makes them; it just has a bit more significance in an acronym. Anyhow, I got a lot more hits with the revised version. Unfortunately, I don't really have time to read through them, and probably wouldn't understand much about it anyway. The one that I looked at a bit (part of a Masters degree qualification) referred to KDP as a magneto-optical medium as opposed to an electro-optical one, but I don't know if it's important or not.
    Still, all being said and done, I'd recommend using a variable power supply rather than a battery. If there's any possibility of accident, stick an isolation transformer into the circuit to keep house juice from coming into direct contact with the setup.
  6. Jun 15, 2006 #5
    Thanks for your help, I guess there's no harm in trying both the KDP and the LCD, hopefully it will work
  7. Jun 15, 2006 #6


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    Good luck with it. Keep us posted.
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