Heat 



93 



FIG. 45. But notice how it sags when it is hot. 



The stopper was in so tightly that I could not pull it out. 

 I might have done any of the following things: Tried to 

 pull the stopper out with a pair of pliers ; plunged the bottle 

 up to the neck in hot water; plunged it in ice-cold water; 

 tried to loosen the stopper by tapping it all around. Which 

 would have been the best way or ways? 



Application 25. I used to buy a quart of milk each eve- 

 ning from a farmer just after he had milked. He cooled 

 most of the milk as soon as it was strained, to make it 

 keep better. He asked me if I wanted my quart before or 

 after it was cooled. Either way he would fill his quart 

 measure brim full. Which way would I have received more 

 milk for my money? 



Inference Exercise 



Explain the following : 



121. Billiard balls will rebound from each other and from the edges 



of the table again and again and finally stop. 



122. In washing a tumbler in hot water it is necessary to lay it in 



sidewise and wet it all over, inside and out, to keep it from 

 cracking ; if it is thick in some parts and thin in others, 

 like a cut-glass tumbler, it is not safe to wash it in hot 

 water at all. 



123. The swinging of the moon around the earth keeps the moon 



from falling to the earth. 



124. A fire in a grate creates a draft up the chimney. 



