Examination of pre-service physics teachers’ epistemologies of scientific models and their model formation during model-based inquiry process

According to Gobert and Buckley (2000), models are representations of a system to make its central features explicit. On the other hand, model formation is the construction of a model of some phenomenon by integrating pieces of information about the structure, function/behavior, and causal mechanism of the phenomenon, mapping from analogous systems or through induction (Gobert & Buckley, 2000). The scientific modeling involving construction, use, evaluation, and revision of models embedded in the inquiry process can be generally defined as the model-based inquiry (MBI) (Schwarz et al., 2009). Windschitl, Thompson and Braaten (2008a) offer MBI as an alternative vision for investigative science to capture the features of authentic science. Involving learners in modeling practices can help them build subject matter expertise, epistemological understanding, and expertise in the practices of building and evaluating scientific knowledge (Ogan-Bekiroglu, 2007; Schwarz et al., 2009). To introduce modelling successfully in science teaching requires that teachers have an appropriate understanding of nature and function of models and their role in the accreditation and dissemination of scientific knowledge. Most science teachers have never directly experienced authentic scientific inquiry during their education in the sciences or within teacher education programs (Hahn & Gilmer, 2000). Hence, this study aimed to evaluate pre-service teachers’ epistemologies of scientific models and their model formation in a model-based inquiry environment.

Theoretical Framework

Individual conceptions of epistemology are an important area for research and may provide further insight into how individuals make meaning and how this in turn affects learning (Hofer, 2000). Some of the general views for personal epistemology derived from the particular ontological and theoretical assumptions are as follows (Hofer, 2001):

Epistemology is developmental and thus, part of the goal of education is to foster epistemological development.
Epistemology exists in the form of beliefs.

Beliefs, in terms of general meaning, are deeply personal, stable, rooted in vivid memories of past experiences, lie beyond individual control or knowledge, and are usually unaffected by persuasion (Nespor, 1987). Because of the complicated nature of beliefs, some researchers talked about beliefs as a system (Block & Hazelip, 1995; Fishbein & Ajzen 1975; Green, 1971; Rokeach 1968; Thompson, 1992). There is consensus that pre-service teachers’ beliefs serve to constrain their knowledge and in turn their pedagogical content knowledge (Johnston & Whitenack, 1992; Kane, Sandretto, & Heath, 2002). The need for teacher education programs to identify and target existing beliefs seems to be at the core of teacher educators’ tasks (Johnston & Whitenack, 1992).

“Teachers’ beliefs, which are interactive with their practices, are thought to drive actions; however, experiences and reflection on action may lead to changes in and/or additions to beliefs” (Richardson, 1996, p. 104). Thompson (1992) also reveals that the relationship between beliefs and practices is dialectic, not a simple cause-effect relationship, and suggests that studies should seek to elucidate the dialectic between teachers’ beliefs and practices.

Therefore, theoretical underpinnings of this paper are the following: Pre-service teachers’ epistemologies of models are structured as their beliefs, can be reshaped by instructional experiences, and may have relationship with their practice i.e. model building.

Science Teachers’ Epistemologies and Views of Models and Modelling

In order to help students in learning science, Justi and Gilbert (2002b) advocate that teachers should have comprehensive understanding of the nature of a model in general, and know when, how and why the general idea of models and specific or historical models should be introduced in their classes. Based on their findings, Summers and Mant (1995) suggest that essential prerequisites for primary teachers if they are to teach astronomy are: knowledge of accurate, scientific, structural models and being able to use these models to explain and predict simple phenomena. Consequently, researchers have developed interest in teachers’ understanding of models and modelling. van Driel and Verloop (1999) conducted a research in the Netherlands to map the experienced science teachers’ practical knowledge with respect to models and modelling in science, in terms of the common characteristics of models, the roles, and the functions of models in science. Two instruments were used: a questionnaire with seven open items on models and modelling, which was completed by 15 teachers, and a questionnaire consisting of 32 items on a Likert-type scale, which was completed by 71 teachers. Their results indicated that the teachers shared the same general definition of models. However, the teachers’ content knowledge of models and modelling proved to be limited and diverse. A group of teachers who displayed more pronounced knowledge appeared to have integrated elements of both a positivist and a social constructivist epistemological orientation in their practical knowledge. van Driel and Verloop (2002) also aimed to find teachers’ knowledge of teaching and learning of models and modelling in science education. Seventy-four science teachers in the Netherlands completed the questionnaire. The results of their study indicated that teachers differed in the extent to which they use teaching activities focusing on models and modelling in science, and their knowledge of students’ conceptions and abilities in this domain was either limited or not very well integrated with their knowledge of teaching activities.

Justi and Gilbert (2002b) used a semi-structured interview to enquire into the knowledge of models and modelling held by a total sample of 39 Brazilian science teachers working in fundamental and medium schools, student teachers, and university teachers. The teachers’ ideas were organized in three groups: the status and value of models; the influences that inform the translation of these general ideas into classroom practice; and how they responded to the outcomes of students’ modelling activities. The teachers generally showed an awareness of the value of models in the learning of science but not of their value in learning about science. They were also uncertain of the relationship that could exist in the classroom between various types of models. In the same research, Justi and Gilbert (2002a) also analyzed the questions around the theme “What are the knowledge and skills that a person should have in order to produce a scientific model successfully?”. Their results illustrated that the participants were not aware of the ‘model of modelling’ framework, and they seemed to be thinking of modelling as something done primarily by scientists, or by other people who were less effective at this than scientists.

