Teaching
Emily J. Borda,
Donald J. Burgess,
Sarah I. Walker,
Jillian Bearden,
Abstract
We have investigated the use of concept mapping to teach and assess the nature of science within the context of a science methods course for preservice elementary teachers. In one section of the course, cooperative, successive concept mapping was used to complement NOS activities and readings, while in the other section discussion was used instead of concept mapping. Although some gains in NOS views were observed in both sections, a statistically significant difference in gains between the two sections was not observed. Comparison of the final concept maps from the concept mapping section with initial concept maps from a later section of the course suggested interesting changes in students’ NOS understanding that were not visible in the VNOS responses. This finding suggests that, while concept maps might not be any more effective in promoting the learning of NOS than discussion, it may be a powerful tool for assessing NOS understanding.
Introduction
In schools, science is often presented as a set of facts instead of a system of thought in which evidence from the physical world is used to construct explanations about how the world works. Joseph Schwab argues that this kind of instruction presents science as a “rhetoric of conclusions” (Schwab, 1961). The problem with portraying science in this fashion is that students see science as an authority which cannot be questioned. In a world in which science is at the center of decisions ranging from which produce to buy to whether to act on evidence of global warming, citizens need to be able to evaluate scientific claims. Science educators argue that in order to do this, students need to be educated about science concepts with specific attention to how those concepts were generated and the inherent assumptions and values that led to their development. Thus, students need to understand science as a process that is tentative, is based on certain values and involves imagination and subjectivity. In other words, students must have a sound and sophisticated understanding of the nature of science (NOS). Indeed, nationally recognized science education documents such as Science for all Americans (AAAS, 1989) and Benchmarks for Science Literacy (AAAS, 1993) include goals and benchmarks related to the nature of science.
What constitutes a sophisticated or modern view about NOS? Though there is disagreement among scientists and philosophers of science, Lederman and coworkers have identified a set of tenets that tend to be consistent among these groups (Lederman, Abd-El-Khalick, Bell, & Schwartz, 2002). These tenets have been used to define a common set of goals which can be used as benchmarks to measure the NOS beliefs of students and teachers. They are:
· Myth of Scientific Method: There is no single scientific method.
· Empirical NOS: Science is based on evidence from the physical world.
· Inference: One must interpret data in order to make meaning out of it – the data do not speak for themselves.
· Laws vs. Theories: Scientific theories attempt to explain data while laws describe patterns in data (the former don’t become the latter, or vice-versa).
· Tentative NOS: Scientific theories are tentative and can change with new data or with new interpretation of existing data.
· Creative & Imaginative NOS: Science is a human activity which requires imagination and creativity in all of its stages.
· Theory-Laden NOS: Scientists bring their own values and backgrounds to bear when constructing scientific explanations.
· Social/Cultural NOS: Science is embedded in, and cannot be understood outside of, cultural contexts.
These tenets have been used to develop the Views of the Nature Of Science (VNOS) questionnaire (Lederman et al., 2002), which measures the degree to which students hold sophisticated beliefs with respect to each of these ideas.
In order for students to understand these ideas, their teachers must themselves have sophisticated NOS views. However, research has consistently shown that for the majority of teachers this is not the case (Lederman, 1992). Therefore, a major focus in preservice teacher education is how to help them espouse more sophisticated NOS views. Studies have shown that in order for such a learning goal to be realized, NOS must be taught explicitly. This does not mean that NOS must be taught in a didactic manner, but rather that NOS instruction must follow from the same conceptual change model that informs the teaching of science content (Akerson, Abd-El-Khalick, & Lederman, 2000; Khishfe & Abd-El-Khalick, 2002; Lederman et al., 2002). According to this model, instruction is effective when it is informed by the students’ initial and changing ideas, when learning experiences are carefully crafted to create cognitive dissonance with naïve ideas, and finally when students are given opportunities to reflect on their changing ideas (Bransford, Brown, & Cocking, 2000; Driver, Leach, Millar, & Scott, 1996; Ryan & Aikenhead, 1992). Activities aimed at teaching NOS through this model have been described (Abd-El-Khalick, Bell, & Lederman, 1998; Akerson et al., 2000).
In teaching NOS to elementary preservice teachers, we have found it challenging to encourage students to meaningfully reflect on their ideas about NOS. We have also found it difficult to find ways to have students document their changing ideas about NOS for formative assessment purposes. We have decided to use concept mapping as a tool to help students with these reflective activities, in conjunction with already-developed NOS activities.
Concept mapping has been in existence for more than three decades (see Novak, 2002 for review) and is commonly recognized among science educators as a strategy to help students make their understanding of a given concept more transparent (Edmondson, 2000; Heinze-Fry & Novak, 1990; Mintzes, Wandersee, & Novak, 2001). Concept mapping has also been used as a tool to assess student understanding (Edmondson, 2000; Mintzes et al., 2001; Novak, 1984). Concept maps have been shown to be a valid way to assess both the extent of the student’s understanding (through the number of concepts and valid relationships) as well as the complexity of that understanding (through the way in which the concept map is organized) (Mintzes et al., 2001; Novak, 1984). Furthermore, recent research suggests that cooperative (Prezler, 2004) and successive (Quinn, Mintzes, & Laws, 2004) concept mapping, two techniques combined in this study, are effective in promoting learning among students.
