High School Chemistry as Preparation for College Chemistry Joseph S. Krajcik Department of Curriculum and Instruction, University of Maryland, College Park, MD 20742

Robert E. Yager Science Education Center, The University of lowa, lowa City, IA 52242

High school chemistry students who determine the pH of astream and compare their data with datacollected inprevi- ous years receive a chemical education different from stu- dents who measure the pH of a solution of hydrochloric acid supplied hy their teachers. For the former group, chemistry is being applied; students experience the relevance of the subject matter. For the latter group, most of the students do not know for what or when hydrochloric acid is used except for performing a step-by-step exercise during chemistry lab. Similarly, high school students who make soap, nylon, and other synthetic products in the high school chemistry lah- oratory receive a different education from those students who halance chemistry equations on paper using symbols that are not tied to any direct experience of the student.

During the '60's, curriculum innovators-often supported with funds from NSF-accepted the then widely held view that science would he interesting and appropriate for all if it considered science as known to scientists. Much time was spent with identifying the central themes, unifying ideas, conceptual schemes that characterized the particular sci- ence. The CHEM Study and CBA courses were the leading examples where the central ideas of chemistry were used as course organizers. Ten to 15 years later, chemical educators like Marjorie Gardner ( I ) suggested that a focus upon chem- istry in ways it is known to chemists may he inappropriate for many students. The Interdisciplinary Approach to Chemistry (IAC) program that emerged was an example of high school chemistry that focused upon applications- something considered completely inappropriate a t an earlier time. Even with the introduction of IAC and the applied focus, few teachers were ready for such moves (2). Most teachers have accepted the view that students must first know basic chemistry; then they can learn about applica- tions and perhaps some can even learn to use the informa- tion themselves.

Measuring the pH of natural waters, making nylon and other synthetic products, and measuring the air quality are not typical experiences for the high school student (3). Most high school students see chemistry as an exercise in memori- zation and in solving mathematical problems. For instance, all "good" chemistry students can draw the Lewis structure for ammonia, can name its geometric shape, and can state that it has an unshared pair of electrons. But few high school students know the importance this chemical has for agricul- ture. The typical high school course often presents a wa- tered-down version of college chemistry. Most high school texthooks are similar to college texts chapter by chapter. We need to examine whether this situation can provide the type of experiences that would he most beneficial for all high achool students.

What type of experiences should a student receive in high school chemistry? This nontrivial question needs to he close- ly examined. The examination of this issue is crucial since over 6,000 scientific and technological articles are written daily. This represents an increase in new knowledge of over 13% yearly (4 ) . Thus, what we memorize in a class may be

obsolete before we even forget it. This information explosion raises some very crucial questions that must he examined closely. Should high school students memorize a watered- down version of quantum mechanics when this model may be obsolete by the time they become adults? Or, should high school students work a t developing reasoning and learning skills that can help them throughout their lives? Chemistry experiences that require students to explain and to test provide experience with reasoning and thinking skills. Ap- plied chemistry and real world experiences provide more omortunities for use and development of student skills. . .

An argument frequently advanced by some high school chemistry teachers and chemical educators is that tradition- n l high schoul chemistry, which presents a simplified version of (dlr.ge rhemistry, is essential for successful completion of college chemistr? ( 5 ) . Often thii argument is used r t ~ justify the tupirs covered in high school chemistry. A ~ t u d y per- formed at thr I'nirersity of loa,a in the early 19:O's sheds some very important insights into this question.

This investigation examined the following general ques- tions:

(1) Do high ability high school students who have not experienced high school chemistry (hut who have high motivation, ability, and snecial tutorine available) oerform as well in a colleee ehem- istry course as highability high school students who have expe- rienced high school chemistry?

(2) Do the attitudes these groups of students hold toward science differ at the end of the college chemistry course?

This study consisted of offering standard college-level general chemistry to high school juniors during an eight- week summer session prior to their senior vear. Outstanding high s<.hwl students k r e selected to take-part in the stud; H;ilfof them had wmplrted high school chemistry and half . did not.

