Common Science 



Now it should be easy to understand why the compass 

 points north. One end of any magnet pulls on one end 

 of another magnet and drives the other end away. The 

 earth is a big magnet. So if you make a magnet and 

 balance it in such a way that it is free to swing, the north 

 end of the big earth magnet pulls one end of the little 

 magnet toward it and pushes the other end away. 

 Therefore one end of your compass always points north. 



Other effects of the earth's magnetism. Another 

 interesting effect of the earth's being a big magnet 

 is to be seen if you lay a piece of steel so that it 

 points north and south, and then pound it on one 

 end. It becomes magnetized just as your needle be- 

 came magnetized when it was rubbed on the small 

 magnet. 



FIG. 105. Magnetizing a needle. 



