Research: Science and Education
New Directions in Teaching Chemistry: A Philosophical and Pedagogical Basis James N. Spencer* Department of Chemistry, Franklin & Marshall College, Lancaster, PA 17604-3003
The Current Status Most college-level teachers of chemistry proceed directly from a graduate program to the classroom without any stops for pedagogical training along the way. Most have little knowledge of the different learning styles of students or of the various classroom strategies and comportments that have been shown to produce effective environments for learning. Most teach what they were taught in the same way they were taught; that is, custom and tradition prevail. The emphasis has been on providing instruction rather than producing learning (1). There has been little formal introduction to the cognitive theories about how we learn or where source materials on the learning process might be found. Quite often a teacher’s career goes through recognizable stages of development. The beginning instructor’s goals are usually too high and only gradually is there an adjustment to more reasonable expectations. Then the realization that students really do not understand the material as well as their test scores might indicate sets in. At this point it is recognized that the ability to answer a test question does not imply mastery of a subject. Too often, chemistry instructors structure examination questions that can be answered by memorization or the application of an algorithm. Sanger and Greenbowe (2) It is possible for students to do well on conventional problems by memorizing algorithms without understanding…. It is possible for a teacher, even an experienced one, to be completely misled into thinking that students have been taught effectively. Eric Mazur (3)
The search then begins for ways of improving students’ understanding. More homework problems are assigned, more problems are solved in class, recitation sections are added, handouts are prepared and distributed. Unfortunately all of this we now know is not likely to improve the students’ ability for problem solving. Katona’s (1940) work on problem solving has shown that the least effective strategy for teaching students to solve problems is working examples for the learner. J. Dudley Herron (4)
When these exertions do not produce the desired and expected results, only one explanation is left to the instructor. The students must be at fault; they are uninterested, don’t work hard enough, or are less well prepared than they used to be. *Email:
[email protected].
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Faculty...assume those who fail to meet standards are underprepared, should study harder, should change majors, or do something else with their lives. S. Millar (5)
The remarkable developments in understanding of the learning process during the past 20 years now allow us to gain some insight into why these well-intentioned efforts do not succeed. Unfortunately, little of this increased understanding has found its way into the contemporary chemistry classroom or laboratory. Cognitive and Classroom Studies The following two classroom scenarios, taken from an example given in a recent report by Stevenson and Stigler (6 ), illustrate different approaches to learning. In classroom 1, the lesson today is fractions. A fraction is written on the board and defined in terms of its parts. Numerator and denominator are defined. The instructor ascertains that students understand the meaning of the terms and the students are asked how to represent other numbers as fractions. In classroom 2, the teacher enters with a pitcher of juice. She asks students to guess how many liters of juice are in the pitcher. “More than one liter,” answers one child. “One and a half liters,” answers another. After several children have made guesses the teacher suggests they pour the juice into some one-liter beakers and see. They pour the contents into one-liter beakers divided by lines into thirds. One beaker is filled and a second is filled to the first line. It is pointed out that one of three parts of the second beaker is filled. Then the fraction is written on the board. The procedure is repeated with other beakers to arrive at different fractions. The terms fraction, numerator, and denominator are not mentioned until the end of the class. The use of the concrete before the abstract to introduce fractions has several advantages: The students begin with a concept that makes sense to them, and then the instructor builds from their understanding toward hers. The students see why fractions are useful. They learn that fractions come about as a result of rational thought (7). The students themselves, with the instructor’s guidance, have developed a mental construct, a pattern of thinking, to which a term, fraction, has been attached. In other words, a concept (a unit of thought with an identifying term) (8) is produced that is meaningful to the students. We have done the cognitive studies that are necessary to improve our teaching. In addition to strategies such as that implied above we have learned a great deal about learning styles. Schroeder, in a 15-year study involving several thousands of students, has identified four basic learning styles and their characteristics, as outlined below (9).
Journal of Chemical Education • Vol. 76 No. 4 April 1999 • JChemEd.chem.wisc.edu
Research: Science and Education Learning Pattern
Ave. SAT Score
Concrete Active
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50% of high school seniors action oriented most practical make lowest grades business nursing allied health
Concrete Reflective
Table 1. Comparison of Objectivism and Constructivism Objectivism
Constructivism
Truths are independent of the context in which they are observed.
