Seeing sound and other changes in air density

Here’s a video on a technique which we can use to see changes in air density that are otherwise invisible to the human eye.

It’s called a Schlieren Flow visualization and, together with a high-speed camera, it lets us see the changes in air density caused by examples like the travel of sound, the natural heat coming from our hands, and sneezes and coughs.

Thinking of what else is actually there but invisible to our eyes because of the types of waves that they can see is a fascinating exercise.

Also published on Medium.