EFFECT OF HEAT ON MATTER 19 



increase of temperature, but the rate of expansion of 

 different liquids and solids varies considerably. 



Questions 



1. What effect does an increase in temperature 

 have on the size of a solid? 



2. Does a decrease in temperature have the same 

 effect? 



3. Why do telegraph wires which are taut in 

 winter sag in the summer? 



4. If street car rails are laid in the winter with 

 the ends touching, why won't the cars run smoothly 

 over them during the summer? 



5. What is meant by linear expansion? 



6. Name two metals which do not expand at the 

 same rate. 



7. With a change of temperature do liquids and 

 gases behave the same as solids? 



8. What happens to a bottle of milk if it is allowed 

 to freeze? How do you account for this result? 



9. If water did not expand when it froze, could 

 we use our present methods for obtaining the water 

 supply for cities? For removing sewage? 



10. Why is it necessary to lay water pipes below 

 the frost line? 



11. Why does concrete frequently crack in the 

 winter ? 



12. Why are air thermometers sometimes used? 



