Measuring the Earth - Livestream

With some simple geometry and some friends on Zoom, we can measure the polar circumference of the Earth. This task was first done by Eratosthenes (276 BCE. - 195/194 BCE). We will watch shadows along the meridian that runs north-south through San Mateo CA, Portland OR, Seattle, WA, and Prince George, BC. Using these measurements we will calculate the distance around the earth through the poles.