T. Cossen University of Georgia Athens, 30602 ond Leslie Forsfer University of Arizona Tucson, 85721
II I
)i self-Paced Laboratory (OWY
for Nonscience M a i o n
Students majoring in Elementary Education a t the University of Arizona are required to take a one-semester course entitled Chemistry 12. The 150-300 students who register for this course each semester have a wide variety of backgrounds, interests, and abilities. Typically, 50% of the students have had no high school chemistry. Many in this category have a fear of the course, believing chemistry t o be a difficult suhject. Others are not sure of their ahilitv and lack self-confidence. Still others dislike chemistry because of a previous unpleasant educational experience. Of those who took chemistry in high school, .an averaee " of 60% (over a two-vear neriod) expressed a disllke for their experience with the subject. It was clear a t the outset that such student attitudes would have to he taken into consideration in any course developed for them. We have developed a laboratory-oriented course in which a major goal is to provide as much personalized instruction as possible, within the framework of a flexible, self-paced format. The philosophy underlying Chemistry 12 is one in which we offer to the student an opportunity for learning, but she must take advantage of it. It is not our intention to coerce students, but rather to encourage them so that they will enjoy the learning process.
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Instructional Philosophy
Ideally, we would like to give each student personalized instruction and a program tailored to the needs of the individual. To this end, the course has a unitized (modular) structure, with provision for optional study, and allows the student to proceed at her own pace. An attempt is made to provide for strong student-instructor interaction wherever possible. The means by which student performance is evaluated is a direct manifestation of this objective and will he described in the following section. A major objective of the Science 12 program (of which chemistry 1 2 is one of four c o m p o n e ~ t s ) i sto improve student attitude toward science and to offer encouragement to those students who lack self-confidence in scientific endeavors. The basic spirit of the course bears most directly on this objective: a t the outset the students are assured that there is no penalty for failure. In essence, a student can ohtain a grade of her own choosing by satisfactorily completing a prescribed amount of work. Students who meet the minimum requirements of the course are maranteed a made of C. and those who do not qualify for this minimum grade are considered not to have comnleted the course ("Incomolete" mades do not revert to another grade). No F or D grades are given. The evaluation of student performance is accomplished through a series of Competency Measures (CM's). They are constructed in such a way that a student may repeat them as often as is necessary to pass them. We have tried to incorporate into the syllabus a number of subjects which touch upon areas of everyday life and which might be suitable for discussion in the elementary grades. An effort has been made t o design experiments which can be used in the elementary school classrwm so that, by performing the experiments in this course, the
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prospective teacher will acquire the familiarity with apparatus and techniques directly related to her career. A further objective of this course is to expose the student to the processes by which knowledge is accumulated and organized in scientific endeavors. Included here are behavioral skills which the student is required to master, such as measuring, weighing, and graphing. Other units bave as their principal objective the illustration of some important ideas in chemistry. Topics have been chosen which are both important and easily understood with minimal background. Whenever possible, an attempt has been made to reinforce concepts learned in earlier units. Details
Chemistry 12 is conducted in a laboratory which is devoted exclusively to the course. This arrangement permits students to work on any experiment a t any time the lab is officially open (30-50 hr/wk depending upon the enrollment) and is an important aspect of the self-paced format of the course. There is at least one instructor in the lab a t all times when i t is open. The syllabus consistsof 20 units, each of which consists of several Activities (Appendix I). In each unit a list of minimal objectives to he attained is set forth. Some of these units, and Activities within a unit, are optional. The 20th unit is entitled Special Topics and serves as a means by which well-prepared students may elect to substitute indenendent studv for anv or all of the other units. To ohtain the minimum grade of C, a student must satisfactorily comnlete 11 specified units plus three additional units bf her-choice. Failure to complete this minimum amount of work results in an "Incomplete" grade. Some of the 11 required units contain optional Activities which need he completed only if a grade higher than C is sought. Such Activities deal with conceptually more difficult topics than are found in the required Activities. To obtain a grade of B, a student must complete 13 specified units, including the optional Activities contained therein, and, in addition, must complete three optional units of her choice. T o ohtain an A grade all Activities in all 19 units must he completed. The use of grades as a motivating factor is important in the context of contemporary student culture. Students register for the course in sections, and they attend the first meeting according to the section in which they bave registered. At this meeting the nature of the course is explained, and a Premeasure, which is composed of questions pertaining to the Activities the students will be performing in the course, is administered. Students may subsequently omit those Activities for which they answer the corresponding questions correctly. The results of the Premeasure can serve as a basis for evaluating student progress a t the end of the course. Several lectures are given a t designated, hut irregular, times throughout the. semester and are primarily concerned with conceptual Presented in part at the Southeastern regional meeting of the American Chemical Society, November, 1972.
