Glass windows are as solid as the materials that surround them, yet they let light through. Learn the physics of why glass can be so transparent -- and why it took humans thousands of years to create totally clear glass -- in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/question404.htm

What Pranks Have Astronauts Pulled?
08:40

How Can Your Body Learn to Tolerate Cold?
10:58

How Did the War of 1812 Settle the American Revolution?
10:23