See Airflow on Camera in This Awesome Harvard Demonstration of Schlieren Optics

Schlieren flow visualization and photography is one of those things that is just too cool. Using an optical trick, it allows a camera to capture, "small changes in the index of refraction in air." In other words, it can see anything that affects airflow: heat, sound waves, or just plain old air currents themselves.

And the video above, uploaded at the beginning of this year by the Harvard Natural Sciences Lecture Demonstrations YouTube channel, is one of the most fascinating demonstrations of Schlieren optics we've ever seen.

Photograph Sound & Heat Waves with this $9 DIY Schlieren Flow Visualization Setup

Schlieren Flow Visualization is a rather fascinating technique by which you can see and capture the differences in air pressure caused by various forces such as sound or heat.

And if the video we shared recently explaining/showing off this photographic trick had you yearning to try it for yourself, you're in luck, because there's a way you can create your own DIY Schlieren Flow setup for only $9.