material, such as atomic structure and bonding, which constitutes certain optional units. Students opting for these units are held responsible for the material that is covered in them, but attendance of the lectures is a t their discretion. Self-study materials are provided for these units. Since Chemistry 12 is a self-paced course a method for testing students is utilized which is consistent with this concept. Each unit has a CM associated with it, which is incorporated into the lab manual at the end of the unit ( ~ ~ p k n d II). i x When a student feels that she is ready t o take a CM the instructor issues the appropriate unknowns and fills in the appropriate blanks.. T h e student is required to execute the CM in the lab. Questions on it are maded as either acceotable or unacceptable. No ~ e n a l t v results from a n unacceptable performance on any portion of the CM. and anv portion mav he repeated as often as is necessary,with thd proviso th& a given CM can he taken only once during any given day. When all parts of a CM are completed in an acceptable manner credit for the unit is recorded. The crucial point to be made is that when the student returns a CM for madine i t is maded immediately, and in her presence, t i u s pr&idingan important opportunitv for personalized instruction and insurine periodic face-tb-face contact between each student and-an instructor. In a self-paced course i t is imperative that chemicals and apparatus he available a t all times. It was our original intent to provide the materials for each Activity a t a designated location in the lab and have the students move about from one station to another, but it quickly became apparent that reagents were used in areas other than those intended, and were not returned to their proper location. Recently, the reagents were color-coded hy applying a strip of Mystik tape to the containers. Although this did not prevent dispersal of the reagents, the problem of locating them was greatly reduced.
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Conclusions The self-paced format of Chemistry 12 appears to be very popular, judging from the response on questionnaires. Many students like the freedom of choosing their own hours in which to work. Indeed, the number of students in the lab a t any given hour is quite variahle, and during the more popular hours it is necessary to have more than one instructor present. It has never been necessary to restrict attendance, however. We have found that serious problems can arise near the end of the semester, as students attempt to repent of their sins of procrastination by engaging in a frenzy of activity. It is with the intention of eliminating excessive congestion in the lahoratorv that a cut-off date has been introduced. The new policy iequires that CM's for the first eight units be completed by the tenth week of the semester. After this date CM's are not administered for these units. Our fears that this would detract from the self-paced feature proved to be unfounded because students who complete the coume are generally well past the eighth unit by the cut-off date. There is no doubt that the teaching assistants connected with Chemistry 12 are the backbone of the course, and it cannot he overemphasized that instructors with great patience and tact are essential. Many students have expressed their appreciation of specific teaching assistants. In fact, this seems to be a reason for the popularity of certain lab hours and points out another virtue of the open lab, namely, that a student can find the instructor that suits her hest. An effort is made to maintain instructional continuity throughout the years by insuring that the experienced, as well as the inexperienced, teaching assistants are engaged in the program. Having hoth kinds of teaching assistants on duty together has proved to be an effective means for
providing on-the-job training. An advantage of this approach has heen a high degree of satisfaction evinced by the teaching assistants in performing as "real" instructors. Appendix I. Partial Syllabus for Chemistry 12 Note: A brief description of each Activity is included. Activities marked with an * are optional. Unit I. Mathematical Skills (Required) Activities are concerned with a review of 1) arithmetic with positive and negative numbers 2) arithmetic with fractions 3),~~~ interconversion of fractions and decimals 4) ~, exnressine numbers - in eawnential natation 5, alilhmeti~w i t h exponent~alnumbers 61 solvma sunplealgrbrair equations 11. Ohscrvatlonsnrid Qualitauw Inferences (Required) Activity 1) identification of an unknown from a closed set of possibilities 2) experiments are done that show it is the carbon dioxide in the breath that causes limewater to turncloudy 3) results of Activity 2 are used to make an inference as to the nature of the gas evolved when Alka-Seltzer is dissolved in water. III. Measurements and Quantitative Inferences (Required) Activity 1) measurement of length and experimental error 2) measurement of mass, use of the balance 3) measurement of liquid volume, use of the graduated cylinder 4) reliability of measurements and significantfigures 5) estimation of mass, volume, and length 6 ) measurement of area and volume (rectangle, circle, rectangular parallelpiped, and cylinder) 7) ecluations and measured ouantities: the relation between the height and volume of liquid in a cylinder are used to introduce the concepts.of linear and proportional relatianships *8)equations with more than two variables: experimental determination of the relation between the height, volume and diameter of a cylinder N. Formulas and Chemical Reactions (Required) Activity 1) chemical symbols and molecular formulas 2) chemical reactions: how equations are used to describe reactions; balancing equations 3) experimental verification of the Law of Conservation of ~~
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Mass
4) atomic and molecular weiehts 5 , idmtdying paniripantz in o chrrnical rraction 6, dlrertion of rhrrnirnl change; reactions that go to completion *7) concept of the "mole" V. Properties and Matter (Required) Activity 1) density determination of regular shaped object 2) density determination of irregularly shaped object 3) determinationof densitv bv buovanevmethod 4) melting point determin&& 5) effect of pressure on boiling point VI. Solutions Activitv 1 solutioncornpoiition-perrentagecalculations 2, expcrmwntal dererminatron of percent SaCl in a solution 3 1 preparation of solutiuns uf knuwn composition: wt wt percent using two liquids 4) ionic solutions: conductivity tests and concept of ions 5) balancing ionic equations 6) measurement of acidity;pH ~~~~~
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Appendix I I . Competency Measure from Unit VI Acc.
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NotAcc.
1. The percentage of salt in a solution prepared by adding-gof salt and-gaf sugar to 135gof water i s . 2. The percentage of NaCl in unknown L, 1
s
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- 3. Using only graduates, demonstrate to an inof a % structor the preparation of-g
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alcohol solution.
- 4. Discuss the way in whichions in a solution can complete an electrical circuit. - - 5. Balance the ionic--equation. -
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6. The pH of unknown %-is-. - 7. The amount of pH 13 solution required to
neutralize 5 ml of unknown f l s ml. - 8. Unknown Q d o e s ,does not contain C1-.
