World 1 · Foundations · 6 minOne octave, half the period
Teaching this? Open projector mode
A periodic tone repeats after T=1/f seconds. Doubling the frequency halves the period while preserving the shape when the harmonic coefficients stay fixed. The time trace, spectrum and optional sound use the same coefficients. The string is deliberately slowed down so its standing-wave modes are visible.
Check yourself
Doubling a pure tone from 220 Hz to 440 Hz makes its period…
0 of 2 required activities complete. Finish each task and quiz.Next lesson →