How does a tuba make noise?

A tuba produces sound when a musician, known as a tubist, blows air through their lips into the mouthpiece of the instrument. The mouthpiece causes the air to vibrate, creating sound waves. These sound waves then travel through the instrument and are amplified by the large, brass body of the tuba. The size and shape of the tuba give it its characteristic low and resonant sound. The tubist can control the pitch of the notes produced by varying the tension of their lips and the amount of air that they blow into the instrument. By using different fingerings and combinations of valves, the musician can produce a wide range of notes across the tuba's range.