Science itself and science teaching depend on a number of scientific models to explain several scientific concepts, such as the atom and black holes, which are functional theoretical models rather than copies of the reality (Lederman, 2004). The concepts modeled are usually inaccessible or unobservable by their nature, and scientific models serve as abstractions or simplifications of these concepts to make their features explicit and visible, and allow scientists, teachers or students generate explanations or make predictions about them.
Scientific models usually have some lacking points from the scientific phenomena modeled because they are approximations of the scientific phenomena that we cannot ever come to know absolutely (Coll, 2006). As in the example of the atomic model for the structure of matter, it is possible to think of atoms as being real but what is meant with the term atom is simply a model of a reality (i.e., the composition of matter) we can never truly come to know (Coll, 2006). Due to this nature, models cannot be completely certain, and are tentative that they are open to further revision and development (Crawford & Cullin, 2004). Moreover, depending on the context, purpose of the scientific research and perspective of the scientist, scientists can have more than one model for the same phenomenon (Sins et al., 2009). That is, multiple models of a given phenomenon may co-exist (Shwartz, Rogat, Merritt, & Krajcik, 2007; Van Der Valk, Van Driel, & De Vos, 2007); and the more the concept is abstract, the more likely it requires multiple models since each model covers a feature of the target concept (Harrison & Treagust, 1998). For example, biochemists and theoretical chemists use different models for the corpuscular structure of water, or physicists use either the model of light as particle-like or as wave-like depending on their purpose of explanation (Crawford & Cullin, 2004; Justi & Van Driel, 2005).
It is undeniable that, the abovementioned characteristics and several others should be taught appropriately by science teachers, and science teachers themselves need to hold sound understandings about scientific models in order to use models effectively in their instructions. Therefore, it is important to uncover pre-service science teachers’ (PSTs’) understandings of scientific models, since teachers play a crucial role in promoting their students’ learning (Davis, Kenyon, Hug, Nelson, Beyer, Schwarz, & Reiser, 2008).
At this point, the research question investigated in this study was:
What understandings do pre-service science teachers hold about scientific models, in respect of ´models as representations´, ´multiplicity of models´, and ´dynamic/changing nature of models´?
