Magnetism and Electricity 



FIG. 106. A compass made of a needle and a piece of cardboard. 



And still another effect of the earth's magnetism is 

 this : Tiny particles of electricity, called electrons, 

 are probably shooting through space from the sun. 

 It is believed that as they come near the earth, the 

 magnetism of the north and south polar regions attracts 

 them toward the poles, and that as they rush through 

 the thin, dry upper air, they make it glow. And this 

 is probably what causes the Northern Lights or Aurora 

 Borealis. 



What happens when a needle is magnetized. The 

 reason that a needle becomes magnetic if it is rubbed 



