132 



Common Science 



FIG. 62. 



The ball bounces from one boy to the other, but it does not return to 

 the one who threw it. 



The mirror is like that plank ; it is something that 

 will reflect (bounce) the light directly. The light from 

 your face goes into the mirror, just as you may throw 

 the ball against the plank, and the light is reflected to 

 your friend just as the ball is bounced to him; so he 

 sees your image in the mirror. If he can see you, you 

 can see him, just as when you bounce the ball to him he 

 can bounce it to you. But you may be unable to see 

 yourself, just as you may be unable to bounce the ball 

 on the plank so that you yourself can catch it. 



In other words, when light strikes against something 

 it bounces away, just as a rubber ball bounces from a 

 smooth surface. If you throw a ball straight down, it 

 comes straight up; if light shines straight down on a 

 flat, smooth surface, it reflects straight up. If you throw 

 a ball down at a slant, it bounces up at the same slant 

 in the opposite direction ; if light strikes a smooth sur- 



