Eratosthenes & measurement of Earth radius
According to the protocol proposed by Francisco L. Ruiz at the February 2014 meeting in Jurançon, the European partner schools of the project conducted from Monday 10th to Friday 14th in March 2014, at each geographic location, the measurements of solar shadows to perform the calculation of the Earth radius by Eratosthenes method.

The general principle is to identify the shadow length of a straight and vertical object when the sun is at its zenith, at about the same time in at least two geographic locations sufficiently distant and located on different latitudes, in order to deduce projection angles, the circumference and the radius of the Earth.

As you can see by looking at photos and video on this page, the work was done in three steps:
  1. Preparation of the equipment and the measurements; 
  2. Measurement and data record; 
  3. Exploitation and interpolation of the results.

Video presentation in French of the work done in Jurançon to take measurements of Earth's radius