The experiment of ERATOSTHENES

Put a staff to the sun, measure its shadow when the sun is at its highest point, deduce the angle of the solar rays compared with the vertical staff, then exchange your results with another class under another latitude. Then, a few geometrical drawings and a rule of three give you the length of earth's meridian.

Original videos:
David Jasmin (La Main à la Pâte): http://diffusion.ens.fr/index.php?res=conf&idconf=746
Mogi Vicentini (Planetario di Milano): http://www.mogi-vice.com/Pagine/Downloads.html

The library of ERATOSTHENES

The archives of the measurements

The schools

Collège Antonin Perbosc

Ecole Lafontaine

Rosa Magro primary school