Here is a link to Alan's talk, his reference to Eratostenes starts at around 51:50.<div><br></div><div>Alan, do you still have a copy of the presentation?</div><div><br></div><div>Stephen<br><div><br><div class="gmail_quote">
On Thu, Sep 29, 2011 at 12:18 AM, Alan Kay <span dir="ltr"><<a href="mailto:alan.nemo@yahoo.com">alan.nemo@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div><div style="color:#000;background-color:#fff;font-family:times new roman, new york, times, serif;font-size:14pt"><div><span>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).</span></div>
<div><br><span></span></div><div><span>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.</span></div><div><br><span></span></div><div>
<span>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 encountered by the children (or most adults) who have read about
Eratosthenes.</span></div><div><br><span></span></div><div><span>Cheers,</span></div><div><br><span></span></div><div><span>Alan<br></span></div><div><br><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px">
<div style="font-family:times new roman, new york, times, serif;font-size:14pt"><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><font face="Arial" size="2"><hr size="1"><b><span style="font-weight:bold">From:</span></b> Steve Thomas <<a href="mailto:sthomas1@gosargon.com" target="_blank">sthomas1@gosargon.com</a>><br>
<b><span style="font-weight:bold">To:</span></b> <a href="mailto:naturalmath@googlegroups.com" target="_blank">naturalmath@googlegroups.com</a>; iaep <<a href="mailto:iaep@lists.sugarlabs.org" target="_blank">iaep@lists.sugarlabs.org</a>>; squeakland <<a href="mailto:squeakland@squeakland.org" target="_blank">squeakland@squeakland.org</a>><br>
<b><span style="font-weight:bold">Sent:</span></b> Wednesday, September 28, 2011 9:06 PM<br><b><span style="font-weight:bold">Subject:</span></b> [NaturalMath] KIds from around the world measuring the Circumference of the
Earth<br></font><br><div><div><div></div><div class="h5"><span style="font-family:Times;font-size:medium"><div style="border-bottom-width:0px;border-color:initial;border-left-width:0px;border-right-width:0px;border-top-width:0px;font-family:inherit;font-size:12px;font-style:inherit;margin-bottom:1.5em;padding-bottom:0px;padding-left:0px;padding-right:0px;padding-top:0px;vertical-align:baseline">
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px">The <a rel="nofollow" href="http://ciese.org/curriculum/noonday/" target="_blank">Goal of the Noon Day Project</a> is to have students measure the circumference of the earth using a method that was first used by Eratosthenes over 2000 years ago.</div>
</div><div style="border-bottom-width:0px;border-color:initial;border-left-width:0px;border-right-width:0px;border-top-width:0px;font-family:inherit;font-size:12px;font-style:inherit;margin-bottom:1.5em;padding-bottom:0px;padding-left:0px;padding-right:0px;padding-top:0px;vertical-align:baseline">
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px">Students at various sites around the world will measure shadows cast by a meter stick and compare their results.</div></div><div style="border-bottom-width:0px;border-color:initial;border-left-width:0px;border-right-width:0px;border-top-width:0px;font-family:inherit;font-size:12px;font-style:inherit;margin-bottom:1.5em;padding-bottom:0px;padding-left:0px;padding-right:0px;padding-top:0px;vertical-align:baseline">
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px">From this data students will be able to calculate the circumference of the earth. <a rel="nofollow" href="http://ciese.org/curriculum/noonday/" target="_blank">Click here to get to their site and register.</a></div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px">Watch the <a rel="nofollow" href="http://youtu.be/0JHEqBLG650" target="_blank">Carl Sagan video,</a> its a treat.</div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px">Thanks to Ihor Charischak for pointing this out.</div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><br></div><div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px">Stephen</div></div></span></div></div>
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