Sizing up earth: A universal method for applying eratosthenes\u27 earth measurement

This article is based on an activity used in a team-taught preservice course, “Integrating Geography and History,” at the University of North Alabama. The antecedents to modern descriptions and calculations of earth\u27s shape and size began more than 2,000 years ago. The Greek mathematician and geographer Eratosthenes made the most accurate ancient measurement of Earth based on fundamental math concepts and Earth-Sun relations that provided a basis for determining latitude with greater accuracy. A brief historical statement about Eratosthenes\u27 experiment is followed by an extended explanation of how teachers can use Eratosthenes\u27 method in the classroom to calculate the size of Earth using shadows and simple mathematics independent of noon time observations. © 1996 Taylor & Francis Group, LLC