EXERCISE No. 68 

 AMOUNT OF WATER USED FOR PLANT GROWTH 



Object: To learn whether or not plants can use all the 

 moisture in the soil. 



Material: Four flower pots, enough of each of the four 

 kinds of soil to fill a pot, and four cuttings of geraniums 

 (corn may be used). 



Method : After the plants have grown to a height of three 

 inches, water thoroughly. Allow the pots to stand without 

 watering until the plants are badly withered. When it is 

 evident that they can no longer absorb moisture from the 

 soil, weigh the soil. Then thoroughly dry it by heating it in 

 a pan, weigh it again, and ascertain the difference in weight. 

 This difference is the amount of water in the soil that the 

 plants cannot use. 



Conclusion: What per cent of water remained in each 



soil that the plant was not able to use? Which soil 



would you prefer in a dry season? Which soil 



would you prefer in a wet season? What can be 



learned from this exercise about the usable amount of water 

 in the different soils?..... 



103 



