WINDS AND WEATHER 



37 



Hunter and Whitman, My Oum Science Problems, pp. 82-86; 

 Science in Our World of Progress, pp. 58-64 



TEST OF MASTERY OF THE TOPIC 



Jn y(mr notebook comp , ete ^ statementS) answef t]l( . 

 Lake, Harley, and Welton, Exploring the World of Science, /questions, and comply with the instructions. 



Chap. 10 1. When condensation takes place a - changes to a 



Pieper and Beauchamp, Everyday Problems in Science, Unit __ 



3 2. Relative humidity is a comparison of the amount of 



water vapor in the air with the amount needed to - 

 it at the same temperature. 



Powers, Neuner, and Bruner, This Changing World, Unit 2 

 Skilling, Tours through the World of Science, Tour 3 

 Van Buskirk and Smith, The Science of Everyday Life, Chap. 



6 



Watkins and Bedell, General Science for Today, Chap. 3 

 Webb and Beauchamp, Science by Observation and Experi- 

 ment, Unit 7 (part) 



Wood and Carpenter, Our Environment: How We Adapt 

 Ourselves to It, Unit 2 



Special references 



Barber, First Course in General Science 



Jameson, The Mountains of Cloudland and Rainfall 



WHAT YOU SHOULD AIM TO ACQUIRE FROM 

 THIS STUDY 



1. An understanding of the conditions which cause 

 moisture in any form to come out of the air. 



2. How condensation differs from evaporation. 



3. How evaporation and condensation working to- 

 gether form a water cycle in nature. 



4. The differences between the various forms of 

 moisture, such as dew, fog, rain, snow, and frost. 



TOPIC 3. WINDS 



3. The dew point is that temperature at which (water 

 vapor, air) begins to (condense, evaporate) 



4. The relative humidity is always one hundred per cent 

 at the (freezing point, dew point) . . 



5. Why does dew always form close to the earth? 



6. Cirrus clouds are formed at (low, high) levels. 



7. From what kind of clouds does rain usually come? 



8. When a vapor condenses it (takes in, gives out) 



heat. 



9. Explain in detail what is meant by the water cycle in 

 nature. 



10. Fog is formed when some of the near the earth 



is cooled below the point and of the moisture 



takes place. 



11. Explain in detail what causes rain. 



12. Frost is formed by the of moisture when the 



point is below the point of water or 32 Fahren- 



SUGGESTED PROBLEMS AND QUESTIONS 



1. What happens to air when it is heated or 

 cooled? 



2. What causes winds? 



3. What are cyclones and anticyclones? From 

 what direction do weather changes come? 



4. What causes land and sea breezes and the 

 various winds of the world? 



SUGGESTIONS AND HELPS FOR STUDY 



1. The answers to the following questions will aid 

 in the solution of the problems. You will be able to 

 answer some from your reference study and some 

 from your own experience, while others will require 

 experimentation for their answer. 



a. Problem 1 

 What change is there in the volume of air when it is 



heated? 

 How do warm air and cold air compare in weight? 



heit. 



13. Drops of moisture are often formed on the outside 

 of water pitchers and cold water pipes in summer because 



the surrounding is cooled below its and some of 



the moisture 



14. On a cold day frost is often formed on the inside of a 

 window pane. Infer the cause of this. 



15. Modern electric refrigerators must frequently be "de- 

 frosted" of the ice which accumulates on the coils inside 

 the box. Infer a cause for this. 



AND WEATHER 



How would the pressure, due to weight, exerted by 

 cold air compare with that exerted by warm air? 



b. Problem 2 



Do all portions of the earth's surface always have the 

 same temperature? What are the conditions which 

 might cause a difference? 



What change would occur in a body of warm air next 

 to or surrounded by a body of cooler air? 



c. Problem 3 



What conditions cause a difference in air pressure on 



different parts of the earth's surface? 

 What is happening to the air over a low-pressure 



area? 

 What is happening to the air over a high-pressure 



area? 



How are the winds blowing over a low-pressure area ? 

 Why? 



In what wind belt is North America located? 

 In what direction is the earth rotating? 

 Would weather changes come from the west in South 



America? 



2. You may find the following new words and 

 phrases in this study : 



