CORN IN A RICH AND A POOR SOIL 



57 



To Make Clear the Meaning of " Carbohydrate." Procedure. Put a 

 tablespoonful of sugar into a tumbler; add a little water to make a thick syrup 

 (keep cool), then add about two tablespoonfuls of sulfuric acid. Note results 

 (Fig. 24). 



Questions. (a) Where did the carbon come from? 



(6) How did the plant get it? 



(r) Why is not sugar black since it contains so much carbon? 



(d) Of what is a diamond made? 

 . (e) What is the difference between a diamond and a piece of charcoal? 



To Show that a Farmer Must Observe Temperature Conditions When 

 Planting Different Seeds. Procedure. Proceed as in demonstration No. 5, 

 and plant a few seeds of wheat, beans and cucumbers in each crock. Place 

 one crock in the greenhouse and the other in a well-lighted place having a tem- 



Carbon 



FIG. 24. What happens when the chemically-combined water is withdrawn from 

 sugar? The carbon in the sugar is set free. Sugar is a carbohydrate = (carbon + water) 

 = 12 atoms of carbon (C) combined with 11 atoms of water (H2O). In this case the water 

 was withdrawn from the sugar by sulphuric acid. 



perature between 35 and 40 F. Observe results regarding germination 

 and growth. 



Question. Construct a table showing the best air temperature at which 

 some of the common farm crops grow the best, and the lowest temperature 

 at which crops can make some growth. 



To Compare the Rate of Germination of Corn in a Rich and a Poor 

 Soil. Procedure. Procure about four quarts of a rich greenhouse soil and 

 the same amount and kind of poor soil. Allow both soils to warm to the 

 same temperature. Moisten both and place in two one-gallon crocks. In 

 each plant about five kernels of corn. Place both in a favorable place, water 

 when necessary, and observe which plants appear first. Continue observations 

 until after four or five weeks. 



Questions. (a) Give reason for the difference in germination and 

 early growth. 



(6) Give reason for the difference in growth after four or five weeks. 

 (Consult text.) 



