Chemical Education Today
Commentary
Considering Laboratory Instruction through Kuhn’s View of the Nature of Science by Daniel S. Domin
There is contentiousness about science laboratory instruction that is almost as old as the field itself. From nearly the beginning until today, both the effectiveness and the manner of science laboratory instruction have often been debated (1–4). Although there has never been a clear consensus as to what should be taught in the science laboratory and how it should be presented, many agree that the laboratory should be a place where students develop a better understanding of the processes of science (5–7). In this opinion piece, I argue that the nature of science can serve as a viable framework from which to base science laboratory instruction and that Kuhn’s description of the different phases of science, as presented in The Structure of Scientific Revolutions (8), can serve as an effective foundation when coupled to the styles of instruction historically associated with the science laboratory. Kuhn’s View of Science Although best known for reconceptualizing the development of scientific ideas within the context of paradigms and paradigmatic shifts, Kuhn’s The Structure of Scientific Revolutions (8) also provides a compact description of the different phases of science. In it, Kuhn described science as a composite of three phases: normal science, discovery, and validation. These phases possess attributes that correspond very well to the different styles of laboratory instruction that have been shown to be part of the science laboratory curriculum: expository, guided-inquiry/openinquiry, and problem-based (9), where each phase corresponds to a particular style of instruction. Normal Science/Problem-Based Instruction The Structure of Scientific Revolutions devotes much space to describing what normal science is and what it is not. According to Kuhn, normal science is the predominant phase of the scientific enterprise and consists almost entirely of puzzle solving. While engaged in normal science, the scientist attempts to solve a problem that has an expected, if not predictable, outcome and that is solvable through the application of deductive reasoning that incorporates a set of known concepts and principles pertinent to the discipline. In Kuhn’s words, “no part of the aim of normal science is to call forth new sorts of phenomena…” (8, p 24). He elaborates, …the man who is striving to solve a problem defined by existing knowledge and technique is not, however, just looking around. He knows what he wants to achieve, and designs his instruments and directs his thoughts accordingly. (8, p 96)
Problem-based instruction closely parallels normal science and should prove to be an excellent vehicle for helping students understand what scientists typically do. Both problem-based instruction and normal science operate primarily through es274
tablished concepts and use deductive reasoning to achieve an expected outcome. As a final parallel between the two, consider Kuhn’s statement regarding normal science: “failure to achieve a solution discredits only the scientist and not the theory” (8, p 80). The same is true for problem-based activities; if set up properly, failure to reach a solution reflects on the ability of the student (or limitations of the equipment), not the guiding concepts and principles. It is important to understand that normal science is not about discovery. Any “discovery” made within the confines of normal science usually corresponds to an improvement in what is already known: an improvement in the precision of a measured quantity or the development of a new synthesis scheme. Consider, for example, the recent “discovery” of planets outside our solar system. Although it is an important achievement, finding a planet does little to change our way of thinking about planets in general. Rather, these events reinforce our understanding of planets and stars. Astronomers looked for planets orbiting other stars outside of our solar system because they expected them to be there. The predominant paradigm of cosmology regarding stars and planets essentially says that they should be there. It would be more significant scientifically if no other planets were found elsewhere in the universe—then we would have to rethink our understanding of how planets form. Discovering new planets is really just normal science where astronomers use their deductive powers to solve the problem of finding, from very far away, very small non-luminous bodies orbiting gigantic luminous objects. Discovery/Guided- and Open-Inquiry Instruction Kuhn restricted discovery, in its purest sense, to a much smaller part of the scientific endeavor. Scientific discoveries are relatively rare events. It is quite possible for a scientist to enjoy a 40-year career in a scientific discipline and yet never engage in the process of discovery. Events that should be construed as scientific discoveries according to Kuhn are those that result in a revolution of thought. When a true scientific discovery is made, a new way of thinking or understanding emerges. The term “discovery” is tossed around quite easily in scientific circles. In fact, many would argue that the main purpose of science is discovery. However, many events labeled as discovery offer no new ways of thinking about the natural world. Rather, these events fall under the rubric of normal science. A true scientific discovery involves a radical change in our worldview and as with guided- or open-inquiry instruction, result in a conceptual change. Scientific revolutions are, according to Thagard, conceptual revolutions (10). True scientific discoveries, although rare, are not unheard of. Examples of truly grand discoveries that have revolutionized scientific thought include those of Copernicus, Lavoisier, Darwin, and Einstein, to name a
