Using Students' Sketches to Recognize Alternative Conceptions about Plate Tectonics Persisting from Prior Instruction

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ABSTRACT

Should instructors assume that students possess conceptual knowledge of plate tectonics when they reach a second college geoscience course? Five cohorts in a historical geology course over 5 y-a total of 149 students-completed an in-class assignment in which they drew sketches of plate boundaries with required annotations. Analysis of the sketches revealed that most students lack an explanatory mental model that links the locations of earthquakes, volcanoes, and magma generation to plate-boundary processes and hold a pervasive alternative conception of Earth's interior structure that does not distinguish between compositional and rheological boundaries. Students who drew sketches that illustrated the most alternative conceptions also scored lower on a beginning-of-the-course administration of the Geoscience Concept Inventory, showing that conceptual understanding of plate tectonics correlates with overall conceptual geoscience knowledge obtained during previous course experiences. In addition, students tracking to the historical geology course via an introductory physical geology course showed stronger conceptual understanding of plate tectonics than those choosing an Earth-system science prerequisite, with those students previously enrolled in both courses illustrating the fewest alternative conceptions. © 2012 National Association of Geoscience Teachers. [DOI: 10.5408/11-251.1]

Key words: plate tectonics, misconceptions

INTRODUCTION

Presuming cumulative knowledge acquisition and skill development, faculty commonly assume that students achieved basic conceptual understanding of a subject in an introductory course that can be expanded on in subsequent courses. Competing with this assumption is the well-known observation from cognitive psychology that students persistently retain alternative conceptions (or misconceptions) regarding key ideas that are resistant to many forms of instruction (e.g., Posner et al., 1982; Bransford et al., 2000; Chi, 2008).

This paper summarizes an ongoing classroom-action research project (Mettetal, 2001) focused on an assignment in a historical geology course that assesses students' basic understanding of causal and dynamic aspects of plate tectonics following a previous introductory course. Our report serves three purposes: (1) to elaborate on the utility of students' sketches to assess mental models of fundamental geological processes (Gobert and Clement, 1999; Gobert, 2005; Libarkin and Anderson, 2005b; Sibley, 2005; Steer et al., 2005; Johnson and Reynolds, 2006) and thus quickly recognize and refute alternative conceptions; (2) to integrate our results with previous research on alternative conceptions regarding plate tectonics (e.g., King, 2000; Sibley, 2005; Clark et al., 2011) and thus generalize implications for instruction; and (3) to illustrate correlations between level of conceptual understanding of plate tectonics and independent measures of previous-course learning.

As the underpinning theory that explains many aspects of ongoing and past processes on Earth, plate tectonics is commonly viewed (e.g., typical textbook statements; Earth Science Literacy Initiative, 2010) as one of the most important concepts that students should understand as an outcome of an introductory college geoscience course, whether it be a terminal general-education course for nonmajors or the foundational course for pursuing a disciplinary major. Learners are typically exposed to elements of the theory in middle-school (typically ages 1214) science (e.g., National Committee on Science Education Standards and Assessment, 1996; Gobert, 2005; Ford and Taylor, 2006) with subsequent informal learning experiences through prominent presentation of elements of the theory in museum exhibits and television programs. Given that science literacy among the public is strongly correlated to courses completed in college (Miller, 2004), it is likely that most comprehension of the fundamental concepts and applications of plate tectonics is achieved in introductory college-level physical geology or Earth-system science courses. …