56 Introduction to the Study of Science 



western states is the annual rainfall very light? Why? 24. Com- 

 pare the rainfall of the eastern slope of the Rocky Mountains with 

 the western slope of the Appalachian Mountains. Give a reason for 

 the difference. 25. How is hail formed? Describe the structure. 



26. How is snow formed? Why may a snowflake be called crys- 

 talline? 27. What are the useful effects of a snow blanket? 

 28. Under what conditions is dew deposited? 29. Which loses heat 

 by radiation more rapidly, air or solid objects? What does this 

 explain? 30. Under what conditions does frost form? 31. What 

 means may be employed to prevent damage from frost ? 32. Explain 

 how a local observer may predict frost. 33. (a) Compare highlands 

 and valleys as to their dangers from frost. (6) Why is frost more 

 frequent in valleys than on highlands? (c) How does the cold air 

 of the hills promote cooling of adjacent valleys? 34. What is the 

 value of irrigation when frost is threatening? 35. Why is a frost not 

 nearly so probable if the dew point is at or above 42 F. ? 36. Smudge 

 fires with their dense smoke may keep the temperature of an orchard 

 five or six degrees above that of the surrounding country. Would 

 this ordinarily be high enough to prevent an orchard from freezing? 

 Explain. 



SUGGESTIVE QUESTIONS 



1. " Without air life is impossible." Explain how fishes live. 

 2. In what ways does electricity enable us to prepare for unfavorable 

 changes in the weather? 3. When the wind is blowing directly from 

 the west, in what direction with reference to the observer is the low 

 area? The high? 4. If the air is still and an automobile without 

 a wind shield moves through it eastward at a rate of 50 miles an hour, 

 how may th.e occupants describe the apparent direction and velocity 

 of the wind? 



5. Show in what ways the climate determines the particular occu- 

 pations of people in your locality. The agricultural products. 

 6. Does frost or freezing kill a plant ? Explain your answer. 7. What 

 is meant by " black frost "? 8. If the air in a closed jar is not satu- 

 rated, in what different ways can it be brought to saturation ? 9. Are 

 clouds formed in your locality or do they always come from a distance ? 

 Give reasons for your statements. 10. Find the relative humidity 

 by means of a wet- and a dry-bulb thermometer in the early morning, 

 at noon, in mid-afternoon, and at night. Account for the differences. 

 11. Air is warmed by the furnace. What change occurs in its abso- 

 lute humidity? In its relative humidity? 12. Air is warmed by a 



