While fluid dynamics sounds like a dull topic, SoapFilmScope promises to make it fun by using your cell phone to observe the interactions between sound waves and liquid membranes. You can make your own with some PVC pipe, some 3D-printed attachments, a speaker, and a few other odds and ends.

If your PVC pipe doesn’t match [DaniloR29’s] exactly, no problem. The files are in OpenSCAD so you can easily change them to suit your needs. One end of the PVC tee dips into soap solution to form a film — think like a soap bubble before you blow it out of the bubble wand. The other ends have the speaker and the cell phone camera.

While the effect is entertaining, there’s real science behind it. You can learn about acoustic propagation, interference, and diphasic patterns, among other things. This would be a fun classroom project or just something to pass the time on a rainy afternoon. Be careful, though. Taking these kinds of pictures can be addictive. If you’d rather make bubbles, why not make giant ones?

If you enjoy this sort of thing, [Danilo] also built the KaleidoPhoneScope, which you can see in action in the video below.