Easy as a whistle

10 minutes

Making your own cheap whistle is as easy as a whistle. All you need is a pair of scissors and a straw. Straw whistles – how do they work?

Requirements

Steps

Step 1

Cut off the bendy part of the straw. Slightly flatten one end of the straw, by pressing it down with your fingernail.

Step 2

Take the flattened end of the straw and make it into a point by using the scissors to cut off two triangles.

Step 3

Bite on the point a few times until it is completely flat.

Step 4

Place your lips on the straw, just past the point. Slightly flatten the straw with your lips and blow into the straw. If you can’t hear anything, that’s because the straw is not vibrating. In that case, make the point of the straw a little flatter. Can you hear a musical note when you blow through the straw now?

Cut a piece of about 1 centimetre in length off the other end of the straw. Blow into the straw again. Listen carefully to the note. Repeat this a few times. Notice any changes?

Step

What did you discover

Did you hear a higher note coming out of the whistle when it was shortened? Why is that? Sound is a vibration. You can feel that vibration on your lips when you blow into the straw whistle. Did it tickle? When you blow into the whistle, your breath causes the straw and the air inside it to vibrate. The vibration of the straw is transmitted through the air to your ears: you hear a sound.

The length of the straw determines how fast the straw and the air inside it vibrate. A short straw vibrates more quickly than a long one. And the faster the straw vibrates, the higher the note that comes out of the straw. So shorter straws produce higher notes! Dogs can hear extremely high notes very easily. That’s why dog whistles are often very small – so they produce high notes!