Picture of a Sound
Amplitude, frequency, time period — reading the wave
What this lesson covers
Why it matters
Sound is invisible — but draw its pressure against time and every property shows up as a shape: tall means loud, tight means high, and the pattern is a wave you can read.
The idea in plain words
The wave dictionary. Tap the words.
amplitude · frequency · time period
A tuning fork vibrates 256 times each second. Its time period?
≈ 0.004 s per vibration
- height: amplitude — maximum swing from the middle — the loudness knob
- hertz (Hz): frequency — vibrations per second — the pitch knob
- second: time period — time for ONE full vibration: T = 1/f
- T = 1/f = 1/256
Predict first
On a wave picture, a LOUDER sound shows up as…
Height = amplitude = loudness. Spacing = frequency = pitch. Two independent knobs, one picture.
- taller peaks (bigger amplitude) — correct
- peaks closer together
- a longer wave
What you do
Stretch the wave tall for loud, squeeze it tight for high — then swap the waveform and see why a violin isn't a flute.
Check yourself
Frequency is measured in…
Hz counts how OFTEN; dB measures how LOUD — different questions.
If frequency doubles, the time period…
T = 1/f: twice as many vibrations each second means each takes half the time.
Two drums make waves of equal spacing but different heights. They differ in…
Same spacing = same frequency = same note; the taller one is simply louder.
- hertz — vibrations per second — correct
- metres
- decibels
- halves — correct
- doubles
- is unchanged
- loudness only — correct
- pitch only
- speed