Chemical Education Today
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A Phenomenographic Study: First Year Chemical Engineering Students’ Conceptions of Energy in Dissolution Processes by Kenneth S. Lyle and William R. Robinson
Phenomenography is an empirical, qualitative research methodology used to explore thinking and learning from the perspective of the learner (1). Since its inception in Sweden during the early 1970s, phenomenography has been used to investigate the ways individuals experience and conceptualize phenomena. Different learners experiencing the same phenomenon in the same context will have different experiences, perceptions, conceptions, and understandings of the phenomenon. These differences are the result of the different ways individuals are aware of the phenomenon at a particular moment. The start of a phenomenographic study is to uncover these differences in experiences, perceptions, conceptions, and understandings and the corresponding meanings the phenomenon holds for the learners involved. The major premise of phenomenography is that although individuals will have different experiences and conceptualizations of a phenomenon in a given context, the number of qualitatively different conceptualizations is limited (2). These different conceptualizations are the focus of a phenomenographic study rather than each individual learner’s conceptualizations. The different conceptualizations are interrelated, with some being more productive than others (3). One major assumption of phenomenography is that individuals can accurately express their experiences and conceptualizations. Although a variety of means can be used to obtain data for a phenomenographic study, the principal method used is to conduct open-ended, in-depth interviews. Once the data for a group of individuals has been collected, it is then organized and reviewed several times in order to identify the limited number of ways a phenomenon has been experienced and conceptualized. These limited numbers of ways, referred to as “categories of description” (2), are defined or described, and the data within each category are reviewed several times to insure internal consistency, a process that can result in categories being modified, added, or deleted. The categories are then compared to establish interrelationships and arranged in a hierarchy according to some criteria. The final product is referred to as the “outcome space” (2). The product of a phenomenographic study is not viewed as “truth” but rather as something useful in understanding the range of ways individuals think and learn. There are two rules that govern the development of the categories of description: consistency and parsimony. (Repeatability is not a requirement of phenomenography.) Different researchers may well arrive at different categories of description for a phenomenon, but what is required is that once the outcome space has been generated and defined,
other researchers could recognize instances of the different ways of experiencing that phenomenon (4). Phenomenography is utilitarian and pragmatic. Its goal is to generate an outcome space that is useful in understanding the various ways a group of individuals experience and understand a specific phenomena in a specific context. Some critics question whether an individual’s depictions of an experience are equivalent to the actual experience (5). Another criticism is that a researcher may not be able to keep his or her personal experiences from influencing the data and analysis (6). Other concerns expressed by critics deal with the reliability of the results and the repeatability of the studies. In response to the critics, proponents cite the fact that there is no physical means to examine an individual’s brain to extract the data (3). Asking for them is the only means available to obtain an individuals’ experiences and perceptions. Direct observation as an individual experiences a phenomenon does not shed light on how it is experienced. Researchers who are skilled in interviewing and establishing a climate in which interviewees feel at ease to express themselves are able to obtain data that closely represents the individual’s actual experiences. While the researcher should remain neutral in the data collection and subsequent analysis, no one is void of experiences or beliefs. However if the researcher is open and up-front about his or her background and beliefs and the potential influence on the results, then readers will know this and be able to judge the validity of the results for themselves (6). A Phenomenographic Study in Chemistry Ebenezer and Fraser (7) used phenomenographic methods to study the range of conceptions about the energy factors involved in the dissolution of ionic compounds held by first-year chemical engineering students. The study was of students enrolled in a university in South Africa, and the knowledge learned from it was to be used to design instruction that would assist all of their students toward a common, consistent understanding of energy in dissolution processes. Data Collection Individual, open-ended, in-depth interviews were conducted and recorded to assess the students’ conceptual understandings of energy in dissolution processes prior to instruction. Each student performed three tasks during the interviews: Each task consisted of holding a beaker of water that was slightly above room temperature, noting the relative temperature, adding a solid to the water, stirring the
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Reports from Other Journals mixture, and then noting the relative temperature of the resulting solution. The three compounds used were sodium chloride, sodium hydroxide, and sodium thiosulfate, presented in this order. Students were encouraged to talk freely about the dissolving process and about energy. Questions were crafted to help obtain a clearer, deeper understanding of the students’ thinking and conceptions. Questions like “How would you explain energy in dissolution?” that requested students to give their understandings, were used rather than “What is the role of energy in dissolution?” a type of question that could lead to recall of textbook definitions or descriptions. Determining Descriptive Categories Transcripts of the interviews were analyzed phenomenographically. A matrix was made for each student that listed their statements about the dissolution process and about energy for each of the three tasks. The matrixes for all students were then reviewed and four descriptive categories were identified as the macroscopic views of energy in the dissolution process. They appear below, in hierarchical order based on the increasing sophistication of concepts. •