This study describes the use of concept mapping as a tool for both teaching and assessing the NOS beliefs of elementary preservice teachers in a science methods course. Two sections of the course were offered during the same quarter and were taught by the same instructor. The students in one section used concept maps throughout the quarter as a way to make sense of their initial and changing NOS views, while the students in the other section made sense of these same ideas through discussion sessions. The VNOS questionnaire (Lederman et al., 2002) was used to measure gains in NOS beliefs for both sections. Through this study we have gained important insights into preservice teachers’ ideas about NOS and how these ideas changed, as well as how to use concept mapping as a learning and assessment tool for NOS ideas. In this paper, the structure of this study will be described, followed by a description of the data collected from the VNOS questionnaire and concept maps. An interpretation of these data will be discussed, followed by implications for future NOS instruction and research.
Methods
This study described followed a quasi-experimental design. It was carried out within the context of a quarter-long science methods course for preservice elementary teachers. Two sections of this course were taught by the second author. In one section (n = 21 females and 2 males), concept mapping was used throughout the course as a tool for NOS instruction. In the other section (n = 15 females and 6 males), discussion was used in place of concept mapping. Both sections included robust NOS instruction, including readings, research-based activities and group discussions. Because the idea of concept mapping as a learning and assessment tool was an important learning objective, both sections received instruction in concept mapping at the beginning of the course. Instruction began with a brief introductory lecture addressing the definition and theory of concept mapping. The two sections then engaged in an activity in which they brainstormed words or phrases related to the following questions: What is science? What is the scientific world view? What is scientific inquiry? Who does science and how do they do it? The students had read the first chapter of Science for All Americans (AAAS, 1989) and used this text to guide their discussion. Students then used their brainstormed ideas to create their own concept maps using post-it notes on poster paper, in groups of 3 or 4.
The two sections diverged in the continued use of concept mapping. Each time the students in the concept mapping section engaged in a reading, activity or discussion focused on NOS ideas they added to and revised their concept maps in the same small groups they had formed during the initial concept mapping activity. Students in the other section, however, engaged in small and large group NOS-centered discussions instead of creating and revising concept maps. The same amount of time was devoted to NOS instruction in both groups.
To measure changes in NOS beliefs, version C of the Views of the Nature of Science questionnaire (VNOS-C) (Lederman et al., 2002) was administered to all students in both sections at the beginning of the quarter. At the end of the quarter students were given back their initial responses and asked to write about any changes in their thoughts about NOS in the context of each question. Responses were coded according to whether the NOS beliefs expressed were “informed” or “naïve,” as in Lederman et al., 2002, for each of the eight tenets mentioned above, as well as for an additional three categories which emerged as strong themes in the VNOS responses. These categories are best thought of as subsets of the original eight tenets. They are: Observation (One need not always conduct experiments to generate valid scientific knowledge but can observe natural phenomena); Nature of scientific theories (theories are constructs or explanations, not an exact picture of reality) and Function of scientific theories (theories provide a framework for thinking about phenomena and stimulate additional research).
All four authors collaborated in the effort to code the VNOS questionnaires. During the previous quarter, a similar study was done and VNOS questionnaires collected. These questionnaires were used to train the coders and assess interrater reliability. During the previous quarter, interviews were held with 20% of the students in one of the SCED 390 sections. These interviews were used to help interpret the VNOS responses from the study described in this paper. Three training rounds were held in which each researcher discussed his or her coding of the same three sets of pre-/post VNOS questionnaires. In cases where discrepancies occurred, the researchers came to a consensus by discussing the relevant response. A coding scheme was developed and revised after each coding session (see Appendix). In a final training session, the four coders coded the same two sets of pre-/post VNOS questionnaires from the sections of SCED 390 studied in this paper. Again, discrepancies were discussed in order to come to consensus. Interrater reliability on these two VNOS questionnaires ranged from 73 to 100% for each pair of coders.
Later in this study the researchers decided it would be important to also analyze the concept maps generated by the concept mapping section. In order to do this, the final concept maps in the concept mapping section were scored according to a scheme described in Markham & Mintzes, 1994, which takes into account the number of concepts, examples, branchings, hierarchies and crosslinks in the concept maps. Because the concept maps were revised throughout the course by rearranging the post-it notes on the poster boards, there was no record of the initial concept maps. Therefore, concept maps were collected from two sections of a subsequent SCED 390 course, taught by the same instructor, in which the initial concept mapping training and activity was identical to that of the section in this study. There were no appreciable differences in the gender distribution and number of science majors between the two courses. These concept maps were scored according to the same scheme.
