Pressure Waves

Compressions, rarefactions and pitch

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Sound is a longitudinal pressure wave: compressions and rarefactions.
• The molecules jiggle in place. The pattern travels.
• Frequency is heard as pitch. Humans hear about 20 Hz to 20 kHz, and $v = f\lambda$.

Steps

1. Squeezes in the air
2. Which kind of wave?
3. In space
4. Pitch and frequency
5. From whisper to rock concert
6. Wavelength