6 NATURE-STUDY LESSONS. 



2. (a) How many panes of glass are there in the 



window? 

 (d) Can a blind person himself find out ? 



3. What sense did you use in answering questions J 

 (a) and 2 (a) ? 



B. The Organ of Sight. 



4. (a) Examine the eyes of different people. 

 (6) Observe their different colors. 



5. Note the different parts of the eye. 



6. Describe each part and, if you can, discover its use. 



7. Draw an eye. 



8. Observe the different means by which the eye is 

 protected. 



9. (a) Have your eyes ever felt tired ? 

 (i5) What caused them to feel tired ? 



10. What is the effect of looking towards a strong 

 light, as the sun ? 



1 1. Infer some rules for the care of the eyes. 



Note. — Through the breaking of a dark glass of his telescope, while 

 looking at the sun, an astronomer lost the sight of one eye. 



C. Light and Seeing. 



12. (a) Close your eyes and tell what you can see. 



(d) Cover the eyes with a handkerchief and tell 

 what you can then see. 



(c) Place a pane of glass before your eyes and tell 



what you can see. 



(d) Why are objects seen indistinctly at night ? 



(e) Why are objects in a dark room not visible ? 

 (/") By means of a mirror, throw light into a corner 



of a dark room. 

 (^) From these experiments, what do you find is 

 necessary for seeing ? 



