EXERCISE 3 

 HOW MUCH WATER MAY EVAPORATE FROM A PLANT? 



Materials. A potted plant ; sheet of dentist's rubber large enough 

 to inclose the pot; balance and weights. 



Directions for work. In order to determine the answer to the 

 question above, proceed as follows: 



Water the pot thoroughly. Wrap it in the sheet rubber and 

 tie the rubber about the stem so that water is prevented from 

 evaporating from the soil or pot. 



Weigh the plant at hourly intervals during the daytime for 

 at least two days. The pupils may take turns in weighing 

 throughout the day, the weights being recorded on the black- 

 board for the benefit of all. 



Tabulate the results as follows: 



Reference 



BERGKN and CALDWELL. Practical Botany, p. 18. 



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