SciShow
Did We Find Longitude Thanks To A...Clock?
The equator is a clear and accurate line around Earth that makes measuring latitude a precise science, but when it came to figuring out how to do that with longitude, British sailors were at a loss. Until they devised a competition.
Curated OER
The Mathematics of Latitude and Longitude
Latitude and longitude lines are explained in this video. Students focus on the mathematics and how to calculate distance using the degrees of various locations.