INSPIRED AND EXPIRED AIR. 



79 



lowing the tube to project but a short distance 

 into the bottle ; attach a piece of rubber tubing 

 to the upper end of this tube (No. 2). Half -fill 

 the bottle with clear lime-water and insert the 

 stopper. (See Fig. 6.) 



1. Apply the mouth to tube No. 2, exhausting 



the .air from the bottle. 

 Describe result. 



2. Draw into the lungs 



through the lime-water 

 a considerable quantity 

 of air in this way. Does 

 any change take place 

 in the lime-water? 



3. Does inspired air therefore 



contain a large amount 

 of carbon dioxid? 



4. Apply the mouth to tube 



No. i (which passes 

 below the level of the 

 lime-water). Expel the 

 air from the lungs 

 through the lime-water. 

 Describe any changes 

 in the lime-water. 



5. What is your inference 



from 4? 



D. Name three differences between inspired and ex- 

 pired air. 



