Ill: Instructional Aids and Equipment Chairman:
Daniel J. Macero, S y r a c u s e University
Plenary Lecture: Laboratory Aids: Promethean Gift or Procrustean Bed? S p e a k e r : Jerry A. Bell, Simmons College, B o s t o n , M a s s a c h u s e t t s 021 15 Many people have suggested that modern technology can be used to eke out the efforts of the instructor and make his work available to more students. In assessing the instructional roles that machines might play, we must remember that the student is the central character in the educational story. Even when the student is surrounded by thousands of dollars worth of equipment and lahoratory aids, his instructor is ultimately the most important and essential laboratory aid he has. Only the example of the instructor, for better or worse, tells the student what being a scientist is like. As a basis for deciding when machines are appropriate adjuncts to our personal efforts, I consider laboratory work as divided into three levels of abstraction: the accumulation, manipulation, and analysis of data. Laboratory aids that help a student attack the experiment itself, accumulate data, include not only well.de. signed laboratories and standard locker drawer equipment but the bewildering variety of communally used instruments whose rapid evolution has filled our laboratories. To teach the proper use and limitations of these instruments while still introducing some chemistry, we can turn to student-oriented instructional laboratory aids, i.e., use machines to teach about machines. Laboratory manuals, film-loops, slides, slide-tape programs, and television are ideal for these very concrete, non-abstract instructional tasks. We can make hooks and journals more easily accessible by using reproduction machines to make copies for an entire class and/or overhead projector transparencies for use in pre- or post-laboratory sessions. We should continuously explore more creative ways to use all these aids. For example, we should bring projectors and monitors into the laboratories to he used side-by-side with the relevant instrumentation and encourage our students to experiment with devices like television cameras and recorders as primary laboratory tools along with spectrometers and balances. Our role in teaching data manipulation is to introduce the concepts, check the calculations, point out the errors, and help set each student hack on the right track a t the derailment point. Practically any of the above auto-tutorial techniques (especially those that are interactive) can help a student master the concepts behind the manipulations. We also must take advantage of, rather than retreat from, the revolution in microelectronics and subsequent calculator boom that has placed unprecedented calculatioual power literally in the hands of essentially all of our students. Considering even more sophisticated machines, advocates of computer-assisted.instruction suggest that teaching data manipulation is a natural use of the computer. However, we should keep in mind that an enormous amount of instructors' effort will be required to create appropriate diagnostic programs. And, even with the right program, the computer is a very inefficient
teacher. It responds to only one kind of stimulus, the depression of a key on a keyboard. It has no way yet to respond to a puzzled look, frown, or hesitation in speech, often the first signals an instructor picks up and acts upon. Data analvsis (analvzine results. drawing conclusions. . and, perhaps, developing restable models) is at the high: est level of abstraction and neneralization: here the students are learning to formurate the questions to which their own data lead them. Much of the help they have available is from texts, monographs, journals, and reference materials; the library should he a natural extension of the laboratory. At certain stages of data analysis a computer can be a great aid as a simulation device either to test models preprogrammed by an instructor or as a primary laboratory tool for the student who programs it to test his own models. Sometimes, however, the wealth of information supplied by libraries and computers is so overwhelming that sorting is essential and there is no suhstitute for another human being, either other students or an instructor, to guide understanding. Despite the number of lahoratory aids available, most instruction is still carried on in some approximation of the tutorial mode. What I am suggesting is that we let machines do the work they are best suited to do, repetitive and automatic tasks, and save our own time to do those things only a human heing does very effectively and efficiently: guide problem-solving by example and hints, help students discover the imdications of what thev have done, and provide large doses of encouragement. Therefore, whether laboratory aids are a Promethean gift or a Procrustean bed depends upon the use to which we put them. We all would deny any tendency to be a Procrustes, fitting the students to the course rather than vice versa. But isn't it easier to say, "You'll find that topic on film loop 46B," than to take the extra few seconds to find out whether the student's real question will he answered by the film loop? Especially if we have put a good deal of effort into making a laboratory aid, we may have a natural tendency to feel that it should solve all the students' problems in that area. Being a Prometheus is more admirable; you are remembered as a symbol of one without whose help no good would have been accomplished. Prometheus did, however, have a liver problem; his success hrought him a lot of personal inconvenience. Likewise, when most of your repetitive teaching tasks are taken care of by machine and you are "free to teach," you may find that all the questions left to come to you will he difficult and challenging, filled with subtlety and amhiwity. But isn't this why you decided to teach in the first place? Then choose the laboratory aids with which you feel most comfortable and put together enough of them so you can achieve this goal. Volume 52, Number 7, January 1975
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Contributed Papers Pre-Laboratory Instructional Techniques David N. Harpp, and Elva Heyge, McGill
University, Montreal, Quebec For the past several years we have been experimenting with various pre-laboratory instructional techniques. Inasmuch as the total class size is quite large (-1000 per semester), methods which are efficient and flexible for disseminating information about safety measures, special experimental difficulties, equipment set-up etc. are of prime interest. Each pre-lab session involves from 50-100 students. We have used different media forms for these talks includina suoer 8mm films. static 35mm slides, overhead projector, biackboard, 35mm lap-dissolve projection and individual student filmstrips. "Double blind" evaluation methods were carried out using the teaching assistant as evaluator of subsequent student lah skills. Qualitative assessments of the classroom methods and demonstrations using the lap-dissolve technique were given. In addition, a novel, inexpensive filmstrip system for each student was described.
