Numerical simulations are computer programs based on simplified representations, which neglect or simplify certain details of a complex, real-life phenomenon or process. ^{45, 46} These simplified models of reality represent a constructivist learning framework centred on the learner. ⁴⁷ More clearly, a numerical simulation is a computer model of an authentic situation. ⁴⁸ Numerous studies agree that the integration of digital simulations provides an interactive, dynamic, and intuitive learning environment. These simulations offer a safer environment compared to physical laboratory experiments, which can be risky, complex, and sometimes costly. Another advantage of using simulations is the time saved, as simulations do not require preparation sessions. ^{49, 50} Simulations facilitate the visualization and understanding of abstract concepts and complex theoretical models, ^{51, 52} such as the concept of chemical bonding ⁵³ and the photoelectric effect. ⁵⁴ In addition, they offer students the opportunity to experiment and explore the effects of changing certain input variables, such as volumes and concentrations. This exploration activates metacognitive regulation and reflection on the content studied. ⁵⁴ These interactive environments give learners the ability to better understand microscopic phenomena that are difficult to visualize using traditional methods, such as blackboards, textbooks, or even real-life experiments. Indeed, according to some authors, these traditional methods are considered to be the source of relative difficulties in electrochemistry. ⁸

The CK-12 platform offers interactive simulations that are accessible free of charge. Each simulation is accompanied by a worksheet containing a key question and the corresponding educational objectives. The worksheet for the “Electrochemical Cell” simulation highlights the half-equations occurring at each electrode and the overall equation for the redox reaction. These worksheets provide guidance and structure for the activity. The simulation highlights the connection between the chemical phenomena of redox reactions and the observable effect on a large scale: the lighting of a lamp. This facilitates a clear understanding of the relationship between redox reactions and electricity, which is usually poorly understood at the secondary level. It is noted that, due to the microscopic transfer of redox reactions, these types of reactions are often abstract for students. This CK 12 simulation illustrates and dynamically represents the transfer of electrons between the electrodes of the electrochemical cell. Students can interact directly with the components of the experiment and modify the metals used in the two electrodes, the anode and cathode, to observe the effects. Furthermore, the educational objectives of the simulation used in this research are closely aligned with those of the theoretical course.

In a solar context, interest stems from the interaction between the learner and the specific content. It refers to motivation triggered by the immediate situation of an activity. In order to assess the impact of interactive simulation, this research opts for situational interest, as it is more relevant to focus on situational interest, which is directly related to the classroom learning context. Unlike personal interest, which is often influenced by factors outside the school environment, such as socioeconomic conditions, family support, or students’ attitudes and previous experiences, ⁵⁵ situational interest can be activated by targeted educational interventions, such as the use of engaging materials or interactive school activities.

This quasi-experimental research was based on a quantitative method with a random sample of 1,020 students in their final year of secondary education, comprising 48.4% female and 51.6% male, with an average age of 18.09 years. during the 2024-2025 school year. They participated in the study after providing their written informed consent, in addition to the written consent of the parents of any minor participants. A local committee affiliated with the Academy of Settat, Casablanca, Morocco, has provided its ethical approval for the research methodology under number 101/25. As part of the course Spontaneous Transformations in electrochemical cell and Energy Production, the CK-12 simulation of the electrochemical cell is integrated according to a planned educational scenario. It is adopted by the learners in the experimental group once they have familiarized themselves with the basic concepts of the course and are ready to move from theoretical abstraction to a dynamic conceptualization of the phenomenon. The quasi-experimental scenario followed in this research is as follows: After completing the same theoretical course, the research sample was divided into two groups: a control group continued learning through the traditional approach, using paper and pencil to do application exercises related to the knowledge covered in the course, and the experimental group attended the CK-12 digital simulation on the electrochemical cell. Both groups took the same pre-tests and post-tests, and in order to analyze the effect of the simulation on student performance, this study opted to compare the gains in test scores for both groups. In addition, a scale assessing situational and individual interest was administered before and after for both groups to evaluate the impact of the simulation on student interest. The data collected was then processed using IBM SPSS version 27 software.

In order to assess the impact of adopting simulation on student motivation and interest, the study chose the IS2G situational and individual interest measurement scale for serious games developed by Chainon and al in 2014. ⁵⁶ As its name suggests, this scale was designed to assess learners’ situational and individual interest in serious games. However, it is widely used for other types of digital activities in an educational context. ⁵⁶ Its design is based on the theory of phased development of interest, ⁵⁵ proposing that individual interest in a given subject develops through situational interest, which can be triggered by external intervention. The questionnaire used to measure situational interest is divided into two sections. The first part focuses on the respondents’ sociodemographic data, and the second part presents a scale for measuring situational interest. It consists of 12 items divided into three distinct dimensions. The first dimension, individual interest, includes items 01, 03, 07, and 09. The second dimension, activated situational interest, includes items 04, 06, 08, and 11. Finally, the third dimension, maintained situational interest, is assessed through items 02, 05, 10, and 12. The 12 items are examined on a seven-point Likert scale, ranging from 1 (strongly disagree) to 7 (strongly agree).

