Schlieren photography allowed a cough to be photographed for the first time ever. *cough* So what?
Dr. Gary Settles and Dr. Julian Tang at Penn State used the technique to explore the gaseous dynamics of a cough. *cough* So what? Apparently there is some good application for using a small bright light source and some lenses with a curved mirror and a razor blade to take pictures of the air. The scientists may finally be able to capture the gaseous energy that propels Mick Jagger. Otherwise they will be left with using the technique to study the accuracy of computer models regarding explosions.
Either way, pretty cool.