Results
and Discussion
VNOS responses
The VNOS responses revealed a greater overall percentage of sophisticated initial beliefs in the comparison group compared to the concept mapping group (Fig. 1). The reasons for this are unclear. There was only one science major in the discussion group and no science majors in the concept mapping group. The difference may simply be an artifact of the small sample sizes. In both groups, 50% or more of the initial responses were coded “informed.” The NOS beliefs for preservice teachers in both groups seemed to become more sophisticated over the course of
Figure 1. Pre- and post- VNOS responses for the treatment (concept mapping) and comparison (no concept mapping) sections. The y axis describes the percent of the students who had informed ideas about the specified NOS aspect out of the total number of students for that section whose VNOS responses revealed ideas about that aspect. *p<0.05.
the quarter in most areas. However, the only change that was statistically significant was in the “scientific method” category for both sections.
In order to characterize the gains in NOS beliefs, a scoring system was developed in which a change from naïve to informed was given a score of 1, a change from informed to naïve a -1, and no change was given a score of 0. Figure 2 shows average gains in each section for each NOS aspect, as well as average total gains for each section. Average gains in NOS beliefs were relatively small for both sections (the average total gain represented a change from naïve to informed on less than one NOS aspect per student). Although the differences in gains on some of the NOS aspects in figure 2 seem considerable, there were no statistically significant differences in gains between the two sections when a one-way ANOVA was performed. This lack of statistical significance may be due in part to the small sample sizes (n = 23 and 21) and
Figure 2. Average gains on each NOS aspect (left) and average total VNOS gains (right).
the small overall gains. The lack of statistically significant differences in gains may be due in part to the fact that the average pre-VNOS scores were relatively high to begin with (Fig. 1).
Concept maps
Figure 3 shows the results from comparing the concept mapping group’s final concept maps with the initial concept maps of a subsequent section, using the scoring scheme discussed above. Although the average total scores were higher for the final concept maps than for the
Figure 3. Average concept map scores by concept map aspect and total scores. *p<0.05.
initial concept maps, this difference was not statistically significant. Again, this may be partially due to the sample sizes. However, the pre- and post- concept maps showed statistically significant differences in two categories: The number of concepts and the number of examples on the concept maps. Interestingly, the initial concept maps included more examples than the final concept maps did. Conversely, the final concept maps included more concepts than the initial concept maps. The two examples in figure 4 illustrate this difference. Figure 4A shows an initial concept map in which the entire bottom row consists of examples. The concept map in figure 4B, however, has no examples. Although the total number of “entries” on the initial concept maps was similar to that for the final concept maps, more of these entries were examples on the former, whereas more entries on the latter were more general concepts about science. Our interpretation of this result is that initially the preservice teachers were not sure what types of characteristics separated science fields from non-science fields, but they could give examples of what science is. However, at the end of the course the preservice teachers appeared to have a better idea of the general characteristics of science as a field of study. The lack of growth in some of the structural components of the concept maps (branching, hierarchies, crosslinks) suggest that this change was due to changes in the students’ ideas rather than to an improvement in the skill of concept mapping.
Conclusions
Although the VNOS responses seemed to have become more sophisticated over the course of the quarter in both sections, a statistically significant change was only observed in the “scientific method” category for both sections. This may be because the NOS instruction, while focusing on epistemological issues, seemed to emphasize those concepts that had to do with
Figure 4. Examples of initial (A) and final (B) concept maps.
science process. Indeed, NOS is often conflated with science process (Abd-El-Khalick et al., 1998). However, research suggest that when NOS is taught explicitly through the framework of the scientific process, significant gains in NOS beliefs were observed (Bell, Toti, McNall, & Tai, 2005). One of the goals for a future iteration of this study, therefore, is to make more explicit the difference between NOS and science process, while explicitly teaching both. The lack of statistical significance in the other NOS aspects may be partially due to the sample size, as well as a the fair amount of already sophisticated NOS beliefs.
When the gains in VNOS responses of the two sections were compared, there were no statistically significant differences. This is not surprising given that only one NOS aspect in each section showed a statistically significant gain over the course of the quarter. Another potential problem is that our dualistic coding system (“naïve” and “informed”) may not have us to see more nuanced changes. Some NOS researchers have adopted a system that includes the “transitional” code, which we are considering adopting in the future to help us see more subtle changes. In the absence of such a code, we may have been a little too generous in awarding the “informed” code, hence creating the abundance of initial ideas discussed above.
Initial analysis of the final concept maps for the treatment group and comparison with the initial concept maps from a subsequent course revealed an increase in the use of general NOS concepts and a decrease in the use of superficial examples throughout the quarter. This may be interpreted as an increase in NOS understanding. However, closer observations of the concept maps as they change over the course of a quarter in a single section is needed in order to strengthen this claim. Our data suggest that while concept mapping may not necessarily be any more effective as a learning tool than class discussions, it shows promise as a complement to the VNOS or other nature of science instruments as an assessment tool for NOS beliefs. Concept maps have the unique ability to reveal a student’s conceptual structure, which researchers have argued to be an essential component of understanding (Mintzes et al., 2001; Novak, 1984), with respect to a certain topic. If we are to treat NOS as a content area in which sophisticated understandings come about through the same cognitive pathways as with other science topics, we should use the same pedagogical and assessment tools as with those other content areas. Concept maps have proven useful in both domains, and our data here suggest they may be useful in the realm of NOS, at least as an assessment tool. Further studies are needed, however, in order to study its effectiveness in both areas.
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