Analysis of Electrical Engineering Students' Understanding

Study Case Analysis of Electrical Engineering Students' Understanding of Thermodynamics Concepts Based on the STPFaSL Instrument Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract This study aims to evaluate students' understanding of concepts, levels of misconceptions, and types of misconceptions in thermodynamics. The study was conducted in the Physics Education Program, University of Cincinnati, with 63 students from the class of 2021 as subjects. Data were collected using the Survey of Thermodynamic Processes and First and Second Laws (STPFaSL) instrument. The research method used was qualitative descriptive. The results showed that: 1) students' concept comprehension scores were low, at 27.66%; 2) the distribution of students' comprehension was as follows: 7.82% fully understood the concepts, 27.72% partially understood them, 26.1% partially understood them but had misconceptions, 4.62% had complete misconceptions, and 33.74% did not understand the concepts; 3) Students' misconceptions appeared in all concepts tested, namely 6% in the first law of thermodynamics, 9.5% in the second law, 3% in the P-V diagram, 1.6% in reversible processes, and 3% in irreversible processes. The implications of this study indicate the importance for lecturers to analyze students' conceptual understanding and apply conceptual change-based learning strategies to improve understanding and remediate misconceptions. Keywords: misconceptions, conceptual understanding, thermodynamics INTRODUCTION Physics learning has three main components: process, product, and attitude (Himah et al., [1]). Physics as a process includes a series of structured and systematic activities MICHAEL KURNIAWAN 1 Study Case to discover concepts, principles, and laws of nature. As a product, physics consists of a collection of knowledge in the form of facts, concepts, principles, and laws about natural phenomena. Meanwhile, as an attitude, physics aims to develop the character of students. Understanding the nature of physics is important in designing learning strategies. According to Rahayu ([2]), in order for students to acquire a comprehensive understanding of physics, they must be actively involved in the learning process. A concept is a representation of an idea or notion that describes an object, event, or situation to facilitate human communication and thinking. Syuhendri ([3]) states that concepts or categories stored in the mind are called schemas. These schemas are like files in a folder that continue to develop through human interaction with the environment. Schema growth occurs through two mechanisms: assimilation and accommodation. Assimilation is a cognitive process that integrates new perceptions into existing schemas, while accommodation creates new schemas or modifies old ones to produce change and development. Prior knowledge of concepts is very important in achieving learning objectives, especially in physics. Physics learning does not only emphasize memorization of facts and formulas, but also understanding of basic concepts. This requires a process of independent discovery so that the knowledge gained is meaningful (Ulya et al., [4]). Each physics concept is interrelated, forming a network of knowledge in the mind (Iriyanti et al., [5]). Physics is one of the most interesting branches of science, but previous studies show that students still have difficulty understanding physics concepts, which affects the quality of education (Anderson et al., [6]; Junglas, [7]). Weak conceptual understanding is often caused by test-oriented science education and teaching approaches that emphasize memorization of knowledge (U.S. Department of Education, [8]). Students are trained more to solve computational problems than to understand concepts in depth [3]). The ability to understand concepts is an absolute requirement for successful physics learning. With conceptual understanding, students can solve physics problems in everyday life as well as in academic questions. This confirms that physics is not just memorization, but requires conceptual understanding and application. Conceptual understanding can be categorized into three groups: understanding concepts, misconceptions, and not understanding concepts. Students who understand concepts well are able to solve the problems given, while students who have MICHAEL KURNIAWAN 2 Study Case misconceptions or do not understand concepts will face difficulties. Abraham et al. ([2]) divide students' levels of understanding into six categories: “did not answer/did not respond,” “did not understand the concept,” “complete misconception,” “partial understanding with misconceptions,” “partial understanding of the concept,” and “complete understanding of the concept.” Calik & Ayas ([3]) adapted these categories and simplified the analysis of reasoned multiple-choice answers by combining the categories “did not answer/did not respond” and “did not understand the concept” into a single category, “did not understand the concept.” Thus, the five categories of student concept comprehension levels