The test items are developed in line with the educational objectives of the course, which are clearly stated in the 2007 educational guidelines for physics and chemistry in Moroccan high schools. These anonymous tests focus on conceptual and procedural understanding related to the lecture, and for all items, the option “ I don’t know” is provided so as not to induce respondents to give random answers.

To ensure the reliability of the results and minimize preliminary disparities between students and contextual variables, such as their prerequisites, the study relies on gains, which represent the difference between pre-test and post-test scores. This allows us to identify the impact of the simulation on student performance. Initially, a comparison of the average gains of the two groups shows that the average gain was significantly higher in the experimental group (M = 0.0370, α = 0.22170) than in the control group (M = 0.0008, α = 0.21482), which is statistically significant, with the t-test indicating a significant difference, t (1018) = 2.643, p = 0.008. Table 3 presents the results of the independent samples t-test.

This demonstrates a significant effect of learning that adopts interactive simulation. Secondly, attention should be paid to incorrect answers that persist in the post-test for the entire sample. Identifying persistent errors makes it possible to identify certain existing learning obstacles. Below is an analysis of the post-test items accompanied by a discussion of the obstacles identified.

The first item is based on the distinction between a battery and a cell. Analysis of the post-test responses for both groups shows confusion between batteries and cells, with 31.1% opting for the distractor: There is no real difference between a battery and a cell; it is a question of size. They believe that the electrochemical cell stores electricity, but in reality, the electrochemical cell is an autonomous source of electricity; it produces electricity from spontaneous chemical reactions without storing it, while 20 % show another misunderstanding by stating that: The electrochemical cell only works when it is connected to a power source, whereas the battery is capable of storing electrical energy. These results reflect an erroneous mental model of the electrochemical cell, where students are influenced by everyday language: the connection of devices, imagining that the cell contains a reservoir that must be powered by an electrical source in order to function, while excluding the link with chemistry and redox reactions. According to a mini review on the difficulties of learning electrochemistry, ¹⁴ this type of representation is fuelled by the contextual language barrier, given that the meaning in everyday language differs from that in the scientific context.

The second item focuses on the ability to write a global equation based on two redox couples. the results highlight difficulties related to balancing redox equations, such as 67.3% of respondents opting for unbalanced equations, due to the incorrect method used for balancing, where respondents added electrons to the overall equation to balance the electrical charges, as in the case of choice: Zn _(s) + Ag ⁺ _(aq) → Zn ²⁺ _(aq) + Ag _(s) + 1e ^- , also the choice of: Zn _(s) + 2Ag ⁺ _(aq) → Zn ²⁺ _(aq) + Ag _(s), This shows an incomplete understanding of the law of conservation of matter, where respondents forgot to add the stoichiometric coefficients, and 12.5 % of respondents chose the option: I don’t know. In fact, balancing redox reactions is a procedural difficulty frequently encountered by students. ²⁰

The third item concerns the direction of electrons outside the generator in an electrical circuit. The results show that 27.8% state that: Electrons flow from the positive terminal to the negative terminal, in the opposite direction to the current outside the generator, and 28.7% opt for the distractor: Electrons flow from the positive terminal to the negative terminal, with the direction of current outside the generator. These results show that some students confused the conventional direction of current (from the positive pole to the negative pole) with that of electrons (from negative to positive), or had difficulty remembering that the conventional direction of current is opposite to the actual movement of electrons. These misunderstandings are not accidental; the source of this confusion is the disparity between the convention of current direction, historically established before the discovery of electrons, and the actual movement of electrons in electrical conductors.

The fourth item concerns the direction of electron flow between the two terminals of the electrochemical cell. During the lecture, students learned that: when the electrochemical cell is operating, electrons are produced during the oxidation process in the negative terminal, called the anode, and are then consumed during the reduction process in the positive terminal, called the cathode, thus circulating in the external circuit. The students (30.2%) who chose the statement: Electrons move from the positive terminal, where they are consumed by reduction (this terminal is called the cathode), to the negative terminal, where they are produced by oxidation (this terminal is called the anode), misunderstand the direction of electron movement between the positive and negative poles of a generator, which is a basic concept in middle school electricity courses. This choice highlights confusion between the direction of conventional current and that of electrons. This recalls the misconception previously discussed in item 3, according to which electrons move from the positive terminal to the negative terminal outside a generator, meaning that this misunderstanding is transposed from a simple electrical circuit to an electrochemical cell. In reality, any representation or misunderstanding that is not explicitly corrected by teachers will affect subsequent learning, ¹² as for the others (36.4%) who opted for the distractor: Electrons move from the negative terminal, where they are produced by oxidation, called the cathode, to the positive terminal, where they are consumed by reduction, called the anode, they show confusion between the anode and cathode, which indicates a partial understanding. These results are similar to those obtained in several studies on barriers to learning electrochemistry. ^{14, 59}

