Process oriented guided inquiry learning: a possible solution to improve high school students’ conceptual understanding of electrochemistry and attitude

2.1 Background of the participants

The target population of the study was grade 12 natural science students of Mehal-meda Preparatory and Secondary School, Ethiopia. Mehal-meda Preparatory and Secondary School is a public government school and the researcher taught chemistry as a subject at the school for over 13 years. The students who enrolled at the school came from the surrounding community and they have a similar socio-cultural background, economic status, language (they speak Amharic language which is the national working language), and educational background. In fact, in Ethiopia, the majority of middle and upper-income families choose the private school option while lower-income families enroll their children in public schools. In all Ethiopian secondary schools (grades 9–12) English language is used as the medium of instruction and both private and public schools use the same curriculum with the same language of instruction.

Chemistry is taught in Ethiopian secondary schools as a core subject. Grade 12 students’ chemistry textbook has five chapters including base equilibria, electrochemistry, industrial chemistry, polymer chemistry, and introduction to environmental chemistry. This study focused on electrochemistry which comprised Oxidation-Reduction Reactions, Electrolysis of Aqueous solutions, Quantitative Aspects of Electrolysis, Industrial Applications of Electrolysis and Voltaic (Galvanic) Cells. Upon completion of grade 12, the students take the national matriculation examination, prepared by the Ethiopian national examination agency, and those who score a minimum pass mark (50 % score) in the examination are eligible to be admitted to university in the country.

2.2 Design of the study

A quasi-experimental research design was employed to evaluate the effect of the POGIL approach on grade 12 natural science students’ achievement in electrochemistry in the second semester of the 2023 academic year. The researcher randomly selected two of the four sections of grade 12 natural science students as the treatment group (TG;14 males and 19 females) and the other two sections as the control group (CG; 15 males and 23 females). Thus, in this study a total of 71 students (i.e. 33 TG and 38 CG) were randomly selected and participated. Each year, the school administrator distributed students heterogeneously into different sections based on their lower-grade transcript scores (high achievers, middle achievers, and low achievers). Accordingly, each class has lower, medium, and higher achievers; thus, the samples were formed from heterogeneous groups. The ages of participants were also between 18 and 20. The treatment group completed electrochemistry concepts with the POGIL approach while the control group completed the same topic receiving traditional instruction. To avoid information sharing between the two groups, the researchers arranged independent tutorial classes presented on two different days. Accordingly, CG students attended the tutorial classes on Monday and Wednesday while TG students attended the tutorial classes on Tuesday and Thursday. The pretest and posttest were administered to both groups at the beginning and the end of the study period, respectively (Table 1).

2.3 Intervention approach for treatment groups

The implementation of a POGIL approach is different from the normal class teaching approach and it has its own implementation procedures. It may be implemented in various ways depending on the nature of proposed goal, class size, the nature of the teaching space, and instructor preferences. ³⁷ However, different implementations have common characteristics such as students working in groups, specifically designed POGIL activities, the teacher having the role of facilitator and coach of the students, and the students completing a work activity with a facilitator. Hence, in this study, the researchers adopted the following POGIL implementation approach and contextualized it by integrating it with electrochemistry.

1. Students were expected to work collaboratively, generally in groups.

2. The activities that the students used were POGIL activities, specifically designed guided-inquiry activities for POGIL implementation.

3. The students worked on the activity during class time with a facilitator present.

4. The dominant mode of instruction was not lecture or instructor-centered; the instructor served predominantly as a facilitator.

5. Students had assigned roles within their groups.

6. The activity was designed to be the first introduction to the topic or specific content.

7. Students were not expected to have worked on any part of the activity before the class meeting time.

8. Groups were expected to complete all of the Critical Thinking Questions or equivalently designated questions during class.

Source: https://pogil.org/implementing-pogil.