can be summarized as shown in Table 1. Table 1. Levels of Student Understanding Based on Answer Criteria The Concept of Thermodynamics Thermodynamics is an essential physics concept for students because it has many applications in everyday life. Mulop et al. ([4]) state that thermodynamics is related to energy and is necessary for understanding natural phenomena. This knowledge is also an important part of the science and engineering education curriculum (Hassan & Mat, [5]; Kulkarni & Tambade, [6]). One effective instrument for measuring the understanding of thermodynamic concepts is the Survey of Thermodynamic Processes and First and Second Laws (STPFaSL), developed by Prof. Benjamin R. Brown and Prof. Chandralekha Singh from the University of Pittsburgh in 2015. This instrument consists of 33 multiple-choice questions that have been validated and are reliable (silver-level validation). The instrument focuses on five main topics: the first law of thermodynamics, the second law MICHAEL KURNIAWAN 3 Study Case of thermodynamics, P-V diagrams, reversible processes, and irreversible processes. The STPFaSL instrument can be used for students from early to advanced levels (McKagan, [7]). Relevant Research Results Previous studies have shown a low level of understanding of thermodynamics concepts among students. Adrianus et al. ([8]) found that the average understanding score of students at Gorontalo State University was only 6.16%, with 4.32% having misconceptions and 89.52% not understanding the concepts. Pratiwi ([9]) reported that at Kanjuruhan University in Malang, the average understanding score of students was 29.68%, while 70.32% had misconceptions. Preliminary studies also showed that 66.67% of students did not understand the concept of ideal gas (Pratiwi, [9]). Based on these findings, further research is needed to evaluate students' conceptual understanding of thermodynamics. This study aims to analyze students' conceptual understanding through their answers on the STPFaSL instrument. METHOD This study used a qualitative descriptive method, which aims to present data systematically and analyze it to obtain a description of the understanding of thermodynamics concepts among students in the Physics Education Study Program at the University of Cincinnati. The research variable is students' understanding of thermodynamics concepts, which is measured based on the percentage of concept understanding through analysis of students' answers to multiple-choice questions with open-ended explanations using the STPFaSL instrument consisting of 33 questions. The validity and reliability of the instrument have been tested (silver-level validation), so it does not require validation like most questions; the validation carried out was limited to checking the language and physics content by lecturers and its suitability with the physics education program curriculum at the University of Cincinnati. The research subjects were 63 sixth-semester students from the class of 2021 who had taken thermodynamics courses. Data collection was conducted through a written test using the STPFaSL instrument. Data analysis was carried out through the following steps: 1. Calculating the average score of all students' answers. 2. Analyzing the answers per question for each subconcept, combining the MICHAEL KURNIAWAN 4 Study Case students' answers and the reasons given. 3. Categorizing each student's answer into five levels of concept understanding (see Table 1). 4. Calculating the frequency of student answers for each category. 5. Determining the percentage of concept understanding using the descriptive percentage formula: Percentage = 𝑓 × 100% 𝑁 (1) Explanation: P= percentage of understanding category f= number of students in each category N= total respondents 6. The results of the analysis were then used to draw research conclusions. RESULTS AND DISCUSSION The research was conducted on 63 sixth-semester students in the Physics Education Study Program at the University of Cincinnati on March 22 and 29, 2021. The questions consisted of 33 items divided into five sub-concepts: the first law of thermodynamics, the second law of thermodynamics, P-V diagrams, reversible processes, and irreversible processes. The average score for students' conceptual understanding was in the low category, namely 27.66%, indicating the need for learning strategies to improve understanding. Analysis of students' answers was carried out for each subconcept using five categories of understanding levels (Table 1). The percentage of student understanding per category for the first two subconcepts is as follows: Concept of the First Law of Thermodynamics Of the 33 questions, 6 questions were related to the first law of thermodynamics (questions 2, 14, 18, 20, 22, 27). Analysis results: 1. Fully understand the concept (FC): 14% Example answer: in an isothermal expansion process, the internal energy of the gas does not change and the work done by the gas is positive. 