Do you think you could make a cup sound like a chicken?

What you need:

A plastic cup, yarn or cotton string, paper-clip, thick tissue paper, a nail, scissors and water.

What to do:

1. Cut the string to a length of 20 inches (40 cm). Tie one end to the centre of the paper-clip.

2. Use the nail to punch a hole in the bottom of the cup.

3. Insert the other end of the string through the hole in the cup.

4. Cut the tissue paper into the size of a ten-rupee note. Make it damp using some water.

5. Now fold the tissue paper over the string near the cup. Make sure the string is stretched tight Hold the cup tightly with your other hand and start tugging on the string. Each jerk of the string should make the tissue slide along it

What happens?

You hear a chicken from the cup!

Why?

Sound travels as vibrations through the air. Our ears pick up those vibrations only if they are loud enough.

As you rub the tissue over the string, the friction between them causes the string to vibrate. Without the cup you would not be able to hear the vibrations of the string. But when you add the cup, it collects all those – vibrations and makes them louder. That is called ‘amplification and the cup is the amplifier.

It is the same principle that is used by musical instruments such as pianos and guitars. The outer wooden box of the piano is nothing but a sound amplifier.

Picture Credit : Google

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