84 NATURE STUDY BY GRADES 



Visit a brickkiln and study the various processes in making 

 bricks. What is the proportion of sand to clay in a brick ? 

 How are bricks colored? Why are they burnt? What 

 effect has heat upon clay? How are bricks sold? What 

 do they cost? 



If convenient, let pupils make some adobes or sun-dried 

 bricks, and construct a small brick house. 



LESSON VI 

 BUILDING MATERIALS STONES 



Mention all the materials you can think of that are used 

 in building a house. Tell for what part each kind is used. 

 Why is stone generally used for the foundation ? What kind 

 of stone is used most commonly for this purpose? Where 

 is it obtained ? What does it cost ? Mention other kinds of 

 stone used in building. Discuss the properties, uses, source 

 of supply, and cost of limestone, granite, marble, onyx, and 

 other kinds of stone used in buildings. Note their hard- 

 ness, cleavage, color, beauty, and adaptability to their 

 respective uses, and account for the frequent or rare use of 

 kinds discussed. Use samples of each kind discussed in 

 the class. 



Visit a quarry, or stone works, and study the processes 

 of preparing stones for use, splitting, sawing, cutting, carv- 

 ing, polishing, etc., and the machinery used for these various 

 processes. 



Let the pupils bring samples of building stones and peb- 

 bles, and test them for hardness, cleavage, polish, etc. Teach 

 the children to recognize and name all kinds of useful stones 

 found near the school. 



