2016 ASEE Annual Conference & Exposition
The effect of pressure and temperature on the properties of water is a critical concept within engineering curriculum. Instructors spend considerable effort training students to use reference databases; traditionally in tabulated forms or more recently with use of computer-aided references. The reliance on tables however, places undue emphasis on the property values over property relationships. Understanding thermodynamic relationships and the trends are of greater value from a student learning perspective than the numeric value of the properties. This value is highlighted by the practice of asking students to sketch thermodynamic cycles on a temperature-entropy T-s or pressure-volume P-v chart. The typical analytical steps involving property retrieval followed by depiction on a property chart is disjointed and reversed. If property values are acquired directly from a T-s or P-v property chart, the process is integrated into a single intuitive step that promotes deeper understanding. While printed charts exist, they can be challenging to read considering a single point must supply up to six discrete values (namely P, T, v, u, h, and s). Instead, an interactive property chart that displays properties values for states identified by the user can be highly effective. This was the inspiration behind the Clausius app. Clausius allows users to simply tap on a desired state within a T-s chart to retrieve property values. The design was driven by the need to visualize thermodynamic property relationships as opposed to simply delivering property values. The app was subsequently studied in thermodynamics courses for its impact on student learning (with a treatment group) when compared to accessing properties via steam tables (with a control group). The intervention involved a guided exploration of water properties by the participants, followed by an assessment of students’ understanding of the property trends. Three sets of treatment and control groups participated, across two campuses and three departments. The outcomes provide a strong endorsement for Clausius and its ability to teach property trends. Student feedback also supported the advantages of more visual and dynamic reference for water properties. Overall, enabling students to ‘touch and explore’ thermodynamic properties seems more intuitive and conducive to deeper learning than the traditional use of tabulated property values.
Bakrania, S., & Carrig, A. (2016, June), Touching Water: Exploring Thermodynamic Properties with Clausius App. Paper presented at 2016 ASEE Annual Conference & Exposition, New Orleans, Louisiana. 10.18260/p.27051