Research: Science and Education
Teacher Perceptions in the Selection of Experiments Luis D. Montes* Department of Chemistry, University of Central Oklahoma, Edmond, OK 73034;
[email protected] Mark G. Rockley Department of Chemistry, Oklahoma State University, Stillwater, OK 74078
Numerous articles have been published detailing the methods and benefits of inquiry experiments (1–9). However, they have apparently had limited impact on the adoption of this laboratory approach. In 1997, Abraham and co-workers reported that fewer than 10% of the general chemistry courses offered by colleges and universities in the United States utilized inquiry-based methods (10). For the past four years we have conducted summer training sessions for secondary school science teachers interested in learning about inquiry-based experiments. By surveying teachers participating in these workshops, we find that typically no more than 15% of the grade 8–12 science teachers have ever tried inquiry experiments, and only 5% of the teachers claim to use inquiry experiments more than once each semester. The teachers at our workshops report that the majority of the experiments in their classrooms follow the verification approach. Despite their reported advantages, inquiry-based experiments are rarely used at the university and secondary school levels. Lawson and colleagues recognized this problem when they concluded their recent article (11) by asking, “Why is it taking so long for teachers to replace verification labs with meaningful student inquiries?” If we are to engage students in meaningful inquiries in the classroom, it is necessary to first understand the reasons that verification experiments have become entrenched. In this article, we share one exercise we have found helpful in getting teachers to think about the role of the laboratory in the science classroom. We then discuss the results of this exercise in an attempt to help explain why verification experiments still prevail in science classrooms at the secondary school level. In Their Own Words Since our workshops focus on inquiry-based techniques, we employ this approach throughout the program. This means that rather than telling teachers about the relative merits of verification and inquiry laboratory styles, we let the teachers discover these for themselves. Before we introduce the methods of the inquiry experiments we engage the teachers in a discussion of the advantages and disadvantages of the laboratory format they currently employ in their classrooms. To do this we ask the teachers as a group to list the advantages that they associate with verification experiments. This results in a list of 15–20 items that the teachers feel justify the use of verification experiments (Table 1). Next, we ask the teachers to list the disadvantages that they associate with verification experiments (Table 2). After initially comparing the lists the teachers are satisfied that they have justified the use of verification experiments, since there are more advantages listed than disadvantages. However, this is not where the exercise ends. We follow this initial comparison with an item-by-item discussion of who the teachers perceive to be most affected by each listed item— the teacher or the student. As the teachers work through the 244
list, they quickly realize that a majority of the advantages associated with verification experiments primarily benefit the teacher, as indicated by a check (✓) in the teacher column, rather than the students, denoted with a check in the student column. Most teachers are shocked to realize that each of the items listed in Table 2 primarily disadvantages the student. At this point, the teachers are receptive to learning about Table 1. Advantages of Verification Experiments as Listed by Teachers Feature
Primarily Affected Student Teacher
Easy to time
✔
Easy to prepare
✔
Easy to grade
✔ ✔
Easy for large classes ✔
Students learn techniques Students learn to follow directions
✔
Students learn use of equipment
✔
Relevant to lecture
✔
Easy to supervise
✔
Structured
✔
Quieter
✔
Less controversial
✔
Everybody does the same thing
✔
High likelihood of success
✔
Instructor knows outcome
✔
Easy to help students with problems
✔
Known expectations of students
✔
Table 2. Disdvantages of Verification Experiments as Listed by Teachers Feature
Primarily Affected Student Teacher
Boring
✔
No flexibility
✔
Not individualized
✔
Students are mentally passive
✔
Students only do what is needed
✔
No excitement of discovery
✔
All perspectives are the same
✔
Easy to manufacture data
✔
Easy to copy
✔
Doesn’t require creativity
✔
Doesn’t teach problem solving skills
✔
No exploration
✔
No learning from unexpected results
✔
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Research: Science and Education
