How students argue scientific claims: A rhetorical-semantic analysis

This paper investigates ways students engage in scientific reasoning practices through the formulation of written argument. Through textual analysis of university students' scientific writing we examined how general theoretical claims are tied to specific data in constructing evidence. The student writers attended a writing-intensive university oceanography course that required them to write a technical paper drawing from multiple interactive geological data sets concerning plate tectonics. Two papers, chosen as exemplary by the course instructor, were analysed in three ways: First, genre analysis was applied to identify the rhetorical moves used by the authors to complete the academic task. Second, a previously developed model of epistemic generality was used to uncover the relationships of theoretical assertions and empirical data. Third, an analysis of lexical cohesion mapped the recurrence and relationships of topics throughout the student papers. These analyses identified ways that the students engaged with the genre (as defined within the activity system of the course): the successful student authors were shown to adjust the epistemic level of their claims to accomplish different rhetorical goals, build theoretical arguments upon site specific data, method, introduce key concepts that served as anchors for subsequent conceptual development, and tie multiple strands of empirical data to central constructs through aggregating sentences. Educational applications are discussed.