You give energy
•
Water gives energy
•
Salt gives off energy
•
Reaction gives off energy
Several microscopic views of energy in the solution process were also identified: breaking bonds gives off energy; breaking bonds takes in energy; forming bonds gives off energy. Looking for Meaning and Interrelationships A chart for each of the descriptive categories was prepared, listing all statements falling in a particular category for each task. This chart was used to generate a final matrix that was used to determine the number and percentage of students that expressed a particular view for each task. For example, 76 percent of the students said that “water gave energy” during the dissolution of sodium chloride, 82 percent during the dissolution of sodium thiosulfate, but only 24 percent during the dissolution of sodium hydroxide. Ebenezer and Fraser used the final matrix “to determine the consistency and/or the variations of each student’s conception across tasks and within a task”. As an example, one inconsistent student indicated “water gives energy” in the dissolving of sodium thiosulfate, the “salt gives off energy” in the dissolving of sodium chloride, and both the “salt gives off energy” and the “reaction gives off energy” in the dissolving of sodium hydroxide. In order to obtain a fuller understanding of the consistencies and/or variations, Ebenezer and Fraser examined the transcripts in each of the categories of description. In the category “you give energy” only one student used this concept for all three tasks. According to Ebenezer and Fraser,
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the student’s comments included, “you are using energy to do that,” “the energy you use to stir it.” The student also stated that energy “made it break,” “you are dispersing the salt,” “you are breaking the attraction.” For the dissolving of sodium thiosulfate, the student explained, “…my hand feels cold to me because it is taking some of my energy.” The student did have problems with explaining the amount of heat generated in the dissolving of sodium hydroxide. He realized, “I don’t think that the stirring would cause this amount of heat in my hand.” From the interview it was found that although the student’s initial argument was that you give energy, other arguments were also made including that the salt crystal has electrostatic energy, the chemical reaction gives off energy, and water provides energy. Similar analyses were performed for all of the students, for all three tasks, across all four descriptive categories. Suggestions for Instructional Strategies The results of the analysis indicated that most students conceptualized differently across the three tasks; however, there appeared to be a greater consistency of conceptualization across two tasks—the dissolution of sodium chloride and of sodium thiosulfate. They concluded that students’ responses were affected by specific task-based perceptual information, implying that teaching should aim for a consistent theory about energy associated with any solution process and which should relate to all solution processes. This requires both the instructor and the student to be involved in task-specific chemical inquiry and then through discourse find a consistent explanation for all three tasks. For the category “you give energy” Ebenezer and Fraser suggest using the following questions to initiate discourse, stimulate inquiry, and help the students realize the significance of the energy that is provided by stirring 1. How much energy is given in stirring? 2. Why do the different tasks lead to different temperature changes with the same amount of stirring? 3. Can you calculate how much energy is given by the stirring? 4. What temperature change would this energy cause? The researchers presented suggestions for instruction for all of the categories of description.
Summary Phenomenography has the potential of categorizing the various ways students experience and conceptualize the world around them. Since the categories developed are related to the phenomenon, not to the individual students, it may be possible to have an outcome space that is stable and applicable from one group of students to another. This applicability eliminates the need to collect data for each new group of students. Thus, appropriate instructional strategies can be developed, tested, and ultimately employed by instructors that will assist each student to build upon current understanding
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Chemical Education Today
and move toward a consistent, common understanding of a phenomenon similar to that which the scientific community has come to accept. Phenomenographic methods can be employed to monitor student progress and changes in their conceptual structures as a result of instruction. But, because open-ended, in-depth interviews, which are very time consuming, appear to be the best means of obtaining data for a phenomenographic study, its use appears more applicable for formal research studies than in general classroom use. However, the results of such studies can help instructors understand the different kinds of concepts held by students, enabling them to help their students focus on the critical aspects of the lesson and to avoid the common errors in understanding that can result when these critical aspects are misinterpreted. Literature Cited 1. Marton, F. J. Thought 1986, 21, 28–41.
2. Marton, F. Instructional Science 1982, 10, 177–200. 3. Marton, F. In Phenomenography. Husen, T.; Postlethwaite, T. N., Eds.; The International Encyclopedia of Education, Vol. 8, 2nd ed.; Pergamon: Oxford, UK; 1994; pp 4424– 4429. 4. Phenomenography Crossroads. http://www.ped.gu.se/biorn/ phgraph/home.html (accessed June 2002). 5. Richardson, J. T. E. Review of Educational Research 1999, 69, 53–82. 6. Webb, G. Higher Education 1997, 33, 195–212. 7. Ebenezer, J. V.; Fraser, D. M. Science Education 2001, 85, 509–535.
Kenneth S. Lyle, a graduate student in the Chemistry Education Program, and William R. Robinson, his research supervisor, are in the Department of Chemistry, Purdue University, West Lafayette, IN 47907;
[email protected].
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