harmonics

When a string vibrates, it does not only vibrate as a whole — it simultaneously vibrates in halves, thirds, quarters, and smaller fractions, each producing a higher overtone. By lightly touching the string at a nodal point (where a fraction divides), the player isolates one of these overtones, producing a pure, flute-like harmonic. Natural harmonics on open strings are the easiest to produce and appear at the halfway point (octave), one-third (octave plus fifth), and one-quarter (two octaves). Artificial harmonics, where the player stops the string and touches a higher point, can produce harmonics on any pitch. Composers use harmonics for ethereal effects and extreme high notes.