PROBLEM 2. Why Coinplex Behavior Is Possible 



Fig. 267 As an object (can- 

 dle) is brought closer to 

 your eye the shape of the 

 lens changes. How? Com- 

 pare the two figures. If this 

 change did not occur the 

 iy/tage woidd be blurred be- 

 cause it would not be 

 focused on the retina. 



281 



Fig. 268 The parts of the 

 human ear. Find the outer 

 ear, middle ear, and inner 

 ear. What names are given 

 to the bo77es in the middle 

 ear? By what passageway is 

 the ear connected with the 

 throat? 



Semicircular canals 

 Auditory nerve 



Cochlea 



Outer ear and canal Eardrum 



Eustachian tube to throat 



done. With age the ability to change the 

 shape of the lens is nearly lost by many 

 people. The condition is farsightedness 

 and it can be corrected by wearing 

 glasses. 



When the eyeball, instead of being 

 spherical, is elongated or shortened, the 

 image does not fall directly on the retina. 

 Vision is then blurred. These faults can 

 also be corrected by wearing glasses. If 

 you do Exercise i i you will understand 

 the reason. 



The ear. If you examine Figure 268 

 you will see that there is an outer ear 

 and canal, a middle ear, and an inner ear. 

 The inner ear contains the receptors 

 used in hearing. They lie within a spiral 

 passageway through one of the bones of 

 the skull. The spiral passage makes sev- 

 eral turns like the tiu-ns in a snail shell. 

 For this reason it is called the cochlea 

 (kok'lee-a). The spiral canal is filled 

 with a liquid and within part of its length 

 lie the receptors which are in contact 



