Capturing the Unseen: How to Shoot Sound and Heat Waves

Capture the unseen movements of air using Schlieren Flow Visualization.

Since the mid-1800s scientists have known a way to visually capture air movement through a process called Schlieren Flow Visualization. The process creates some amazing effects. In fact, there is an entire sect of photography specifically designed for capturing this phenomenon.

How is this possible?

In short, Schlieren Flow Visualization is achieved by aligning light waves using a parabolic mirror. When the light waves are obstructed by an object, say the heat of a candle, the result can be captured by a camera. Instead of confusing you further, check out this explainer video made by NPR.

Do-It-Yourself Schlieren Project

Getting Schlieren Flow Visualization is actually not as hard as the NPR video makes it out to be. Basically all you need is a parabolic mirror and a light. You can purchase a parabolic mirror for about $100 on ebay. The following video by Green Power Science shows how to create the effect (the video is low-budget, but bear with it, as it explains the process quite well):

Schlieren Flow in Action

Here are some awesome videos made using the Schlieren Flow Visualization principle.

1. The Millennium Falcon at Mach 3

2. Color Schlieren Filters with a Supersonic Nozzle

3. Penn State Experiments

What do you think of the Schlieren Flow Visualization principle? Got other ideas how you can use this effect? Share in the comments below.