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Asia-Pacific Forum
on Science Learning and Teaching, Volume 10, Issue 1, Article 3
(June, 2009) |
In science, metaphors are used in the formation of new knowledge. The use of metaphors can be a way of making it possible to approach and handle abstract scientific information, often expressed in a mathematical or visual code, more directly. This can be a tool for scientific thinking (Boyd, 1993; Hesse, 1963; Kuhn, 1993). For example, scientific discussion and thinking can be facilitated by conceiving of a DNA-molecule as a ‘string’, even though everybody who takes part in the scientific communicative practice understands that it is not a ‘string’ in the everyday sense of the word. Another example might be ‘chaperon’, which has made a transition from meaning an apron to an older person accompanying a younger (often female) person, to referring to a special class of molecules that decreases the probability that a newly formed protein will fold in an inappropriate way. Here, we refer to these ubiquitous metaphors as metaphors used by the scientific community.
When learners use metaphors in acquisition of new knowledge, the metaphors take on a different role. Here the educational and rhetorical aspects of the metaphor are its core value.
There is a wide variety of standard metaphors used in science teaching (Duit, 1991), and there is a continuously growing mass of metaphors invented by individual teachers. In this paper we use the term metaphors used in teaching for this category.
Apart from the metaphors used by teachers to facilitate learning, there is also a wide and wild flora of metaphors used by and invented by the students. Levin and Wagner (2006) differentiate between planned and spontaneous metaphors. While emergent metaphors, according to their classification, are spontaneous, planned metaphors are the product of a purposeful process of thinking and deliberation. Here we use the term spontaneous metaphors for all metaphors invented by the students, whether produced spontaneously or planned beforehand. A true distinction between planned metaphors and metaphors that are produced spontaneously requires a long-term study of individual students that lies beyond the scope of this study.
Furthermore, many verbs that are normally used in everyday contexts appear in learners’ explanations in science (Cameron, 2002). Examples of such everyday verbs used in molecular life science are: ‘cut’, ‘break’, ‘coil’, ‘copy’ and ‘translate’. Interestingly, these words are also used by the experts in the field, but then with a well-defined, precise meaning with an extensive depth of intention. These metaphorical expressions offer educational opportunities to link molecular processes to the life-world of the students, but at the same time they pose special problems due to the rich flora of everyday associations to which they connote. The challenge for the science educators is to make the students understand and apply the precision with which these terms are used in science. To achieve this, the students need to narrow the range of meaning of these terms, making them more precise and less vague. In other words, they must learn to ‘kill’ the metaphors in science. For example, for a beginner in bioscience, it may seem to be of little importance if they use the term ‘break’ or ‘cut’ when a DNA-molecule is divided. For the expert, however, ‘cut’ means a well-defined breakage of a binding, for example by a restriction enzyme which cleaves a DNA-molecule at specified positions; while ‘break’ means unspecific breakage, for example as the effect of exposure to radiation.
These verb-metaphors can be regarded as constituting special cases of spontaneous metaphors (when coming from the students), metaphors used in teaching (when coming from the teacher or text book author) or metaphors used in science – and thereby given a special, well-defined scientific meaning – (when coming from the area of science itself).
Although there is an extensive literature on metaphors in science education (Clement & Rea-Ramirez 2008; Duit, 1991), the spontaneous metaphors produced by the learners themselves have been less studied, although there are some exceptions (Bloom, 1992a, 1992b; Clement, 1998; Jakobson & Wickman, 2007).
