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contact Ihor

Dear Noon Day participants,

Welcome to the Fall, 2006 version of the Noon Observation Day Collaborative Project. 

In the course of the next four weeks your students will:

  1. learn about Eratosthenes and his amazing measurement of the circumference of the earth,
  2. do a similar experiment by collaborating with another school or schools and
  3. analyze and reflect on the data collected to see how correct your measurements are and what you learned from this project.
There are a variety of ways you can approach this project depending on the amount of time you have available and the level of your students. What I've done is outline one possible scenario that would give you some ideas about how you might proceed. Feel free to do whatever is comfortable for you. The only requirements we have is that you observe these deadlines.

1. Register for the Project by September 8th.

2. Include your location on our guest map.

Free Guestmap from 

2. September 6th - Project Begins! Write the Class Letter of Introduction and submit it to the Discussion Area by September 15th.

3. Learn about the project. Detailed Lesson Plans are located in the Teacher Guide.

3. Complete your shadow measurements by September 25th and enter your measurement data at the Project Data website that is now open.

4. Do your circumference calculations by October 2nd. See Teacher Guide for details.

5.  Write and submit a Final Report by October 13th. See instructions for final report.

If you have difficulty meeting this time line, please let me know. Also, feel free to contact me with questions and concerns as we go along. 

Week 1: September 6th - 8th
"Setting the Stage" Activities To prepare your students for the measurements that will take place, you might start off by making them more aware of shadows and the "stories they tell." For example:

Activity: Shadow Stories
Have your students look at a shadow (like the one on the right.) Have them describe what a shadow does over the course of a day (from sunrise to sunset.) Make a graph to tell the shadow's story.  

See Making a Shadow Plot in the Northern Hemisphere for details.

Related questions: 
When is the sun directly overhead? What happens to the length of the shadow at that time? Is there any time when the sun would be directly overhead and NOT cast a shadow?

(Please share your student's stories in the discussion area.)

Some questions to ponder

  • Do you think ancient man thought the earth was round or flat? 
  • Let's say you belonged to the "Flat Earth Society." What arguments would you make for the earth being flat? 
  • What arguments would you give if you were a member of the "Earth is Round" Club? 

  • Interesting sidebar: One of the myths that James Loewen debunked in his book "Lies my Teacher Told Me - Everything Your American History Textbook got Wrong" (p. 45-48) is that most people at the time of Columbus' voyages thought the earth was flat. Columbus was not so daring, nor did his crew want to mutiny because they feared they would drop off the edge of the earth. The truth is that most people around 1492 believed the earth was round. Historians give credit to Washington Irving's biography of Columbus in 1828 for starting the myth. He had an account of how Columbus had to convince his investors of the spherical nature of the earth. Pure fiction.

Week 2: September 11th - 15th
Understanding the Math & Science: What Eratosthenes did and why the experiment worked (More about this on Friday, September 8th.)

Introducing the project to your students 
(See suggested lesson for more detail.)

Imagine that you are living over 2000 years ago and you are convinced that the earth is round. How would you go about measuring it? One way would be to start walking in one direction and keep track of how far you go. If the earth is round as you believe, eventually you should return to where you started. Do you think anyone actually contemplated trying this back then? Why or why not? What would be some of the obstacles?

Another method would be to drill a hole to the "other side" of the earth and measure the distance. Once you knew that distance, could you determine how round the earth is? Is there a relationship between the distance around a circle (circumference) and the distance through the center of the circle (diameter)? (You might try one of the activities at to see if you can discover a relationship between the circumference of a circle and its diameter.*) Unfortunately, digging a hole through the center of the earth is just as out of the question as circumnavigating the globe by foot.

This brings me to someone named Eratosthenes who was born 2000 years ago in Cyrene, a town in northern Africa. He actually found out how round the earth is by doing an experiment. His idea was to think of the earth as an orange cut in half. The cross section is divided into wedges just like pizza slices.  But I'm getting ahead of myself. Read the full story.

Week 3: September 18th - 22nd
Doing the Measurements

  • You should try to get your measurement done during this extended week. This year the Autumnal Equinox falls on September 23 at 04:02 UT. See

for details.
  • Since you need a sunny day for shadow measuring, we suggest you check your weather forecast and pick a day when you will most likely have sun. 
  • Do the measurement when the sun is highest in the sky (at your local noon time.)
Week 4: September 25th - 29th
Analyzing the Data, Determining the Circumference and reporting your results

Week 5: October 2nd - 6th
Reflections and Final Report

Other Notes

  • Much of the background for this project is included at this website. Please familiarize yourself with this material.
  • This website is a work in progress. My hope is to continue to develop a very detailed, rich project that is flexible, but at the same time captures the spirit of Eratosthenes' discovery. I will be contributing regularly to our discussion board. I hope you find that useful.
  • We encourage you to participate in this project as much as possible. We are interested in your methods, strategies, anecdotes, and wild ideas. Please share your experiences with us. What makes this project so special is that this is a collaboration. I am eager to make this project work for you as best as possible and to learn from our collective experiences so we can keep on improving it.
  • Stay tuned for daily updates. In the meantime let us know something about your class, situation, etc. by posting a letter of introduction in our discussion area. There is no right or wrong way to do this. We are all learning as we go along.
*More about "pi" can be found at
I'm very happy to have you join us on this adventure.


Ihor Charischak
Coordinator Noon Day Project

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