EXPERIMENTS AND PRACTICAL WORK 73 



HEAT-GIVING FOODS 



(See Tropical Readers, Book II, pp. 140-144.) 



Expt. 151. Heat-giving Foods. Collect small samples 

 of five heat-giving foods, e.g. arrowroot, rice, corn, yam. 



Expt. 152. Many Foods contain Starch. 



(a) Prepare starch from yam, corn, potato, and rice, 

 by grating or pounding, putting on a piece of muslin, 

 washing and squeezing through the cloth into a vessel; 

 allow the fine grains of starch which pass through to 

 settle. 



(b) Pour iodine on to a slice of Irish potato, and ob- 

 serve the dark-blue coloration, due to the presence of 

 starch. 



Expt. 153. Sugar found in Plants. 



(a) Prepare sugar from cane juice by adding lime 

 (about one tablespoonful to a quart), skimming, and 

 evaporating a small quantity. 



(b) Squeeze some juice from an orange or pineapple, 

 put it in a vessel, and evaporate it; observe the sugar. 



Expt. 154. Oils obtained from Plants. 



(a) Coconut Oil. Find out how coconut oil is pre- 

 pared, and write an account of the method. 



(b) Oil in Citrus Fruits. Squeeze the fresh rind of a 

 tangerine or shaddock into a candle flame, and observe 

 how the oil takes fire. 



Expt. 155. Effect of Heat on Starch. Soak some rice 

 grains in hot water, and note how quickly they swell. 



Expt. 156. Fat is a better Heat - producer than 

 Meat. Put a lighted match to a bit of lean meat and 

 to a piece of fat, and observe which burns more readily. 



Expt. 157. Tapioca. Obtain some tapioca, and write 

 an account of how it is made. 



