100 INTRODUCTION TO GENERAL SCIENCE 



72. REFRACTION AND DISPERSION 



If a beam of white light is allowed to pass through a tri- 

 angular piece of glass, or other transparent medium, it is not 

 only bent towards the thicker side of the prism, as a piece of 

 glass so shaped is called, but it is also separated into the seven 

 primary colors, red, orange, yellow, green, blue, violet, and 

 indigo. These colors are called the prismatic colors, since they 

 are produced by means of a prism. The bending of the path 

 of light is called refraction ; the separation into the component 

 color is called dispersion. 



The gorgeous colors of sunrise and sunset are caused by 

 drops of water in the atmosphere breaking up the white light 

 of the sun into the primary colors. Some of these colors are 

 scattered or bent so that they do not reach the eye. We then 

 receive the sensation which is due to the other colors. In a 

 cloudless sky, with a very small amount of fog or haze, there 

 will be no colors in the sunset or the sunrise. 



References : 



1. 1002 : 142-143. Refraction of Light by the Atmosphere. 



2. 1103 : 166-168. Refraction of Light. 



3. 1103 : 169. Diffraction of Light. 



4. 1304:232-233. Color Effects. 



5. 1803:398-399. Refraction, 

 a. 1801:211-142. Refraction. 

 6. 1801:230-231. Dispersion. 



c. 1802:226-228. Refraction. 



d. 1802:252. Dispersion. 



e. 1804:346-348. Refraction. 

 /. 1804:368-370. Dispersion. 

 g. 1805:227-232. Refraction. 

 h. 1805:238-239. Dispersion. 

 i. 1806 : 171-175. Refraction. 