alternative laboratory formats. By the end of the workshop it is apparent to the teachers that inquiry experiments can provide many of the same benefits for teachers as verification experiments, while also providing advantages that are not present for the students in the verification approach. Furthermore, by learning how teachers view the role of the laboratory we gain a better understanding of some of the factors that lead to the prevalence of verification experiments in the secondary school science classroom. Advantages of Verification Experiments One of the primary reasons why the verification approach is entrenched in the classroom is related to the perceived convenience of this style. For example, several of the advantages consistently topping the teachers’ lists deal with the ease of verification experiments. The teachers appreciate the fact that they can fit an experiment into an allotted amount of time. Teachers also report that verification experiments save time because they are well tested, simple to prepare, and easy to grade. An additional characteristic of verification experiments that teachers value concerns the adaptability of the experiments. That is, the experiments are easily adjusted to accommodate small or large classes. It has been noted that the present form of verification experiments at the introductory college chemistry level has evolved for these same reasons, specifically a need to minimize demands on time, space, equipment, and personnel (12), and it has been pointed out that the choice of experiments used is often based on expediency rather than pedagogy (13). The exercise we conduct in our workshops indicates that these same factors play a major role in determining the laboratory approach used at the secondary school level. At the secondary level, many schools have 45–50-minute class periods, so it is essential that an experiment fit into that time frame. Often, the verification experiments used have been designed so that they can be completed within a single class period. Since these experiments are familiar to the teachers, they need to do little extra planning and scheduling. While we understand that teachers are often busy and do not have time to develop an entirely new set of experiments, these perceived advantages of verification experiments do not provide a compelling reason for avoiding inquiry experiments. These advantages are related to convenience, rather than pedagogy. Although there are currently a wealth of experiments designed for verification labs, the number of published inquiry experiments is on the increase and a few articles in this Journal have discussed how to convert traditional verification experiments into inquiry-based experiments (14–16 ). Thus, after the initial time invested in changing from verification to inquiry experiments, the new inquiry experiments provide many of the same advantages related to the ease of preparation and time management. The ease of grading that teachers associate with verification experiments stems from the expectation that the students must arrive at a certain experimental value or reproduce a given chemical concept. Many such experiments base a major portion of the grade on how well the student has done this. However, it is important to keep in mind the purpose of grading experiments. While the verification experiments may be useful in determining how well a student performed an experiment, they are often not designed to assess other equally important experimental goals. These include assessing how
well the student understood the goals of the experiment and determining if the student gained insight into how an experiment fits into the larger scheme of laboratory investigations. The laboratory experience should provide a way to assess, for both the student and the teacher, the knowledge and understanding that the student gains as a result of the experiment. In the teacher training sessions we conduct, discussion of this point will often lead to an elaboration of the fundamental role of the laboratory in a chemistry class. A second set of advantages identified by teachers deal with a few of the perceived learning goals associated with the laboratory experience. Teachers indicate that verification experiments help students learn to follow directions, master certain experimental techniques, become skilled in the use of equipment, and reinforce material discussed in the lectures. It may be desirable that the students know how to follow directions, but to our knowledge it is not mentioned in the literature as an important goal of the laboratory in the chemistry curriculum, nor is it mentioned in the National Science Education Standards (17). Furthermore, it is doubtful whether verification experiments really teach students to follow directions, as opposed to demonstrating that students already know how to follow directions. It is possible that teachers confuse the idealized view of orderly, methodical research with the ability to follow directions. Arguably, by teaching students to follow directions, we are not teaching them to do science. Teachers also indicate that verification experiments enable students to learn important laboratory techniques and proper use of equipment. It is important to understand the context in which teachers claim these items as advantages. Teachers point out that, at the secondary school level, many science classes are taught without a laboratory component. They understand that the acquisition of laboratory techniques and proper use of equipment are advantages only with respect to learning science without a laboratory experience. Although verification experiments provide these benefits to