This course was announced as a part of a series of special offerings available through the Secondary Science Training Program (SSTP) for high school students; it was not adver- tised as a studv. About half of all the students who annlied were selected for participation by the SSTP administrative staff and the chemistrv instructional team. Half of the stu- dents selected came from Iowa schools; the remaining stu- dents came from various states in the nation. All students who were selected for the course were told that some of those selected would have had previous experience with chemistry and that tutors would he-provided fbr those needing special help.

All students participating in the study had a minimum grade point average for all high school courses of 3.0, re- ceived A's in high school scietxe, scored above the 80th percentile on available standardized examinations, and had the suooort of their hieh school teachers and counselors.

~ h i i ktudy was coniucted over a two-year period. Twen- ty-eight students participated the first year, 14 who had completed high school chemistry and 14 who had not. For the second year a total of 25 participated, 13 who had com-

Volume 64 Number 5 May 1987 433

pleted a chemistry course in high school and 12 who had not. Mean science and math ACT scores were similar for the four erouos.

he students lived in university dormitories. Special counselors were employed to live in the dormitory with the students, to monitor their study and to provide special assis- tance and support. All of the counselors were exoerienced high school t&hers.

The regular instructor for the general chemistrv course during the academic year taught both groups each oi'the two summers. He used the same textbook, laboratory guide, ex- aminations, and teaching procedures as employed during the regular session. The major difference, of course, was the daily schedule that characterizes the summer session. Each day classes met for a lecture followed by a three-hour labora- tory session, used also for discussions and quizzes.

Since this study was conducted, the general chemistry course a t the Universitv of Iowa has changed. No longer are laboratory periods assbciated with lectures. students now register for lahoratory experience indeoendentlv of the lec- ture section. ow ever, the course, the instructor, and the mode of instruction were typical of the general chemistry course taught then with the only difference being the avail- ability of the tutors as needed. Such availability of tutors is not common with the typical college section of general chem- istry. During the academic year the course enrolls several hundred students each semester. I t is viewed as a difficult course, which many students drop before completion and in which others do ~ o o r l v in terms of grades. Ao~roximatelv one-third of the students who initially enroll in the course drop. Of the remaining students, grades are equallv distrih- . . . uted from A to D.

-

The students all completed a chemistry pretest and an attitude instrument before instruction began. Records were kept regarding study time and time spent with a tutor. At the end of the eight-week period all students completed the ACS-NSTA Achievement Examination. the reeular final examination for the course, and the same attitude measure used initially. In addition, course grades were assigned.

The results obtained from the experiment are recorded in Tables 1 through 3. Table 1 provides a record of the means and standard diviations in the academic criterion measures. Table 2 lists the means and standard deviations for the hours tutored. Table 3 orovides similar information dealing - with the pre- and posttest attitude measures.

Statistical tests were performed on the data in order to answer the following specific questions:

(1) Does the performance of the four groups on the chemistry pre- test differ?

(2) Does end of the course performance as measured by the ACS- NSTA Examination. the course final exam. and the course final made differ for the four erouos? " .

(3) boes the number of hours tutored differ for the four groups? (4) Does attitude toward chemistry as measured by the pre- and

pasttests for the four groups differ?

With use of one-wav analvsis of variance. onlv Dretest . - . scores and hours tutored were found to differ significantly among the four groups. A statistical procedure, known as the

I While the statistical procedure of analysis of variance is a power- ful test to determine if means are unequal, it does not provide a way for determining which means are unequal. A significant F value from ananalysis of variance only indicates that at least one inequality holds among the means. To determine which means differ from each other, further statistical tests must be done. These tests are referred to as follow-up tests. The Tukey-Kramer follow-up test is one statistical test which can be used after a significant F value has been found to perform pairwise comparisons among the means. The Tukey-Kramer follow-up has the advantage of allowing for variable sample sizes, yet allows for the control of Type 1 error, that is, the rejection of a null hypothesis when the null hypothesis is true. Readers who wish to learn more on this topic should see Hays (9).

Table 1. Means and Standard Deviations of the Academic Criterion Measures

Chemistry Pretest ACS Exam Final Exam Final Grade

Source Means S.D. Means S.D. Means S.D. Means S.D.

