VI. THE ATMOSPHERE 



SOME PROPERTIES AND USES OF AIR 



1. Empty a filled bottle of water. What goes into the 

 bottle as the water flows out? 



2. Press a bottle mouth down into a jar of water, and 

 over a floating bit of cork. Explain why water fails to 

 enter and fill the bottle. 



Repeat, having an outlet through a rubber tube for. the 

 air that is in the bottle. 



3. By means of a piece of rubber tubing attached to a 

 glass tube that passes through the stopper of a bottle, force 

 into the bottle as much air as possible, and keep it there. 



What must be true of the condition of the air within the 

 bottle now. Explain how it is possible to force more and 

 more air into the bottle. 



Unclasp the delivery tube after putting its outer end under 

 water, and observe what occurs. What must the air particles 

 have done to one another? Explain how it is that water 

 vapor finds place for itself in the atmosphere. What prop- 

 erty of air is involved? 



4. Through a pipette 1 whose large end reaches down 

 into water in a tightly stoppered bottle, force as much air 



1 Make by heating a piece of glass tubing till sufficiently softened to be 

 easily drawn out into any desired size when removed from the gas flame. 

 Allow it to cool, and break tubing as desired, making use of a sharp-edged 

 file. 



52 



