A Course in Inorganic Chemistry for Students of Agriculture' EDGAR Z. FRIEDENBERG Oklahoma Agricultz~raland Mechanical College, Stillwater, Oklahoma AN WE make chemical knowledge more accessible to students by assisting them to see how chemistry can be used as one factor in the solution of problems of real concern to them? When chemistry is taught by traditional methods, applications of facts and principles are usually studied after the facts and principles themselves have presumably been learned. Considerable time and effort may be devoted to teaching such applications, but this teaching remains incidental. The student is not taught to seek in chemistry an arsenal of weapons dective in combating problems which arise in his living. Chemical knowledge, therefore, as all teachers know, often remains on a verbal level, and does not prevent even proficient students from getting into difficulties from which even a small working knowledge of chemistry would probably protect them. At Oklahoma A. and M. College, an attempt has been made to assure to students the ability to use chemistry when needed by employing such problems of living as a basis for the organization of the subject matter of the chemistry course. Since this approach tends to eliminate from the course study material, the usefulness of which to students, as people, cannot be demonstrated, the choice of problems for study becomes extremely important. The problems are not merely motivating devices, or vehicles for the display of chemical facts and principles; their role in the philosophy of the course is much more fundamental. If the student is to count on chemistry as a major source of help, he must have had experience in using it in all areas of need to which it can apply. A classification of students needs valid for most students a t Oklahoma A. and M. was therefore a necessary basis for the selection of problem topics. The following pattern has been devised subjectively by the author, working under the direction of Professor Alvin C. Eurich a t Stanford University, and has been found helpful in the development of previous courses as well as the course discussed in this article. The student needs:
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To be in as g d health as possible.
2. To be as personally attractive to others as possible. 3. To be an effective consumer of goods. To support intelligently necessary public services. 5. To earn his living by some worth-whiie contribution to the community. 6. To make effective use of his leisure time. Presented before the Division of Chemical Education of the American Chemical Saciety, 105th meeting, Detroit, Michigan, April 12, 1943. 4.
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To be able to defend himself against hostile environmental farces. 8. To participate effectively in the processes of democratic society. 9, To develop into an adult-a mature, self-reliant personality. 7.
Obviously, there is nothing specifically chemical about this pattern of needs, nor should there be. A student is a whole personality. His environment is a total environment, embracing many factors, but in no sense either atomistic or fragmentary. His needs do not, in general, differ as he moves from course to course. Instead, the techniques-the learnings-contributed to the fulfillment of his needs by each educative experience diier. It is apparent that knowledge and understanding of chemistry can contribute markedly to student effectiveness in each of the first seven areas, while the method of conducting the course may greatly augment growth in the 6nal two. The foregoing pattern is, of course, insw3ciently speafic to provide adequate guidance in developing a chemistry course to be taught to students of agriculture, and must be broken down into a much more detailed statement. I t does not reflect the agricultural objectives of the students for whom the course was designed, since the broad needs of all human beings are similar, regardless of vocational objective or place of origin. The fact that these students are largely Oklahoma boys who have spent most of their lives on farms does not invalidate the premise that they need to consume private goods intelligently, earn a living usefully, and use leisure time profitably and wisely. It does, however, affect markedly the kinds of goods they will consume, the manner in which they will earn their living, and the opportunities available to them for the enjoyment of leisure. Furthermore, the pattern as stated was not perfectly adapted to the teaching situation and had to be changed in order to avoid wasting the time of the students participating in the experiment. To avoid duplication of their efforts, i t was decided, a t the suggestion of Professors J. E. Webster and J. G. Lee who were responsible for the offering in Chemistry for students of agriculture, to disregard the first two areas of need, those related to health and to personal appearance. Most of the problems involved iil them require chiefly the application of facts and principles which form a part of the organic chemistry course which is later required of all agriculture students. Because of this deletion the course is called inorganic chemistry rather than general chemistry, although the
latter would correspond more closely with the philosophy implicit in adapting a course to student needs. The breakdown of the areas of need resulted in the statement of a series of problems within each area, samples of which are given below: Area One: The student needs to be as effective a consumer of goods as possible. How can chemistry help me:
To chmse suitable metalware for the plumbing system, kitchen utensils, and other exposed metal devices for my home. 2. To choose, use wisely, and conserve a fuel for heating my home. 3. To choose safe antiseptics, disinfectants, and germicides for various uses. 1
Area Two: The student needs to support necessary public services intelligently: 1. How can chemistry help my community or farm purify its water? 2. Haw can chemistry help my community detect crime? 3. How does chemistry help olrr government maintain quantity and material standards?