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few. However, as Thagard pointed out, a scientific discovery does not have to be monumental; it need only result in conceptual change. Thagard, in fact, regards the essential feature of a scientific discovery to be radical conceptual change. This is illustrated quite nicely by the work of Neil Bartlett who, in 1962, prepared the first noble gas compound, xenon hexafluoroplatinate (11). Although no one would claim that this event is of the same caliber as the contributions of Copernicus or Darwin, it is still regarded as a significant scientific discovery because it totally contradicted chemists’ understanding of the concept of valency. Chemists had to rethink their ideas of chemical bonding. One should not regard Bartlett’s work as normal science; it was not an expected problem waiting to be solved. The contemporary scientific thought did not allow for the existence of noble gas compounds,1 thus any research in this area would be regarded as pure folly. It was through his work with strong oxidizers that Bartlett noticed similarities in the ionization energies for O2 to O2+ and Xe to Xe+. This allowed him to speculate about the reactivity of the noble gases: if O2 could be ionized by platinum hexafluoride, then maybe Xe could be ionized as well (12). A scientific discovery, like inquiry learning, is an inductive process leading to the construction of new understanding that can be generalized. The true act of discovery, although emergent from normal science, rarely occurs during a typical scientific investigation and is virtually unheard of in the instructional science laboratory. When it does occur, it is usually a serendipitous event in both venues.2 In the instructional laboratory, all we can hope to achieve, pedagogically speaking, is for students to experience a phenomenon new to them and to utilize the same inductive reasoning skills as “real scientists” when they conceptualize and generalize their new findings. Both guided- and open-inquiry simulate scientific discovery in the sense that students construct new concepts through inductive thought processes. The primary difference between the two is the level of freedom afforded the students. True open-inquiry instruction possesses a high degree of freedom; not only do the students get to develop their own procedures, they also play a significant role in determining what will be the outcome of the activity. It is the coupling of procedure generation with finding out something new that makes open-inquiry so attractive and makes many people associate it to a greater extent with authentic science relative to the other styles of instruction (13–15). However, true inquiry instruction, while reflecting a significant portion of the scientific enterprise, does not present a complete picture. Yes, it should be a part of the curriculum, just not the entire curriculum. Guided-inquiry is more structured (9, 15, 16). Students follow a given procedure to experience a specific phenomenon from which they will construct the specific concept previously determined by the instructor. This difference in structure creates a unique set of constraints for the two inductive styles of instruction. Although both are suitable for concept formation, each communicates a different message to students. Open-inquiry instruction is more complex and presents a more sophisticated portrayal of science. This may be more suitable for older or more experienced students (17, 18). Guided-inquiry, may be a better choice if the concept to be “discovered” needs a lot of attention
from the students. Concepts about which students are likely to have misconceptions are probably best introduced via guidedinquiry rather than open-inquiry (18). Validation/Expository Instruction Both of the above-mentioned aspects of science invariably lead to the third and final phase, the validation of research findings. Whether or not something becomes established as scientific knowledge depends almost exclusively on the ability of others to replicate the work. Consider the fate of cold fusion. Despite its “discovery” by two respected scientists and the hype surrounding the announcement, until the experiments conducted by Pons and Fleischmann have been verified and replicated, cold fusion will, at best, remain on the fringes of science. The validation of knowledge claims by replicating another’s work is an essential aspect of science that must be communicated to students. The best way to do this is through expository instruction. Historically, however, this often gets convoluted into mindlessly following a recipe from the laboratory manual. A far better alternative is to give students the opportunity to evaluate the experimental procedures constructed by others, which can be done a variety of ways. One possibility is to have the students validate the knowledge claims of their peers by attempting to replicate a procedure generated via a problem-based or inquiry activity. Another is to have students evaluate competing procedures presented in academic journals. For example, three activities were published in this Journal that describe how students could apply Charles’s Law to determine absolute zero (19). Although all three used the same law, the procedures varied. Students follow the published procedures and attempt to replicate each experiment in a manner not unlike conventional expository instruction. However, by incorporating the process of evaluating each procedure (a higher-order cognitive process), students must become cognitively engaged with the material. Students not only get to verify established phenomena from which to further develop their conceptual understanding, they also get to use higher cognitive levels with a style of instruction that has too often been regarded as devoid of any thoughtprovoking attributes. Whether in the authentic science laboratory or in the instructional laboratory, the evaluation of another’s claim of new knowledge is an exercise in following instructions. In both environments the objective is the same—follow as closely as possible the procedure generated by someone else to achieve the expected outcome. The main difference is the consequence of not achieving the expected outcome: in the real world, failure to obtain the expected result typically delivers a severe blow to the reputation of the person responsible for generating the procedure. In the educational setting, not achieving the desired outcome may reflect poorly on the person replicating the experiment, or the person who generated the procedure, or both. Summary Each of Kuhn’s three phases of science demonstrates a particular aspect of science and the essence of each is best conveyed through a different style of instruction. Experiencing
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Chemical Education Today
Commentary a laboratory curriculum with only one or two instructional formats provides the learner with an incomplete depiction of the scientific enterprise. Thus, to fully apprehend science’s complex and multifarious nature, one must actively participate in all three phases. This can only be achieved by a curriculum that includes inquiry (guided- and/or open-), problem-based, and expository activities.
