Lecture 4: Measuring the Earth
What is the shape and size of the Earth? This lecture traces historical\nideas about the shape of the Earth, from ancient flat-Earth models to\nthe compelling demonstrations by Aristotle in the 3rd century BC that\nthe Earth was a sphere. We then discuss ways people measured the size\nof the Earth, describing the results of Eratosthenes of Cyrene in the\n2nd century BC and Claudius Ptolemy in the 2nd century AD, and their\nimpact. Recorded 2006 Sep 25 in 100 Stillman Hall on the Columbus\ncampus of The Ohio State University.