Design of Experiments in Introduction to Thermodynamics Course

This paper describes an easily implementable new approach to thermodynamics laboratory instruction that directly addresses ABET Criterion 3, an ability to design and conduct experiments, as well as to analyze and interpret data. In a traditional lab, students conduct preconfigured experiments based on established procedures. They then gather, analyze and interpret data, and write reports. However, little is done to train engineering graduates to design experiments for a specific purpose and without a prescribed procedure. Engineering professionals are frequently tasked with designing experiments to demonstrate performance of a device they designed or developed in order to prove a physical phenomenon in a research setting, etc. Hence, it comes as no surprise that ABET has embraced this criterion for close to a decade. Introduction to Thermodynamics requires that students learn basic, yet complicated concepts, such as determining properties of pure substances, calculating heat and work exchanged during a process, and the first and second law of thermodynamics, before they can tackle complex applications, such as thermodynamic cycles or combustion systems. These basic concepts are conducive to simple, conceptually oriented laboratory assignments that parallel the classroom instruction. Those laboratory assignments are an ideal place to implement design of experiments because the concepts are still fundamental and intuitive. We have implemented this approach in our weekly Introduction to Thermodynamics labs. Teams of 3-5 students are given a set of basic supplies and are tasked with designing an experiment with a specific purpose such as determining the efficiency of a light-bulb as an emitter of light. In this experiment they are given a light-bulb with pre-built leads, a plastic cup, a power supply, ampand volt-meters, a thermometer, a scale, and several other items they may not use. Students brainstorm about ways to test efficiency, build a test apparatus, conduct measurements, and calculate the efficiency. This paper contains examples of three such labs, including theoretical concepts covered in lectures and homework, pre-lab handouts, assignment descriptions, equipment lists, and photos of student solutions. The paper also summarizes our assessment of this approach. The assessment utilizes: 1) student surveys, and 2) direct measures, i.e., student performance on related course outcome scores. The assessment was applied to two student groups, one that simply followed lab procedures and the other that were tasked with designing the experiments.