Paul Haake and James D I J C I O S ~ Wesleyan University Middletown, Connecticut 06457
A Freshman Laboratory That Turned Students
This note provides a brief description of a lahoratory program for freshman chemistry which merits attention because of the spectacular results in student enthusiasm and numbers of chemistry majors. The lectures followed a conventional organization of "General Chemistry" roughly based upon the outline of subjects i? Mahan, "University Chemistry." 2 However, the lahoratory, which was called "Environmental Chemistry," was conceived as a separate experience leading to the development of expertise in the intellectual and laboratory skills that are associated with analytical chemistry. These skills are of fundamental importance to most students who take freshman chemistryfuture chemists, physicians, biologists, paramedicals, etc. all have frequent need to use stoichiometry and other concepts involved in analytical chemistry. One now encounters chemistry students weak in analytical chemistrye.g., those who have never done a titration. While titrations are not a sacred part of the chemical curriculum, the intellectual and laboratory skills associated with doing titrations are essential for many students to function effectively in their field of work. This lahoratory program was designed to give students the self-satisfaction inherent in the preparation and purification of crystalline compounds and in quantitative analysis of interesting materials to considerable accuracy.3 The students in this lahoratory program first learned how to work with compounds by doing column chromatography and thin-layer chromatography. They then learned about acid-base equilibria through titrations, including the titration of vinegar and aspirin. Having learned these fundamental skills, a variety of analytical techniques were covered (Table 1). A further development of skills in working with compounds was acquired by the degradation, separation, and synthesis of thiamine. This experiment on an interesting compound, which was known to the students as a vitamin, involved the concept that one not only must be ahle to analytically determine what is present in an environmental medium, such a s water, hut one must he ahle to extract compounds and determine their structures. In summary, students developed some skills needed to accurately determine amounts of materials, to isolate and purify compounds, and to degrade and determine the structure of a n unknown. After these experiments, the students had a lengthy period for a lahoratory project of their choice. Some of the topics are listed in Table 2. During the laboratory project, the students were free to come into the laboratories a t a wide variety of times. Most of the students worked very hard-only a few put a minimum of effort into the project. But it provided an opportunity for all to develop independent, original thinking and work in chemistry-for most, their first experience of this kind. A common problem in university chemistry is the inclusion of well-prepared and poorly prepared students in the same course leading to boredom in the former and frustration in the latter. This laboratory seemed to he sufficiently different from the experience of the well-prepared students but sufficiently straightforward for the others, so that all of them appeared turned on to chemistry. Of the 37 students enrolled in freshman chemistry with this lahoratory, 19 chose chemistry for their major even though
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to Chemistry Table I. Outline of Freshman Laboratory in Environmental Chemistry
I1 111 IV
v
V1 VII VIII IX X XI XI1 XI11 XIV
xv
XVI XVII
orientatinn -~~ ~~-~~ Staichiornetry The Isolation of s Compound by Column Chromatography Thin-Layer Chrornsto~raphy(TLC) Acid-B~seEquilibrium. I. Titration of Vinegar Acid-&- Equilibrium. 11. Titration of Aspirin Determination of the Concentration of Sulfate Determination of the Concentration of Pho5phste in a Detergent Determination of the Concentration of Dissohed Oxygen in water The Riological Oxygen Demand of Water Spectrophotametry: The Phenomena of Color and Spectra Models of Molecules Determination of the Concentration a t Diesolved Iron netermination of the Hardness of Water Thiamine 1: Degradation and Separation Thiamine 11: Synthesis Laborstor" proiect
Table 2. Typical Laboratory Projects by Wesleyan Freshmen in Environmental Chemistry Laboratory --
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Bacterial Growth in High Phosphate Media Chloride Content in Surface Wsler a s s Hervlt of Saltins Hiehwsyr Sewaxe ~ i f f u ~ i oand n the Connectirvl Riuer-A Mathematical Model Destructive Distillation of Garbage Protein Determination in Food Determination of Phosphate in Deteipents Bacterioloeical Stvdv of the Connecticut River water Anslg.is of Sumner Brook Pollution Anslwis of Doolev and Pameache Ponds Analyai~of theoxohoro RGer Pollution in the Nnshua River Dissolved Oxyeen in ~ h Connecticvt s Iliver am a Function of Depth ~
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most entered with predominant interest in biology or medicine. There are a number of advantages that this educational experiment had over conventional lahoratory instruction for freshman. First, the laboratory work provided, because of its environmental emphasis, a focus and rationale for the entire course. Normally, only the very best freshman can see any clear relation between freshman chemistry and their existence, both present and future. This lahoratory provided objectives for learning which were sufficiently clear so that the students were able to make good progress on their own initiative. Second, the students had to acquire skill in analytical chemistry-both the lahoratory techniques and the calculations-skills which are frequently critical problems for freshman chemistry students. The lahoratory used a 1imited.numher of concepts 'Present address: Department of Chemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609. 2Mahan, B. H., "Uniuersity Chemistry," Addison-Wesley Publishing Co., Inc., Reading, Massachusetts, 1969. 3A labmatmy manual was prepared specifically for this course. It included the procedures for the experiments, introductions to environmental problems, and descriptions of the relevant chemistry not normally found in freshman textbooks. An introductory chapter on the fundamentals of stoichiometry succinctly gave the basis for most of the chemical calculations which were involved in the experiments. This manual was given to the students at the beginning of the course and may have been partially responsible for the sense of direction, purpose, and achievement which most studentsfaund in the co,rse. Volume 52, Number3, March 7975 i
