This project is rated EASY to do.

What you need:
• a pen
• white or coloured paper
• glue
• cardboard (bristle board or cereal boxes are good)
• scissors
• string
• crayons or markers
• mathematical compass or jar lid to trace

How to make it:
1. Trace a circle of cardboard with a diameter of about an inch-and-a-half (anything goes as long as it's not to big -- experiment!).

2. Cut it out, and trace two paper circles the same size as the cardboard.

3. Cut them out. On one circle, draw and colour a lightning bolt. On the other, draw a cloud. Colour these.

4. Glue one picture on each side of the cardboard circle.

5. Punch two holes in the cardboard; one on each side.

6. Thread a piece of string through each hole.

7. Tie a knot in each piece of string to make 2 loops.

8. Twirl the disk by first twirling the string. As you twirl, watch the lightning bolt and the cloud. Like magic, the lightning bolt will be coming from the cloud!

How does it work?
Your eye holds onto the image of the cloud for a split second after it's gone. By that time the lightning bolt is in sight, and you seem to see the lightning bolt in the cloud. The same thing happens at the movies. If you look at a piece of movie film, you'll see that it is a series of pictures separated by black spaces.

Variations:
You can make a bird in a cage or a person with funny glasses but if you have pictures with a specific direction you have to LINE THEM UP PROPERLY with one of them upside-down or it won't work properly.

Also, some people write part of their name on each side, such as:

K I T

R S A

Together, they spell KRISTA.

This is really fun to make with a group of kids. You don't have to have a circle, either. A square or triangle -- anything goes!

The idea for this comes from Scienceworks, a Kids Can Press book by the Ontario Science Centre published in Toronto in 1984. Check it out!

Page 1 of 1