PRESSURE AND CHANGE OF STATE 71 



5. Would the pressure cooker be of any advantage in Denver? Why? 



6. When air is allowed to bubble up through a tall cylinder of water, 

 the bubbles get larger as they rise. Why? 



7. Explain why a bottle of "charged water" or "soft drinks" over- 

 flows as soon as the cork is pulled. 



8. At what time of the year is the cork in the ammonia bottle likeliest 

 to pop out? 



9. Would it be possible to use air in place of ammonia in refrigeration? 



10. Water boils on Mount Blanc at 183F. At Denver, Colorado, it 

 boils at 203F. Which place is the higher? 



11. Air is often compressed over water in tanks for the purpose of 

 lifting the water to a higher level. Sometimes the system fails to work 

 because most of the air has disappeared. Explain (63). 



12. Fill a large bottle half full of water, cork with a one-hole stopper 

 through which a glass tube extends down into the water. With one 

 breath blow in as much air as possible. Explain what happens (62). 



13. How is the elasticity of the air made use of in automobile and 

 bicycle tires, air cushions, and the like? 



14. How is compressed air made use of in the air gun or pop gun? 