Area Three: The student needs to earn his living by some worth-while contribution to the community. It is within this area that the agricultural emphasis of the course becomes clear. Information collected from the students at the beginning of the course indicated that comparatively few of them expected to bemme "dirt farmers," but rather sought technical or semitechnical work in agriculture, such as a position as county agent, entomologist, or regional laboratory technician. Their vocational objectives were, however, so uniformly agricultural that area three could be conceived as a study of the contribution chemistry might make to important problems of agriculture and its technically related fields. Among these were: How may undesirable odors and flavors in milk be prevented? What physicochemical problems must he considered in producingfrozen dairy products? How can chemistry help control insects which may attack agricultural products? How can chemistry help me choose a fertilizer to replace lost essential soil constituents as cheaply a s possible? How can I adapt my faml production to the needs of industry for farm-produced materials?
Area Four: The student needs to make eflective use of his leisure time. 1. How can chemistry contribute to my enjoyment of photography? 2. Haw can chemistry contribute to my enjoyment of the fine arts?
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Area Fhe: The student needs to protect himself against hostile environmental forces. 1. How can I protect myself against the commoner types of war gases? 2 . How can I contribute most, through chemistry, t o conservat'on of critical materials?
Area Six: The student needs to participate effec-
tively in the processes of democratic society. (These are stated as needs rather than problems, since they served as factors in determining the course method. rather than as problems involving chemical fact and principle to be studied directly. The same is true of area seven.) The student needs: 1. To use libraries and other sourcesof information effectively, ju that his political hehavior will be well informed. 2. To participate in making decisions concerning the policies of his group, in dassroom or nation. 3. To distinguish reliable sources of information from those which may be unreliable, or sources of special pleading. 4. To understand the nature of the language in which he expresses himself, and to use it according t o its semantic limitations. 5. To understand the effects which the advance of science has had on possible standards of peacetime living, and on the validity of current economic concepts and social attitudes.
Area Seven: The student needs to develop into an adultmature, self-reliant, balanced personality. The student needs: 1. To be able to organize his work with the minimum of assistance from others, except experts called in to settle points beyond his experience. 2. To complete undertaken obligations promptly and responsibly. 3. To find his chief motivation in his awn values and goals, rather than in praise or blame. 4. To exhibit respect for the personality of others--tolerance and cooperation.
The objectives of the last two areas require that a minimum of coercive regulation and a maximum of flexibility characterize the program, so that students may have opportunity to plan their own work, carry it out in the way best suited to their needs, and assume responsibility for success or failure. But it is also essential that the instructor he able to predict most of the possible alternatives for carrying out the work, so that learning resources may be provided. Furthermore, in the interest of order, i t is necessary that certain coordinating procedures be adopted by the group and enforced against all its members. These policies should be open to modification by parliamentary measures, should they become oppressive, but while in force they must be rigidly followed. These considerations led to the adoption of the following methodology for the course: 1. A list of problems within each area of need, similar to and including those cited above as examples, is prepared and furnished to each student. 2. Each student chwses one topic in each area, except area three, in which two are chosen, and writes an intensive report on the contribution of chemistry to the solution of this problem. 3. A bibliography of available resources is provided to the students. These resources are augmented with funds derived from a fee charged the students in lieu of a texthook charge, since no textbook is used. 4. Each student submits a card listing, summarizing, and evaluating his readings, each fortnight. He is not required to read during each period, but must submit a card stating that no reading has been done if this is the ease. In certain cases, particular referenres may
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be declared required reading, to provide a common background for class discussions. Laboratory exercises related to the problems within each area are prepared and distributed to the students. Reports may consist of answers to questions on the experiment, or brief "quizzes" on its content. Class discussions consist c h i d y of considerations of the basic chemistry underlying each problem selected by one or more students. Selections are indicated on a specially prepared sheet which is returned to the instructor as soon as possible after the opening of an area, so that he may guide his preparations by it. Evaluation is carried out by carefully prepared, machinegraded tests designed to measure the ability of the student to use chemistry to help solve the problems involved in each area. Examples will be cited. Each laboratory section of the course elects two or three persons, depending on its size, to meet each week with the insmctor t o discuss difficulties which may have arisen with the work, t o suggest modifications in procedure, and to plan future work, so as to adapt i t as fully as possible t o the students' conception of student needs.
