Right Side of the Law
A nontraditional thermodynamics assignment offers a model for teaching engineering fundamentals.
By Peggy N. Van Meter, Carla M. Firetto, Stephen R. Turns, Thomas A. Litzinger, Chelsea E. Cameron, and Charlyn W. Shaw
Improving students’ knowledge of foundational principles is a major concern of engineering educators. These principles are often complex, involving multiple interconnected knowledge elements. One particular challenge occurs in introductory thermodynamics, when many students struggle to understand the first law, or conservation of energy principle.
Our study shows that students’ knowledge of the first law can be improved by an educational intervention designed as a homework assignment. The goal of the intervention is to improve conceptual reasoning ability by helping students organize their knowledge and generate connections across associated knowledge elements. Although we focused on learning in thermodynamics, the design principles underlying the intervention can be applied to other engineering-related content that requires understanding of the organizational structure across knowledge elements and how connections should be drawn across that structure.
We named our intervention “Organization-Elaboration-Monitoring in Thermodynamics” (OEM-Thermo) because it was designed to stimulate cognitive operations involved in meaningful learning, i.e., organization, elaboration, and monitoring. Organization directs students to determine the structural relations of knowledge elements. Elaboration engages students in the generation of connections across new knowledge elements and between new and prior knowledge. Monitoring occurs when students consider the accuracy of developing knowledge. These cognitive operations can be stimulated by assigned tasks that direct students to think in particular ways.
OEM-Thermo uses three exercises to stimulate these cognitive operations. Exercises 1 and 2 ask students to complete a set of matrix notes. Rows of the matrix show three processes, such as constant pressure expansion. Ten different columns were labeled with prompts for supporting concepts: for example, relate P to V using ideal-gas equation of state EOS and/or process relations; sketch the P-V plot; and determine if work is in, out, or zero. Students organize knowledge into this structure by completing the matrix cells for each row-by-column combination. Exercise 3 stimulates elaboration and monitoring through a set of questions. Students compare cell entries across rows and down columns of the matrix to answer these questions; for example, they compare the magnitude of the work for each of the three processes.
In addition to these exercises, OEM-Thermo uses a cognitive model to support students’ completion of Exercises 1 and 2. A cognitive model is a person, usually an expert, who verbalizes aloud the thoughts he has while thinking through a task. This model makes visible the ways of thinking about the content. In OEM-Thermo, the course instructor served as the cognitive model. Students watched videos that showed the model’s written work as he talked through how to think about cells of the matrix. The cognitive model completed part of the matrix, and students completed the rest independently.
We tested OEM-Thermo with 90 students from two introductory thermodynamics courses. Half of the students completed OEM-Thermo as a homework assignment; half completed traditional textbook-style problems that covered the same content. All students completed the Thermodynamics Conceptual Reasoning Inventory (TCRI) both before and after the assigned homework. The TCRI measures conceptual reasoning ability with fixed-mass, ideal-gas systems undergoing quasi-static (i.e., quasi-equilibrium) processes. Statistical analyses showed that students who completed OEM-Thermo had significantly greater improvement in TCRI scores than students who completed traditional homework problems. On average, students who completed OEM-Thermo had an increase of 20 percent between their pre- and post-test TCRI scores. The average increase was only 3 percent for students who completed traditional homework problems.
This test of OEM-Thermo shows that a homework activity that stimulates the cognitive operations of meaningful learning can support the development of conceptual reasoning ability to a greater degree than traditional homework problems. The design of this intervention provides a structure for a homework assignment that could be adapted to fit foundational principles in a variety of engineering courses.
This research was conducted by an interdisciplinary team at Pennsylvania State University. At the time, Peggy Van Meter, Carla Firetto, Chelsea Cameron, and Charlyn Shaw were all members of the Educational Psychology program. Stephen Turns and Thomas Litzinger were engineering faculty members. This article is based on “Improving Students’ Conceptual Reasoning by Prompting Cognitive Operations” in the April 2016 Journal of Engineering Education. The work was supported with NSF grant TUES 1043833.