Air and sound have a few things in common. For one, they are both things we use to live and sense every day of our lives. For another, even though they are such a big part of our lives, we've never actually SEEN them with our own eyes. Sure, we've seen representations, but have you ever seen air move? Well, a technique called Schlieren Optics is about to do just that.
This first video will introduce you to it, and the second includes some more amazing examples of air moving (from a candle, from a hair blower and many other sources).