We've announced the Photo Contest Winner - September 2017

Check out the winner and the finalists!


Welcome to the Eratosthenes Experiment platform!

  • Register by creating your account.
  • Come in contact with a registered school at the same longitude with you (this info will be provided to you by the organizing team)
  • Join efforts with the matching school and record your data
  • Calculate the circumference of the Earth
  • Submit your data and take part to the Eratosthenes Photo Contest March 2018

This year the experiment will take place on Wednesday the 21st of March, one day after  the spring equinox day (Tuesday, 20 March 2018, 16:15 UTC). You can perform the experiment in collaboration with another school on the same longtitude, if no other schools can be found on the same longitude -  for your matchup – you can consider the existence of a virtual school on the equator with experimental data 0 (shade of a one-meter stick measured at local noon). This way you can also have an accurate outcome by conducting the experiment by yourself. Schools that register till Monday 12th of March 12:00 CET will receive on Tuesday 13th of March an e-mail with the coordinates of potential matching schools along with the information (email) of their contact persons, so that they can communicate and arrange their match-up during the day of the experiment. Schools that register till Friday 16 of March 12:00 CET, will receive the same email during the day (after 16:00 CET). Schools that register on Friday 16th of March after 12:00 CET and  until Monday 19th of March (15:00 CET), will receive email on Tuesday morning, 20th of March.

If you would like to perform the experiment by yourself on a date other than the 21st  of March, you can use this simulator  to find the exact angle from your school to the place where the sun rays are perpendicular to the ground. 

The Eratosthenes Experiment is organised with the collaboration of the Hellenic Mathematical Society, the participation of the UNESCO regional bureau for Science and Culture in Europe, Venice (Italy) and is approved by the Department of Education in Greece.


Contest Winners





The Eratosthenes Experiment 2018 is organised with support from the European Commission in the context of the Seventh Framework Programme (FP7). This Website reflects only the views of the Ark of Inquiry consortium members, the Commission cannot be held responsible for any use that may be made of the information contained herein.



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Ark of Inquiry


  • Dr. Angelos Lazoudis
  • Phone: +30.210.8176795
  • Email: angelos@ea.gr


Ellinogermaniki Agogi
Research & Development Department
Dimitriou Panagea Street
GR 15351 Pallini