students, any approach that allows students to work with laboratory equipment would also provide these benefits. Studies in our own laboratories indicate that inquiry experiments not only reinforce the physical skills associated with a piece of equipment, but may also lead to a better understanding of the advantages and disadvantages associated with the use of a particular technique or piece of equipment. Ultimately, the decision about which laboratory approach to use should not be made based on perceived benefits associated with equipment and techniques. If a teacher decides that it is important for students to learn the proper use of equipment and experimental techniques, then a hands-on laboratory activity would be more appropriate. However, an overemphasis on techniques and equipment has led to a perception among many teachers that science can only be carried out with expensive or precision equipment. This perception further limits the experiments teachers are willing to use, since often they are working under tight budgets for supplies and equipment. Teachers often claim that a close relationship between a particular experiment and lecture is an advantage of the verification approach. By choosing an appropriate experiment a teacher can ensure that the laboratory experience complements the lecture. It is not the laboratory approach itself that provides this advantage. Rather, it is the teacher taking the time to find a suitable experiment. Taken together, the learning goals that
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Research: Science and Education
are listed by teachers as advantages of verification experiments cannot be used as a point of difference between verification and other types of laboratory approaches, since these outcomes are present with inquiry-based experiments as well. Teachers specify a third set of advantages for verification experiments that are related to the overall orderliness of the experiment as it is being performed. They state that verification experiments are easy to supervise because these experiments are structured and the laboratories are often quieter. Paradoxically, however, teachers also note that this structure is disadvantageous, as will be discussed in a later section. The structure that the teachers refer to involves the specific directions provided to students. This reduces the number of activities being carried out by students at any one time, and reduces the amount of chaos in the laboratory. As a result, the teacher is able to retain more control in the laboratory. While teachers appreciate the relatively controlled atmosphere that is associated with a quieter laboratory, the fact that verification experiments are quieter is an indication that very little discussion occurs between students. As a result it is much more difficult for collaborative or peer learning to take place. In a stimulating learning environment students will discuss and debate their results with each other. This does lead to a little more noise during an experiment. However, as the students informally present and defend their ideas to their peers, they gain confidence in their ability to do science and are usually more comfortable discussing and explaining the results of their experiments in front of the entire class. Teachers also find it advantageous that all the students are following the same procedures. Since the teachers know what the procedures are and what the outcome should be, it is easier for them to help students with problems. In the context of verification experiments this seems to mean that teachers can more easily give students directions that will allow the students to get the “right” answer. This is contrary to one of the main goals of an experiment, which should allow for the student to be the problem solver. For experiments in which there is one correct answer it may seem necessary to help students so that they do not get too discouraged. However, if the experiment focuses instead on justifying an explanation or idea with experimental results, there is less need to help students arrive at a single right answer. In inquiry experiments, any guidance provided by the teacher can be more easily posed as leading questions, thereby challenging the student to think about his or her procedures and results. In contrast, with verification experiments the assistance will often be in the form of restating directions or procedures. A final item listed as an advantage by teachers is the fact that verification experiments are not controversial. There are at least two possible reasons teachers perceive verification experiments to be uncontroversial. The first reason is that most teachers were exposed to chemistry and other sciences using verification experiments. The verification approach serves as their primary model for teaching chemistry in the laboratory. One recent study reports that many teachers entering the profession through alternative certification embrace a teaching model with which they are familiar (18). It is not unreasonable to believe that, despite exposure to the advantages of the inquiry-based approach in their teaching methods courses, many traditionally certified teachers also ultimately adopt the style in which they were taught science. 246
