PREFACE 



THE purpose of the book is to introduce boys and girls in 

 their first science course in high school to a scientific study of 

 some of the principal features of their environment. Such an 

 introductory course in the scientific study of common things is 

 now generally recognized as an essential part of the educational 

 opportunities afforded by our secondary schools. 



The general method of the book in dealing with the topics, 

 or projects, selected for study is broadly inductive or heuristic, 

 the presentation following the time order of mental develop- 

 ment of boys and girls as closely as effective teaching permits. 

 This emphasis upon the psychological rather than the tradi- 

 tional logical or dogmatic method of procedure aids in realizing 

 the purpose of the book, which is to guide students in the 

 development of a scientific habit of mind, that is of a method of 

 investigating and mastering their projects and problems, which 

 is economical as well as effective. 



By dealing intensively and extensively with significant and 

 typical features of everyday experience, the student is led to 

 observe intelligently and with a definite purpose dominating his 

 observation, to test experimentally the observations, and in 

 due course to form a working understanding or theory of the 

 subject under consideration. This is vastly more educative 

 and valuable than any fund of so-called useful information a 

 textbook may offer. The information, therefore, which is 

 given in the book is to be used as a tool or means of under- 

 standing and acquiring better control of the situation in hand ; 

 it is not for the sake of some possible future emergency that 

 may never occur. 



Such a course as is here outlined helps to fulfil the function 

 of scientific instruction in our public schools. This function is 

 conceived to be the initiation of young students into what 

 scientific thought has accomplished for the human race. One 



