Explaining the Fascinating Photographic Trick that Lets You See Sound Waves

NPR just released a fascinating video that does a fantastic job of explaining something called Schlieren Flow Visualization or Schlieren Photography: a photographic trick that allows you to see density changes in air and, therefore, actually capture sound waves on camera.

Starting off with a simple diagram and heat as an example, producer Adam Cole breaks down how this type of photography works, after which he shows you several examples of actual sound waves captured using a high-speed camera and Schlieren Flow Visualization.

  • superduckz

    The question MUST be asked…. what is the “visualization” of one hand clapping?

    sorry… I just couldn’t help myself..

  • akaawol

    That was freaking amazing! I almost wanna try it myself… but that looks like a lot of work and gear that I’d have no idea how to find.

  • ImUrAssassin

    Yeah, I don’t even know if a Phantom v1610 could do that. I mean it might. But that’s $100k, who wants to test it?

  • akaawol

    LOL If they gave it to me I’d gladly test it! (hint hint just in case they are looking in here)

  • John

    Very cool. Especially loved how the engineers use the technique to study the aerodynamic flow of Millennium Falcon. :D

  • Gary

    Not a freaking “trick”, its a technique. Stop with all this click bait sheeesh…

  • Christye Sisson

    There are actually two videos featured here that are student work from the Photo Sciences department at Rochester Institute of Technology (the hand and the straightening iron). All of the students learn this technique in a scientific photography class – no trickery :)

  • louisleblanc

    Have a look at shadowgraph techniques. They’re not as widely used as schlieren techniques in technical fields as the later is more insightful. However, you can make a shadowgraph quite easily. You might have seen some happen without realizing. My bbq is next to a white wall. On a sunny day with the light hitting it, it heats up enough to have a draft of air on top of it. When the sun is directly behind it, I can clearly see the plume of air casting a shadow on the wall. You might see it with the hot air on top of hot pavement casting a shadow on something.

    Really, you only need sunlight and a flat wall to give it a go, candles are good test subjects. A speedlight would also work if you want to work indoors. Have a look on the web, there are some fairly simple and setups if you want to go a step further after that.

    You don’t need hundred thousands of dollars to get started. Though, the phantom v1210 is one nice camera to work with ;).

    Google “schlieren photojojo” they seem to have a decent cheap setup you could make. I tried posting this comments a few minutes ago but seems to have been deleted or unproved by petapixel, not too sure what’s up with that (that’s why I didn’t put a link to the article)…

  • Tiktian C

    the wind tunnel lab at the university I’m going to uses a schlieren device for flow visualization around an airfoil.

    It isn’t terribly hard to make them on the cheap