The Use of a Small Television Studio in MultiSection Laboratory lnstruction Wilbert Hutton and Dale E. Larsen, Iowa State
Uniuersity, Ames, Iowa Extensive use has been made of closed-circuit television in the instruction in large multi-section chemistry courses with two objectives in mind: (1) to utilize the advantages of color television to better demonstrate lahoratory tchniques and procedures and (2) to effectively "put" the professor in the laboratory to give the pre-laboratory and post-laboratory presentations so that each student is exposed to the same core of instructionalmaterial. To this end, a small TV studio has been constructed within the chemistry building. From this "mini-studio" the professor can broadcast "live" to his first lahoratory section meeting each week and simultaneously videotape his presentation for play hack to the other sections meeting later. The studio is equipped with the necessary accessories, controls, and special effects, and switching equipment to permit very acceptable presentations to be made without professional assistance and with a minimum expenditure of the professor's time. Demonstrations of laboratory techniques are presented in color from a library of prerecorded tapes which have been produced in the University's educational television facility or filmed "on location" using a small portable color camera. A feature of the installation is that conventional portable videotaping equipment is utilized; this equipment is simple to operate and can be used elsewhere in the department's teaching program. The details of the assembly of the mini-studio and an evaluation of this approach to laboratory instruction was presented.
Improving Pre-Laboratory lnstruction through Student "Hands-on" Use of Videocassettes
J. Emory Howell, Frank Woodruff and Hugh P. Garraway, University of Southern Mississippi, Hattiesburg, Mississippi Lack of student preparation has long been a hindrance to the attainment of the instructional objectives of laboratory sessions in general chemistry. When student prepara36
/ Journal of Chemical Education
tion is limited to glancing through the printed lahoratory instructions and listening to a lecture by the laboratory instructor before beginning the session, the quality of the lecture varies greatly from instructor to instructor and often the student does not have time to digest the information given within the laboratory period. Recently published manuals and modules contain "advance study" and "pre-laboratory" assignments hut even conscientious students often have difficulty conceptualizing the objectives and design of the assigned experiment sufficiently well to complete the assignment without additional help. A novel. flexible combination of e r o u.~and individual student "hands-on" use of videocassette recorded pre-lahoratow instruction a t the Universitv of Southern Mississinoi ha6 resulted in a dramatic improvement in pre-lahoratb~y preparation of students for general chemistry laboratory sessions which serve 450-500 students per year. Details of production of the tapes and a unique method of delivery to students were discussed. An outline of the content of representative tapes was presented in order to illustrate how the instructional objectives of the laboratory session are conveyed to the students without doing it for them. Instructor and student acceptance of student "hands-on" usage of videocassette pre-laboratory instruction has been excellent and data collected regarding attitudes towards usage and improvement in student achievement was presented. Projected expanded use at USM of student paced laboratory instruction enhanced by videocassette recordings was discussed briefly.
Personalized Video-Taped lnstruction as a Motivational Factor for Students E. G. Nash and E. J . Nienhouse, Ferris State
College, Big Rapids, Michigan Over the past several years a variety of video-taped instructional aids have been developed for our undergraduate organic chemistry course. While some of these have been prepared with our black and white portable VTR without the aid of sophisticated visual technology, others have been done in color using the specialized facilities of our Audiovisual Center. Recently the Science Building at FSC has been wired for cable TV emanating from the AV Center. Master control in the telecine room of this Center allows transmission of live or taped programs on two channels. In addition, a communications facility has been installed in lah-lecture rwms to allow instant communication between the instructor and the technician running the program in master control. Although a number of quality AV tapes and films are available commercially, we feel that personal involvement by the instructor can add an additional dimension toward motivating students to study and master the topics under consideration. Given the time, cooperation and support of the AV staff, a high quality video-tape can he prepared that can match or surpass the commercial product and, in addition, can contain as much (or little) as the individual instructor desires. Specifically, we would like to describe our experience in the development of color video-tapes in analytical organic chemistry (spectroscopy, solubility tests, qualitative tests, etc.), stereochemistry, and the production of "commercials" for organic chemistry. The use of these tapes with and without the new cable communications arrangement was discussed.
