Eratosthenes and the Measurement of the Earth's circumference

De Medición del radio de la tierra por 3º ESO Bilingüe

Last Thursday 26th March we did an experiment with our Bilingual teachers: we tried to measure the circumference of the Earth in the same way Eratosthenes did in the century II before Christ. He discovered then that the Earth was not flat.
We studied Eratosthenes's life in the English class, in Geography we learnt all the processes he followed until he calculated the radius of the Earth. In Maths we learnt some trigonometry, specifically tangents, to be able to measure the angle of the sun's shadow length. Finally, in the technology class we spent a week building a gnomon, or stick, to be able to measure the sun's shadow length every ten minutes when the sun rays were overhead.
We took the data and sent the results to an observatory centre in Barcelona.