42 



WEATHER AND CLIMATE 



4. Why winds blow in different directions about 

 low- and high-pressure areas. 



5. The causes and results of the various winds of 

 the world. 



TEST OF MASTERY OF THE TOPIC 



In your notebook complete the statements and answer 

 the questions. 



1. Warm air is __ than cold air. 



2. Winds blow because of a difference in ___ of various 

 parts of the atmosphere due to a difference in 



3. In what wind belt does North America lie? 



4. A cyclone is a pressure area. 



5. Winds blow in a direction about a high-pressure 



area. 



6. Air over a low-pressure area is (warm, cool) 



and (rising, falling) 



7. Winds blow in a 

 area. 



direction about a low-pressure 



8. Air over a high-pressure area is (warm, cool) 

 and (rising, falling) 



9. What are some of the conditions that cause unequal 

 heating of the earth's atmosphere? 



10. A tornado is sometimes spoken of as a cyclone. Is 

 this correct ? Explain. 



11. Weather changes come from the west in North 

 America because it lies in the known as the 



12. Convection currents are movements set up in 



or due to a difference in density caused by heat- 

 ing. 



13. An observer noticed that on a certain day the wind 

 was blowing steadily from the southeast toward the north- 

 west. How did the air pressure at the point of observation 

 compare with the pressure at some point northwest of the 

 observer? At which point was the air warmer? Was the 

 air rising or falling at the point of observation? 



14. Aviators frequently fly at altitudes where they can 

 take advantage of so-called "tail winds." Can you establish 

 a reasonable cause for such winds above the earth on the 

 basis of the facts which you have learned in this study? 



15. What cause would you establish for what the avia- 

 tor calls "bumpy air"? 



16. Aviators frequently strike air pockets. On the basis 

 of the facts learned in this topic, establish a reasonable 

 cause for these. 



TOPIC. 4. HOW THE WEATHER MAN PREDICTS THE WEATHER 



SUGGESTED PROBLEMS AND QUESTIONS 



1. What is the weather lore of your locality? 



2. How are thermometers used in foretelling 

 weather? 



3. Of what value are barometers in weather fore- 

 casting? 



4. Of what importance are winds in weather 

 prediction? 



5. How is rainfall measured? 



6. How is the weather map made, and for what 

 is it used? 



7. What are some of the recent advances in 

 weather forecasting? 



SUGGESTIONS AND HELPS FOR STUDY 



1. The answers to the following questions will 

 prove helpful in the solution of the problems suggest- 

 ed above. Some of these can be answered by experi- 

 ment, others by reading. 



a. Problem 1 



How much weather lore do you know? Make a list in 

 your notebook. Secure as many from your com- 

 munity as possible. Some are given below. 



WEATHER LORE 



1) "Mackerel sky never leaves the ground dry." 



2) "When the wind veers against the sun, 



Trust it not, for back 'twill run." 



3) "When the glass falls low, prepare for a blow ; 



When it rises high, let all your kites fly." 



4) "When the wind is in the east, 



'Tis good for neither man nor beast." 



5) "If hoar-frost comes on mornings twain, 



The third day surely will have rain." 



6) "If the sun goes pale to bed, 



'Twill rain tomorrow, it is said." 



7) "If Candlemas Day is bright and clear, 



There will be two winters in the year." 



8) "If March comes in like a lion it will go out like 



a lamb." 



9) "If on the trees the leaves still hold, 



The coming winter will be cold." 



10) "Evening red and morning gray 



Help the traveler on his way." 



11) "Evening gray and morning red 



Send the traveler wet to bed." 



12) "Long foretold, long last, 



Short notice, soon past." 



b. Problem 2 



How does the maximum-minimum thermometer aid 

 the weather man? 



c. Problem 3 



How may low- and high-pressure areas be detected? 



How does the mercury barometer work? 



How does the aneroid barometer work? 



What weather conditions usually accompany a high- 

 pressure area? A low-pressure area? 



How can a barometer be used to fortell weather con- 

 ditions? 



d. Problem 4 



How are winds studied? 



What information regarding weather do they give us? 



