CHAPTER V 

 STRUCTURE OF THE AIR MOLECULAR THEORY 



54. Questions for Discussion. 1. When an automobile or bicycle 

 tire has been pumped up, is there more air in the tire than before 

 pumping? 2. Bicycle and automobile tires which have been filled in 

 the early morning sometimes burst, or blow out, near midday or in early 

 afternoon, although they are not punctured. Why? 3. What becomes 

 of milk or sugar when it is thoroughly stirred in coffee or tea? 

 4. Could you take the milk or sugar out of the coffee or tea after it 

 was thoroughly stirred into it? 5. Why is it that if a small amount 

 of musk or other strong perfume is released in a closed room, the per- 

 fume may soon be detected in any part of the room, possibly in adjacent 

 rooms ? 6. Do you know of any substances which can be changed from 

 solid to liquid and from liquid to gas, or changed in the opposite direc- 

 tion? Is the substance destroyed during any of these changes ? 7. What 

 happens to a solid, such as ice, when it is changed into a liquid? when 

 it is changed into a gas ? 8. If a room is full of air, how is it possible 

 for another gas which is released in the room also to fill the room? 

 9. When a tumbler full of water has a drop of red ink placed in it, 

 how can the ink become distributed throughout the water ? 10. What 

 is the nature of the structure of gases which makes it possible for 

 one gas to pass throughout a room which is already occupied by 

 another gas? 



55. Compressibility of air. In Chapter I we learned that 

 air pressures vary and that they may be measured. If a 

 pneumatic tire is rilled with air so that it is fully expanded 

 and also feels quite firm, we say that it is " filled " with air. 

 If it were filled with water in like manner we should not 

 expect to be able to get any more water into it, but we 

 know very well that if we apply the pump we can force 

 in more air. As we continue to pump, the tire gets firmer 

 and the pump works harder, showing that there is greater 



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