ELEMENTARY SCIENCE 



CHAPTER I 

 INTRODUCTION 



Air, water, soil, heat, light, plants, and animals these 

 are the principal things that make up what we call nature. 

 You will find that your life is a sort of partnership with 

 nature. To live in it the best way, you need to under- 

 stand this partnership as well as you can. You need to 

 know how to do your part in it. Life is the most interest- 

 ing thing in the world. You want to find out all you can 

 about it so that you can make your own life as happy 

 and successful as possible. A good way to go at this busi- 

 ness of finding out about life is to study first the things 

 that are necessary to all kinds of life, plants as well as 

 animals, and see how these things work together to make 

 our own lives possible and pleasant. That is what we shall 

 do in this book. We shall study the seven things mentioned 

 in the first sentence. We shall study the conditions that 

 are necessary for our own lives, and this will help us a 

 great deal in finding out how we ought to live. 



For thousands of years men have been finding out more 

 and more about the world. Each year new knowledge is 

 added to the old, and this knowledge of nature is called 

 natural science. You have read about cavemen and other 

 ancient people, and you know that the savage men of long 

 ago had a hard struggle for existence. They did not under- 



