NPR's Skunk Bear recently shined the spotlight on Schlieren Flow Visualization, an incredible method that is able to capture vibrations as images. Waves (even sound waves) created by an action can be seen as lines in this video (courtesy of mechanical engineering professor Mike Hargather). By using a parabolic-mirror technique, Hargather and others were able to deconstruct complex images into their most basic visual components.
“When light travels through areas of different air density, it bends. You’ve probably noticed the way distant pavement seems to shimmer on a hot day, or the way starts appear to twinkle. You’re seeing light that has been distorted as it passes through varying air densities, which are in turn created by varying temperatures and pressures,” Skunk Bear Tumblr explains.