FIRST SCIENCE BOOK 

 PART I. PHYSICS 



CHAPTER I 



MATTER AND ENERGY 



SECTION I 



DEFINITIONS 



1. Introduction. It is important, in beginning a new 

 study, to have some clear idea of what the study is to 

 be. The word science may perhaps call to mind strange 

 things of which we have heard, so that we think of it 

 as the study of uncommon things. We shall find, how- 

 ever, that science treats of very common matters, many 

 of which we already understand and most of which 

 affect our daily lives. The main difference between 

 scientific study and simply seeing things happen is a 

 difference in the manner of doing it. Scientific study 

 is orderly; each fact is studied in connection with 

 others that are like it, thus making the whole more 

 simple. In science we are not content to find that a 

 thing does happen, but we try to find out how it hap- 

 pens, what causes it, and what is its effect upon other 



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