Knowledge is constructed.
Learner observes the order inherent in the world. Aim is to transmit knowledge experts have acquired.
Group work promotes the negotiation of and develops a mutually shared meaning of knowledge. Individual learner is important.
Exam questions have one correct answer.
The ability to answer with only one answer does not demonstrate student understanding.
thoughtful realists
Abstract Active like challenges
Abstract Reflective
Inductive
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10% of high school seniors scholarly thoughtful innovators make highest grades arts, sciences
Most faculty prefer the abstract reflective pattern; only about 10% of faculty prefer concrete learning patterns. Most students in the contemporary college classroom have a learning style different from that of the instructor and one that is not preferred by the instructor. Thus there may be a mismatch between the preferred styles of faculty and students, and this mismatch may lead to a misinterpretation of why students have difficulties with a class. Schroeder’s work has shown that concrete active learners seek direct, concrete experience, moderate-to-high degrees of structure, and a linear approach. Instructors prefer the global to the particular, are stimulated by concepts, ideas, and abstractions, and assume that students need autonomy. There is, then, a need to look for greater congruence between teaching and learning styles. Schroeder has suggested several ways to create a better match between student learning styles and faculty approaches to instruction: Use active modes of teaching and learning Use experiential learning that actively engages their senses in the subject matter; for example: – small group discussions and projects – in-class presentations and debates – monitored experiential learning – peer critiques – field experiences – developing simulations – case method approach
We have also found out what doesn’t work in the classroom. Donald Woods at McMaster University has carried out very interesting studies on problem solving (10). His work and that of others gives us an important insight into classroom comportment. What have we learned about learning? That having students solve exercises at the board, That teacher demonstrations of how to use algorithms, That having students solve countless homework exercises
do not improve the student’s critical thinking skills. Thus the staples of the classroom, those stemming from custom and tradition rather than pedagogical research, have been shown to be ineffective in enhancing the critical thinking and problem-solving skills of the students.
Deductive
I
E Exploration
Concept Invention
•What did you do?
•What did you find?
•Data acquisition
•Is there any pattern to the data? •What does it mean?
A Application •Organizes information •Predict, form a hypothesis •Test hypothesis •Higher level of thinking
Figure 1. The learning cycle.
The traditional method of teaching science has its roots in what is called “behaviorism”, which is the belief that an idea can be transferred intact from the mind of the instructor to the mind of the student, or that telling is teaching. An alternate methodology, the cognitive learning paradigm, stresses the thought processes of the learner and assumes that prior knowledge, attitude, motivation, and learning style affect the learning process (2). Recently there has been a slow shift from the behavioral to the cognitive paradigm or, in current terminology, from objectivism to constructivism. Table 1 lists some comparative features of objectivism and constructivism (2). Cognitive studies have shown that the model that is the closest to the way we learn is that of the learning cycle (11). A learning cycle is illustrated in Figure 1. The best methodology to enable students to grasp and retain a concept begins with an exploration or data collection. The next step involves the invention of the concept. Some workers prefer to label this phase “term introduction”. The final step is the application of the new knowledge. The example on the teaching of fractions illustrates the learning cycle as students proceed from the concrete to the abstract. The instructor in classroom 1 interchanged two parts of the cycle: the concept invention or term introduction phase preceded the data collection or exploration phase. The second teacher did not introduce the term numerator, denominator, or fraction until the end of the period—that is, not until after the exploration phase. Studies have shown that all learners learn new concepts better when “concept invention” or “term introduction” is the second phase of the learning cycle (11). Students also prefer that concept invention follow the exploration phase. Interestingly, this suggests that students may learn better if the text is read after an initial discussion has established some mental constructs; that is, it may be important that an initial exploration provide images to which terms may be attached. Most texts are written in a fashion that requires the intro-
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Research: Science and Education
duction of the term or model, followed by the data to clarify or support the term or model. Thus these texts do not follow the logical sequence presented by the learning cycle. Even though a data collection phase provides the images necessary for concept invention, this may not be enough. Students need social interaction to create the new concepts. Lawson has pointed out that “remarkably little of what is introduced in text and lecture is understood and retained” (8). The constructivist-learning-cycle approach (also called “inquiry-based”) has been shown to “facilitate retention of information and the transfer of thinking skills and content.” New Directions The NSF-supported New Traditions systemic initiative project for reform in teaching chemistry has succinctly stated the hoped-for changes in chemistry instruction (12): The overarching vision of the New Traditions Project is that we can facilitate a paradigm shift from facultycentered teaching to student-centered learning throughout the chemistry curriculum, such that students obtain a deeper learning experience, improve their understanding and ability to apply learning to new situations, enhance their critical thinking and experimental skills, and increase their enthusiasm for science and learning.