If the description of method is to be meaningful, examples of materials used in the course must be given. Some of the books which were made available to the students for extensive use were: , AND EASLEY, "Living Chemistry," Ginn 1. A x n e ~ s BUSH, 2.
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and Company, New York, 1942. BERNAL."The Social Function of Science," The Macmillan Company, New York, 1939. RIEOEL, "Industrial Chemistry," Fourth ed.. Reinhold Publishing Corporation, New York. 1942. RHODES,''Forensic Chemistry." Chemical Publishing Company. Inc., New York, :%0. ROGERSAND AS~OCIATES,"Fundamentals of Dairy Science," 2nd ed., Chemical Catalog Company, New York, 1935. (A. C. S. Monograph No. 41.) RICE, "Electronic Structure and Chemical Binding," McGraw-Hill Book Company. Inc., New York, 1940. GORTNER,"Selected Topics in Colloid Chemistry," Cornell Universitv Press. New York. 1937. U. S. Dept. Agr. YEARBOOK, "Sails and Man," Washington, D.C., 1938. MARTIN,"Scientific Principles of Plant Protection," 3rd ed.. Longmane Green and Company, New Yark, 1940. PREN~SS, "Chemical? in War," McGraw-Hill Book Company. Inc., New York, 1937.
This is by no means a complete list of materials used. nor are all the titles listed equally important. Obviously, a very wide range of difficulty is represented, from Ahrens, an elementary book which is invaluable because its unique arrangement coincides closely with that of the course, to Rice, which was useful only to the more able students for special reference purposes. The laboratory work performed must also he more completely described, if its role in instruction is to be fully understood. The following titles exemplify the experiments performed by the class: the effect of some reagents an them; to mix and apply a lacquer; to test the effect of certain reagents on painted wood and metal strips. 2. To study the relation of heat and temperature. 3. Tostudy the purification of water. 4. To study certain applications of chemistry to the detection of crime (finger print development, identification of stains, and disclosure of alterations in documents). 1. To synthesize certain paint pigments, and study
5. To study certain colloidal and physicochemical properties of milk; to stndy the eflect of lyotropic series on the rate of coagulation of milk and the role of calcium in such coagulation. 6. T o determine the percentage of copper in Bordeaux mixture.
The foregoing does not include several experiments of the more conventional type, designed to familiarize students with units of measurement, titration, colorimetric determination of pH,t he colloidal state, and others, which were derived from "Semimicro Exercises in General Chemistry," by Burrows, Arthur, and Smith, with the permission of the authors. The examinations by which student achievement in this course was evaluated were developed with one prime consideration in view: the examination must measure the kinds of behavior which i t is the objective of the course to foster in the student. No item is included, therefore, unless it is logical to suppose that a student must apply chemistry to the solution of an important problem, or some part of one, in order to succeed on it. I t is naturally an additional virtue if the items may be stated in such a form that they may be rapidly, conveniently, and accurately graded. It was found possible to prepare all examiuations-in a form suitable for machine grading without sacrificing the prime consideratioe. Some of .the items resemble conventional objective items very closely, while others are more unusuil in structure. To illustrate this the followiue samoles of items included in the first semester final examination are reproduced: A. Directions: In each of the questions asked or implied helow, select those of the nossible answers which are correct. and
answers, from none to five. 1. If certain of the following statements were true of aluminum, it would be much less suitable for the manufacture of pots and pans than i t is: 1. If there were only half as many aluminum atoms in the world as there are. 2. If aluminum did not become coated with a film of its own oxide when exposed to air. 3. If aluminum had 13 less protons in its nucleus. 4. If aluminum were less active than copper. 5. If aluminum lost electrons mnch more easily than it does. 2. Charcoal is used in water purification in order to: 1. Destroy pathogenic organisms that may be in the water. 2. Remove most odorous or colored impurities. 3. Soften the water. 4. Increase the epsilon potential of the water a t the expense of the zeta potential. 5. Show whether the bacterial content of the wstet has been reduced. 3. I n the time required to heat an enameled saucepan eontaining its awn weight in water t o the boiling point of the water, an empty saucepan of the same kind heated over the same size flame might be ruined. Among the reasons why thisis trueare: 1. A saucepan cannot he heated mnch above the boiling point of its contents for very long. 2. The coefficients of thermal expansion of metal and enamel are not precisely the same.
