70 



SIXTH GRADE. 



PLANTS. 



Earth, air, and water play such an important part in the develop- 

 ment of plants it is well for the children to have some simple experi- 

 ments which will show how some of the work is done. 



OSMOSIS. 



1. Experiments. 



(a) Place some thin slices of red beet, carrot and turnip in a vessel 



of fresh water, in a 5 per cent, salt solution, and in strong 

 sugar solution. Examine after a few ho'urs. Remove slices 

 from salt solution and sugar solution, wash, and place in 

 fresh water. Compare results. 



(b) Treat bean and corn seedlings in the same way; leaves of 



geranium and coleus, allowing petioles to preject above 

 liquid. 



(c) Compare stewed prunes and raisins and dried fruit with un- 



cooked. 

 (dj Soak cucumbers in strong salt water; in fresh water. 



(e) Tie tightly a piece of bladder membrane over the large end 



of an argand lamp chimney. Place a strong solution of 

 sugar two parts sugar and one part water in the chim- 

 ney, allowing it to extend partway up the chimney. Im- 

 merse in water in a wide-mouthed vessel, having both solu- 

 tions on the same level. Support chimney by means of 

 corks. Note change in level of liquids. What is the direc- 

 tion of greatest flow? 



(f) Use same apparatus. Change liquids. Color fresh water in 



chimney. What is the direction of greatest flow? 



2. Absorption of Liquid Nutriment. 



Roots are composed of cells. Cell sap more dense than soil mois- 

 ture; flow of soil moisture through protoplasmic lining of cell wall; 

 cell sap diluted; cell sap of next cell dense, diluted sap flows toward 

 denser sap and so on until large ducts are reached. 



Plant peas, beans, corn or buckwheat in soil, distilled water, and 

 undistilled water. The water cultures can be set up by tying a thin 

 piece of cotton over the top of a glass jar and germinating the seed on 

 it. Note the time they grow equally well and give reason, and any 

 difference afterwards. 