Highschool 27.3 3.0 51.2 7.1 82.0 8.0 3.2 0.58 Chemistry First Year

High School 25.8 4.0 49.2 7.7 79.9 8.2 3.1 0.64 Chemistry Second Year

No High 15.7 4.6 49.3 7.6 80.6 8.0 3.1 0.62 School Chemistry First Year

NO High 15.3 3.6 49.7 7.0 80.9 8.1 3.1 0.66 School Chemistry Second

Table 2. Means and Standard Deviations for Hours Tutored

Standard Source Means Deviations

High School Chemistry 16.9 5.7 First Year

High School Chemistry 17.2 5.2 Second Year

NO High School Chemistry 60.8 1.8 First Year

No High School Chemistry 64.4 10.7 Second Year

Table 3. Means and Standard Deviations on Pre- and Posttests lor Science Attitude

Pretest ~osttest Source Means S.D. Means S.D.

High School Chemistry 8.6 1.2 7.8 1.1 First Year

High School Chemistry 8.8 1.0 7.4 1.3 Second Year

NO High School Chemistry 8.7 1.0 7.4 1.2 First Year

NO High School Chemistry 8.8 1.0 7.2 1.2 Second Year

Tukey/Kramer follow-up, was used to determine which of the means differed from each other.' This procedure re- vealed that the groups who had experienced high school chemistry had similar pretest scores; they also utilized a similar number of hours for tutoring. Similarly, the groups who did not experience high school had similar pretest scores and requested about the same number of hours for tutoring. However, when the two groups who had experi- enced hieh school chemistrv were comoared with the two - groups who had not experienced high school chemistry on oretest scores and hours tutored, there were significant dif- ferences. Examination of the data shows tha t the students who had experienced chemistry scored higher on the pretest than the students who had not had high school chemistry. In addition, the students who had not experienced high school chemistry utilized more than three times the total hours for tutoring services than did the groups who had experienced high school chemistry.

434 Journal of Chemical Education

These analyses indicate:

(1) Students who had completed high school chemistry performed better on the pretreatment chemistry test than did the students who had not comoleted chemistrv.

(2) The groups were similar at the end of the treatment period with respect to achievement as measured by the ACS-NSTA exami- nation, the course final examination, and the course grade.

(3) The number of haursspent with tutors toassit withthe study of chemistry was higher for the nonehemistry groups.

(4) The groups were similar with respect to their attitudes toward chemistry-both on the pretests and posttests.

The results of the study indicate that students of high ahility are able not only to perform satisfactorily in college chemistry without completing a high school course in the subject, they can do as well as students who had such a course provided they work harder. Of course, the experiment was conducted with high ahility students; similar results with students of lesser abilities might produce different re- sults. Nonetheless, the usual claim that traditional high school chemistry is important for all students as preparation for the study of che&istry a t the college level seems to be seriously challenged. Since most students who pursue col- lege chemistry have the characteristics of the above-average students involved in this study, the results may he more generalizable than one would first assume.

What do these results suggest about what should be taueht in hieh school chemistry? High school chemistry proibahly do& not have to he taught as a college preparatory course for high ability students headed for science-related careers. High ahility students appear to have the prerequi- site skills necessary to complete college chemistry success- fully. Teaching these students a watered-down version of college chemistry while in high school does not provide an optimal learning experience for these students. They may he bored or led to a false sense of security about the necessity for challeneine thoueht and work. Perhaps other learning ekperiencesshould b l offered to these &dents so they can develop in other ways. Surely the development of creativity and higher-order processing skills, the ahility to integrate and identify interconnections of suhject matter, experience with creating models to explain data they collected, and first-hand experience with applying and using science would be valuable activities for all.

Now what about regular students? Should they continue to have the traditional high school chemistry? We do not believe so. These students would profit more from experi- ence with high school chemistry if teachers worked a t devel- oping intellectual and learning skills such as reading, writ- ing, broportiona~ reasoning, comhinatorial reasoning, de- ductive logic, making sense of data, drawing inferences, usine mathematical skills. and usine information and evi- deuce to make decisions. These skill;; are necessary for stu- dents to learn independentlv and to continue to learn once they leave the class~ooms ofsecondary schools.

