Eratosthenes

Arras, France

May 2007

Flag City Country School Latitude (°) +N/-S Longitude (°) +E/-W
Arras France Ecole Lafontaine 50.283 2.733
Date Gnomon Shadow Angle
May 11 100 cm 64 cm 32°37’ = 32.619°
May 25 100 cm 57 cm 29°40’ = 29.683°

2007/05/11
Really, we have been fortunate when we took these measurements! The weather was rather unfavourable, gray and cloudy, but the wind blew out gradually the clouds and let appear the sun intermittently. So, we seized these rare opportunities to take measurements of the shadow of the gnomon around solar midday, between 13:30 and 14:00. We set horizontally a wooden plan, and then perpendicularly, our gnomon. In that way, it was vertical. Then we noted precisely, the end of the shadow of the gnomon. Every 5 minutes, we measured the size of the shadow . When the weather was more favorable, the frequency of our measurements was shorter, in order to find the exact solar noon. That is simple: it occurs when the shadow ceases to decrease and when it starts to increase. The sun then reaches its highest point in the sky (zenith) and it is solar noon. Rémy - Mathilde - Antoine - Gaëlle.

2007/05/25



Home page | Contact | Site Map | | Statistics | visits: 3500

Site created with SPIP 2.1.10 + AHUNTSIC