This 10-minute video lesson looks at the four fundamental forces: Gravity, weak interaction, electromagnetic force, and strong interaction. [Cosmology and Astronomy playlist: Lesson 15 of 85]

This 4-minute video lesson looks at the predicted collision of the Milky Way Galaxy with Andromeda (forming "Milkomeda"). [Cosmology and Astronomy playlist: Lesson 37 of 85]

This 8-minute video lesson looks at how the Hawaiian Islands were formed by a stationary hot spot under the Pacific plate. [Cosmology and Astronomy playlist: Lesson 49 of 85]

This 20-minute video explains how Earth's tilt causes the seasons. [Cosmology and Astronomy playlist: Lesson 70 of 85]

This 6-minute video lesson explains how we know about the Earth's core. It shows how S-wave shadow and P-wave detection patterns give us information about the core. [Cosmology and Astronomy playlist: Lesson 55 of 85]

This 4-minute video lesson looks at Hubble Telescope images of galaxies. [Cosmology and Astronomy playlist: Lesson 6 of 85]

This 11-minute video lesson looks at Hubble's Law. [Cosmology and Astronomy playlist: Lesson 26 of 85]

This 12-minute video lesson provides an overview of evolution from from the extinction of the dinosaurs to humanity. [Cosmology and Astronomy playlist: Lesson 64 of 85]

This 10-minute video lesson provides a basic introduction to light and electromagnetic radiation. [Cosmology and Astronomy playlist: Lesson 68 of 85]

This 11-minute video lesson works through a calculation for K-Ar dating (it is good to have some prior experience with e and logarithms to understand). [Cosmology and Astronomy playlist: Lesson 80 of 85]

This 13-minute video lesson ponders how we get calories from the land and the limits of human population density. [Cosmology and Astronomy playlist: Lesson 83 of 85]

This 7-minute video lesson looks at the lifecycle of massive stars (stars with masses greater than 9 times the sun). [Cosmology and Astronomy playlist: Lesson 27 of 85]

This 13-minute video lesson looks at how changes in Earth's rotation can effect Earth's seasons and climate. It discusses Milankovitch Cycles, Precession, and Obliquity. [Cosmology and Astronomy playlist: Lesson 71 of 85]

This 6-minute video lesson looks at the idea of Pangaea and some of the evidence behind it. [Cosmology and Astronomy playlist: Lesson 56 of 85]

This 7-minute video lesson explains what parallax is and how it is used to determine distances between stars. [Cosmology and Astronomy playlist: Lesson 21 of 85]

This 8-minute video lesson defines parsec a unit of distance used in astronomy. [Cosmology and Astronomy playlist: Lesson 25 of 85]

This 8-minute video lesson looks at plate tectonics and the difference between crust and lithosphere. [Cosmology and Astronomy playlist: Lesson 43 of 85]

This 13-minute video lesson looks at plate tectonics and the evidence of plate movement. [Cosmology and Astronomy playlist: Lesson 45 of 85]

This 6-minute video lesson continues to explore plate tectonics. It covers the geological features of convergent plate boundaries. [Cosmology and Astronomy playlist: Lesson 47 of 85]

This 6-minute video lesson coninues to look at plate tectonics. It discusses plates moving due to convection in mantle. [Cosmology and Astronomy playlist: Lesson 48 of 85]