118 EFFECTS OF HEAT. 



Q. Why will a POT (filled with water) NEVER 

 BOIL, when immersed in ANOTHER vessel full of 

 water also ? 



A. Because water can never be heated 

 above the boiling point : all the heat 

 absorbed by the water after it boils, is 

 employed in converting the water into 

 steam. 



Q. How does the conversion of water into 

 steam prevent the INNER POT from BOILING? 



A. The moment the water in the 

 larger pot is boiling hot (or 212), steam 

 is formed, and carries off some of its heat ; 

 therefore, 212 deg s - of heat can never 

 pass through it, to raise the inner vessel 

 to the same heat. 



Q. Why do SUGAR, SALT, &c. RETARD the 

 process of BOILING ? 



A. Because they have a tendency to 

 fix water by chemical attraction; and 

 therefore retard its conversion into steam. 



Q. If you want water to boil, without COMING 

 IN CONTACT with the SAUCEPAN, what plan must 

 you adopt ? 



A. Immerse the pot (containing the 

 water you want to boil) in a saucepan 

 containing strong brine, or sugar. 



