# [IAEP] [NaturalMath] KIds from around the world measuring the Circumference of the Earth

Steve Thomas sthomas1 at gosargon.com
Thu Sep 29 00:40:06 EDT 2011

```Here is a link to Alan's talk, his reference to Eratostenes starts at around
51:50.

Alan, do you still have a copy of the presentation?

Stephen

On Thu, Sep 29, 2011 at 12:18 AM, Alan Kay <alan.nemo at yahoo.com> wrote:

> But consider a flat Earth and a low small sun directly over the well. This
> will yield exactly Eratosthenes' result. The key here, which I've never seen
> mentioned in any books for children, is that the Greeks had to have a very
> good set of reasons for thinking the Earth round and the sun large enough
> and far enough away (and they did).
>
> I gave a talk on how they did this in the Kyoto Prize lecture followups in
> San Diego in 2005. Aristarchus was one of several key figures.
>
> The shame of it is that for both math and science learning, the important
> heuristic of trying to identify all the possible cases for a result is never
> Eratosthenes.
>
> Cheers,
>
> Alan
>
> ------------------------------
> *From:* Steve Thomas <sthomas1 at gosargon.com>
> *To:* naturalmath at googlegroups.com; iaep <iaep at lists.sugarlabs.org>;
> squeakland <squeakland at squeakland.org>
> *Sent:* Wednesday, September 28, 2011 9:06 PM
> *Subject:* [NaturalMath] KIds from around the world measuring the
> Circumference of the Earth
>
> The Goal of the Noon Day Project <http://ciese.org/curriculum/noonday/> is
> to have students measure the circumference of the earth using a method that
> was first used by Eratosthenes over 2000 years ago.
>  Students at various sites around the world will measure shadows cast by a
> meter stick and compare their results.
> From this data students will be able to calculate the circumference of the
>
> Watch the Carl Sagan video, <http://youtu.be/0JHEqBLG650> its a treat.
>
> Thanks to Ihor Charischak for pointing this out.
>
> Stephen
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