Making a Screamer

It has been a while since I did one of the noisy, annoying sound experiments which kids love and parents hate. Just keep in mind, that it is all in the interest of science.

You will need:

- a piece of paper about one inch wide and about 5 inches long.
- scissors

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Making the screamer is very simple. Put the two ends of the paper together and crease it to fold the piece of paper in half. Use the scissors to carefully cut a half inch slit along the center of the fold.

Then fold about half an inch of each end of the paper strip outwards, forming a T shape. The fold, with the slit in it, will be at the bottom of the T.

Place the T shaped piece of paper between the first two fingers of your hand, with the two folds that form the cross of the T against your finger tips and the vertical part of the T sticking out from the back of your hand. Hold the palm of your hand towards your face and blow firmly against the paper. As the air flows between the two sides of the paper, you will hear a loud noise.

Why does blowing through this piece of paper make that much noise? As the air is forced between the two halves of the paper, it forces them apart. The fast moving air does not produce as much air pressure against the paper (Remember the Collapsing Tent a few weeks back), and the pressure on the outside forces the sides of the paper back together. This process happens over and over, very quickly, and the paper vibrates. Things that vibrate produce sound.