Everything has a Note

Natural vibrations — and the knobs that tune them

Setting up the lab…

What this lesson covers

Why it matters

Flick a glass, a ruler, a guitar string, a bridge — each answers with ITS note, not yours. Everything that can shake has a frequency it calls home.

The idea in plain words

The vibration vocabulary. Tap the terms.

free · damped · forced

Why does a sitar string sound lower when the player slides UP the fret (lengthening the vibrating part)?

Longer string, lower note — the fretboard is a frequency ruler

  • the reference: free (natural) — vibrating at its own f₀ with no outside push — the tuning fork after the strike
  • every real vibration: damped — amplitude dying away as friction drains energy — frequency almost unchanged
  • the setup for resonance: forced — made to vibrate at SOMEONE ELSE'S frequency by a periodic push
  • the factors: f of a string — rises with tension, falls with length and thickness — the sitar player's three knobs
  • f ∝ 1/l: more vibrating length → fewer vibrations per second

Predict first

Shorten a guitar string (fret it) and its natural frequency…

f ∝ 1/length: halve the string, double the note (one octave up). Tension raises it too — that's what tuning pegs do.

  • rises — shorter strings vibrate faster — correct
  • falls
  • stays the same — frequency belongs to the material

What you do

Tune the string to a 256 Hz middle C, then find 512 Hz — the same note, one octave up.

Check yourself

A struck tuning fork gets quieter over seconds but keeps its pitch. Its vibrations are…

Damping drains AMPLITUDE (loudness); the fork's geometry still sets the frequency.

Thicker guitar strings are used for…

The bass strings are the fat ones: mass slows the vibration, dropping f.

Your table hums only while the phone on it is on silent-vibrate. The table's vibration is…

Remove the driver and the table falls silent instantly — the signature of forced vibration.

  • damped — amplitude falls, frequency (pitch) barely changes — correct
  • forced
  • resonant
  • lower notes — more mass per length vibrates slower — correct
  • higher notes
  • louder notes only
  • forced — it shakes at the PHONE's frequency, not its own — correct
  • natural
  • damped free vibration
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