PREFACE 



Laboratory work and the experiences of home and school furnish an important basis for the course 

 in general science. The following outlines for experiments and demonstrations have been developed 

 so as to include the exercises which have proved most valuable for use in the first year of the high 

 school. The outlines are the result of the cooperative work of several high-school teachers through 

 a period of years, and have been tried with more than a thousand pupils. Experiments other than 

 those here included have been tried, bat through constant trial, elimination, and addition the work 

 has assumed its present form. 



It is the purpose of the outlines to direct the pupils into the habit of finding out about many kinds 

 of common problems in science. To do this in the best way common materials are used for experi- 

 mentation, since common and simple phenomena are likely to be more educative for young pupils 

 than those which are uncommon and complex. The materials needed are listed in connection with 

 each exercise. It is hoped that teachers will encourage pupils to use their own initiative in devising 

 new ways to perform the experiments, as well as in working out additional problems which are sure 

 to be suggested in the discussion of the experiments here outlined. At the close of the directions 

 for work, one or more additional problems are suggested, and the use of these as topics for 

 discussion will make the work more valuable. 



The exercises have been planned so that each one requires a shorter period of continuous atten- 

 tion than is usually true in the more advanced laboratory work in high-school science. Experience 

 has shown that first-year pupils work more effectively when the units of work assigned are relatively 

 short and definite. This plan results in a larger number of exercises than would be used in a more 

 advanced course in. science. In many cases, however, two or more exercises may be performed in a 

 single laboratory period. 



Supplementary or alternative experiments, which sometimes require more complex apparatus, are 

 often given. These supplementary experiments are indicated by the same arabic number as the 

 preceding experiment, but with a letter added. Thus 22 A is an experiment which may be used 

 in addition to or instead of Exercise 22. 



When diagrams, charts, or graphs are called for, the proper kind of paper for such work is 

 provided. 



The Directions to Students should be carefully read by teacher and pupils. These directions, in 

 addition to giving instructions about how to proceed, are designed to develop interest and give the 

 proper point of view. 



The outlines are provided in both bound form and in loose-leaf form. The loose-leaf form 

 makes it possible for teachers who wish to vary the order to do so. 



THE AUTHORS 



[iii] 



