Erathosten experiment and solar eclips with students from PG po KTS, Pravets, Bulgaria. We used gnomon 100 cm, lenth of shadow was 92,6 cm and we calculated Circumference of the Earth 40 266,80 km. You can find my presentation about Erathosten experiment here:
http://www.vishub.org/excursions/1571
More information about Eratosthen experiment here: http://eratosthenes.ea.gr/en/node/98/done?sid=1138
