62 



PLANT GROWTH AND NUTRITION 



Conclusion. — What amount of water seems best for germina- 

 tion? Give your reasons. 



Problem :M: To determine tJie temperature best fitted to 

 cause peas to germinate. (Home Experiment.) 



Materials. — Soaked peas, sawdust, boxes. 



Method. — - Plant twenty soaked peas in each of three boxes 

 filled with moist sawdust. Put one box where the temperature 

 is about 90° F., another where the temperature is about 70° F., 

 and the third where the temperature is about 40° F. Give all 

 the same conditions of air, light, and moisture. Observe them 

 for ten days. 



Observations. — Tabulate the daily observations as follows : 



Conclusion. — What temperature seems best for germinating 

 seeds? Reasons. 



Problem 35 : To show that seeds need some part of the air in 

 order to grow. 



Materials. — Wide-mouth bottles, sand, soaked peas, corks, 

 paraffin. 



Method and Observations. — Fill five flasks with varying 

 amounts of wet sand so that one bottle contains very little air and 

 others are one quarter, half, and three quarters full of air. Put 

 an equal number of soaked peas into each bottle. Cork, and 

 paraffin each cork so as to allow no air to enter. Place where all 

 will have the same conditions of heat and light. Note daily 

 growth on a table like the following. 



Conclusion. — In which bottles do the peas grow best? Why? 



