In the Classroom
Cooperative Learning in Organic II. Increased Retention on a Commuter Campus
W
James P. Hagen Department of Chemistry, University of Nebraska at Omaha, Omaha, NE 68182;
[email protected] Organic II chemistry students enter the class with trepidation and often drop when the demands of the course become clear. I had seen DFW rates (grades of D or F or withdrawals from the class) increase from 30–35% to levels as high as 50% in the early 1990s. I report here a series of interventions that have increased retention by 20% on average with no concomitant decrease in performance on ACS standardized exams. Cooperative quizzes, interactive problems posed by the instructor, and extensive class notes have been added to a traditional lecture course to effect these results. Hypothesis I teach at a four-year urban university with a commuting student body. Many students work at least 20 hours per week. I surmised that the high DFW was due in part to inadequate conceptual development exacerbated by severe time constraints. My conversations with failing students revealed the absence of an internal dialogue. They had not developed a concept verification mechanism. They did not ask “Does it make sense in terms of other concepts I have seen?” These students, moreover, had not developed any means to judge the degree of their conceptual development. Such students often claimed to have done all the review problems in the chapter, but could not answer when I asked them what percentage of problems they typically answered correctly. Self-evaluation of their understanding had never occurred to them. I hypothesized that an internal dialogue and an external gauge of understanding might best be encouraged by improved conceptual communication. Such communication was clearly not occurring, either between the professor and the students, or between students themselves. Students would rarely ask me questions and would seldom have conversations among themselves before or after class. Since students often came to campus for one or two classes and immediately afterward rushed off to work or family duties, it is not surprising that little interaction with the instructor or peers was occurring. Another factor influencing the DFW rate was our laboratory course. The organic course sequence involves a lecture with no laboratory component followed by Organic II with a required lab. The lab requires seven contact hours per week. Typically, students do not expect to be in lab for all the hours scheduled nor do they estimate well the time required for homework. Students receive separate grades for the lab and lecture. Since the credit-hour value of the lab is close to that of the lecture, they are more than normally motivated to keep up the lab grade. Consequently, with so much time being diverted to the laboratory, students are challenged to keep up in the lecture course. While the students are trying to adjust to the demands of the lab, they also must cope with a significant change in the lecture portion of the course because neither Organic I instructor teaches Organic II.
The Experiment Groups are formed in the first day of class. Selection of group members is problematical. Arguably, the groups should be academically diverse and gender balanced. Practically, on a commuter campus, students have to be grouped by compatible work schedules. I place the students into diversified groups as a starting point, but emphasize that they must agree upon two separate meeting days and times. If the initial groups cannot agree on a schedule, they are free to move to another group. We plan to significantly reduce this problem by requiring the students to register for discussion sections at fixed times. I provide detailed information on the characteristics of effective group work and specific instructions on peer evaluation. A mock peer evaluation, done in the fifth week of class, serves as feedback to the students. Elected chairpersons, group minutes, and written weekly agendas submitted to me are features of the current groups. My full course syllabus describes the details of the group organization and is available in the supplemental material.W For the few students radically opposed to group work, I provide a contract for individual work. However, students cannot sign this contract until the fifth week of class. Few elect this option because all appreciate by the fifth week that the quizzes are challenging, that the peer points will probably help improve their grades, and that they actually enjoy working with their peers. My course is now organized into four testing cycles in which group quizzing leads to individual exams. The four exams count as 50% of the grade, and the final, an ACS standardized exam, represents 25%. Group quizzes are worth 20% and peer evaluation 5% of the point total. The grading scale is criteria based—sometimes called an “absolute” scale. Every testing cycle has at least one take-home group quiz. Another quiz format is the group class quiz, in which the group must come to agreement on a quiz during the class period. I also use double quizzes, in which individuals take the quiz first. This is followed by a group take-home effort. The score the student earns is the average of the two marks. Most students prefer take-home quizzes even though they complain that they are too challenging. However, a significant fraction of the class believes each of the other quiz types contributes best to their learning. Take-home quizzes promote extensive discussion. Class quizzes and double quizzes promote individual preparation. Dinan and Frydrychowski published a method featuring daily double quizzes with immediate electronic grading (1). This quizzing frequency was not practical in my class. In addition to the group quizzing, I use activities such as the “muddiest point” essay and think-write-compare problems to punctuate the lecture period (2). In the first of these techniques the students write a short essay during the last three minutes of the period detailing that portion of the preceding lecture that they least understood. This technique gives immediate feedback, but does not encourage internal and peer communication.
