Wednesday, September 22, 2010

The Noon Day Project - Let the Measurements begin!

See the previous post (from last March) introducing the Noon Day Project.

Today (9/22/10) is the perfect day for doing the CIESE sponsored Noon Day project measurements. Why, you ask? Well, assuming you have lots of sunshine (like I do today in White Plains, NY) it's a great way to celebrate the Fall Equinox. This activity is a recreation of the famous experiment that Eratosthenes did over 2200 years ago to determine very accurately the circumference of the earth.

Want to learn more about the experiment quickly? Watch (skip Ad) Carl Sagan's 6:42 min story about Eratosthenes's amazing discovery 2200 years ago. And it's not too late. You can still sign up for the fall, 2010 running of the project. (See current list of participants from all over the world.)

It will be done again in March, 2011. Let me know if you want a "heads up" early next year.

Noon Day Central -
Article: Ihor Charischak. In the Spirit of Eratosthenes - Measuring the Circumference of the Earth (Learning and Leading with Technology, ISTE. April, 1997) - pdf
Article: Al Rodgers. Eratosthenes in the Schools. - link

Next time: CLIME Update - Planning for the NCTM meeting in Indianapolis - April 13-16th, 2011


  1. I love solar star clocks, sidereal and solar, published by Peter Lancaster Brown, and Whitney's Star Finder ... by protractors tucked into the flap of the front/back cover.

    The awe of our universe, and how to determine cycles of our heavens appling an easy to read Chinese Remainder theorm (that aligned Chinese calendars in 1951 BCE ... within 'string of pearls' myth validated by NASA a few years ago) and a hard to read Dresden Codex version used by Mayans.

    Thanks for the heads up.

    Milo Gardner

  2. All great stuff. I love it when the math and the science blend together in such a natural way.