We believe strondv that societal issues should become more of a central c&e providing both student motivation and real situations for applying knowledge. A focus upon such issues provides a real reason for studying chemistry; and it can help students see the importance of knowledge. Instead of being told they will need knowledge, that is, that it will be useful, students will he the ones experiencing the use, the value, of applied, basic chemical knowledge.

To provide such learning experiences, the number of top- ics covered in the present high school chemistry course will need to he reduced drastically. Such reduction will allow the teacher not only to spend more time on the development of learning skills hut also on the integration of ideas and on the

incorporation of applications. This will mean greater focus on fewer ideas and the integration of those ideas with real exoeriences of students. Makine these interconnections be- twken chemistry and the students' previous knowledge will belo students internalize concepts and principles much moie clearly. Herron et al. (6) expressed a very similar view- point.

Our ideas call for restructuring the way high school chem- istry is being taught. Rather than structuring high school chemistry around various concepts, perhaps-a better ap- proach would be the study and analysis of various applica- tions or societal orohlems. One such examole would be the study of water c&ality. The topic of water quality has many directions for study allowing chemistry teachers to take ad- vantage of students' abilities and interests. Various avenues that could be explored include water treatment plants, water hardness, turbidity, chemical oxygen demand, and acidity- to mention just a few of the possibilities. Concepts such as solution chemistry, reaction rate chemistry, acidbase chem- istry will become a natural part of such an investigation. Such an approach would allow chemistry teachers to make chemistry more relevant by emphasizing connections to stu- dents' lives. orovidine a more motivatine environment. al- lowing studkits to seethe relationship between science, s&- ety, and technology, and providing a medium for learning concepts.

Zoller (7) presented two examples, including "Alcohol and Alcoholism" and "Smoking and Cigarette Smoke", that il- lustrate our approach of arranging high school chemistry around the study and analysis of applications or societal problems. These examples illustrate that chemistry does not have to be taught void of application or relevance to the student, but rather that applications can serve as a vehicle for learning concepts while a t the same time students be- come motivated and learn the relationship between science, their lives, and society.

Other examples of our approach would include the recy- cling of natural products, the analysis of air, soil analysis, and environmental issues. We realize that this approach is radically different, yet we helieve this approach will help develop young people to live in our scientific and technologi- cal society.

A recent survey by Razali (8) indicates that college chem- istry professors and science educators do not place a heavy emohasis on hieh school students learnine such traditional - concepts as electron structures, shape of molecules, neutral- ization reactions. and so on. Rather. colleee chemistrv pro- fessors would prefer to see high school stu&nts develop such personal traits and learnine skills as motivation and interest in science, ability to read a i d write, an inquisitiveness, good study habits, and the ahility to do experiments and solve problems. We believe strongly that our approach, which stresses applications and societal issues, will allow such per- sonal traits and learning skills to he developed. Who knows? Perhaps more concepts will be learned because students will be more motivated to learn them! Literature Clted

Washingfon, DC. nd. . 038-WO-00364. 3. stake, R. E.: Edey. J. Coae Studies in Science Education; U.S. Government Printing

Offir-. Waah indnn nC. 1978 Vnls. I S : 038-WO-038-WO-W376-3. ~, ~~ ~,

4. Naishitt, J. Megatrends; Warner: New York, 1982. 5. Harms. N. C.: Yscec. R. E.. Mr. What Research S o w to rho Science Tearher: NSTA: ~ ~~

washington. o?, &; vol. 3,471-14776. 6. Herron,J. 0.; De Ro9e.J. V.; Harris J.: Heikkinen, H. W.; Kallus, D. J.: Mellon, E. K. In

F o c u on E~cdianca: Chemistry: Penick. J. E.: Krsjcik, J., Eds. NSTA: Washington, DC; 1965:Vol. 3, ( 1 ) .

7. Zoller, U. The Sci. Teach. 1986.54 (9). 32. 8. Raza1i.S. Ph.D.Thesis,Universify of Iowa, 1986. 9. Hays, W. LStolislicr,3rded.:Holt: New York, 1981.

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