The Impact of Mini-Calculators in General Chemistry Laboratories
Examples from a Laboratory-Centered Chemistry Course
John E. Bauman, Jr. and Robert McFarland,
Gerald L. Abegg, Physical Science Group, Boston Uniuersity, Boston. Massachusetts
Uniuersity of Missouri, Columbia, Missouri A study was made of the effect of mini-calculators on the performance of students in a large beginning chemistry class. At t h e beginning of the 1973-74 academic year only 20% of the students possessed calculators; by the end over 70% had acquired or borrowed them. This represented a significant new resource available to general chemistry laboratories. Although performance grade-wise improved insignificantly for those with calculators, marked changes in the laboratory procedure occurred. All lab calculations could he finished within the 3-hour period assigned to experimentation; realistic practice problems employing actual experimental data could be introduced as both pre-lab and post-lab study; lab examples employing actual data could be placed on hour exams. On the negative side students without calculators exhibited marked antagonism towards the suggestion that such devices be recommended for the course. Their antagonism was shown to be due to their fear of unfair competition on timed hourly exams and not a t all as opposing the lab use of calculators. The advent of mini-calculators is predicted to change testing and grading methods significantly in a typical state university general chemistry program.
Teaching Chemistry Using an Interactive Mode
H. Graden Kirksey, M e m p h i s S t a t e Uniuersity, Memphis, Tennessee Much of what is learned in chemistry is based upon the results of considerable experimental work. In the urge to teach our students as much chemistry as we can, many of us often shortcut the experimental work and present summaries and resulting theories in an ex cathedra fashion. In an effort to create a more experimental approach to teaching-learning, the physical science group of Boston University has developed and piloted a sophomore-level chemistry course for college students preparing to teach high school chemistry. The course has laboratory work as its focus and is designed to be taught to classes of 24 students. The student experiments are constructed in such a way that the data are pooled and the conclusions are drawn bv the class as a whole. This effort results in an interactivemode of teaching and learning. This mesentation will outline the basic stratew of the course with a detailed description of the a p p r o a c ~ u s e din two of the chapters devoted to chemical equilibria. The first chapter, on analysis, is a sequence of experiments in which the student develops a systematic approach to the analysis of a metal sample. Working in the laboratory the students find that equilibria can he shifted by adjusting concentrations of one or more ions, and utilizing amphoteric properties of some substances. The second chapter is a unique approach to synthesis. Given the task of preparing baking soda, the class finds that the most direct approach yields nearly 100% side reaction. After examination of the Dossible comnetine . equilibria and trial runs on ways to shift these equilibria, the class develo~sa stratem for controlline the side reaction, thus producing the'hesired p r o d u k The points raised in this paper will be further developed in the next two papers. w
To integrate the laboratory and the lecture effectively, the student must learn to ask the right questions as he seeks evidence for the laws of chemistry. Since this questioning ability develops slowly, i t is necessary to select materials carefully and develop a class atmosphere in which students pool their data to draw conclusions. Examples of this topic selection and the instructional style utilized are shown in this paper. In an introductory chapter on equilibrium, the question "How does the presence of chloride ions affect the solubility of lead chloride in water?" is raised, and the students are sent to the laboratory to find out. The data, student analysis, graphical plots, a n d conclusions which lead to the Law of Chemical Equilibrium are discussed to show the interplay between the student and the materials. A second example uses a slightly different approach. A freezing point depression experiment with data is presented in the textual materials as a way to find the molar mass of solids. After a thorough analysis of the text data and a student discussion of the a ~ d i c a t i o nof this law. the student goes to the laboratory to conduct his own experiment. He selects and calibrates a svstem and determines the molar mass of one or more unknowns. In concluding the experiment the results of the entire class are used to show the power and limitations of the experimental method. A.
The Gray-Box Approach to Chemical Instrumentation
Peter O'D. Offenhartz, Physical Science Group, Boston Uniuersity, Boston, Massachusetts The use of black boxes is a common part of the laboratory experience. However, every student should also understand some of the operating principles of the instruments he uses, and above all he must learn to calibrate a black box by studying its response to controlled inputs. In this way, an instrument is transformed from a black box to a gray box, and the student learns that instrumental data are not to be a c c e ~ t e duncriticallv. The physical scienck group, now part of the Department of Science and Mathematics Education a t Boston University, has developed a large number of experiments for the undermaduate laboratory. Two in articular were designedto reinforce a critical attitude toward instrumental data. In the case of the p H meter, students measure the resnonse of the meter tovarious dc voltaees and find the relationship between indicated p H and voltage for various settings of the instrument. Then thev studv the relationship between indicated p H and the aiidity if standard solutions. The second experiment involves the use of a low-cost infrared grating spectrometer developed by members of the physical science group. Students calibrate the spectrometer with a laser, study the response of the detector to light of various wavelengths, and take their own spectra. The "lid" on this particular box is quite literally open-all components are visible-and the student can begin to appreciate not only the response of the instrument to controlled input but also some of the operating principles.
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Volume 52, Number I , January 1975
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