Main Event 2021

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The live broadcast of the Eratosthenes 2021 experiment was concluded with great success! Students from Greece and South Africa worked together to calculate the circumference of the Earth using simple materials and ICT technologies. The event started with an introduction by Dr Sofoklis Sotiriou, head of the RnD Department of Ellinogermaniki Agogi, Professor Matie Hoffman from the University of the Free State of South Africa and Mr James Mashapa, Senior Education Specialist in Math & Sciences.

The baton passed to students from Ellinogermaniki Agogi, who presented the Eratosthenes experiment and explained the Science and the History behind it. After that, at 12.22 (local noon in Bloemfontein) students from South Africa who participated in the event from the premises of the Naval Hill Planetarium in Bloemfontein conducted the measurement of the shadow length of a 1m long vertical stick. The measurement in the North Hemisphere was conducted at 12.31 (local noon in Pallini ) by Physicists of Ellinogermaniki Agogi , in the premises of the School Observatory, under the guidance of the students who participated from a distance due to Covid19 restrictions, while Greek students performed the measurements from their own rooftops and exchanged results with the two teams.

The measurements were announced online and were followed by a live calculation of the Earth’s circumference which can be found at the end of this page. Finally, the event was flanked with a presentation about the sun by professor Matie Hoffman (UFS) and a live solar observation from the solar telescope of Ellinogermaniki Agogi, presented by Manolis Chaniotakis (EA). In total, more than 200 students from Greece and South Africa participated in the event, performed their own calculations and filled dedicated worksheets. The enthusiasm of the participating students and professionals was high, as, despite the pandemic crisis they were given the opportunity to participate in this interactive, didactic and collaborative international experience.


You can see the replay of our event here:


Moments of the event 





Measurement in Greece and South Africa 


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Contest Winners




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


The Eratosthenes Experiment is endorsed by the European project GEOACADEMY




  • Dr. Angelos Lazoudis
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