JChemEd.chem.wisc.edu • Vol. 77 No. 11 November 2000 • Journal of Chemical Education
1441
In the Classroom
The think-write-compare (TWC) approach is more flexible and applicable to organic problems (3). Here a question is posed; the students ponder it, write an answer, and then discuss the problem with their neighbors. Organic chemistry is a foreign language for students, and learning the subject requires mastery of many language skills. Students need to speak, listen to, and write in this language. They must learn the vocabulary (names, functional groups, elementary mechanistic steps, spectroscopic tools) and the grammar (reactions, mechanisms) in order ultimately to develop a rudimentary style of composition (retro synthetic analysis, mechanistic explanations, spectroscopic proof of structures). TWC problems model for the student the translational processes needed to learn organic chemistry. For example, consider the following problem in aromatic chemistry. The first item represents a particularly difficult passage in the language of chemistry because it contains a great deal of encoded information, particularly if the problem is delivered to the students orally. 1. Draw the structure of the product of chlorination of benzenesulfonic acid. 2. Benzenesulfonic acid + chlorine/aluminum chloride → ? 3. PhSO3H + Cl2/AlCl3 → ? Cl
O
4.
S
O
H
+
Cl
Cl / Al
S O
→?
Cl
O
5.
Cl
Cl
O
O
H
+
Cl
Cl
/ Al
Cl
→? First Cooperative Learning Quiz
Cl
As one proceeds down the series, the problem, as presented, is more decoded, and must be presented in writing. At level 3 the students are still faced with quite a challenge because they must translate PhSO3H into a benzene (not a cyclohexyl) ring attached to a sulfur (not to an oxygen) atom. They must further deduce that the sulfur has no lone pair to identify the SO3H group as a meta-directing group. Adequate time must be allowed for the students to think and discuss the problem, since much of the “translation” often requires peer help. Following Trahanovsky’s suggestion (4 ), I devoted one semester toward preparing a supplement containing all the lecture notes. I now write less in class, expecting the students to “translate” the written notes, converting chemistry presented as names to structures, and vice versa. Other authors have described more elaborate and intrusive approaches that involve more than cooperative learning methods (5–8). Dougherty, for example, described a number of items, such as a “Performance Contract” that guarantees a C to the student at the expense of considerable extra student and instructor time. He reports good results with his approach compared to those of a control section. However, the degree to which the improvements seen were due to cooperative learning methods rather than to other techniques simultaneously introduced is unclear. I argue that cooperative learning techniques alone are worth the effort and will produce results, since the interventions described in the literature all rely on these methods to a significant degree. The initial introduction to group work should be carefully considered. I provide a group take-home quiz in the first week of class to introduce the students to cooperative learning. This project is presented as a review of Organic I 1442
and a mechanistic preview of Organic II. Since the students will need to communicate ideas to each other clearly in their group work, and since I am a new instructor to them, I propose that we all need to develop common terminology and understanding of mechanistic concepts. Of course, it is also always true that students recall and understand only a portion of the material from the first semester. Cooperative work seems an ideal approach in this situation, since it calls upon the student’s existing conceptions (and misconceptions) and requires communication of them. I use material borrowed from Paul Scudder on this quiz (9). Scudder uses “organic reaction mechanisms to teach chemical intuition”. He assigns an elemental mechanistic descriptor to each step of a reaction mechanism. Thus, acidcatalyzed dehydration of an alcohol is described as Pt , DN, DEπ (Proton Transfer, Departure of a Nucleophile, Departure of an E lectrophile to give a π bond). Any postulated mechanistic step must be consistent with a set of guiding concepts. He makes an interesting heuristic analogy between his method and an expert system computer program. A computer might approach the solution of a mechanistic problem by applying database knowledge (elemental mechanistic steps) according to guiding concepts. (See the supplemental material for the slightly modified mechanistic descriptors and guiding concepts that I currently use.W) Scudder’s approach is perfectly suited to illustrate and help develop a conceptual dialogue, particularly when it is introduced in the form of a cooperative quiz. See the box for the current quiz.
