How do stretched strings create sound in a violin or guitar?

In stringed instruments like the violin and guitar, sound is produced through the vibration of stretched strings, which are categorized as chordophones.

When a string is set into motion—whether by bowing, plucking, or striking—it vibrates in a complex manner. The entire string oscillates to produce a fundamental frequency, while segments of the string vibrate independently to create overtones, which determine the instrument's characteristic timbre.3

Because a vibrating string alone produces a very weak sound, these instruments rely on a bridge to transmit those vibrations to a soundboard. The soundboard, often part of a larger resonant body, vibrates in response to the strings, significantly amplifying the sound. The pitch produced is determined by the string's tension, length, thickness, and density; musicians alter the pitch by changing the resonating length of the strings, such as by pressing them against a fingerboard.12