162 



LEAVES 



145. LEAVES 

 Object. To show that leaves give off oxygen. 



Apparatus. Battery jar, funnel, test tube, and some water 

 plants, such as nitella or other submerged pond plants. 



Method. Place the plants in water in the battery jar, 

 invert the funnel over them, and fill the test tube with water 



and invert it as in 

 Figure 71. 



Set the whole ap- 

 paratus in the strong 

 sunlight. What hap- 

 . Battery jar pens? Remove it 



to a shady place. 

 Result ? Again set 

 the jar in sunlight 

 and allow to remain 

 until the test tube 

 is filled with the 

 gas. 



Remove the test 

 tube and test for 

 oxygen with a glow- 

 ing splinter as in 

 Experiment 1. 



Conclusion. State the result of your test. 



Note. If the water about the plants is charged with a little car- 

 bon dioxide before this experiment is made, there will be much 

 more oxygen produced than if ordinary water is used. 



Generate the carbon dioxide with marble and sulphuric acid ; 

 otherwise proceed as in Experiment 3 and pass a little of the gas 

 through the water. 



\0x\jgen bubbles 

 escaping. 



.Water plant. 



FIG. 71. 



