EXERCISE 44 

 WHAT CHANGES IN VOLUME TAKE PLACE WHEN WATER FREEZES? 



Materials. A short test tube or a small vial without a constricted neck ; a two-holed rubber 

 stopper to fit the test tube or vial ; a thermometer ; a glass tube about one foot in length 

 and fitting tightly one of the holes in the stopper ; ice or snow ; salt. ~ 



Directions. Fill the test tube or vial with water and close it with a two-holed rubber 

 stopper in which are a glass tube and a thermometer. The tube should not extend below the 

 lower surface of the stopper. Push the stopper down until the glass tube is about half full of 

 water. Fasten on the back of the glass tube a paper centimeter scale cut from cross-section 

 paper. 



Set the test tube or vial in a beaker or cup and surround it with a freezing mixture 

 made by adding ice or snow to a heavy brine solution. 



Watch the tube from the beginning, and record the changes in height of water in the tube. 

 Note the height of the column for each degree of change of temperature, and record each 

 measurement with the reading of the thermometer at the same time. 



After you have recorded your observations, try to make conclusions, with proof, on the 

 following points : What changes in volume take place when water freezes ? At what tempera- 

 ture does a given amount of water occupy the least volume ? When is water heaviest per 

 cubic inch ? When lightest ? Compare your results with results' known to be correct, which 

 will be given by the teacher or in the textbook. 



Additional problems. Why does ice float ? 



Why do water pipes burst when the water within freezes ? 



