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SCIENCE OF HOME AND COMMUNITY 



Refrigerator. In order to keep foods from decaying in 

 warm weather, the refrigerator is now widely used. The 

 bacteria which cause decay do not thrive at low temperatures ; 

 hence food may be kept for some time in refrigerators. 

 Melting ice remains at a temperature of 32 degrees till all is 

 melted. The air around the ice is cooled and being heavier 



FIG. 33. Circulation of air in a refrigerator. 



sinks, and the warm air in the refrigerator comes in to take 

 its place. Thus there is a circulation of air in the refrigerator 

 similar to that which takes place in a room heated by hot air. 

 The walls of the refrigerator are made of materials which do 

 not conduct heat easily from the outside, and air spaces are 

 usually left in the walls, as air is a poor conductor of heat. 

 Ice cream freezer. The freezing of cream and other 

 liquids in the preparation of desserts is accomplished in an 

 ice cream freezer. A freezing mixture surrounds the vessel 



