Converting heat to work: A thermodynamics design project

The conversion of heat into work is a fundamental concept addressed in the study of thermodynamics. While the concepts involved in the conversion process are developed thoroughly through course work and lecture there remains a disconnect between learning the subject on paper and fully appreciating how difficult the conversion is to accomplish. This paper discusses an open-ended design project in which students bridge the gap by designing a device that converts heat produced by a candle into the work of raising a quarter vertically. The act of designing and testing the device allows students the opportunity to analyze the conversion process using material learned in class and provides a valuable hands-on experience dealing with the physical phenomena involved (i.e. friction, heat loss, sudden expansion, etc). The project has been administered at multiple universities with students participating in small teams and feedback gathered through post-project surveys. Several iterations of the project have been administered with variations in the analysis required, in-class time dedicated to the project, budget provided and final testing procedures. The lessons learned regarding these different iterations are synthesized, an overview of some of the different design concepts is presented and suggestions are provided for successful implementation of the design project.