III. CHEMISTRY.

A. Why reorganization is necessary.-In addition to the general reason calling for reorganization of science in secondary schools, which have been stated in the first section of this report, the following considerations apply particularly to chemistry:

1. The average person looks upon chemistry as a mysterious, occult science, tinged with necromancy. This almost superstitious ignorance prevents appreciation of the chemist's power to serve society. In industry it is likely to result in great economic waste through failure properly to utilize raw materials, develop byproducts, and apply chemical methods of control to processes of manufacture. The high-school chemistry course in its reorganized form should attract a larger number of pupils and do much to supplant this ignorance by a measure of broad understanding.

2. In the past, chemical laws, theories, and generalizations have usually been taught as such, and their applications in industry and daily life have been presented largely as illustrative material. In the reorganized course, this order should be reversed. Laws and theories should be approached through experimental data obtained in the laboratory and through applications with which the pupil is already familiar and in which he has a real interest.

3. In the past, chemistry courses over-emphasized theories, concepts, and information of value principally to these who will pursue advanced courses. A course which emphasizes the chemistry of industry, of commerce, of the soil, and of the household furnishes a wider outlook, develops a practical appreciation of the scope of chemical service, and moreover arouses an interest which leads naturally to further study.

4. The war showed the lack of a sufficient number of chemists trained to work out such problems as arose in that national emergency. The reconstruction period and the new conditions of world competition in trade will increase the demand for specialists in the chemical problems of manufacture. High-school courses in chemistry should therefore be so reorganized as to arouse an interest in the science of chemistry, and thereby stimulate more and more pupils to specialize later in this and related fields.

B. Principal aims.-The principal aims in teaching chemistry in the high school should be

1. To give an understanding of the significance and importance of chemistry in our national life. The services of chemistry to industry, to medicine, to home life, to agriculture, and to the welfare of the nation, should be understood in an elementary way.

2. To develop those specific interests, habits, and abilities to which all science study should contribute.

The powers of observation, discrimination, interpretation, and deduction are constantly called for in chemistry and are so used in this subject as to require a high type of abstract thinking. The principles and generalizations of chemistry are often difficult. For this reason chemistry should occur in the third or fourth year of the high school.

3. To build upon the earlier science courses, and knit together previous science work by supplying knowledge fundamental to all science. Coming after at least a year of general science, and usually also a year of biological science, the work in chemistry should further use these sciences. It should furnish a new viewpoint for the organization of science materials, and develop wider and more satisfactory unifying and controlling principles. By this means the desirable element of continuity in the science course will be secured.

4. To give information of definite service to home and daily life. This aim has been the chief influence in reorganizing high-school chemistry courses, and will undoubtedly produce further changes. The criterion of usefulness, as a basis for the selection of subject matter, should not be limited to the immediately useful or practical in a narrow sense, but should be so interpreted as to include all topics which make for a better understanding of, and a keener insight into, the conditions, institutions, and demands of modern life.

5. To help pupils to discover whether they have aptitudes for further work in pure or applied science, and to induce pupils having such aptitudes to enter the university or technical school, there to continue their science studies.

C. General considerations concerning content and method.-This statement is based on the assumption that chemistry will usually be given in the third or the fourth year of the four-year high school. Investigation shows that a little more than one-half of the four-year high schools present chemistry in the third year, and that pupils electing chemistry usually have had one year of general science and often a year of biological science.

(1) Difficulties. Some difficulties in organizing courses in chemistry on the basis of individual and specific pieces of work are:

(a) Many of the most important principles are impossible of direct or experimental proof. They can not be demonstrated in specific, individual problems, and hence can not be grasped easily by the immature mind. These concepts must be accepted on the basis of their service to the science and the useful conclusions based upon them, for example, the assumptions of the atomic hypothesis and the rule of Avogadro.

(b) The number of important principles and facts is so great that organization of the information supplied by discussion, investigation, and experiment is difficult. Appreciation of the science as

such is impossible until the bases for establishing relationships and controlling facts are developed.

(c) Many problems and questions which the pupil tends to raise involve complex phases of chemistry, or ideas too advanced for his understanding.

Some motive, some compelling desire to know, must actuate the pupil in any study which is really educative. Progress in chemistry, therefore, is dependent upon a specific purpose, a conscious need to learn the facts and their underlying causes or explanation. The educational value of any problem depends upon the degree to which the pupil makes it his own and identifies himself with it, rather than upon its concreteness, or the useful applications involved, or the familiar associations connecting it with other problems, important as these considerations are. The basis for organizing a course in chemistry should lie in the changing character of the pupil's interest and the increased intensity of his needs as a result of his growing abilities and of his increased power to direct and use them. A topic in chemistry which would have seemed abstruse and uninteresting a year or even a few months earlier may suddenly become a real problem to the pupil. Such questions as what the constitution of things really is, what properties the atoms possess, or why the volumes of gases have such simple relations to one another, may become problems of real significance to the pupil. Ultimate causes and reasons. appeal to the adolescent pupil. Problems having to do with home, farm, local industries, the civic and the national welfare, are limited only by the time and energy available for their pursuit.

