How to make your bike tyre sing
Create music with a tyre and a ruler
(Image source: Pixabay)
1. Turn and spin
The first thing you need to do is turn your bike over — rest it on the seat and straighten the handlebars to make sure it doesn’t fall over. Make sure you ask an adult to help you if you need a hand.
You need to spin the tyre in order to start making music. The easiest way to do this is to turn the pedals as if you were riding the bike. This will cause the back wheel to spin round really fast.
2. Make music
Take a plastic ruler and press it against the side of the spinning bike tyre. You should hear a humming noise. The sound is created as the ruler hits the bumps in the tread of the tyre and the air between the tyre and the ruler is squeezed out. It’s the same effect as when you clap your hands, only with the spinning tyre it happens over and over, creating a humming noise that goes on for as long as the ruler is held to the tyre.
3. Speed it up
Turn the pedals faster to speed up the tyre, then hold the ruler there again. You’ll find that the note that is played is higher than when the tyre spins slower. This is because the impacts come more quickly on the tyre, so the vibrations are closer together and the sounds reach your ears as a higher note.
Try pressing the ruler onto different parts of the tread too — does the tyre create a different note depending on where you touch it?
(Image credit: Ed Crooks/ Future PLC)
Summary
As the ruler impacts on the tyre it creates vibrations that form sound waves. The quicker the vibrations occur, the higher the note that you hear. This is how musical instruments work too — guitar strings vibrate at different frequencies to create different notes.
This article was originally published in How It Works issue 107
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