134 Common Science 



no light can get through, you have a real mirror ; most 

 of the light that leaves your face is reflected to your 

 eyes again. 



Why smooth or wet things are shiny. When a sur- 

 face is very smooth, we say it is shiny or glossy. Even 

 black shoes, if they are polished, become smooth enough 

 to reflect much of the light that strikes them ; of 

 course the parts where the light is being reflected do 

 not look black but white, as any one who has tried to 

 paint or draw a picture of polished shoes knows. Any- 

 thing wet is likely to be shiny, because the surface of 

 water is usually smooth enough to reflect light rather 

 directly. 



If a surface is uneven, like a pool with ripples on 

 it, the light reflects unevenly, and you see a distorted 

 image; your face seems to be rippling and moving in 

 the water. 



Application 34. Some boys were playing war and were 

 in a ditch that they called a trench. They wanted to make 

 a simple periscope so that they could look out of the ditch 

 at the " enemy " without being in danger. They had an 

 old stovepipe and a mirror. Practically all of them agreed 

 that if the mirror were fixed in the top of the stovepipe and 

 if they looked up through the bottom, they would be able 

 to see over the side of the ditch. But they had an argument 

 as to how the mirror should be placed. Each drew a diagram 

 to show how he thought the mirror should be arranged, using 

 dotted lines to show how the light would come from the 

 enemy to their eyes. Three of the diagrams are shown in 

 Figure 64. 



The boy who drew the first said : "If you want to see the 

 enemy, the mirror's got to face him. Then it will reflect 

 the light down to your eyes." 



