Eratosthenes' experiment model

Completed by a parallel beam source modeling the solar rays, this model allows the student to realistically reproduce Eratosthenes' experiment. The student will be able to measure and then calculate a length comparable to the length of the Earth's meridian using Eratosthenes' method. The radius of the Earth can be calculated from the length of the meridian. Usage: The model consists of a platform on which the Earth is represented in a 30° longitudinal cross-section. Syene and Alexandria are indicated, as well as the distance between them (approximately 800 km, according to Eratosthenes). A graduated arm in mm rotates relative to the center of the Earth; illuminated by a parallel beam of light, it projects the shadow that can be directly measured on the graduated platform, fixed perpendicularly on the arm. This platform slides along the arm to elongate the shadows, allowing for more precise measurements.