Physics 1 Circumference of the Earth

This course is really designed for anyone. If you have no background in physics but know a little bit of algebra, you’re going to succeed in the course. In Unit 1, we’re going to begin with a question that fascinated the Greeks–how big is our planet? Today, it’s easy to answer that question. You can go to Google and type “what is the circumference of the earth?”
But 2,000 years ago the Greeks didn’t have Google. Still, a man named Eratosthenes was able to answer this question using nothing more than some basic assumptions about the earth and the sun along with an understanding of geometry, trigonometry and shadows. In this unit, we’ll learn everything we need to answer this question ourselves, and in doing so, we’ll learn some of the important mathematical tools that we’ll be using throughout the course. By the end of this unit, you’ll be able to go outside on a sunny day and estimate the circumference of the earth yourself.