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Thread: Calculating pi (π), your own way

  1. #1 Calculating pi (π), your own way 
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    How would do you for calculate pi, using the physic?


    -Just physic! Of course, the metrology is included.

    -The experiment should be feasible.

    -We must think of accuracy.

    -Be creative!


    It's a good pastime...


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  3. #2  
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    First idea:

    In a circular glass chamber sealed placed horizontally, about 10 'diameter, placed an emitter of radiation like a laser on a mechanical arm that allows it to rotate 360 degrees. The camera there will be a gas. The gas is ionized by releasing radiation as we increase radio. The laser ionizes with less intensity as the radio range is larger. We just need measures the intensity of the light, and define an intensity basis and mark the points at which we find that intensity, making a circle. For measurements, we can use a very small photovoltaic sensor, about the size of a LED.

    To make the marks, we have a small circular stamp with ink, measure the diameter, and to close the circle, count the number of marks made and multiplied by diameter. Another idea is to use a high definition camera that can photograph the circle, put it into a program and calculate the circumference of this circle (here stepped it infeasible). The result is to divide the circumference of the average diameter, and you get pi.


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  4. #3  
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    How do you make sure al these circles are perfectly circular?

    You can just take a CD, put a tiny mark on the edge and roll it on a flat surface, making marks each time the mark hits the surface. Measure the distance between the marks and take the average, then measure the diameter of the CD with a optical measurement microscope. You should be able to get within 5 Ám accuracy on both the diameter and the circumference. On a 12 cm diameter CD, that's an error of less than 0.0001
    If you don't have an optical measurement microscope, you could try putting the CD on a projector to magnify it, calibrate the projector and measure on a big screen with an accuracy of about one mm, which could yield an accuracy of 0.005 on a two meter screen.
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  5. #4  
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    If you don't have an optical measurement microscope, you could try putting the CD on a projector to magnify it, calibrate the projector and measure on a big screen with an accuracy of about one mm, which could yield an accuracy of 0.005 on a two meter screen.
    A good idea.

    But about pi, how do you control the contact between marks, for measure circumference? It should be constant, isn't? Are you using CD's burned marks?
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