Prior to the implementation of POGIL, the researchers organized TG students into cooperative learning groups. This is because some researchers reported that students remember the concept more when they engage in cooperative learning and the inquiry approach plays a significant role in scaffolding POGIL. ^{33 , 34 , 35} Accordingly, the TG students were assigned in to cooperative learning groups (4–5 students in one group) based on their lower grade academic achievement and, in each group, there were a randomly selected group of high achievers, middle achievers, and low achievers (to promote diversity within the groups and avoid self-assignment driven by friendship). The next step was to assign the students into different roles, such as one student assigned as the leader (to ensure that the group process functioned properly), one as secretary (to record the important ideas jotted down by the group members), while the remaining students acted as reflectors. Within such a structure, an independent tutorial class was arranged for both group students (i.e. TG and CG) and they were continuously encouraged to meet with their group members two times per week for 1 h for five consecutive weeks without a regular class schedule.

The researchers selected some challenging electrochemistry topics which students struggled with as reported in the literature namely conductivity, redox reactions (reduction and oxidation), oxidizing and reducing agents, electrolysis of substances in aqueous solution, voltaic or galvanic cells, electrodes and electrode reactions, cathode and salt bridge, half-cell potentials and cell potential. Then, four POGIL models and experimental activities related with the identified topics were designed. Some of the activities were designed by the researchers, while some of them were adopted and contextualized from reported scientific activities. The researchers also prepared questions requiring critical thinking that were directly linked to the models and activities.

The teacher began the tutorial class by providing and explaining the designed model and experimental activities to the students lasting for 10 min. These models and activities guided the student to develop conceptual understanding of the topic through Exploration (students are requested to analyze information provided in a model or diagram), Concept Invention (students combine multiple pieces of data identified in the exploration phase and develop a particular concept), and Application (students apply the newly constructed concepts to new situations). Accordingly, a total of four POGIL models (Oxidation and Reduction; Oxidation, Reduction and Electron Exchange; Electrical Conductivity; and Electrolysis), and experimental activities were prepared on the electrochemistry topic. Then, TG students worked on the planned POGIL models and activities with their cooperative learning groups, following a three-phase POGIL learning cycle (exploration phase, concept invention phase, and application phase). Each group had 40 min to accomplish the activities. Then, the students worked with their group members, analyzed the model and experimental activities in the given time range and answered the questions based on their discussions. While the groups worked, the teacher circulated the classroom and checked the answers recorded by the groups’ secretaries. The teacher intervened and guided students in their learning process when necessary. Sometimes, the teacher interfered in the group discussion and asked the students to respond to the questions requiring critical thinking, encouraging students’ interaction within the group and among the groups. Sometimes the groups shared their experiences with each other. In this way, the groups had the opportunity to compare their answers and thus discuss their differences. The group members reached a consensus and the secretaries compiled the output and prepared a final report for evaluation. The teacher advised the group leaders to report their group’s progress and present that at the end of each activity within 10 min. Then, the group leaders submitted brief reports of their group’s progress at the end of each activity. This process continued in the same way until the assigned activities were accomplished.

2.4 Treatment approach used for control groups

Similar to TG students, the researcher arranged independent tutorial classes for CG students which lasted for five weeks (2 h per day). The researcher organized students in groups (4–5 students in one group) based on their lower-grade academic achievement. The groups were a random mix of high achievers, medium achievers, and lower achievers (to avoid self-selected grouping). Each cooperative learning group, was encouraged to solve selected electrochemistry questions together. During the instruction, the researcher placed more emphasis on selected difficult concepts of electrochemistry reported in the literature, such as redox reaction, oxidizing and reducing agent, conductivity, electrolysis, cell potential, half-cell reactions, electrode and galvanic cells. Then, the researcher defined these selected concepts, gave brief explanations, solved selected problems, gave some additional questions and encouraged students to solve the problems in their groups. To mitigate the potential bias between the treatment and control groups the following were the same: course teacher (chemistry teacher), teaching material (grade 12 students’ chemistry text-book), time coverage (two times per week for 1 h each), worksheet questions, pre- and posttest questions. Thus, the only difference was the implementation approach. In such a way, all the students were kept active, and they were involved in the learning process, the same posttest was administered to both groups at end of the treatment period.

2.5 Data gathering methods

The relevant data were collected from the study participants using multiple instruments (pretest, posttest, questionnaire, interviews and observation).

