The Effect of Inquiry-Based Activities and Prior Knowledge on Undergradu- ates' Understanding of Reversibility

Research has shown evidence of problems understanding heat, temperature, and energy concepts. Even after instruction, undergraduate engineering students have been found to still hold misconceptions about thermodynamic concepts. The prior knowledge students bring to the classroom can also represent a challenge when trying to alter these misconceptions. One promising pedagogical approach is the use of inquiry-based activities. However, the way these activities are implemented can impact outcomes. This NSF funded (DUE 0717536) quasiexperimental study investigated the use of inquiry-based activities and their method of implementation, as well as the role of prior knowledge, in reducing misconceptions in five key areas of thermodynamics (Entropy, Reversibility, Equilibrium and Steady State, Internal Energy, and Enthalpy), with a more detailed focus on reversibility. Pre-post data from 26 different undergraduate thermodynamics classes from multiple institutions was analyzed. The Concept Inventory for Engineering Thermodynamics (CIET) and its Reversibility Sub-Test were used to measure conceptual understanding and change. Some classrooms used a series of inquiry-based activities in each key concept area as part of their instruction and some did not. Data was also collected on whether students had previously taken fluid dynamics and heat transfer courses. Finally, instructors were asked to indicate how they had implemented a packet of inquiry-based activities specifically designed to teach reversibility. Results showed that conceptual understanding of thermodynamics (five concept areas) as measured on the CIET was significantly higher for the inquiry-based activities group than the no activities group, although the effect size was small. Post-test scores were significantly higher for students who had previously taken courses in fluid dynamics and heat transfer when compared to those who had not. There was a significant difference between the activities and no activities groups on students’ understanding of reversibility, with a small effect size. A survey of faculty revealed that reversibility activities were implemented by some in ways that differed from the directions provided. Finally, understanding of reversibility was impacted by students’ previous coursework in fluid dynamics and heat transfer. Introduction and Background Conceptual difficulties with heat, temperature, and energy have been documented at all educational levels. 17, 23, 31, 34) Thomaz et al. found that secondary level physics students had difficulty discriminating between heat and temperature. Carlton found that many teacher education students, when their prior knowledge was assessed, defined temperature as “...a measure of how hot or cold something feels” (p. 102). Some students have been found to believe that there is no difference between heat and temperature or that heat is a form of energy. 10, 30, 35) Even after instruction, some individuals have been found to have incorrect understandings of these concepts, or what have been labeled misconceptions. A key reason behind these misconceptions is that terms like heat, temperature, and energy are also used in daily life to identify other processes. In other words, when students come to science classes they are not “blank slates,” but are informed by scientific knowledge that comes from out-ofclass settings as well as previous courses. These same conceptual difficulties have been found in undergraduate engineering students. 25, 28) For example, Prince and Vigeant found that many engineering undergraduates viewed heat and temperature as equivalent entities. Self et al. determined that almost 30% of chemical and mechanical engineering seniors could not, “...logically distinguish between temperature and energy in simple engineering systems and processes” (p. S2G-1). The field of thermodynamics examines interchanges of energy in chemical and thermal systems, particularly changes between heat and work, making it key to many engineering disciplines. The content of undergraduate thermodynamics courses can be especially difficult for students to grasp due to its equation-based abstract nature. This makes conceptual change challenging, because it has been shown that students are able to get the math correct even when their conceptual understanding is incorrect. Reversibility, defined by the degree “...the system and all parts of its surroundings can be exactly restored to their respective initial states after the process has taken place” (p. 212), is especially challenging. As can be seen in Table 1, misconceptions are regularly found in the learning of thermodynamics. Table 1: Misconceptions Regularly Found in Thermodynamics Concept Area Misconception Entropy Students often misconstrue the impact of entropy on the efficiency of real systems, believing if a system is reversible, frictionless, and appropriately adiabatic, it can have thermal efficiency of 100%. That is, they often assume the thermal efficiency of a Carnot engine is 100% regardless of heat source and sink temperatures. Reversibility Students often assume reversible behavior for real systems where such an assumption is inappropriate. That is, students fail to grasp what reversibility would mean for the behavior of a real system. Steady State vs. Equilibrium Students confound steady state and equilibrium, believing they are synonyms or that one necessarily implies the other for a given system. Internal Energy vs. Enthalpy Students confound internal energy and enthalpy, assuming they are interchangeable. Students often conflate “flow work” (that which distinguishes enthalpy from internal energy) with kinetic energy. Reaction Equilibrium vs. Reaction Rate Students often believe that a reaction that favors products strongly will react rapidly. That is, they confound factors that impact reaction rate with the factors that impact how much product is produced. There is an increasing understanding that prior knowledge acts as a filter for new learning. This prior knowledge can interfere with concept mastery. There is also a broad realization that meaningful learning of science content requires conceptual understanding rather than memorization of facts and formulas (2, , as well as a growing understanding that traditional instructional methods can be ineffective at altering students’ misconceptions. Consequently, the challenge in teaching is to make academic knowledge of real value by constructing it in a meaningful way so that the students learn and understand the concept correctly. Interactive pedagogy can help facilitate the remediation of misconceptions and the learning of new concepts. 14, 20, 26, 39) Use of inquiry-based activities is one way that instruction can be more interactive and engaging. 6) Inquiry-based activities allow students to participate in hands-on activities, which can permit the students to experience the information being presented in a more meaningful way. This can help them to better grasp the complexity of these different thermodynamic concepts. Purpose of the Study The purpose of this research was to investigate whether inquiry-based activities affected undergraduate engineering students’ conceptual knowledge and understanding of thermodynamic concepts, especially reversibility, as measured by the Concept Inventory for Engineering Thermodynamics. It also investigated whether the way reversibility activities were implemented affected students’ knowledge of this concept. Finally, it looked at the influence of prior knowledge on participants’ understanding of thermodynamics concepts. For the purposes of this study, prior knowledge was operationally defined as having previously taken courses in fluid dynamics and heat transfer. It was anticipated that students with some prior knowledge from other engineering courses would have a better understanding of thermodynamics concepts.