Oscillations and waves
Physical and perceptual characteristics of sound
See how amplitude, fundamental frequency, and overtones shape a sound wave. Relate pitch to frequency, loudness to amplitude/intensity level dB, and timbre to the overtone spectrum.
⚠ Display-only simulation; with real sound, avoid levels above ~85 dB for extended periods to protect hearing.
Equipment
- Sound-wave model drawn as a displacement curve on canvas
- Wave-amplitude slider
- Sliders for fundamental frequency and second-overtone ratio
- Quantity readouts and a Pause button
Procedure
Change amplitude: loudness
Drag the amplitude slider: the wave peaks grow taller while the shape stays the same. Larger amplitude = stronger pressure swings = louder sound; intensity scales with amplitude squared, so rises ~6 dB per amplitude doubling.
Change the fundamental frequency: pitch
Drag the frequency slider: the wave compresses or stretches along the time axis. Higher frequency means higher pitch — doubling frequency raises the tone one octave. Note the f reading and relate the period T = 1/f on the figure.
Add overtones: timbre
Raise the second-overtone slider: the waveform departs from a pure sine and sharpens — same pitch and loudness but different timbre, like two different instruments. Return to 0 to compare with the elementary sine wave.