Development of Active-Learning Curricular Materials in Thermodynamics for Physics and Chemistry

1. Development of Active-Learning Curricular Materials in Thermodynamics for Physics and Chemistry David E. Meltzer Department of Physics and Astronomy And Thomas J. Greenbowe Department of Chemistry Miller Faculty Fellows 1999-2000

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 DSsystem and DSsurroundings (Present DSsurroundings information both explicitly, and in form of DG or DH 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. Question Types Incorporated in the Worksheets • “Expository” Material (Lecture Notes/Text Material designed in highly interactive format to guide students toward development of concepts.) • Multiple-Choice Questions for Peer Instruction in Large Classes(Structured sequences of multiple-choice questions stressing qualitative, conceptual understanding: for use with classroom communication systems [e.g., “flash cards” or “Classtalk”] in which instantaneous feedback is obtained from the whole class simultaneously.) • Material to Elicit Learning Difficulties (Questions designed to elicit well-known learning difficulties, and to lead students to confront these difficulties directly.) • Material to Deepen Comprehension (Questions designed to deepen students’ understanding of a concept, by presenting concepts in a wide variety of contexts using multiple representations [verbal, mathematical, graphical, diagrammatic, pictorial, etc.]) • Material to Improve Quantitative Problem-Solving Ability (Questions designed to improve students’ problem-solving abilities by “conceptually dissecting” quantitative problems and breaking them up into conceptual elements.)

10. 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.