4. HOW PLANTS FEED. 



Illustrative material : Dissolve a bit of camphor gum in a small bottle 

 of alcohol; then pour a part of the solution into a glass sauce dish, and, 

 when the alcohol has evaporated, show the recovered camphor. (If con- 

 veniences for boiling water are at hand, a solution of sugar in water may 

 be used.) 



Burn a little dry hay or straw on a plate, in the presence of the class, 

 and show the ashes. Show also a bit of starch, and a piece of charcoal to 

 illustrate carbon. ^ 



Solutions If we 

 put a teaspoonful of 

 sugar into a glass 

 of water and then 

 stir the water with 

 the spoon, the sugar 

 will soon pass out of 

 sight. We say it has 

 dissolved in the wa- 

 ter. We explain its 

 disappearance by 

 supposing that i t 

 has separated into 

 particles that are too 

 small to be seen, and 

 that these particles 



haVC etltered am n S 

 p art icleS of the 



F.O. ,0.- Diagram showing spaces be- 

 tween particles. 



water, something as a quart of peas might be poured 

 into the spaces between apples in a peck measure. (Fig- 



