Linking Physical and Computational Models in Preservice Teacher Education

• In Event: Thinking Across Representations: Designing to Leverage Material and Computational Investigations for Science Learning

Abstract

Objectives. This paper investigates modeling practices that arise in an engineering course for pre-service teachers (PSTs). All participants are non-science majors and most aspire to be elementary or special education teachers. Across the course, the PSTs move across physical, mathematical, and computational models of phenomena. Specifically, we focus on PSTs’ design of truss bridges and their sensemaking about tensile and compressive forces in their physical bridges, in a truss analysis simulation, and in calculations using free body diagrams and the method of joints.

Theoretical framework. Professional civil engineers leverage computational modeling out of necessity. However, for children and non-scientists, the interdependence of design with theoretical and computational tools are rarely evident in engineering learning opportunities, such as bridge design challenges. We draw on the Bifocal Modeling Framework (Author, 2014) to describe the complementarity of simulations and physical investigations in ways that support learners to consider the epistemic relationships of practical and theoretical knowledge in science and engineering. We seek to understand how PSTs leverage complementarity among modeling forms while accepting various affordances and constraints of different representational infrastructures.

Research question: How do pre-service teachers reason about differences in models of “real” and ideal systems? What new learning opportunities arise across representational forms?

Methods and data. The data were collected in an introductory engineering course for educators, taught during Spring 2019 and Spring 2020. Most participants were in their first or second year at the university. The courses included modules on structures, simple machines, electricity, and computational making. The data include contributions from 35 consenting PSTs. Forms of data include classroom artifacts, field notes, and assignments.

The focal project of the poster is the first design project of the course. Student teams design a truss bridge from K’Nex members that spans 1.3 meters and will support a centrally-located 1kg load. Students identify trends in truss performance using their designs and a simulation (Truss Solver, 2012) to iteratively refine their design to minimize cost and weight of materials. Students also use principles of statics and the method of joints to solve for tensile and compressive forces in various bridges. Across two semesters, we find that reconciling across the assumptions of the method of joints (e.g., joints are connected by frictionless pins) with forces evident in the K’Nex designs (Figure 1) poses substantial learning opportunities about models and modeling as well as physics content.

Results and Significance. Students learn principles of statics through modeling and are challenged by the range in utility of various model forms for different design purposes. We find that students are surprised when their determinations of forces on individual truss members (using the method of joints) agree with the simulation or their visual observations of their own physical designs. However, students find it challenging that different model forms have different affordances for predicting or explaining the relative success of their design decisions in physical construction. The poster will thus share how a ubiquitous bridge design task becomes an exploration of the epistemology of modeling across complementary model forms.

Authors

• Amy Voss Farris, The Pennsylvania State University

• Gözde Tosun, The Pennsylvania State University