Shock waves emanating from a trombone have been caught on video for the first time, researchers say. It was first suggested in 1995 that the intense pressure waves, which can briefly exceed the speed of sound, could come from trombones.
Shock waves can form when energy is quickly put into a confined channel; weak shock waves can be formed as trains enter tunnels. Researchers revealed the video at the Acoustical Society of America meeting.
Shock waves are just a particular kind of pressure wave – which is what sound itself comprises.
Read the rest of the article (which includes video of the shockwave) here.