Since the vast majority of teachers learned science using the verification approach, they will most likely employ this same approach in their classes. A second reason that verification experiments are seen to be uncontroversial is that most administrators and parents are familiar with this approach and often view it as the “right way” to teach a laboratory class. Very often, any changes that the teacher wishes to make must be justified to at least one of these groups. By continuing to use verification experiments teachers are able to avoid possible confrontations. In our workshops we address these concerns in two ways. First, we refresh the content knowledge of teachers using an inquirybased approach. In the process we provide teachers with a new model for science teaching. Second, by introducing teachers to the advantages of inquiry-based experiments and placing this approach in the context of state and national science education standards, we provide teachers with sound arguments to justify a change in the laboratory style they employ. Disadvantages of Verification Experiments Among the disadvantages of verification experiments, one of the first listed by teachers is that verification experiments are boring or monotonous. This is also the comment made most frequently by college-level general chemistry students in our own classes when asked what they dislike about verification experiments. A few other disadvantages listed by teachers may help explain this overall impression that verification experiments are monotonous. Teachers note that students are often mentally passive, do only what is needed, and experience no excitement of discovery. Since students are given a set of directions to follow, it should come as no surprise that they are mentally passive. If students are expected to think about the experiment, it is in the form of pre-laboratory questions or a post-laboratory report. Most students have learned that while they are in the laboratory, they need only to follow the directions and perform the required analyses in order to get satisfactory results. Since all procedures and expected results are spelled out for them, any excitement must come from “special effects”, such as sounds or colors, rather than from discoveries they make. A second set of disadvantages of verification experiments listed by teachers involves the more rigid structure of verification experiments. While teachers value this structure for the manageability it provides, they are also aware that certain aspects of it can inhibit learning. Teachers note that verification experiments offer no flexibility; they are not individualized, and all student perspectives are the same. In other words, all students are expected to do the same experiment and are further expected to obtain similar results. These contrasting views of the value of structure in verification experiments might arise from the emphasis that this approach places on facts. While teachers recognize that these experiments are useful for demonstrating the reproducible nature of science, these same experiments give the impression that science is only a collection of facts. The rigidity of the verification approach to experiments removes the scientific discovery aspect from the laboratory, and instead reinforces the view that the chemistry laboratory is only a place where students learn proper use of glassware and techniques. If a student does not obtain the desired results, it gives the impression that the deficiency rests with him or her. It further encourages the belief that there is only one way to interpret the results.
Journal of Chemical Education • Vol. 79 No. 2 February 2002 • JChemEd.chem.wisc.edu
Research: Science and Education
The rigid structure of verification experiments leads to another set of disadvantages pointed out by teachers. Students find it very easy to manufacture or “cook” data for the experiments, and also to copy results from other students. When emphasis is placed on a final experimental value or fill-in-the-blank answer, students may find it easier to backcalculate from an expected answer in order to artificially generate acceptable experimental data. Although we would ideally want students to think about the procedures they are carrying out, in practice students will sometimes opt for the most expedient method. In fact, verification experiments that are focused on obtaining a predetermined answer may inadvertently encourage this behavior (12). The final set of disadvantages that teachers associate with verification experiments is related to the overall outcomes of a chemistry laboratory. Teachers note that verification experiments do not require creativity, do not teach problem-solving skills, do not allow for exploration by the students, and do not enable students to learn from unexpected results. While most students fail to appreciate the creative nature of science, most scientists would assert that their research involves a considerable degree of creativity. In other words, laboratory research presents opportunities to develop new ideas from the synthesis of two or more concepts, or to apply an experimental technique to a problem in a new way. Verification experiments