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and methods so that the students developed proficiency. This enabled them to attack the laboratory project with real confidence in their ability to do the kind of laboratory work required for most projects. Learning was reenforced from week to week as one went from a simple titration to titrations resulting in estimates of dissolved oxygen to understanding the biological oxygen demand of water samples. Third, the concern of students for environmental chemistry and environmental prohlems led to great enthusiasm for the whole laboratory which was carefully called a t all times "Environmental Chemistryn-not "Analytical Chemistry." Some readers may object that the coverage in this lahoratory course was too narrow. Frequently, freshman chemistrv laboratories cover a wide-ranging variety of techniqies including physical chemical phenomena which some chemists argue are important for those students who will he taking only one or two years of chemistry. However, we must realize that most of the students taking one or two years of chemistry are going into such disciplines as medicine, paramedical fields, geology, and biology. Are these physical chemical phenomena the most important ones to cover for such students? They are clearly important to chemists and are of great interest to chemists hut the students going into these more or less biological fields will not normally need to use such physical chemical phenomena and they have little interest in them. In fact, they are going into these biological disciplines because they are not as capable in physical science as other students. It does no good to destroy the interest of a student in a course by providing material which is too difficult for him. Provide material that gives a student confidence, self-satisfaction, and enthusiasm and a superior performance will result! Provide material that discourages him and destroys his enthusiasm, and a poor performance will result! In addition, many of the most important activities in biological disciplines involve analytical chemistry: Consider the infusion of the correct amount of electrolyte a t the correct concentration into medical patients. Consider the injection of proper amounts of drugs by nurses. Consider the man" analvtical techniques now being used in geology to date mateiials and gain information about geolo&cal uroblems. Consider the many examples of chromatography, preparation of buffers, and analysis for materials that is part of many biological experiments. There is a great need for students who take only one or two years of chemistry to learn the laboratory techniques and principles which were covered in our course. It is unfortunate that a recent report4 of the Biochemistry Subcommittee of the Curriculum Committee, Division of Chemical Education, American Chemical Society did not consider the
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I Journal of Chemical Education
essential laboratory techniques needed in fundamental chemistry courses. Chemists have important responsibilities in meeting some of the prohlems in society that may challenge the survival of civilization. Manv eminent scientists have commented on the need for atrentnun to envinmmenrnl orublems and the need to diven come of our heir thinkerfrom careers in conventional scientific areas into environmental areas. Although these claims have drawn the counterclaims that environmental problems have been overly magnified, any rational person can see that, at the minimum, a need for more scientific attention to this area is justified. Even if the claims of future destruction of civilization by Forresters and by the Club of Rome are inaccurate6 there is no question about the future severity of the prohlems. We need to give students the knowledge to distineuish the real nrohlems from emotional bandwagons, . to discern charlatans and demagogues. There is a great need for more critical thinking and more effective analvtito students in this course. cal methods of the kind For example, i t may he true that much of the environmental concern about both phosphate and DDT was due to inadequate knowledge and uncritical thinking. Despite this, it is also true that inertia within universities bas led to very little change. It seems clear that-the best students are still entering conventional areas and are not being diverted into areas from which they might be better able to attack problems of concern for civilization and the United States.? This course was not only an effective way to teach essential chemistry, hut it also was a means of giving students greater competence in addressing prohlems of pre~entand future importance. This ahility enlarges the career choices of chemistry majors (at present, a matter of no small concern to American chemistry), and it widens the potential for future application of chemical skills for those who choose careers in conventional areas of chemistry. Further testing of this program is required, hut it was so eminently successful that we thought it wise to share it with our colleagues at this stage of development.
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*J. CHEM. EDUC., 50,203 (1973). JForrester, J. W., "World Dynamics," Wright-Allen, Cambridge. Massachusetts. 1971. 6Meadows, D. H., Meadows, D. L., Rangers, d., and Behrens, W. W., "The Limits to Growth," Universe Books, New York, 1972.
'This group of students demonstrated the effectiveness of action possible by relatively untrained people given some knowledgeable direction. This educational experiment may lend support to the ideas proposed by Barmann, F. H., Bioseience, 22, 706 (1972).
