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AIR 



e. Blow through the glass tube into some limewater. 

 Do you think that you exhale the same gas as a candle 

 produces? 



The illustration shows a method of collecting the 

 oxygen which is given off by a plant. In this case it 

 must be a water plant, but oxygen is given off by all 

 green plants. If you wish to perform this experiment yon 

 must collect some water plants and place them in the 

 bottom of a large dish. Cover them with a funnel, 

 which must be of glass, and fill the dish until the top 

 of the funnel is covered with water to a depth of. one 

 inch. Take a test tube, fill it with water, cover the end 

 with your thumb, and invert it in the dish, not letting 



any water escape. Slide the 

 test tube over the end of 

 the funnel and set the whole 

 apparatus in the bright sun- 

 shine. In a few minutes you 

 will see bubbles forming, 

 and in a day or two, the test 

 tube will contain enough 

 oxygen for a test. To remove 

 the test tube lift it from the 

 funnel, putting your thumb 

 again over its mouth, while 

 it is under the water, and re- 

 move from the water. Turn 

 the test tube right side up. 



