Book 14, Question 23
Why Do Two Nearly Matching Sounds Make a Wobbling Wah-Wah?
Two nearly matching sounds make a wobbling wah-wah because their waves keep lining up and canceling! You hear loud, then quiet, then loud again. That wobble is called a beat.
More fun facts
- When two notes are almost but not quite the same, you hear a wobble called a beat.
- The closer the two notes are, the slower the beats.
- Beats are proof that sound is made of vibrations.
- An old instrument called the siren was used to count how many sound waves are made each second.
- A wobbling movement is the vibration that makes the sound we hear.
Sources: Scientific American, BBC
Questions kids ask
What happens when two notes match exactly?
The beats slow down and disappear.