It is these factors of the guitar that allow it to produce the specific sounds required to create music. In order to understand music and how guitars produce it, it is helpful to understand the physics of sound.
Sound is created when the vibration of material bodies causes energy to propagate in pressure waves through a medium, usually air. All forms of musical instruments create vibrations in order to produce the sound waves that make music.
Guitars are a type of musical instrument called string instruments, meaning that they create their sound through the vibrations of a string. Vibrating strings on a guitar are fixed at both ends and are elastic. When a guitar string is either strummed or plucked, vibrations in the form of waves travel in both directions along the string and are reflected back at each fixed end.
These waves do not cancel each other out as they reflect back upon themselves, but instead form a standing wave where crests and troughs remain at fixed positions while the displacement of the envelope of the wave as a whole increases and decreases.
