1. Active-Learning Curricula for Thermodynamics in Physics and Chemistry David E. Meltzer Department of Physics and Astronomy And Thomas J. Greenbowe Department of Chemistry Iowa State University Ames, Iowa

2. Our Goal: Produce effective new curricular materials on thermodynamics Carry out research to identify introductory students’ learning difficulties with thermodynamics; Devise methods for directly addressing these learning difficulties; Develop curricular materials for both introductory physics and introductory chemistry courses; Test materials with students in both courses; use insights gained in one field to inform instruction in the other.

3. Nature of the Materials “Guided-Inquiry” Worksheets: Carefully sequenced printed worksheets which guide students step-by-step through reasoning process. Primarily qualitative questions. “University of Washington” Model: Elicit, Confront, Resolve. Aim to deliberately trigger common learning difficulties, then guide students to confront and resolve them directly Heavy use of multiple representations (diagrams, graphs, charts, sketches, etc.)

4. Development and Testing: An Iterative Process Initial draft of materials subject to review and discussion by both physics and chemistry education research groups; Revised draft tested in lab or recitation section; New draft prepared based on problems identified during initial test; Additional rounds of testing in lab/recitation sections; further revisions; Analysis of student exam performance (“treated” vs. “untreated” groups); Entire cycle repeats.

5. Initial Hurdle: Different approaches to thermodynamics in physics and chemistry For physicists: –Primary (?) unifying concept is transformation of internal energy E of a system through heat absorbed and work done; –Second Law analysis focuses on entropy concept, and analysis of cyclical processes. For chemists: –Primary (?) unifying concept is enthalpy H [H = E + PV] (  H = heat absorbed in constant-pressure process) –Second law analysis focuses on free energy (e.g., Gibbs free energy G = H – TS)

6. Learning Difficulty: Weak Understanding of “State Function” Concept Instructional Strategy: Examine two different processes leading from state “A” to state “B”: –What is the same about the two processes? –What is different about the two processes? Elicit common misconception that different heat absorption must lead to different final temperatures (i.e., ignoring work done) Guide students to identify temperature as a prototypical state function Strengthen conceptual distinction between changes in state functions (same for any processes connecting states A and B), and process-dependent quantities (e.g., heat and work)

7. Learning Difficulty: Failure to recognize that entropy increase of “universe” (not system) determines whether process occurs spontaneously Instructional Strategy: Present several different processes with varying signs of  S system and  S surroundings (Present  S surroundings information both explicitly, and in form of  G or  H data) Ask students to decide: Which processes lead to increasing disorder of system? Which processes occur spontaneously? Etc.

8. Learning Difficulty: Not distinguishing clearly between heat and temperature Instructional Strategy I: Confront students with objects that have equal temperature changes but different values of energy loss. Instructional Strategy II: Guide students through analysis of equilibration in systems with objects of same initial temperature but different heat capacities.

9. Summary We have initiated a long-term project to develop improved thermodynamics curricula: –for both physics and chemistry –for both introductory and advanced courses –which will be usable in both large and small classes New curricular materials will be based on extensive research on student learning (employing written diagnostics, student interviews, etc.) New materials will be continually tested and revised, and their effectiveness assessed.