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Help replicating Eratosthenes' experiment

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  1. Nov 27, 2017 #21

    Thanks a lot for your participation. We will use all that you mention in our work. We will be doing the experiment on the first of december at our local noon, if you think you can make it on your local noon please keep in touch.
     
  2. Nov 27, 2017 #22

    OmCheeto

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    Going through the thread from the start, it looks as though Haruspex had the best method, IMHO.

    And as I pointed out the other day, I'm 1/3 of the world away from you, in longitude. I think that would make my measurements meaningless, unless we knew how much our shadow lengths change each day. I would recommend we take measurements at least 2 days in a row.

    ps. My local weather report tells me that I might be a bad lab partner around that date. :redface:
     
  3. Nov 28, 2017 #23

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    Hi Frenchies! :)

    I may be able to do the measurement for you.
    My location is latitude 52.379189 and longitude 4.899431. If I'm not mistaken that's at a nice distance almost straight north from you girls. :cool:
     
  4. Nov 30, 2017 #24

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    Just checking, how are you gals, Maylis, Clara, and Hélèna, doing with practicing your English? :oops:
     
    Last edited: Nov 30, 2017
  5. Dec 1, 2017 #25

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    Well, turns out I just couldn't make out any shadows with the current cloud cover.
    So instead I've marked 2 spots that are 1 meter vertically apart on the wall of a building.
    Then I looked directly at the sun, which I could still make out without burning my eyes due to the thin cloud cover.
    And with my eye at the same level as the lower spot (along a seam in the wall), I aligned the sun with the higher spot.
    Measuring the distance I got 3.75 meters with an estimated accuracy of about 0.25 meters.
    I measured it at my local noon, which is 12:29.
    That's about the best I can do right now, and in the meantime the cloud cover has thickened, so that I can't make out the sun any more.
     
    Last edited: Dec 1, 2017
  6. Dec 6, 2017 #26

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    Hey Frenchies!

    Did you ever complete the experiment?
    I'm actually feeling at bit dissatisfied, since I still don't know the circumference of the earth with our measurements...
     
  7. Dec 7, 2017 #27
    Hello thank you a lot for the investissement you put into doing the experiment. We couldn't be working on our project this week. We actually did the experiment and measured the angle (wich is located up the stick) (we found approximatively 62,5 degrees), using different propreties (sinus, cosinus and pythagore) maybe we can achieve to calculate your angle and calculate the circumference of the Earth. But the main point is to prove that we do not have the same measures.

    Thank you a lot for your response
     
  8. Dec 7, 2017 #28
    Guys.. They are in the 11th grade, you're over complicating it.
     
  9. Dec 7, 2017 #29
    Using your measures we find an angle of 75 degrees, we are currently working on calculating the circumference of the Earth with our values.
     
  10. Dec 7, 2017 #30
    We found out the distance between the parallel of our city is 1400.
    75-62,5 = 12,5 degrees
    (1400x360)/12,5 = 40320km ! So there's less than 0,6% of error from the modern value of 40075km.
     
  11. Dec 7, 2017 #31

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    Good!
    Btw, I've looked up what my angle should really have been, which is 74.2 degrees.

    Shouldn't it be 931 km instead of 1400 km for the distance between our latitudes?
    My latitude is 52.37919 and yours is 44.01211.
    With an earth circumference of 40075 km that is a distance of 40075 x (52.37919 - 44.01211) / 360 = 931 km.
     
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