Benchmarks for Science Literacy: Chapter 15 THE RESEARCH BASE


    11B) MODELS

There is important research into the use of interactive computer models to teach students certain scientific concepts (e.g., Smith et al., 1987; White, 1990). Most models being developed are qualitative for two reasons. Because the prior knowledge and models students bring to their science instruction are themselves usually qualitative, qualitative reasoning is closely connected to that prior knowledge. Moreover, problem-solving studies have shown that qualitative reasoning is not engaged if students move too quickly into memorizing and applying formal laws. There is still a need to examine student understanding and use of models in general and the characteristic knowledge and misunderstandings they hold about models.

Middle-school and high-school students typically think of models as physical copies of reality, not as conceptual representations (Grosslight et al., 1991). They lack the notion that the usefulness of a model can be tested by comparing its implications to actual observations. Students know models can be changed but changing a model for them means (typical of high-school students) adding new information or (typical of middle-school students) replacing a part that was made wrong.

Many high-school students think models help them understand nature but also believe that models do not duplicate reality. This is chiefly because they think that models have always changed and not because they are aware of the metaphorical status of scientific models (Aikenhead, 1987; Ryan & Aikenhead, 1992). These difficulties continue even for some undergraduate chemistry students (Ingham & Gilbert, 1991).

Students may not accept the explanatory role of models if the model shares only its abstract form with the phenomenon, but will usually accept the explanatory role of models if many of the material features are also the same (Brown & Clement, 1989). Middle-school students may have severe difficulties understanding the hydraulic analogue of an electric circuit and think the two circuits belong to entirely different areas of reality (Kircher, 1985).

Middle-school and high-school students may think everything they learn in science classes is factual and make no distinction between observation and theory (or model) (Brook et al., 1983). If this distinction is to be understood, it should be made explicit when models like the atomic/molecular model are introduced (Brook et al., 1983). Irrelevant aspects of the concrete model can distract students and should be pointed out.