Everything That Sounds, Trembles
Vibrations — where every sound is born
What this lesson covers
Why it matters
Touch your throat and hum — your fingers feel the buzz. Sprinkle rice on a drum and strike it — the rice dances. No trembling, no sound. Ever.
Predict first
Every sound is produced by something that is…
String, drum skin, vocal cords, bee's wings — behind every sound is a to-and-fro trembling, pushing the air in waves.
- vibrating — correct
- hot
- electric
What you do
Pluck the string — change its length and tightness and hear the trembling change its tune.
Check yourself
A ringing bell held gently between your fingers goes quiet because…
Kill the trembling, kill the sound — the surest proof they're the same thing.
Sound travels through air as…
The air passes the push along like a stadium wave — the pattern travels, not the crowd.
The AMPLITUDE of a vibration is…
Amplitude = size of the swing (loudness). Frequency = swings per second (pitch). Time period = time for ONE full swing.
- you stopped its vibration — correct
- fingers absorb sound from the air
- metal cools down
- a wave of pushed-together and stretched-apart air — correct
- flying air molecules that reach your ear
- tiny sparks
- how far it swings from its middle position — bigger swing, louder sound — correct
- how many times it vibrates each second
- how long the string is