18 GETTING ACQUAINTED WITH THINGS 



Indian, with the life of the average boy or girl of today, 

 we would find a vast difference in the environment. The 

 Indian lived simply on natural foods ; if he had a fire, 

 it was rarely used for anything but cooking ; his shelter 

 was primitive and his methods of transportation and 

 communication even more so. Contrast his life with 

 that of the boy or girl who reads these lines paved 

 streets ; rail, motor, and air transportation ; the telegraph, 

 telephone, and radio; the elaborate homes and great 

 apartment houses of the cities ; the systems of water 

 supply, lighting, and heating that are now a part of 

 our lives would seem very strange to the Indian who 

 occupied this land not so many years ago. Man has 

 greatly changed his original environment and made this 

 world a pretty complicated place in which to live. This 

 book will help us to understand better how to enjoy and 

 control our environment. 



SELF-TESTING EXERCISE 



Select from the following list the words that best fill the blank spaces 

 in the sentences below and arrange the words in proper numerical 

 order. A word may be used more than once. 



chemical continuous particles electrons 



compound physical elements factors 



molecules largest oxide magnesium 



atoms electricity protons oxygen 



masses smallest * pressure separated 



united microscope rust inanimate 



composition environment electron weight 



Water, air, and light are three of a group of things which are 



called (1) of the (2) Matter which appears (3) is 



really made up of minute (4) called (5) which are (6) 



by spaces. These (7) are made up of atoms, and according to 



the latest theories, all matter is composed of still smaller electrically 



charged bodies called (8) and (9) When the element 



magnesium is burnt, it combines with the element (10) and 



produces the (11) magnesium (12) . Chemical changes 



