March 21st, 2017 : The Eratosthenes experiment
How to measure the circumference of the Earth?

Suscribe the experiment on http://eratosthenes.ea.gr/
and watch this video to have mathematical explanations !
That's great ! Thanks to Gordana for this nice idea !
CROATIA
21st March 2017 - by the way it is an International Day of Persons with Down Syndrome
(that's why we have the picture with different socks)
Weather ... excellent and sunny
Latitude: 45.339537 / Longitude: 16.9727611
Solar noon: 11.59 h (GMT+1)
Stick length = 100cm / Stick's shadow length = 100cm --> angle = 45°
Distance from the Equator = 5037.53km
Circumference of the Earth = 40 300.24 km

We have also cooperated with school from Wroclaw/Poland (teacher: Anna Bukiewicz-Szul) and here are their results:
Latitude: 51.11 / Longitude: 17.013
Stick length = 100cm / Stick's shadow length = 123.3 cm --> angle = 50.95°
Distance between two schools: 642.63km
Circumference of the Earth = 38 881.82 km
Interesting: Spring is in the air ... there were many, many bees in the tree behind students :)
FRANCE (March 21 st, 2017)
The french students participated in this experiment too.
We were very lucky : the sun appeared 10 minutes only before we started our measurements, and it disappeared 10 minutes after we finished !!!
Here is a video about this adventure !
ROMANIA

TURKEY
