Common Science 





FIG. 47. Why did the bottle break when the water in it turned to ice? 



raindrops are carried up into colder, higher air while 

 they are forming, they freeze and turn to hail. When 

 snow or frost or hail or ice is heated, it melts and turns 

 back to water. 



But here is a strange fact : although heat usually 

 expands things, water expands when it freezes. Like 

 everything else, however, water also expands when it 

 becomes hot, as you found when you made a kind of ther- 

 mometer, using a flask of water and a glass tube. 

 But if you should put that flask into a freezing mix- 

 ture of ice and salt, you would find that when the water 



