Science Projects And Inventions

YOU NEED:

• A small paper cup
• Some string

To make a paper cup squawker make tiny hole at the bottom of a paper cup. Push a thread through the hole and tie a knot on one end as the illustration. Hold the cup in one hand. Wet the fingers of your other hand and pinch the hanging thread just below the cup. Now slide down the thread. The cup will make an astonishingly loud squawking sound!

HOW DOES IT WORK?

The fingers create just the right amount of against the thread. The thread is caught and many times a second once you slide your down. The string vibrates rapidly and that in turn forces the bottom of the cup to vibrate. Once this happens, the surrounding air vibrates, which is heard as a loud squawking sound. The sides of the cup actually work like a megaphone and help direct and amplify the sound.