CHAPTER XI 



REFRACTION 



107. Bent Rays of Light. A straw in a glass of lemonade 

 seems to be broken at the surface of the liquid, the handle of 

 a teaspoon in a cup of 

 water appears broken, and 

 objects seen through a 

 glass of water may seem 

 distorted and changed in 

 size. When light passes 

 from air into water, or from 

 any transparent substance 

 into another of different 

 density, its direction is 

 changed, and it emerges 

 along an entirely new path 

 (Fig. 64). We know that light rays pass through glass, 

 because we can see through the window panes and through 

 our spectacles ; we know that light rays pass through 

 water, because we can see through a glass of clear water; 

 on the other hand, light rays cannot pass through wood, 

 leather, metal, etc. 



Whenever light meets a transparent substance obliquely, 

 some of it is reflected, undergoing a change in its direction ; 

 and some of it passes onward through the medium, but the 

 latter portion passes onward along a new path. The ray RO 

 (Fig. 65) passes obliquely through the air to the surface of 



CL. GEN. SCI. 8 IM 



FIG. 64. A straw or stick in water seems 

 broken. 



