SCIENCE ACTIVITIES FOR FUN!!!

Whirling Wailer!

Make a Whirling Wailer that never stops moving. You can keep it going by pulling on its strings at just the right moment.

For this exercise you will need:

• string
• a glass or cup
• scissors
• a strong card or cardboard
• a bendy straw
• pencil or paper hole puncher

1. Use the glass or cup to trace a circle about 10 cm across on the card. Cut the circle out. This is your disk.
2. Make eight big holes around the edge of the disk with the pencil or hole puncher. Put two small holes on either side of the center of the disk.
3. Thread the string through the two holes in the middle of the disk and tie the ends of the string together.
4. Hold the string in both hands. Swing the disk around to wind up the string.
5. The disk whirls around as the string winds and unwinds. To keep the disk whirling, give a quick pull with both hands just as the string winds right up to your fingers.
6. Bend the straw. Then blow a stream of air onto the holes in the spinning disk. It makes a strange wailing noise!

What happened?

With each pull of the string, you add a force that speeds up the disk again.

The changing speed of the disk makes the sound go up and down like a wail.