The fifth item concerns the polarity of the electrochemical cell. Analysis of the responses shows that students have poorly understood the idea that the anode is the negative terminal and the cathode is the positive terminal. The two distractors are chosen by 64% of respondents, who claim that the cathode is the negative terminal because it receives electrons, or that the anode has a positive charge because it attracts electrons. This misconception is often cited in research on alternative conceptions in electrochemistry. It has been validated by various experimental studies conducted with students in their final year of secondary school in Australia, ⁶⁰ Germany, ¹² and even with first-year university students in the United States. ³⁷ Indeed, confusion between the cathode and the anode or between the positive and negative terminals completely affects the understanding of how galvanic electrochemical cell and electrolytic cells work, which is why this type of misunderstanding is one of the main obstacles to the assimilation of electrochemistry. ⁵⁹

The sixth item concerns the physical aspect of the device essential for maintaining electrical neutrality in electrochemical cell. The analysis shows that 52.2% of respondents opted for the two distractors implying that electrical neutrality is necessarily linked to the presence of a salt bridge. The lecture always begins with the Daniell cell, which provides a simplified educational model for understanding how electrochemical cells work, describing the device, how it works, and the associated quantitative study. In the Daniell cell, electrical neutrality is ensured by a U-shaped salt bridge made of an ionic substance. As for the alkaline cell most commonly used in everyday life, a solid, porous separator (electrolyte paste) integrated into the electrolyte ensures electrical neutrality. Although it does not take the form of a conventional salt bridge, it performs the same function. This indicates that learners tend to reinforce and retain the knowledge assimilated at the beginning of the lesson. This poor assimilation is explained by the primacy effect, psychological education has shown that in the first stage, learners are more attentive and engaged, retain information without cognitive fatigue, and store what they learn in their long-term memory. ^{61– 63}

The seventh item concerns the difference between the mechanisms of electrical neutrality in electrochemical cell. The analysis shows that 62.6% of respondents opted for the two distractors implying that electrical neutrality is ensured by the passage of all charge carriers: cations, anions, and electrons via the salt bridge. These errors are not random; they reflect a flawed mental model according to which the salt bridge ensures the movement of all electric charge carriers, including electrons. In reality, the salt bridge only ensures the transfer of ions, electrons move through the external metal circuit. Indeed, the passage of electrons through the salt bridge or through solutions in general is a common misconception among high school seniors. This erroneous model is widespread and appears in many studies, ^{8, 9, 12, 14, 37, 59, 60, 64} Some studies consider that this representation is reinforced by textbooks, ³⁷ as the origin of this misunderstanding lies in the use of scientifically imprecise language that associates electric current with the flow of electrons without specifying the medium, leading students to believe that electrons are the carriers of electric charges even in solutions. ⁶⁵

Thirdly, a comparison of the number of incorrect answers in the experimental group in the post-test with those in the control group shows that the simulation led to a considerable reduction in incorrect answers. Table 4 illustrates the difference between the percentage of incorrect answers in the control group and that in the experimental group for each item in the post-test.

Item analysis showed a decrease in the percentage of incorrect answers in the experimental group, indicating an improvement in the assimilation of knowledge related to the lecture, corresponding to items 1 and 2. A more significant decrease in errors was also observed in the remaining items in favor of the experimental group, indicating that the simulation effectively addressed conceptual and procedural difficulties and representations, including: confusion between the direction of current flow and that of electrons, confusion between the anode and cathode, electrical neutrality is necessarily ensured by the salt bridge, and the flow of electrons in the salt bridge. These results confirm the positive contribution of the simulation in reducing misconceptions, particularly those related to visually interpretable knowledge.

The functioning of the electrochemical cell is taught visually in the form of animated content with a voiceover describing the process of electrical energy production. The results support certain hypotheses of dual coding theory ⁶⁶ and multimodal learning theory (2005), ⁶⁷ which assume that learners are more engaged and memorize knowledge more effectively when information is processed through visual and verbal channels simultaneously. The results also agree with the conclusions of numerous related studies, which consider simulation to have a positive impact on concept comprehension ^{68– 70} and memorization. ⁵⁸ These convergences reinforce the credibility of the results revealed in this quasi-experimental research, which has provided new experimental confirmation in a different context.