# Utilizing Documented Problem Solutions in a Thermodynamics Course

# Course Information

- Course Name: EMS 160: Thermodynamics of Materials Processes and Phase Stability
- Enrollment: 54
- Brief Description: This is a lecture-based course that covers the thermodynamics of material systems and material reactions. This class is very quantitative, focusing on thermodynamic derivations and calculations.

# Description of Tool/Strategy

“Documented problem solution” is an assessment technique in which students are assigned a problem and are required to explain their steps in addition to finding the correct solution.[1] I chose to implement this into my class to require students to more actively consider the steps required for a solution, instead of blindly utilizing equations. Additionally, I wanted to provide an alternative grading tool beyond traditional homework and exams.

Logistically, documented problem solutions were implemented in my course by assigning specific homework problems that required students to complete the following steps:

- Identify the type of problem
- Describe the general method of solving the problem
- List all known information
- Solve the problem, using words to describe each step
- Provide analysis as to whether the answer is reasonable.

The full instructions with point values are linked (Documented Solution Instructions). Only 35% of the assignment grade was allocated to finding the correct answer; the majority of the points were for explaining the relevant principles and steps required. Throughout the course, three of the homework problems were designated as documented solution problems, requiring students to complete steps 1-5. These problems were selected as they contained key thermodynamic concepts and required several steps beyond plugging numbers into equations.

# Assessment and Analysis

Documented problem solutions were implemented in my thermodynamics course to spur on student learning. The topics can be very heavy on abstract equations, and I wanted my students to think beyond numbers that go into the equations. For example, below is one of the problems that students were assigned to solve as a documented problem solution:

*The change in Gibbs free energy of a reaction can be determined from the enthalpy and entropy changes as **. What is for the following reaction at 800 K?*

This is a traditional thermodynamics problem which requires students to use their knowledge of heat capacity, enthalpy, and entropy to find the specified value. However, an important assumption that is needed to derive the equations is that enthalpy and entropy are state functions, or path independent. This means that the reaction energy can be calculated a room temperature, and then the heat capacities of the components can be used to adjust the calculation to a different temperature. This is a key idea that can be overlooked when simply using equations to perform a calculation.

Overall, I found this activity to be insightful into students’ thought processes, but found no evidence that it enhanced student learning. Angelo and Cross noted that students benefit from this activity by “gaining awareness of and control over their problem solving skills” [1], which I did not see in my course. However, I did not find a difference in the quality of the student work for the documented solution problems as compared to the traditional homework problems. When similar problems appeared on exams, there did not seem to be increased comprehension. Despite the uncertain learning gains for the students, I found this activity to be very valuable at providing feedback to myself as the instructor. The student explanations elucidated their misconceptions and limitations in problem-solving skills, which is one of the highlights of the method noted by Angelo and Cross [1]. In the current implementation, I found the activity to be difficult to grade, as the assignments were lengthy and the explanations were open-ended. In conclusion, I found this to be a useful exercise to gain feedback for the instructor, but the assignment needs to be modified to achieve the goal of significantly increasing student learning.

*“Thermodynamics is a funny subject. The first time you go through it, you don’t understand it at all. The second time you go through it, you think you understand it, except for one or two small points. The third time you go through it, you know you don’t understand it, but by that time you are so used to it, so it doesn’t bother you any more.”—commonly attributed to Arnold Sommerfeld.[2] *

# References

[1] T.A. Angelo and K.P. Cross, “Classroom Assessment Techniques”, Second Edition, 1993. pp 222-225.

[2] https://en.wikiquote.org/wiki/Arnold_Sommerfeld. Accessed on 1/23/2016.