Modes of Meaning in High School Science. CELA Research Report.

Using the framework of systematic functional grammar, this study compares two modes of presenting the same scientific topic: in a physics textbook and in interactive teacher talk. Three aspects of scientific meaning making are analyzed: representations of physical and mental reality, lexical packaging, and the rhetorical structure of reasoning. Both the textbook and teacher talk use verbs of action to represent scientific processes but the teacher talk constructs the teacher and students as active participants in these processes, while the textbook constructs the readers as distant observers. The textbook contains more grammatical metaphors, which are frequently left unpacked, whereas in the teacher talk grammatical metaphors are always unpacked. Both the textbook and the teacher talk show similar thematic organization but while this is explicit in the textbook, in the teacher talk it is interactionally constructed. The authors conclude with a discussion of the implications of these findings for the socialization of students to science discourse through different instructional modes. (Contains 51 references.) (Author/MM)