1. Give an example (using structures and electron pushing) of the first eight of the elemental mechanistic processes. 2. Consider the following reaction in which a tertiary alcohol is treated with aqueous hydrochloric acid. Classify each of the following elemental mechanistic steps (a through e). Discuss each step in terms of the guiding concepts that you believe to apply. Determine which elemental step is most reasonable and which steps are not reasonable. Be sure to explain thoroughly for each possibility. Use additional paper as required. OH
+ a
b
c
H3O +
d
+ Cl − e O + H2
+
H3O + −
H2O
H3O +
Cl −
Cl −
HCl OH
−
OH O−
Cl H3O + −
H3O +
OH
HCl
3. Provide a mechanism for the following transformation. Show all the likely intermediates produced by each elemental mechanistic step. Show all the electron pushing and label each elemental mechanistic step. OH HO
H+
+ H2O O
Journal of Chemical Education • Vol. 77 No. 11 November 2000 • JChemEd.chem.wisc.edu
In the Classroom
This quiz is intended to lead students from definitions of simple mechanistic steps (problem 1) into the application of chemical common sense to mechanistic questions (problem 2). In problem 3 the groups are required to “discover” a mechanism for a reaction not explicitly covered previously. In the particular problem shown, many groups will carefully indicate that resonance occurs in the oxycarbocation intermediate. This care clearly reflects a debate upon which of the two resonance structures is the “correct” product of the [1,2] rearrangement step. The structure and reactivity of resonancestabilized oxycarbocations are important themes in the chemistry of aldehydes and ketones, the first chapter covered in the second semester. By solving this problem, the students have discovered and discussed a challenging concept before its full exposition in the course. In this way the quiz serves to carry mechanistic concepts into the material of the second course. When the graded quizzes are returned, specific misconceptions are addressed in the terms the students used to describe them. The lecturer is thus brought into the discussion and common understanding is developed. Results The effects of these interventions can be viewed in terms of DFW rates, final exam performance, student evaluation of the instructor, and student assessment of their own group performance and of group work in general. Most of these performance criteria are presented in Table 1. Prior to the fall of 1995, when these interventions began, the DFW rate averaged 40% and the median was 37.5%. After this semester the average and median were 19% and 18%, respectively, an improvement of 20% in retention. The averages of the x¯ values on the 1991 ACS exam over these same periods are 40.2 before the fall of 1995 and 40.5 afterwards. The corresponding averages of the median values are 39.2 and 39.2. This comparison indicates that the additional students retained are performing acceptably. A similar comparison of student evaluation of teaching shows a small improvement. The average responses before and after implementation are 17.7 and 15, respectively. As retention improves, student attitude might be expected to improve and with it student evaluation of teaching. The modest degree of improvement is not surprising, however, since all these interventions are directed at improving peer interaction, peer learning, and retention. From the students’ viewpoint, the instructor’s role in orchestrating better outcomes in these areas is not obviously relevant in evaluating instructor teaching. Students enter my class comfortable with a teaching style based exclusively on lecturing. They tend to consider teaching something that only instructors can do. A semester’s exposure to cooperative learning does not completely overturn this preconception. The new burden of the lab added in the second semester also influences the evaluation adversely. Other assessment methods are anecdotal. Table 2 shows the results of a survey question that asked students to rate group work in general. Few believe the groups should be discontinued. As mentioned earlier, I have added an individual grade contract so that people can opt out of group work. Those who like the groups overall but suggest changes often complain about busy work (group minutes) or the method of choosing groups.
Another group evaluation question posed (following Angelo and Cross [2]) was “Have you learned or understood more with the group than without the group? Give a specific example of something you learned from the group that you probably wouldn’t have learned on your own.” Typical responses to the first question are that the group enhances learning. Some comments were that the group “made me work harder”; “the learning-by-teaching phenomenon definitely kicked in”; and “the group [made me learn] more than you could possibly fathom.”
