What vibrates to make the sound when a guitar is played?

When you play a guitar or any string instrument, you pluck a string with your finger or a pick, causing it to vibrate. For this, you need three basic components: a vibrating string, a soundboard, and a resonating chamber.

The vibrating part is the musical string, which is made of a thin, highly elastic material such as nylon or metal. When you pluck it, the vibration propagates along the string producing a mechanical wave.

The soundboard, which is usually a flat piece of wood underneath the strings, receives these vibrations and amplifies them. It acts like a diaphragm that converts the mechanical waves into sound waves. The soundboard's shape and material determine the tone of the instrument.

Finally, the resonating chamber, which in the case of the guitar is the hollow space inside the body of the guitar, receives these amplified sound waves from the soundboard. The size, shape, and materials of this chamber contribute to the instrument's timbre by boosting or dampening certain frequencies.

As these sound waves travel through the air, you perceive them as a pleasant musical note.