Physics ยท Chapter 06

๐Ÿ”Š Sound Waves

How sound travels and echoes.

๐Ÿ’ก Sound is a Wave

Sound is a vibration travelling through air (or water, or solids). When a guitar string vibrates, it pushes air particles, which push the next, and so on โ€” like a chain reaction reaching your ear.

Frequency is how many waves per second (measured in Hertz, Hz). High frequency = high pitch (squeaky). Low = low pitch (deep).

Amplitude is wave height โ€” bigger amplitude = louder sound.

v = f ร— ฮป

In air, sound travels at about 343 m/s. That's why you see lightning before hearing thunder.

Sound waves โ€” compression and rarefaction, frequency determines pitch
Sound waves โ€” compression and rarefaction, frequency determines pitchWikimedia Commons / CC BY-SA 3.0
Ultrasound scan โ€” medical use of sound waves above 20,000 Hz
Ultrasound scan โ€” medical use of sound waves above 20,000 HzWikimedia Commons / CC BY-SA 3.0
๐ŸŽฌ

The Travelling Wave

Animation
waveform โ†’ FREQUENCY 2 Hz AMPLITUDE 50

Sound waves ripple outward from the speaker, reach the ear. Adjust pitch and volume below.

๐Ÿงช

Tune the Sound

Experiment

Drag pitch and volume. Higher frequency โ†’ more waves squeezed together. Bigger amplitude โ†’ louder peak.

2 Hz
50
PitchMedium
LoudnessNormal
โ†
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