2.6 Data analysis

The data obtained using different instruments for data collection were analyzed using both quantitative and qualitative analyses. The data collected using pre- and posttests were analyzed by using an independent samples t-test. This is used to compare the means of the population and determine if a statistically significant difference was observed or not. The effect size was used to evaluate the magnitude of the difference between groups. ^{33 , 34 , 35} The data collected through questionnaires, observation, and interviews were analyzed using Statistical Package for Social Sciences (SPSS 27). The data from students’ semi-structured interviews were transcribed and analyzed qualitatively.

3.1 The pretest and posttest results

The result of a comparative analysis of the two groups on the pre- and posttests is reported in Table 2. The pretest results revealed that no statistically significant difference was observed between the two groups before the intervention. This means that the two groups were found to be similar in terms of preknowledge and suitable to use for a comparison of the effects of using the POGIL approach with the lecture method on the conceptual understanding of electrochemistry.

In contrast, a statistically significant difference was observed between the two groups on the posttests. The treatment group students performed better in the posttest exam than the control group students (Table 2). This shows the effectiveness of POGIL in improving students’ understanding which, in turn, enhanced their achievement in electrochemistry. This result is in agreement with earlier reported studies on the effectiveness of the POGIL approach in enhancing students’ academic achievement in different chemistry concepts. For instance, Suwarni, Hastuti and Mulyani ²⁸ evaluated the impact of the POGIL model combined with a Science–Technology–Society-Environment approach on chemical literacy and science process skills on buffer solutions, and he stated that the approach played a significant role in elevating students’ chemical literacy and science process skills. Vincent-Ruz, Meyer, Roe and Schunn ⁴⁰ investigated the short-term and long-term effects of POGIL on students’ understanding and attitude towards a General Chemistry Course and the study revealed the significance of the approach in improving students’ achievement and attitudes. Other researchers also reported that POGIL helps students to build and restructure their knowledge, develops their higher-order thinking skills, and improves conceptual understanding. ⁴¹

3.2 The effect size measures of the two groups

In addition to the independent samples t-test, we used Cohen’s (d) effect size test to determine the size of the difference between the two groups or the magnitude of the effect of the intervention. We calculated the effect size of the pretest and posttest which were 0.037 and 1.070 respectively. Cohen ⁴² interpreted that an effect size d of 0.2 is small, 0.5 is medium, and 0.8 or above is a large effect. Accordingly, the effect size of the pretest result indicates that the difference between the TG and CG on the pretest is negligible while a large difference was observed on the posttest (1.070). The large effect size of the posttest result signifies the large favorable effect of the intervention (Table 3).

The effect size result indicates that the effect of the intervention was high compared to the traditional. lecture method. Several researchers also reported the effectiveness of POGIL in improving students’ performance. For instance, Hein ²⁶ compared the final exam results of students who completed an organic chemistry course by the POGIL approach with the traditional lecture approach and the result revealed that students taught by the POGIL method had better content knowledge and achieved better in the final exam than the students taught by the traditional lecture approach. Furthermore, Boda and Weiser ⁴³ studied the effect of using POGIL in challenging students’ preconceptions in an introductory chemistry course and they revealed the effectiveness of the approach in reducing students’ misconceptions and enhancing their achievement in introductory chemistry courses. Wilujeng, Wibowo and Haris ²⁹ investigated the effect of the POGIL learning model on high school students’ problem-solving abilities in thermodynamics and their findings indicated that POGIL has a significant effect on improving high school students’ problem-solving abilities in thermodynamics concepts.

3.3 Comparison between treatment and control group students on targeted electrochemistry questions

The researchers also analyzed individual student’s exam script performance on selected and targeted electrochemistry questions which required critical thinking and compared the results between the two groups (Figure 1).

Figure 1:

Comparison of performance between TG and CG in selected concepts.