Table 1. Performance Criteria YearSemester 1992-2
ACS Exam 1991a
ACS Exam 1994b
DFW Student (%) Evaluationc 39 18.2
M = 44, x = 44.6 σ = 11.0, N = 27
—
1993-1
M = 36, x = 36.7 σ = 9.2, N = 61
—
36
16.7
1993-2
M = 39, x = 41.3 σ = 9.25, N = 25
—
36
14.3
1994-1
M = 41, x = 42.0 σ = 8.38, N = 67
—
29
20.6
1994-2
M = 37, x = 36.2 σ = 8.91, N = 25
—
52
18.6
1995-1
M = 38, x = 40.3 σ =11.5, N = 51
—
48
17.8
1995-2d
M = 33, x = 35.3 σ = 8.86, N = 35
—
33
19.4
1996-1
M = 37, x = 37.8 σ = 11.8, N = 38
M = 44.5, x = 45.5 σ = 9.82, N = 38e
26
14.3
1996-2
M = 39, x = 41.0 σ = 8.53, N = 25
—
17
12.7
1997-1
M = 40, x = 40.4 σ = 10.4, N = 53
—
33
18.4
1997-2
M = 37, = 40 σ = 11.14, N = 18 M = 41, x = 42.95 σ = 13.24, N = 37 M = 36.5, x = 36.7 σ = 11.3, N = 24
—
11
11.5
M = 48, x = 46.4 σ = 9.63, N = 31
M = 44, x = 44.74 σ = 9.59, N = 23
M = 43, x = 45.4 σ = 9.1, N = 30
1998-1 1998-2 1999-1 aACS
—
9 f 17.3/12.2 f .
19
18.6
18 f 14.4/18.7 f .
norms for 1991 exam: M = 32.3, x¯ = 33.9, σ = 11.62, N = 2025. exam: M = 38.3, x¯ = 38.92, σ = 11.22, N = 3296.
bACS norms for 1994
c These numbers represent the average of the responses to eight evaluation questions. The smaller the number, the better; 8 is the best possible. d Group eA
method began, in part.
large section was divided and separate forms were used.
f Two sections were taught. The DFW% is the combined rate from both sections.
Table 2. Assessment of Group Work Year (Spring Semester) Response
Useful/definitely continue Continue Continue with modifications Not useful/discontinue
1996
1999 Section 1
Section 2
No.
%
No .
%
No.
%
34
56
11
44
14
61
9
15
4
16
5
22
13
21
8
32
4
17
5
8
2
8
0
0
JChemEd.chem.wisc.edu • Vol. 77 No. 11 November 2000 • Journal of Chemical Education
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In the Classroom
Conclusion A limited introduction of cooperative learning into Organic II has resulted in significant improvement in retention with no decrease in performance on an ACS final exam. Extensive lecture notes permit a more open and flexible use of class time, which enhances dialogue while maintaining coverage of the material. W
Supplemental Material
Supplemental material for this article is available in this issue of JCE Online. This material includes a syllabus, a rationale for group work, a minutes form, instructions for peer evaluation, a guide to study groups.
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Literature Cited 1. Dinan, F. J.; Frydrychowski, V. A. J. Chem. Educ. 1995, 72, 429. 2. Angelo, T. A.; Cross, K. P. Classroom Assessment Techniques: A Handbook for College Teachers, 2nd ed.; Jossey-Bass: San Francisco, 1993. 3. For suggestions for other useful cooperative activities see Olmsted, J. A. III. J. Chem. Educ. 1999, 76, 525. 4. Trahanovsky, W. S. J. Chem. Educ. 1968, 45, 536. 5. Katz, M. J. Chem. Educ. 1996, 73, 440. 6. Felder, R. M. J. Chem. Educ. 1996, 73, 832. 7. Dougherty, R. C. J. Chem. Educ. 1997, 74, 722. 8. Coppola, B. P.; E g¯ e, S. N.; Lawton, R. G. J. Chem. Educ. 1997, 74, 84. The authors describe the use of semi-structured groups and open-ended group problems in the context of a wider program. 9. Scudder, P. H. J. Chem. Educ. 1997, 74, 777.
Journal of Chemical Education • Vol. 77 No. 11 November 2000 • JChemEd.chem.wisc.edu
