Radiant Heat and Light 161 



rough ; there are too many little uneven places that reflect 

 the light at all sorts of angles ; the light is scattered and 

 the lens in your eye cannot bring it to a focus. 



Application 38. Explain why a scrim curtain will keep 

 people from seeing into a room, but will not shut the light 

 out ; why curtains soften the light of a room ; why indirect 

 lighting (i.e. light thrown up against the ceiling and then 

 reflected down into the room by the rough ceiling) is better 

 for your eyes than is the old-time direct lighting. 



Inference Exercise 



Explain the following : 



231. The alcohol formed by the yeast in making bread light is 



practically all gone by the time the bread is baked. 



232. The oceans do not flow off the earth at the south pole. 



233. Lamp globes often have frosted bottoms. 



234. A damp dust cloth will take up the dust, without making 



it fly. 



235. The stars twinkle when their light passes through the moving 



air currents that surround the earth. 



236. Shears for cutting tin and metal have long handles and short 



blades. 



237. A coin at the bottom of a glass of water seems raised when 



you look at it a little from one side. 



238. You have to brace your feet to row well. 



239. Light from the northern part of the sky, where the sun is 



not, does not make sharp shadows. 



240. Pokers and lifters for stove lids often have open spiral 



handles. 



SECTION 27. Color. 



What makes the ocean look green in some places and blue 

 in others? 



What makes the sky blue? 

 What causes material to be colored? 

 What makes a rainbow ? 

 What is color ? 