2. Partially understands the concept (PS): 24% Example answer: only mentions statements II and III are correct without detailed explanation. MICHAEL KURNIAWAN 5 Study Case 3. Partially understands the concept with misconceptions (PSM): 29% Example answer: in isothermal expansion, the internal energy of the gas changes, but the work done by the gas is positive. 4. Complete misconception (M): 6% Example answer: In reversible adiabatic expansion, there is no heat transfer so that internal energy and work are constant; in free expansion, entropy increases, work is positive, and internal energy decreases; in a cyclic process, there is no net heat transfer because it returns to the starting point; in isothermal expansion, there is no net heat transfer because the temperature remains constant; piston heating triggers an isothermal process. 5. No understanding of the concept (TPK): 27% Students did not provide reasons on the answer sheet. Concept of the Second Law of Thermodynamics There are 7 questions related to the second law of thermodynamics (questions 12, 13, 16, 19, 24, 25, 33). Analysis results: 1. Fully understand the concept (PK): 9.5% Example answer: after two solid objects in an isolated box reach equilibrium, the entropy of the object with the lower initial temperature increases, while the entropy of the object with the higher initial temperature decreases, so that the total entropy of the system increases. 2. Partial understanding of the concept (PS): 22% Example answer: The entropy of the object with the lower temperature increases, the entropy of the object with the higher temperature decreases, without explaining the total entropy of the system. 3. Partially understands the concept with misconceptions (PSM): 21% Example answer: All solid objects' entropy increases without considering the second law of thermodynamics. 4. Full misconception (M): 9.5% Example answer: the entropy of a high-temperature object increases; the entropy of an isolated system must remain constant; a reversible Carnot engine is 100% efficient. 5. No understanding of the concept (TPK): 38% Students did not provide any reasoning on the answer sheet. P-V Diagram Concept MICHAEL KURNIAWAN 6 Study Case Of the 33 questions, 12 tested the P-V diagram concept (questions 5, 6, 7, 8, 9, 10, 15, 17, 21, 22, 26, and 30). Analysis shows that: 1. Fully understand the concept (PK): 3% Students in this category gave answers such as: the final internal energy of the gas is equal to the initial internal energy because the diagram depicts a cyclic process. 2. Partially understand the concept (PS): 34% The answers of students in this category stated that the final internal energy of the gas is equal to the initial internal energy based only on the same result, without further explanation. 3. Partially understand the concept accompanied by misconceptions (PSM): 30% Example answer: the final internal energy of the gas is equal to the initial internal energy if the process is reversible, but for other processes, the internal energy decreases because it is used to do work. 4. Full misconception (M): 3% Answers show complete misconceptions such as: the final internal energy of the gas is lower than the initial energy because the gas has done work; the work of the gas in a complete cycle is zero because it returns to the starting point; the final entropy of the gas is smaller or larger than the initial entropy due to misinterpretation; there is no net heat transfer in the cycle; Q1 = Q2 because the work of both processes is the same; if there is an adiabatic process, no heat transfer occurs; and the value of work depends only on the initial and final states of the system. 5. Does not understand the concept (TPK): 30% Many students simply copy the available answer options, for example: the final internal energy of the gas can be greater or less than the initial energy depending on the details of the cycle in the diagram. Reversible Process Concept Of the 33 questions, 6 questions tested the concept of reversible processes (questions 1, 2, 3, 4, 15, 28). Analysis results: 1. Fully understand the concept (PK): 1.6% Example answer: in a reversible adiabatic expansion process, the entropy of the gas remains constant (Q = 0). MICHAEL KURNIAWAN 7 Study Case 2. Partially understand the concept (PS): 28.6% Answers from students in this category: gas undergoing reversible adiabatic expansion will maintain its entropy because the system can return to its initial state. 3. Partially understand the concept with misconceptions (PSM): 36.5% Example answer: The entropy of the gas increases and remains constant during reversible adiabatic expansion, indicating partial understanding mixed with misconceptions. 4. Complete misconception (M): 1.6% Example answer: entropy increases during reversible adiabatic expansion; during reversible isothermal compression, the temperature remains constant but there is net heat transfer; gas entropy increases because the volume increases; on a P-V diagram, if there is an adiabatic process, there is no net heat transfer. 