7.
Acknowledgments
8.
The author thanks the anonymous JCE reviewers for their helpful suggestions.
9. 10.
Notes
11.
1. This is not entirely true. Thirty years prior to Bartlett’s success, Linus Pauling predicted the existence of both krypton hexafluoride and xenon hexafluoride (11). However, the prevailing theory during the 1960s, Lewis’s Octet Rule, regarded the noble gases to be totally inert to chemical combination. 2. An example is provided by George Bodner (personal communication, May 21, 2007) who related the story of a group of general chemistry students who accidentally discovered a previously unknown transition metal complex while performing an expository laboratory activity.
12. 13.
Literature Cited 1. Ault, A. J. Chem. Educ. 2004, 81, 1569. 2. DeBoer, G. A History of Ideas in Science Education: Implications for Practice; Teachers College: New York, 1991. 3. Hawkes, S. J. J. Chem. Educ. 2004, 81, 1257. 4. Monteyne, K.; Cracolice, M. S. J. Chem. Educ. 2004, 81, 1559– 1560. 5. Abraham, M.; Cracolice, M.; Graves, A.; Aldhamash, H.; Kihega, J.; Gil, J.; Varghese, V. J. Chem. Educ. 1997, 74, 591–594. 6. Duschl, R. A. Restructuring Science Education: The Importance
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14. 15. 16. 17. 18. 19.
of Theories and Their Development; Teachers College Press: New York, 1990. National Research Council. America’s Lab Report: Investigations in High School Science; Committee on High School Science Laboratories: Role and Vision, S. R. Singer, M. L. Hilton, and H. A. Schweingruber, Eds. Board on Science Education, Center for Education. Division of Behavioral and Social Sciences and Education. The National Academies Press: Washington, DC, 2006. Kuhn, T. S. The Structure of Scientific Revolutions, 2nd ed.; University of Chicago Press: Chicago, 1970. Domin, D. S. J. Chem. Educ. 1999, 76, 543–547. Thagard, P. Conceptual Revolutions; Princeton University Press: Princeton, 1992. Idhe, A. J. The Development of Modern Chemistry; Dover: New York, 1984. Hyman, H. H. Science 1964, 145 (3634), 773–783. Roth, W.-M. Authentic School Science; Kluwer: Dordrecht, 1995. Cacciatore, K. L.; Sevian, H. J. Chem. Educ. 2006, 83, 1039– 1040. Apedoe, X. Sci. Educ. 2008, 92, 631–663. Pavelich, M.; Abraham, M. J. Chem. Educ. 1979, 56, 100–103. Hodson, D. J. Curric. Stud. 1996, 28, 115–153. Jenkins, E. J. Curric. Stud. 2007, 39, 723–736. Petty, J. T. J. Chem. Educ. 1995, 72, 257. Rockley, M. G.; Rockley, N. L. J. Chem. Educ. 1995, 72, 179–181. Snyder, D. M. J. Chem. Educ. 1995, 72, A98–A99.
Supporting JCE Online Material
http://www.jce.divched.org/Journal/Issues/2009/Mar/abs274.html Abstract and keywords Full text (PDF) with links to cited URLs and JCE articles
Daniel S. Domin, formerly of Tennessee State University, is the curriculum/instructional designer at Triton College, 2000 Fifth Avenue, River Grove, IL 60171;
[email protected].
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