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Homework Help: Easy scientific measurement

  1. Oct 7, 2008 #1
    1. The problem statement, all variables and given/known data

    The Shadow cast by a vertical pillar in Alexandria at noon during the summer solstice is found to be 1/8 the height of the pillar. The distance between Alexandria and Syene is 1/8 the Earth's radius. Is there a geometric connection between these two 1-to-8 ratios?

    2. Relevant equations

    Not sure exactly what kind of answer they are looking for here.
  2. jcsd
  3. Oct 7, 2008 #2


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    Welcome to PF!

    Hi NateTheGreat! Welcome to PF! :smile:

    You've left out that at noon during the summer solstice, the sun at Syene is directly overhead.

    (I know that 'cos this is a well-known experiment by Eratosthenes in about 200 BC :wink:)

    Does that help? :smile:
  4. Oct 7, 2008 #3
    Re: Welcome to PF!

    Ah! So then would that explain why they are both 1/8 of the Earth's radius? I'm trying to figure out what they mean by a "geometric connection"?
  5. Oct 7, 2008 #4
    Look at this flashy simulation of the experiment, it is a demo but you can see from it the basic geometry used.

    http://www.edumedia-sciences.com/a287_l2-eratosthenes-experiment.html" [Broken]
    Last edited by a moderator: May 3, 2017
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