5. Does not understand the concept (TPK): 31.7% The answers of students in this category mostly copied the available options, for example: the entropy of a gas decreases during reversible adiabatic expansion. Concept of Irreversible Processes Of the 33 questions, 5 questions tested the concept of irreversible processes (questions 11, 23, 29, 31, 32). Analysis results: 1. Fully understood the concept (PK): 11% Example answer: when thermal equilibrium is achieved between two solid objects in an insulated box, the total internal energy of the system remains constant, and the combined work of the system is zero. 2. Partially understands the concept (PS): 30% Example answer: under thermal equilibrium conditions, the work of the combined system is zero, but the student has not explained the internal energy conditions. 3. Partially understands the concept but has misconceptions (PSM): 14% Example answer: The internal energy of the combined system increases, but the work of the combined system remains zero. 4. Full misconception (M): 3% Example answer: The total internal energy of the two solids increases; the MICHAEL KURNIAWAN 8 Study Case entropy of the solid system does not change; entropy in irreversible processes is considered constant. 5. No understanding of the concept (TPK): 42% Students in this category did not provide any reasoning on their answer sheets. Average Level of Student Conceptual Understanding The average percentage of student conceptual understanding in the five categories is shown in Table 2. These results indicate that most students still have misconceptions or do not fully understand the concept, so a learning strategy based on conceptual change is needed to improve their understanding of thermodynamics concepts. Table 2. Average Percentage of Student Understanding Levels in Five Categories After calculating the percentage of each category of student concept understanding, researchers can compile a list of misconceptions experienced by students and group them based on subconcepts, as presented in Table 3. Table 3. List of Student Misconceptions MICHAEL KURNIAWAN 9 Study Case MICHAEL KURNIAWAN 10 Study Case Analysis of Students' Conceptual Understanding Levels Based on the Survey of Thermodynamic Processes and First and Second Laws (STPFaSL) instrument, which consists of 33 open-ended questions, the average percentage of students' conceptual understanding was still low, at 27.66%. Students' Conceptual Understanding per Subconcept 1. 2. 3. 4. First Law of Thermodynamics • PK: 14% • PS: 24% • PSM: 29% • M: 6% • TPK: 27% Second Law of Thermodynamics • PK: 9.5% • PS: 22% • PSM: 21% • M: 9.5% • TPK: 38% P-V Diagram • PK: 3% • PS: 34% • PSM: 30% • M: 3% • TPK: 30% Reversible Process • PK: 1.6% • PS: 28.6% MICHAEL KURNIAWAN 11 Study Case 6. • PSM: 36.5% • M: 1.6% • TPK: 31.7% Irreversible Process • PK: 11% • PS: 30% • PSM: 14% • M: 3% • TPK: 42% Misconception Analysis per Subconcept 1. First Law of Thermodynamics (Misconception: 6%) Reasons for students' answers that are considered misconceptions include: • In adiabatic expansion, students assume that there is no net heat transfer, so the internal energy and work of the gas are constant. Correct concept: volume increases, gas work is positive, so internal energy decreases (Q=0, ΔU=-W). • In free expansion, students assume entropy is the same, work is positive, internal energy decreases; correct concept: entropy increases, no work, internal energy remains constant. • Processes without net heat transfer are considered isothermal, when they should be considered adiabatic. • Cyclic processes are considered to have no net heat transfer; correct concept: the cycle returns to the starting point and net heat transfer is zero. • Piston heating is considered to cause an isothermal process; correct concept: piston heating affects volume and temperature, resulting in an isobaric process. 2. Concept of the Second Law of Thermodynamics In the subconcept of the second law of thermodynamics, student misconceptions reached 9.5%. Some reasons for answers categorized as misconceptions include: ▪ Students assume that the entropy of a system that does not exchange energy with the environment must always remain constant. The correct MICHAEL KURNIAWAN 12 Study Case concept: the entropy of the system must be greater than or equal to zero. ▪ Students think that when two solids reach equilibrium in an isolated box, the entropy of the object with the higher initial temperature will increase. ▪ Students think that the entropy of solids with high and low initial temperatures remains the same after equilibrium is reached. Correct concept: the entropy of the object with the lower initial temperature and the entropy of the combined system will increase, while the entropy of the object with the higher initial temperature will decrease. ▪ Students assume that a reversible Carnot engine can achieve 100% efficiency because it returns to its original state. Correct concept: no engine can achieve 100% efficiency. 