(2) Laboratory work. The relation between class and laboratory work is a most important problem for the chemistry teacher. Unfortunately, theory and practice have not been properly related. Some of the reasons for this situation are:

(a) It is difficult to correlate recitation and experiment. One lags behind the other. The remedy is a greater flexibility in the program, so that the time may be used for either purpose as needed. There is a growing tendency to make all periods of a uniform, 60-minute length instead of 40 or 45 minutes on some days and 80 and 90 minutes on other days. This change helps to make possible a closer correlation between experiments and the discussion of them. (b) Experiments often fail of their object because of insufficient directions, failure to provide needful data, or lack of a definite and clear purpose. This needful information must be supplied, but in such a way as to stimulate interest and raise questions to be answered by the experiment itself. Some teachers prefer to take the first few minutes of each laboratory exercise in talking over the work, suggesting important questions, pointing out difficulties, and giving necessary cautions. It might be well to embody more of the infor

mation usually supplied by the text in the laboratory directions themselves, so that they would be thought-producing and stimulating rather than simply directions for manipulation and observation.

(c) Too many experiments involve repetition of work described in the text or have no outcome beyond the mere doing and writing in the note book. Unless the experiments contribute to the recitations and provide data or information which is used, they are largely a waste of time.

Laboratory experiments, to accomplish their purpose, must concern a problem or a question which the pupil seeks to answer because he is interested in doing so. The titles of experiments can often be worded so that they become suggestive by stating them in problem or question form. For example, instead of the title "Mordant dyeing," a better one would be, "Why are mordants used in dyeing?" Or, in place of " Equivalent weight of magnesium," substitute "How much magnesium is needed to produce a gram of hydrogen?" Or, for "Analysis of ammonia" substitute, "What is the most economical brand of household ammonia to purchase?" The mere rewording of a title itself is not enough. The question itself must be a vital one to the pupil either through his own independent thought or as a result of the stimulating influence of the class discussion.

Flexibility in the keeping of notebooks is desirable, provided that the essential facts and conclusions are always included. The notes should usually include a clear statement of the problem in hand; a description of the method of procedure, making use of a diagram of such apparatus as may have been used; and a statement of results and conclusions, with answers to any specific questions which have arisen. If the pupil's notes cover this ground, they should be accepted, and he should be encouraged to work out any plan of his own for the improvement of his notebook. To require all to use exactly the same plan may make the checking of notebooks more easy and their appearance more satisfactory, but it stifles the pupil's originality and prevents him from discovering and correcting his own faults in this direction.

The notebook has often been a fetish with chemistry teachers, and time has been demanded for making a record which, while beautiful in appearance and completeness, is yet full of needless repetition and useless detail. The notebook should not destroy the interest attached to an experiment, for the experiment is not for the notebook but for the pupils' clearer understanding of important chemical facts. Only when properly used will the notebook enhance the value of laboratory work.

The teacher in the laboratory should not set up apparatus, weigh out materials, or attend to other purely manual matters, which in most cases should be done by the pupils. The teacher should see

that pupils are trained to observe accurately, to draw correct inferences, to relate their conclusions to the facts of previous experience in and out of school, and to find the answers to questions and problems brought out.

It is proper that the teacher should perform laboratory demonstrations that are too difficult, too costly in materials, or too long, for student assignment. These should be done with model technique, for the pupils will imitate the teacher's methods. They should be recorded in the student's laboratory notebook just as any other experiment, but with the notation "performed by instructor."

(3) Aids to the chemistry teachers.-(a) Reference books and magazines. A part of the requisite equipment of every chemistry department is a well chosen set o reference books, available and in constant use. Each pupil will need a textbook as chief reference book, but he should find it necessary to use additional books. There should be provided duplicate copies of the better textbooks, other books on special subjects, articles, newspaper clippings, etc. These books are necessary in order that the pupil may investigate all the questions that arise. He will profit by the training which comes from learning how to find the answers to his questions from many sources of information. These books should provide entertaining reading by which the pupil's interest in things chemical may be stimulated and developed.

(b) Individual topics and reports. The study of special topics and reports upon them by individual members should be a regular feature of the class work. Pupils should be encouraged along the line of their special interests, and lists of topics should be suggested by the teacher from time to time. By this plan individual initiative and ability may be given encouragement and the whole class stimulated.

(c) Optional experiments. The pupils should be given encouragement to bring in materials to test in various ways and, whenever time permits, to perform additional experiments, the results of which may be reported to the class. In the chemistry laboratory it is not neccssary or desirable that all pupils be always at work on the same experiment. Even if the experiment is essentially the same, a variety of materials may often be used, and each pupil may contribute to the general result. For example, if colored cotton cloth is to be bleached by chloride of lime, let the pupils bring in samples from home so that a variety of colors may be tried out; or, if the presence of coal-tar dyes is to be tested in candy or food products, each pupil should be responsible for his own materials. In this way the work of the class will have a breadth and scope which will make the results more significant.