The student-focused active learning (SFAL) paradigm is based on the learning cycle and the belief that students construct their own knowledge derived from what they already know. When most chemistry instructors see the learning cycle for the first time they imagine its application to a laboratory situation. However, the cycle, while most readily appreciated in a laboratory setting, can be applied to a classroom as well. To implement the SFAL philosophy the traditional roles of instructor and student have to change. The role changes are contrasted in Tables 2 and 3. The tenets of modern cognitive theory and on-site classroom findings are evident in the student–faculty role changes envisioned by SFAL. A transportable philosophy, based on sound practices, can be used to achieve some or all of the
goals of the philosophy of student-focused active learning. Neither extreme presented in these comparisons is likely to be seen in any modern classroom or laboratory. However, the continuum along which we need to move to fully realize the benefits of cognitive learning theory is clear. It is equally unlikely that the ideal implementation of SFAL learning will ever be attained in many classrooms owing to size of the class, physical limitations on seating arrangements, or other local reasons. However, given different circumstances, beneficial steps may be taken to achieve a better learning environment. The SFAL approach has obvious application to the laboratory. To follow the guiding pedagogical principles, the “guided inquiry” laboratory philosophy can be used. A guided inquiry experiment begins with the assumption that knowledge is not directly transferred from the instructor to the student; that is, the constructivist approach is implemented and laboratory exercises follow the learning cycle. Students need to see the laboratory as a place to construct new knowledge and not simply as a place to verify the textbook. The rubric under which this approach operates moves from a prelaboratory discussion to the experimental phase to postlaboratory discussion, as outlined below (13). Prelaboratory Discussion The prelab discussion provides a focus and structure for the lab activities. A focal question orients the students toward the goal of the investigation. Hypotheses or predictions are solicited from the students. Experiments that allow testing of the various hypotheses are discussed. The students are asked what results are expected on the basis of each hypothesis. Experimental Each student (or group) is assigned a variation of the data to be collected. Data are pooled. The students are asked to find patterns or trends in the data.
Table 3. The Role of the Student
Table 2. The Role of the Instructor Traditional
Student-Focused
Traditional
Student-Focused
Lectures
Acts as a consultant for students
Asks for the "right" answer
Explains concepts
Asks probing questions of students to derive concepts
Provides definitive answers
Elicits responses that uncover what the students know or think about the concept
Explains possible solutions or answers and tries to offer the "right" explanations Tries alternate explanations and draws reasonable conclusions from evidence Has a margin for related questions that would encourage future investigations
Tells the students they are wrong or right
Provides time for students to puzzle through problems
Has little interaction with others
Has a lot of interaction and discusses alternatives with other companions Checks for understanding from peers
Explains to students step-by-step how to work out a problem
Allows students to assess their own learning and promotes open-ended discussion Refers students to the data and evidence and helps them look at trends and alternatives Encourages students to explain other students' concepts and definitions in their own words
Accepts explanation without justification
Is encouraged to ask questions such as Why did this happen? What do I already know about this? Is encouraged to explain other student's explanations
Reproduces explanation given by the teacher/book
Tests predictions and hypotheses Uses previous information to ask questions, proposes solutions, makes decisions, and designs experiments
N OTE: This comparison is taken in part from Lawson ( 8) and from M. Abraham, who prepared a similar comparison for a project on “Revitalizing Introductory Chemistry” under the direction of R. Lamba, Inter American University.
