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Can some one tell me what it is ?

  1. Sep 12, 2014 #1
    can some one tell me what it is ?
    o8gb3a.jpg
     
  2. jcsd
  3. Sep 12, 2014 #2

    jedishrfu

    Staff: Mentor

  4. Sep 12, 2014 #3

    berkeman

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    Staff: Mentor

    Welcome to the PF.

    Do you know what it is? Where did you get the picture?
     
  5. Sep 12, 2014 #4

    sophiecentaur

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    Science Advisor
    Gold Member

    Is there any electrical resistance between the 'peg holes'?
     
  6. Sep 12, 2014 #5

    AlephZero

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    Science Advisor
    Homework Helper

    I wonder if it's an ancient visual aid for teaching trig functions. If you join the holes to the "origin" you get lots of angles with sin, cos and tan equal to ratios of small integers.

    That would explain the holes along the circular arcs at all the intersections with the lines "y = 1", "y = 2", etc.
     
  7. Sep 12, 2014 #6

    jedishrfu

    Staff: Mentor

    I think it was made by Archimedes before he made the Antikythera device.

    http://en.m.wikipedia.org/wiki/Antikythera_mechanism

    Joking aside, the center hole seems to be different from the other holes. It looks like it may be a socket for a lead and so maybe the resistance idea is right.

    Can we get a picture of the backside too? Is there any writing on it? Where did you get it? From a school or college environment?

    As an aside, we had some long lost geometry models called Olivier models that were being restored made apparently in the 1820's or later:

    intersections3asm.jpg
     
    Last edited: Sep 12, 2014
  8. Sep 12, 2014 #7
    An adaptation of this,
    July%202star.JPG
    http://nrich.maths.org/2864
     
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