Tools "Project Stick"

Calculation Spreadsheet

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In this site we intend to provide the necessary tools to be able to specify the measurement of the circumference of the earth.

We share a video of students from Argentina with the explanation of the experience, offering the possibility of seeing it with subtitles.

You can get the latitude of where you live.

You can use a spreadsheet, in which the two participating schools must complete:

  • Name of participating cities
  • Latitudes expressed in decimals
  • Stick length
  • Shadow length shorter.

The spreadsheet will do the calculations and will throw the value of our calculation, including our error and the error obtained by Eratosthenes 2200 years ago.

  ΏSTICK? Ώ Measuring the Circumference of the Earth?


Stick is a collaborative project of international scope that invites students and their secondary teachers to repeat the experience of measuring the circumference of the earth as Eratosthenes did 2200 years ago, using simply a stick, a lot of imagination and a little information.


This project will be carried out with secondary school students and the main objective is to measure the perimeter of the Earth, in a similar way to that used by Eratosthenes more than two thousand two hundred years ago.

For this, each group of students and their teachers will measure the height and shadow of a stick during the solar midday of the autumn or September equinox. In the event that the sky is cloudy, it can be measured on the first clear day afterwards. Each school will share the values of their measurements by completing the spreadsheet created in Google..
This activity will allow students to know old units of longitude, the inconveniences of their use and why the convenience of using the current measures of the International System of Measurements.
In addition, make a concrete use of mathematics, put into practice experimentation as a means of obtaining information about nature and feel part of a joint project involving students from distant places.

Central Objectives
• Describe the different units of length.
• Describe the geometry of how the sun's rays strike the Earth at different latitudes.
• Describe how the perimeter of the Earth was measured for the first time thousands of years ago.
• Describe how to determine when it is midday in the place where one lives.
• Measure the angle formed by the sun's rays with the vertical in a given place at solar noon.
• Calculate the circumference of a terrestrial meridian.
• Being part of a collaborative project, in which, with the contribution of several groups, an objective can be reached (in this case, measuring the circumference of the Earth).

Collateral Objectives
• Integrate knowledge from different areas
• Know an ancient culture
• Translate information in English.
• Prepare a video to expose the experience.