A bullet flying at almost Mach 1.5 (1.5 times the speed of sound) causes air to be compressed as it pushes its way through "thin air" causing a classic "V" shaped shock wave to appear reminiscent of the "bow" wave of a boat moving on a smooth water surface. In this case the wave is made visible by the fact it flew though a color schlieren system where density variations in air caused by air being compressed by the flying bullet cause light rays passing through these regions to pass through a "color filter array in a Schlieren beam in a manner unlike that which would be the case if the air would not be disturbed by these density variations.