3. The specific heat of water is higher than that of most substances. 4. Enamelware is attacked more rapidly by boiling water than by water at room trmpcraturc. 5 The boiling of water wosumL.. lea$ than 101) ral./g. (Example abridged) ~
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Mr. and Mrs. Smith, a young couple with a good scientific background and a high priorities' rating, are setting up their new home and establishing themselves in the community. In doing so, they make the following choices:
66-6 Materials camposed chiefly of mixtures of metal silicates resist most kinds of corrosion. 67-7 Metals below hydrogen in the electromotive series cannot react with water containing no oxidizing materials, no matter how long they are exposed to it. 68-8 Metals denser than aluminum can react only with strong oxidizing agents. 69-9 When a solution of sodium hypochlorite is used as an oxidizing agent, common salt is the only product derived from it which remains in solution.
Until the statistical comparison of the experimental course and its control group have been completed, no 121. Mrs. Smith chooses pyrex baking dishes for her kitchen. 122. Mrs. Smith chooses a paint with a zinc-white base as a statements as to the superiority or inferiority of the wall finish for her kitchen. experimental procedure can be made, but certain sub123. Mr. Smith chooses copper plumbing for installation jective, noncomparative judgments may be stated throughout the house. now. The morale of the students in the experimental 124. Mrs. Smith chooses chloron t o help in washing the dishes course has been excellent. Despite the very much and dishcloths. 125. Mr. Smith chooses copper sulfate to help keep algae out greater responsibility imposed on the student, and the of the fish pond. greater latitude allowed in discharging it, there has been no widespread feeling of insecurity, and little Below, you will find listed a series of chemical facts and prinslackness. The results with reference to reading have ciples which may be reasons why the Smiths made the choices above. Some of these reasons are true statements, some are not been so good; the students' reading pattern tends to false statements. They bear two sets of numbers, 61-75, and become somewhat amorphous. But this has been par1-15. tially corrected by citing references more specifically. Identifying the statement by the first set of numbers (61-75). The student committee has functioned admirably and blacken the space marked T in your answer sheet if you believe in the author's opinion is largely responsible for the the statement t o be true, and F if you believe it to be false. Then, no matter how you marked each statement, assume every good morale maintained in the face of new and often statement t o he true and decide whether, if i t were true, it would disconcerting procedures. Factual learning appears to he a reason for one or more of the choices which Mr. and Mrs. have proceeded satisfactorily, although any judgment Smith made. If you believe i t would be such a reason, then on this point must be made cautiously; preliminary identi* i t by its second number (1-15) and, in the row on your answer sheet bearing the same number as the choice you think it statistical results are, however, favorable. The chief defect of the course as it is now offered justifies, blacken the space hearing the same number as the reason. appears to be over-intellectualization of the instructional method. I t should be revised to depend less on R-ns: reading and interpretation of laboratory results, and 61-1 Materials composed chiefly of mixtures of metal sili- more on utilization of visual aids and student particicates are usually highly resistant to mechanical pation of a less cerebral sort. The Oklahoma farm boy breakage. has not an active literary heritage nor the semantic 62-2 Cupric ions are very toxic t o plants. 6 3 3 Glass bas a lower specific heat and better thermal con- ability to interpret abstractions easily in terms of his ductivity than most metals. own living. Provision for these limitations is the most 644 There are fewer protons in a zinc atom than there are urgently needed improvement in a method which apelectrons in the orbits surrounding its nucleus. 65-5 Compounds containing copper are harmless to animal pears, in the light of our experience a t Oklahoma A. and M., to be promising. life.