Harrison (2001) interviewed 10 experienced science teachers about their understanding of the analogical models that they used to explain science to their students. The author found that the teachers’ view of modelling, taken together, satisfied “almost all the recommendations in the literature for effective model use” (Harrison, 2001, p.10). However, individually, almost half of the sample displayed a problematic level of knowledge of models and modelling. Five teachers saw a need to negotiate with their students the shared and unshared attributes of teaching models and two consistently discussed the limitations of their models. Harrison (2001) also reported that physics teachers used more models and showed greater creativity in this area, followed by biology teachers, and lastly by chemistry teachers. Reviewing of the literature indicates that teachers may have general idea of models but their knowledge of using models in teaching and learning science is limited.

Research Focusing on a Shift in Pre-Service Teachers’ Understanding of Models

Pre-service science teachers’ inadequate epistemologies of models directed some researchers to improve them. For example, De Jong and van Driel (2001) worked with eight pre-service chemistry teachers to improve their emphasis from exclusively teaching content to teaching about the nature of models. Although the participants discussed articles on modeling, examined model-oriented curricula, and collaboratively developed lessons for teaching about specific models, most of them did not come to an understanding of some of the most fundamental functions of models.

Crawford and Cullin (2004) had secondary pre-service teachers design an open-ended investigation of a plant, soil, and water system, and later build computer models of the relevant environmental phenomena. Of the 14 participants, 13 were initially classified as midlevel modelers. Consistent with other studies, the pre-service teachers viewed models as representations used by "someone who understands" to explain to "someone who doesn't." After the modeling experience, the participants shifted their thinking, from models being used by someone to explain an idea to another, to the model being considered by a “user” to understand the phenomena him- or herself. Overall, however, no participant moved from a mid-level understanding to an expert level.

Windschitl and Thompson (2006) examined 21 pre-service secondary teachers as they engaged in activities aimed at fostering their understanding of models and how models are used in inquiry. The study culminated in independent inquiries by the students, in which they were required to develop a model of a natural phenomenon, empirically test some aspect of that model, and use the results to support or revise the original model. They found that instruction could help pre-service teachers develop more sophisticated understandings of scientific models and promote incorporation of model-based lessons in their classrooms. However, they indicated that even with scaffolding, the majority of these pre-service teachers were unable to use theoretical models to ground their own empirical investigations.

Schwarz and Gwekwerere (2007) worked with 24 pre-service elementary teachers to engage them in model-based reasoning and move a majority toward their own model-based lesson designs. Though some participants used models in their lessons in ways inconsistent with model-centered inquiry, the researchers experienced some success using an “engage, investigate, model, and apply” framework.

According to Windschitl and Thompson (2006), undergraduate experiences do little to advance the idea of models beyond that of acting as pedagogical props. Schwarz, Meyer and Sharma (2007) claim that the depth of students’ understanding of the nature of models is likely to arise or emerge by having students deeply engage in modeling with a variety of inquiry tasks. Research results indicate the need for more robust instructional designs that include opportunities to work with models in varied and mutually reinforcing contexts, and routinely connect the principles of model-based inquiry to classroom practice (Windschitl, Thompson & Braaten, 2008b). However, there is not much research on engaging pre-service science teachers in inquiry with an emphasize on modelling. The participants of a research done by Akerson and her colleagues (2009) were 10 practicing elementary teachers participating a K-6 professional development program that emphasized scientific inquiry and nature of science within the theme of scientific modeling. During the 2-week summer workshop and follow up school year workshops, the instruction modeled a 5-E learning cycle approach. Scientific modeling proved useful in illustrating the distinction between observation and inference as teachers were asked to make observations and use their inferences to make their own models. Teachers added the use of mathematical formulas to their views of scientific modeling. Moreover, they used models mostly at the elaboration stage of the learning cycle, finding it a good place to ask students to apply their scientific knowledge.

Whereas there has been substantial amount of research regarding the effects of model-based instruction on pre-service teachers’ conceptions of models, research focusing on pre-service science teachers’ epistemologies in a model-based inquiry environment and looking for a relationship between their epistemologies and their model building is not ample.

The Purposes of the Study

To optimize classroom learning around epistemically rich forms of model-based inquiry, teachers need a sophisticated understanding of the nature of scientific models as well as how they are used in authentic inquiry (Windschitl et al., 2008b). Pre-service science teachers’ epistemologies of models and modelling is crucial because it may influence the way they implement modelling in their future classrooms. Specific activities may be designed to anticipate pre-service teachers’ epistemological orientations. Therefore, teacher education courses need to pay more attention to models and modelling in science education (Justi & Gilbert, 2001).

The following research questions put a light on this research: 1) Does model-based inquiry influence pre-service physics teachers’ epistemologies of nature and function of models, 2) Does model-based inquiry have impact on pre-service physics teachers’ models that they created, 3) Is there any relationship between pre-service teachers’ epistemologies of models and their model formation?