Pitch and loudness
Why does a big drum sound low, and a tiny whistle sound high?
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Explain
Small things sound high.
Big shakes sound loud.
Pitch is how high or low a sound is. Fast vibrations make high notes, and slow vibrations make low notes.
Loudness depends on how big the vibrations are. Bigger shakes carry more energy.
Press "Hear it", then change the sliders. Look at how the wave shape changes.
Pitch depends on frequency, in hertz. Loudness depends on amplitude.
Doubling the frequency raises a note by one octave. Loudness is often measured in decibels (dB).
Example: orchestras tune to the note A at 440 Hz. The A above it is 880 Hz.
- Fast vibrations: high pitch
- Big vibrations: loud
- Your ears sense both
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Loudness also depends on your ears, and they are most sensitive around 1000–4000 Hz. Instruments sound different because they add extra higher notes, called harmonics. The decibel scale goes up by 10 dB for every 10 times more sound energy.
Try it at home
Ask a grown-up to help
You need some glasses, water, a spoon.
You need: some glasses, water, a spoon.
Tap a glass gently with a spoon. Ting!
- Pour different amounts of water in some glasses.
- Tap each gently with a spoon.
- Put them in order from low to high.
What's happening: more water makes the glass vibrate more slowly, so the note is lower.
Physics is life
Your body
Your ears can hear high and low.
Daily life
Instruments play high and low notes.
Nature
Dogs hear sounds we cannot.
Space
The Sun rings like a bell.
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Words to know
Pitch: How high or low a sound is.