View full lesson: http://ed.ted.com/lessons/how-heavy-is-air-dan-quinn

Too often we think of air as empty space — but compared to a vacuum, air is actually pretty heavy. So, just how heavy is it? And if it's so heavy, why doesn't it crush us? Dan Quinn describes the fundamentals of air pressure and explains how it affects our bodies, the weather and the universe at large.

Lesson by Dan Quinn, animation by Sandro Katamashvili.