A flute is a woodwind instrument that is made of metal and shaped into a tube. To play it, you blow air across the “embouchure,” which is an opening with a specific shape. The stream of air passing over this opening causes the air inside the flute’s long tube to resonate, creating a pleasant tone. The pitch of this tone is controlled by fingering valves along its length. The flute differs from other woodwind instruments in that it does not contain a reed. Rather, the embouchure is entirely responsible for creating the vibrations necessary to produce sound. Because the embouchure is located on the side of the tube, the modern flute is sometimes referred to as a transverse flute — named so because air passes across the tube rather than directly into it.