Modelling in science lessons: Are there better ways to learn with models?

School Science and Mathematics, Dec 1998 by Harrison, Allan G, Treagust, David F

Nearly every textbook we have examined, however, failed to warn its readers that models are human inventions that break down at some point. Teachers may assume that their students understand the limits of models; but Grosslight et al. (1991) showed that this belief is too ambitious. This raises a major thinking and learning problem for students. Students need time and help in coming to realize that models are contrived and limited representations of reality. According to Grosslight et al., the legitimacy of multiple scientific models is a function of epistemological expertise; however, middle school students are usually Level 1 modellers who believe that one model is right. It is not surprising, then, that students are perplexed when teachers and textbooks at this level move from one model to another without explanation. Inexperienced students believe that the teacher knows the right model, and the trick for them is to discover which model is right (Perry, 1970). Yet, modelling that is multiple, flexible, purposeful, and relational is the essence of scientific thought (e.g., Gilbert, 1993), although the ability to model in these ways is rarely found in schools students. The pressing question for school science education is "How can students with naive and realist world views be encouraged to progressively adopt expert modelling skills?"

This is why the typology of school science models is useful. The typology outlines the level of conceptual difficulty inherent in each model type, and the model types are generally ordered in terms of increasing conceptual demand. Awareness of these demands should encourage teachers to match the model types they choose to use in their lessons to their students' cognitive ability. As an aid to teachers, the FAR guide is a systematic framework within which teachers can structure their students' model-based learning. Another issue of importance is whether teachers should teach with models situated at the students' intellectual level or higher than the students' intellectual level. Finster (1991) claims that intellectual progress is maximized when teaching is situated just ahead of the students' current cognitive ability.

In psychological terms, this means challenging students to think within their "zone of proximal development" (van der Veer & Valsiner, 1991, pp. 336-340). Vygotsky described this zone as the intellectual range bounded at the lower level by what students can do on their own and at the upper level by what they can achieve with teacher cues or peer help. This is why socially negotiating the meaning of difficult concept and abstract models is so important. Vygotsky argued that students' intellectual growth is optimized when they are challenged to do, with help, what they cannot do on their own. Perry's (1970) model of intellectual and ethical development made similar claims, and Grosslight et al.'s (1991) modelling levels suggested that modelling is an intellectual skill that develops with help and experience.