Is light a particle or a wave? Or both? Or neither? Learn how humans have defined light throughout history -- including our best attempts today -- in this classic episode of BrainStuff.

BrainStuff Classics: What's the Controversy Behind 'Mary Had a Little Lamb'?
06:30

What Was the World's Largest Nuclear Weapon?
10:52

How Do Red-Tailed Hawks Work?
09:24