Sea Level! What is it and how do scientists calculate it? As it turns out, there are actually many complexities in determining this measurement. For example, Earth isn’t actually a sphere, gravity is stronger and weaker at different points around the globe, and of course, there are a lot of mountains that are no where near water — so how do we know what sea level would be? In this video, Minute Physics explains the details.
After you’ve watched, check out these related links: ellipsoid, geoid, geodesists, Mount Everest, Chimborazo Volcano, Space.com’s Best Gravity Map Yet Shows a Lumpy, Bumpy Earth, and this clarifying and not-to-be-missed animated gif of Earth’s gravity field.