Weather 129 



storm, as they are formed by the condensation of moisture in the 

 air currents that precede a storm. 



Stratus clouds are dark colored, more or less broken clouds 

 that often appear low in the sky in the early morning or toward 

 evening at a height of from one-fourth to three-fourths of a mile. 



Nimbus clouds are the kind that affect us the most, since 

 they actually bring the rain. They are of a dark gray color and 

 have no special form. All storm clouds may properly be called 

 nimbus clouds. They often cover an area of thousands of square 

 miles and appear at various heights, according to the atmospheric 

 conditions. Frequently they are only a few hundred feet above 

 the earth's surface. 



SUMMARY 



Weather refers to the state of the atmosphere at any given 

 time. 



Weather determines in what sections of a country different 

 crops may profitably be grown. 



The primary cause of weather is the constant change in the 

 amount of heat in the atmosphere. 



The climate of a region is its average weather condition for 

 a long period of time. 



There are five zones of heat ; two frigid zones, two temperate 

 zones, and one torrid zone. 



Rainfall is a topic of great interest to all because our food 

 supplies are dependent on it. 



The distribution of rainfall is greatly influenced by the varia- 

 tions in the land surface. 



Clouds are caused by the condensation of moisture in the air. 

 The important forms of clouds are the cumulus, the cirrus, the 

 stratus and the nimbus. 



FACT AND THOUGHT QUESTIONS 



1. Name several ways in which your habits of life and your occupa- 

 tions differ in summer and in winter. 



2. Give several important causes of weather. 



3. What is meant by the climate of a region? 



4. Which affects our lives more, weather or climate? 



5. Name the zones of heat on the earth's surface. 