For questions focused on the conductivity of metals and electrolytes, about 69.5 % of TG and 50.0 % of the CG students gave correct answers. For questions focused on the redox reactions, about 63.0 % of TG and 37.5 % of the CG students gave correct answers. However, the majority of CG students failed to give correct answers. For questions focused on the concept of oxidizing and reducing agents, about 65.0 % of the TG, and 42.5 % of the CG students gave correct answers while majority of CG students did not. For questions focused on the concept of electrolysis of substance in aqueous solution, about 73.8 % of TG students and 52.5 % of CG students gave correct answers. For the items focused on the concept of electrode and electrode reactions, about 67.3 % of TG students and 45.0 % of CG students gave correct answers. For these questions the majority of CG students failed to give proper answers. For questions focused on the concept of voltaic cells, about 71.6 % of TG and 55.0 % of CG students gave correct answers. For questions focused on the identification of electrodes (the anode and cathode), about 76.0 % of TG and 37.5 % of CG students gave correct answers. Similarly, for these questions the majority of CG students couldn’t properly distinguish electrodes (the anode and cathode) compared to TG students. For questions focused on the purpose of the salt bridge and how it works, about 82.5 % of TG and 52.5 % of CG students gave correct answers. This indicates that the majority of TG students understood the purpose of the salt bridge and answered the given questions correctly, whereas only about half of CG students understood the concept. This may be attributed to the fact that during the POGIL session, the TG students conducted a galvanic cell experiment which could promote a better understanding of the migration of cations and anions (i.e. the cation migrates towards the anode and anions towards the cathode). However, many of the CG students remained confused about the migration of cations and anions. It is evident from the posttest result, that, compared to CG students, the TG students understood the concept of oxidizing and reducing agents, distinguishing the substance that could be oxidized and reduced in redox reactions. As before, the majority of CG students remained confused about redox reactions. Overall, from the above selected targeted questions analysis, it is evident that TG students understood electrochemistry concepts better than CG students who completed the topic with a traditionally designed lecture method. This outcome can be ascribed to the effect of the POGIL approach. Several other researchers also reported that students who experienced even a few inquiry activities developed more self-confidence, possessed high science process skills and critical thinking, and were unafraid of doing science. ^{28 , 29}

3.4 Attitudes

The researchers used open and closed-ended questions to evaluate the cognitive and affective components of student attitude while observation was used to evaluate the behavioral component (students’ participation in group work, confidence in asking and answering questions, interaction, and interest or participation). A detailed description of TG students’ interview data will be presented in this section.

3.4.1 Observation of treatment group

The researcher evaluated the overall learning environment in POGIL sessions while TG students participated in different activities by preparing an observation checklist on students’ interest and participation, self-efficacy, interaction, and communication ability. The evaluation results are presented in Figure 2.

Figure 2:

Summary of observation checklist results.

During the intervention process, about 87.5 % of TG students have shown high interest and actively participated in performing practical activities, in group discussions, and in answering questions. However, about 12.5 % of students didn’t actively participate in group discussions and they only observed and listened to what others did. This may be due to group work not being their preferred learning style. Mundy and Potgieter ⁴⁴ also reported that because students’ learning styles vary from individual to individual, the POGIL approach may be difficult for some students. Self-efficacy is important to achieve the designated goals. Bandura ⁴⁵ defined self-efficacy as people’s judgments of their capabilities to organize and execute courses of action required to obtain designated types of performance. About 75.0 % of TG students showed self-efficacy (in reflecting or presenting their ideas). A number of researchers also reported that POGIL enhances student’s self-efficacy. ^{40 , 46 , 47 , 48 , 49 , 50} In contrast, about 25.0 % of students were shown with a weak sense of self-efficacy. This might be due to those students are at level of academic development stage and they need more help from the teacher through conventional instructions. According to Mundy and Potgieter, ⁴⁴ students in the academic development program often lacked confidence in their own work and looked to the instructor for guidance, which is at odds with the student-centered nature of the POGIL approach. In the same way, about 82.5 % of students actively engaged and interacted with their peers during group work or in solving problems. However, about 17.5 % of students showed little interaction. Worth mentioning is that students’ interaction and discussion habits were low at the beginning of the POGIL class. However, they gradually developed interaction habits through the course of intervention. About 80 % of TG students developed communication skills through interaction with their peers by the end of the course. This idea was also raised during students’ interviews. Other studies also reported that POGIL enhances students’ communication skills. ^{51 , 52} However, about 20 % of them showed weak communication skills, which may be due to an instructional language barrier between primary and secondary schools. In the primary school, students learned all subjects except English (which was taught as a standalone subject) in mother tongue. In contrast, high school uses English as the medium of instruction and all subjects are taught in English. A number of researchers also emphasized the importance of instructional language on students’ communication ability and their understanding of complex chemical concepts. ⁵³