CHAPTER III 

 AIR TEMPERATURES AND THE SEASONS 



31. Questions for Discussion. 1. Is your distance from the sun the 

 same in the morning and at noon? 2. Would any difference in your 

 distance from the sun at morning and at noon have any important 

 effect upon the temperature? 3. How can you account for differences 

 in temperature between morning and noon, and noon and evening? 

 4. What changes in air temperatures might make it difficult for a 

 balloonist to keep his balloon afloat at night? What adjustments could 

 he make so as to keep afloat at the same elevation ? 5. Why is it not 

 warm at the north pole during the season of long days in that region ? 

 6. What differences are there in the length and intensity of shadows 

 of objects or persons at noon, in the early morning, and in the later 

 afternoon? How are these differences explained? 7. If we have two 

 adjoining sections of level farm land from which wheat has just been 

 cut short, and plow one field so that the soil is finely pulverized, over 

 which field will the air be hotter during July and August? 8. In south- 

 ern Texas corn may sometimes be planted in February ; in Oklahoma, 

 in March or April ; in Iowa, in April or May ; in Minnesota, in June or 

 early July. Why is there this seasonal progression in corn planting? 

 Why is it not possible to grow the same kinds of corn in all these 

 regions? 9. Why cannot corn be grown in most parts of Canada? 

 10. What are the relative advantages and disadvantages of the daylight- 

 saving legislation ? 



32. How the air is warmed. It does not usually occur to 

 most people that the presence of the earth's atmosphere has 

 a great deal to do with its temperature. In a later section 

 of this book it will be shown that astronomical bodies, as 

 the moon and others, cannot have as even temperature as 

 the earth, because these bodies do not possess atmospheres. 

 However, the air itself does not get much warmth directly 

 from the sun's rays, even though the rays pass through it 

 The air is relatively transparent, and both heat and light 



