AIR. V. 



27. Air is necessary for life of any kind. 



Experiment 35. Deep breathing and 



holding the breath. 

 Experiment 36. The effect of depriving 



a plant of air. 



28. There is air in the soil. 



Experiment 37. To show the presence 

 of air in the soil. 



29. The composition of the air. 



Experiment 38. The amount of oxygen 



in the air. 

 Experiment 39. The amount of carbon 



dioxide in the air. 



30. Oxygen. 



Experiment 40. To prepare and use 

 oxygen. 



31. Nitrogen. 



a. Dilutes the oxygen. 



b. Is used by plants. 



32. Respiration. 



a. The number of breaths per minute. 



b. The amount of air inhaled at each breath. 



Experiment 41. The capacity of the 

 lungs. 



33. Carbon dioxide. 



a. Used by plants. 



b. Exhaled by animals and given off by fires. 



Experiment 42. Carbon dioxide from the 



breath and from a candle. 

 (This subject, Air, is continued in the work 

 for the sixth grade.) 



