Earth’s Radius (Eratosthenes’ Method)
Author: Maria Guida, Palmira Ronchi
Implemented in:Belgium (Flemish Community), Spain and Hungary
Description: The aim is for the students to learn about Eratosthenes’ Earth radius measurement and to make practical estimations of the error in measurement of physical quantities as well as to develop the capacity for abstraction. Students have to work with GeoGebra to draw ellipses using the gardener’s method. In order to get the feeling for it, the students can go into the garden to put a stick in the ground and observe the shadow and its length at different hours of the school day. It’s not meant to be a precise measurement but a device to promote discussion among students in order to train them in arguing scientifically. Back in the classroom, the teacher introduces Eratosthenes’ idea about the measurement of the Earth’s radius, which the students have to reproduce using GeoGebra. The students are asked to do online research and to calculate the difference between Eratosthenes’ measurement and the current value. This should encourage a discussion on what Eratosthenes’ imprecision was.
More information:Spice GP - Earth’s Radius (Eratosthenes’ Method)