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N OTE: This comparison is taken in part from Lawson ( 8) and from M. Abraham, who prepared a similar comparison for a project on “Revitalizing Introductory Chemistry” under the direction of R. Lamba, Inter American University.
Journal of Chemical Education • Vol. 76 No. 4 April 1999 • JChemEd.chem.wisc.edu
Research: Science and Education Postlaboratory Session The students interpret the pooled data. Graphical analysis or other means of discovering patterns or trends used. Each hypothesis is evaluated on the basis of the data collected. The goal is the discovery of a concept. To ascertain if this concept has been understood, an application of the concept is requested. This may be an additional experiment, problem solving, or an answer to a question that requires demonstration of understanding of the concept.
Conclusions What do these philosophical and pedagogical findings have to do with the present-day classroom and laboratory? First, students must be allowed the opportunity to become involved in their learning. They should learn how to create knowledge and test that creation. Straight lecture is not the best way to accomplish this. Horowitz has shown that after a few minutes of a lecture, 50% of students tune out and never again in the course of the lecture is more than half of the class attentive (14 ). Students need to work together, not only because this prepares them for the way science and, indeed, most professions work, but because they learn better through social interaction. Students should reach their own conclusions and not be called upon to verify what the textbook or instructor has indicated to be the expected result of an experiment. The student must be an active learner. The belief that whatever worked for us in the past will continue to do so is no longer supportable. It is now clear that science, math, and engineering attrition “cannot be viewed as a natural consequence of differential levels of ability; classroom climate and activities play critical roles” (15). These conclusions are supported by a number of classroom and cognitive studies (16 ). To ignore what we now know about learning puts us in an awkward position. If we do not admit to the evidence that now exists we no longer can claim to be willing to judge a phenomenon on the basis of the collected data.
Acknowledgments Most of the background for this article came from support provided by the NSF for The Task Force on the General Chemistry Curriculum and the New Traditions project. I am also strongly indebted to R. S. Moog and J. J. Farrell for many discussions, critical reading of the manuscript, and encouragement when it was most needed. Literature Cited 1. Barr, R. B.; Tagg, J. Change 1995, Nov/Dec, 13. 2. Sanger, M. J.; Greenbowe, T. J. J. Chem. Educ. 1996, 73, 532. 3. Mazur, E. Peer Instruction; Prentice-Hall: Upper Saddle River, NJ, 1997. 4. Herron, D. The Chemistry Classroom; American Chemical Society: Washington, DC, 1996. 5. Millar, S. B. Teaching on Solid Ground; Jossey-Bass: San Francisco, 1996; Chapter 7, p 155. 6. Stevenson, H. W.; Stigler, J. W. The Learning Gap; Summit Books: New York, 1991. 7. Bodner, G. M. J. Chem. Educ. 1992, 69, 186. 8. Lawson, A. Science Teaching and the Development of Thinking; Wadsworth: Belmont, CA, 1995. 9. Schroeder, C. A. Change 1993, Sep/Oct, 21. 10. Woods D. R. In Developing Critical Thinking and Problem-Solving Abilities; Stice, J. E., Ed.; New Directions for Teaching and Learning, No. 30; Jossey-Bass: San Francisco, 1987. 11. Abraham, M. R.; Renner, J. W. J. Res. Sci. Teach. 1986, 23(2), 121. 12. Landis, C. R.; Peace, E. Jr.; Scharberg, M. A.; Branz, S.; Spencer, J. N.; Ricci, R.; Zumdahl, S. A.; Shaw, D. J. Chem. Educ. 1998, 75, 741–744. 13. Ditzler, M. A.; Ricci, R. W. J. Chem. Educ. 1994, 71, 685. 14. Horowitz, H. M. Student Response Systems: Interactivity in a Classroom Environment; Proceedings of the 6th Annual Conference on Interactive Instruction Delivery; Society for Applied Learning Technology: Warrenton, VA, 1988; pp 8–15. 15. Seymour, E.; Hewitt, N. M. Talking about Leaving; Westview Press: Boulder, CO, 1997. 16. Johnson, D. S.; Johnson, R. T.; Smith, K. A. Active Learning: Cooperation in the Classroom; Interaction Book Company: Edina, MN, 1991; Chapter 2, p 12.
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