158 EXPERIMENTAL GENERAL SCIENCE 



20. Would you say that ponds are deeper or shallower than they appear 

 to be? 



21. In spearing a fish, ought one to aim a little above or a little below 

 it, as it appears in the water? 



22. Recalling the different densities of the air at sea level and at high 

 altitudes, tell whether the sun's rays are bent toward or away from the 

 earth at sunrise and sunset? 



23. Explain how we can see the sun after it has really set, or before it 

 has risen? 



24. In the short-sighted or near-sighted eye, the rays of light come 

 to a focus before reaching the retina. Do such eyes need concave or 

 convex glasses? Why? 



26. What kind of glasses should the far-sighted eye be fitted with 

 if in such eyes the light does not come to a focus when it reaches the 

 retina? 



26. Could a burning lens be made of ice? 



27. When an object is viewed through a double convex lens, why is 

 the image blurred except when the glass is held at a definite distance 

 from the object? 



28. By means of a mirror, examine the pupil of your eye after looking 

 at an object in bright light, and again after being in a dim light. What 

 effect on the size of the pupil has an increase or decrease in the amount 

 of light? 



29. Would you expect the pupil of the eye to be expanded or contracted 

 when one is walking at dusk? 