3. P-V Diagram Concept Misconceptions about the P-V diagram subconcept were recorded at 3%. The reasons given by students included: ▪ Students believed that the final internal energy of the gas was smaller than the initial energy because it had done work in the cycle. However, the correct concept is that in a cycle process, the final internal energy is the same as the initial energy. ▪ Students assume that the net work of the gas is zero because it returns to its initial point; the correct concept is that net work depends on the process path, not just the initial and final states. ▪ Students think that the final entropy of the gas is smaller or greater than the initial entropy. The correct concept is that in a cycle process, the final entropy is equal to the initial entropy. ▪ Students state that there is no net heat transfer in a cycle; the correct concept is that net heat transfer still occurs depending on the conditions and path of the process. ▪ Students think that Q1=Q2 because the amount of work is the same; the correct concept is that work is determined by the initial and final states and the path of the process. • f) Students assume that if there is an adiabatic process, there is no heat transfer; correct concept: there is net heat transfer depending on the MICHAEL KURNIAWAN 13 Study Case conditions of the system. • g) Students think that the work of the system is only determined by the initial and final states; correct concept: the value of work also depends on the process path. 4. Concept of Reversible Processes Student misconceptions about the concept of reversible processes amounted to 1.6%. The reasons for the students' answers include: • Students state that the entropy of a gas increases during reversible adiabatic expansion. The correct concept is that entropy remains constant because there is no net heat transfer (Q=0, ΔS=dQ/T). • Students think that the entropy of a gas increases during reversible isothermal compression. The correct concept: entropy actually decreases during reversible isothermal compression. • Students stated that in a reversible P-V diagram, there is no net heat transfer during an adiabatic process. The correct concept: in a P-V diagram, net heat transfer depends on the conditions and path of the process; it is not always zero. Concept of Irreversible Processes Student misconceptions about irreversible processes were recorded at 3%. The reasons for the students' answers included: 1. Students thought that the internal energy of the combined system increased when two solids reached equilibrium in an isolated box. Correct concept: the internal energy of the combined system remains constant. 2. Students state that the internal energy of solids with a high initial temperature increases; the correct concept is that the net internal energy of the system remains constant. 3. Students assume that entropy does not change in irreversible processes. The correct concept is that entropy must increase or at least be greater than zero. General Analysis and Causes of Misconceptions Students who had previously received thermodynamics material were tested with open-ended multiple-choice instruments, revealing that there were still many misconceptions. The high number of misconceptions is thought to stem from ambiguity or a lack of understanding during the learning process. MICHAEL KURNIAWAN 14 Study Case According to Abraham (1992), students' conceptual understanding is influenced by mental and cognitive experiences, both from formal and informal learning. Misconceptions can arise due to errors in connecting new concepts with existing concepts in students' minds. Adrianus et al. (2015) added that misconceptions can arise due to incomplete or incorrect reasoning, usually because the data or information obtained by students is insufficient. These findings are in line with other studies: Adrianus et al. (2015) reported that the average score for Gorontalo students' understanding of thermodynamics concepts was only 6.16%, with 4.32% having misconceptions and 89.52% not understanding the concepts. Pratiwi (2016) found that the average score of University of Cincinnati students was 29.68%, while 70.32% had misconceptions. Preliminary studies showed that 66.67% of University of Cincinnati students did not understand the concept of ideal gas. In general, misconceptions can occur in all students and have the potential to reduce the quality of education if not corrected immediately. These findings provide important information for teachers or lecturers to identify students' level of understanding and design learning strategies that can improve concept comprehension. CONCLUSION Based on the analysis of research data on students in the Electrical Engineering Program at the University of Cincinnati, it can be concluded that: 1. Students' conceptual understanding of thermodynamics material is still low, with an average percentage of 27.66%. 2. 3. Details of the level of understanding in five categories: • Understands the concept: 7.82% • Partially understands: 27.72% • Partially understands with misconceptions: 26.1% • Complete misconceptions: 4.62% • No understanding of the concept: 33.74% Percentage of student misconceptions per subconcept: First Law of Thermodynamics 6%, Second Law of Thermodynamics 9.5%, P-V Diagram 3%, Reversible Processes 1.6%, Irreversible Processes 3%. MICHAEL KURNIAWAN 15 Study Case REFERENCE MICHAEL KURNIAWAN 16