Earth and Space: Science Videos

This series explores Earth and space. You will learn how ancient scientists measured Earth, what causes a lunar eclipse, and how scientists estimate the number of civilizations that might exist in our galaxy. You will also take a tour of the electromagnetic spectrum, from radio waves to gamma rays, and see how telescopes like Spitzer use them. No background is needed, though a few videos use basic algebra.

Note: All Khan Academy content is available for free at www.khanacademy.org