by John Bertles


You can make musical instruments change their pitch (make high and low sounds) by making them longer and shorter. The most familiar example of this is the trombone.

In this article, we will be building a Tube Trombone out of cardboard, and a reed trombone out of plastic straws - the Strawmbone!

Tube Trombone

You will need:

2 telescoping cardboard tubes (one must be able to slide inside the other). The best kind are gift-wrap tubes or something similar, but in a pinch even paper towel tubes will work. A good rule to remember is the wider the hole, the longer the tube should be.

One tube must be able to slide freely in and out of the other, but it should also be a snug fit. If the inner tube is much smaller than the outer one, then the slide effect will not work. For example, plastic-wrap tubes often slide nicely into paper towel tubes.
First, practice blowing through your lips to make them buzz. It's kind of like making a motor sound with your lips, or the way a horse makes a shuddering sound.
Press your lips into the end of the smaller tube and buzz. Try making your lips buzz faster or slower, at higher and lower pitches. You'll soon discover that if you buzz your lips at the right speed, you'll get the best sound from the tube.
Then slide the bigger tube down to make your trombone longer. If you are blowing just right, it should sound lower. Hint: You can help the effect along by buzzing your lips slightly faster when the slide is in and slightly slower as you pull the slide out.
The Strawmbone!
You will need:
2 telescoping plastic straws (one must be able to slide inside the other). For example, one of the white-paper-wrapped straws you get in a restaurant or a deli should fit nicely inside a fast-food restaurant straw (the striped ones).

How to make it:
Flatten one end of the thinner straw by smooshing it a bit, or creasing the sides with your fingernails.
Then, using relatively sharp scissors (maybe ask an adult to help you), cut the corners off the flattened end.
Put the flattened end of the straw in your mouth with the open sides to the sides of your mouth. Bite down a bit with your lips - not your teeth - and blow as hard as you can through the straw. Make sure air is coming out the other end, or the sound will not happen.

If you don't get a buzzing sound, consider flattening the straw a bit more, or putting it a bit further in or out of your mouth. Also, you might try really pushing with your stomach muscles as you blow.
Once you get a good sound, slide the bigger straw onto the one you're blowing, and slide it up and down as you blow. You should be getting a nice trombone effect.
Wind instruments often work better with a funnel on the end. Take a nice thick piece of construction paper and shape it into a cone with a hole just big enough for the end of your straw or cardboard tube. Tape it into place. Now blow your straw or tube again. The sound should be much louder!