50 A YEAR IN SCIENCE 



13. What is meant by distillation? 



14. State several ways in which the process of 

 distillation is of commercial value. 



15. Why is it impossible to cook potatoes, by boil- 

 ing, on top of Pike's Peak? 



16. How many calories of heat are required to 

 change one cubic centimeter of water into steam? 



17. Why is it cooler after the streets have been 

 sprinkled ? 



18. How does perspiration cool the body? 



19. What is the method used in the production of 

 artificial ice? 



20. Why can you see your breath on a cold winter 

 day? 



21. Explain how heat is transferred by means of 

 steam from the coal burning in the furnace to the 

 rooms of a house. 



22. What change takes place in the volume of a 

 substance when it changes from a solid to a liquid? A 

 liquid to gas ? A gas to a liquid, or a liquid to a solid ? 



