4 GENERAL SCIENCE 



a field or lawn checks evaporation since the soil is so closely packed 

 together it is no longer porous, hence, allowing no place for the 

 water to rise between the dirt particles. 



In order to show that water does not rise as quickly through very loose fine 

 soil, fill two lamp chimneys with soil. Place at the top of one chimney about 

 two inches of fine, dry, loose soil and in the other chimney pack the soil 

 closely together. Place both chimneys in a basin of water. 



QUESTIONS 



1. What do people mean when they say that clothes on the 

 line " freeze dry "? 



2. Why will water evaporate from a lake in Arizona more 

 quickly than in New York? 



3. What is wrong with the idea that heat dries up water? 



4. Why do clothes dry better on a warm day than on a cold day; 

 on a dry than on a damp day; on a windy day than on a still day? 



5. Why are forests important to the rainfall of a country? 



6. Give a good argument for the conservation of the forests. 



7. What effects do the trees and the well-kept parks in a city 

 have on the atmosphere? 



8. How much moisture, on an average, do the students of your 

 school give off to the atmosphere during the day? 



9. In setting out plants, why should we take care to pack the 

 soil nicely around the roots, but to leave the soil loosely packed 

 about an inch from the surface? 



10. Why does a farmer cultivate his garden shortly after a shower? 



11. Why are fruits and vegetables spread out in thin layers 

 while drying? What is dehydration? 



12. Why are pans for evaporating water from sugar and salt 

 large and shallow? 



EFFECTS OF EVAPORATION 



Experiments to Show the Effects of Evaporation. Arrange in 

 a vertical position two thermometers with similar scales. Attach 

 to one of the thermometer bulbs a piece of cheesecloth or wick. 

 Allow the cloth to extend into a small bottle of water. The ther- 

 mometer to which the cloth has been fastened is called the wet 

 thermometer because water is rising in the cloth and evaporating 



