Every Equation Tells a Story: Using Equation Dictionaries in Introductory Geophysics

Abstract

Many students view equations as a series of variables and operators into which numbers should be plugged rather than as representative of a physical process. To solve a problem they may simply look for an equation with the correct variables and assume it meets their needs, rather than selecting an equation that represents the appropriate physical process. These issues can be addressed by encouraging students to think of equations as stories, and to describe them in prose. This is the goal of the Equation Dictionary project, used in Western Washington University's introductory geophysics course. Throughout the course, students create personal dictionaries consisting of (a) the equation itself, (b) a brief description of variables, (c) a prose description of the physical process described by the equation, and (d) additional notes that help them understand the equation. In writing these definitions students learn that equations are simplified descriptions of physical processes, and that understanding the process is more useful than memorizing a sequence of variables. Dictionaries also serve as formula sheets for exams, a task that encourages students to write meaningful, organized definitions. Furthermore, instructor review of the dictionaries is an excellent way to identify student misconceptions and learn how well they understand derivations and lectures.