limit the creative opportunities for students. The instructor chooses the questions being investigated and the approach used to investigate them, leaving very few choices for the students to make. This also means that there is little room for problem solving and exploration by the student. If the goal is to obtain an experimental value or to observe some phenomenon, there is no opportunity for the student to freely investigate the variables that may affect the experimental value to be determined. Furthermore, as the student is expected to obtain a predetermined value, there is no opportunity to pursue unexpected observations or serendipitous results that are obtained during the course of the experiment. Finally, because the questions to be investigated and the approach used to investigate them are specified by the instructor, the students’ efforts are focused more on following a set of directions than on solving a problem. As a result, verification experiments do not allow students to fully develop their problem-solving skills. Summary The advantages of verification experiments that the teachers list fall into two main categories. The first is related to the teacher being comfortable and familiar with a certain laboratory approach. When examined in detail, these advantages are seen to benefit the teacher rather than the student. The second category involves the perceived instructional advantages of traditional laboratory styles. Teachers indicate that most of the advantages in this category are only benefits relative to teaching chemistry without offering any laboratory experience. While the decision to provide students with practical laboratory experience is based on pedagogical reasons, the decision about what approach to use is often made for reasons of familiarity or convenience. While a number of articles have detailed the methods and advantages of inquiry-based approaches, and indeed these approaches are now an integral component of the National Science Education Standards (17, 19), many of these ideas
have not yet filtered down to science teachers at the secondary level. If we are to have students involved in meaningful inquiries, this breakdown in communication between science education researchers and secondary school science teachers must be addressed. Clearly there is a need for greater dissemination of inquiry-based experiments. As teachers gain experience with the inquiry approach they will understand the pedagogical advantages these experiments provide. Furthermore, in order to increase the benefits of convenience associated with inquiry experiments it is necessary to increase the availability of these experiments. As teachers gain familiarity with inquiry experiments and the availability of these experiments increases, teachers will be more comfortable choosing a laboratory approach that has advantages based on both pedagogy and convenience. When teachers examine who gains and who loses from the use of verification experiments, we find that they are much more eager to learn a different approach to teaching chemistry laboratories. This exercise and the discussion it leads to also encourage the teachers to think about the overall goals of the science laboratory. They begin to see the laboratory as more than a place for the students to demonstrate a few concepts learned in lecture and get hands-on experience with some laboratory glassware. They discover that the laboratory can be a much richer learning environment for students—where students learn what it really means to do science. Literature Cited 1. Richardson, V.; Renner, J. W. J. Chem. Educ. 1970, 47, 77– 79. 2. Pavelich, M. J.; Abraham, M. R. J. Chem. Educ. 1979, 56, 100–103. 3. Derske, W. J. Chem. Educ. 1981, 58, 565–567. 4. Whisnant, D. M. J. Chem. Educ. 1982, 59, 792–794. 5. Hilosky, A.; Sutman, F.; Schmuckler, J. J. Chem. Educ. 1988, 75, 100–104. 6. Lloyd, B. W. J. Chem. Educ. 1992, 69, 866–869. 7. Pushkin, D. B. J. Coll. Sci. Teach. 1997, 238–242. 8. Domin, D. S. J. Chem. Educ. 1999, 76, 543–547. 9. Spencer, J. N. J. Chem. Educ. 1999, 76, 566–569. 10. Abraham, M. R.; Cracolice, M. S.; Palmer Graves, A.; Aldhamash, A. H.; Kihega, J. G.; Palma Gil, J. G.; Varghese, V. J. J. Chem. Educ. 1997, 74, 591–594. 11. Lawson, A. E.; Lewis, C. M. Jr.; Birk, J. P. J. Coll. Sci. Teach. 2000, 191–198. 12. National Advisory Group. An Exploration of the Nature and Quality of Undergraduate Education in Science, Mathematics, and Engineering: a Report; Sigma Xi, the Research Society: New Haven, CT, 1989. 13. Lagowski, J. J. J. Chem. Educ. 1979, 56, 561. 14. Olney, D. J. Chem. Educ. 1997, 74, 1343–1345. 15. Plumsky, R. J. Chem. Educ. 1996, 73, 451–454. 16. Allen, J. B.; Barker, L. N.; Ramsden, J. H. J. Chem. Educ. 1986, 63, 533–534. 17. National Research Council. National Science Education Standards; National Academy Press: Washington, DC, 1996. 18. Duggan-Haas, D. Ph.D. Dissertation; Michigan State University, East Lansing, MI, 2000. 19. Center for Science, Mathematics, and Engineering Education, National Research Council. Inquiry and the National Science Education Standards: a Guide for Teaching and Learning; National Academy Press: Washington, DC, 2000.
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