How Does Flipped Learning Work? A Case Study in Signals and Systems Teaching

Abstract

Student-centered teaching approaches emphasize student responsibility and learning. Flipped learning is a student-centered approach to promoting student learning. In this paper, we describe a flipped learning strategy that involves fostering collaborative, problem-based, and project-based learning in engineering courses. In addition, we delineate the role of student assessment and teacher–student interactions in the flipped learning teaching strategy. In this study, we compare academic achievement and student perceptions of instruction in a lecture-based and a flipped classroom. The results show that the students in a flipped classroom had higher grades than those in a lecture-based classroom. In addition, students in the flipped classroom assessed the learning materials, activities, and evaluations more positively than the students in the lecture-based classroom did. Students in the flipped classroom were also found to be more likely than those in the other class to perceive that they could apply the knowledge and skills they developed in the course. They also had higher motivation to learn than the students in the lecture-based class and perceived that the instructor generated a positive climate that fostered student participation.

1. Introduction

Several initiatives have been launched to reform engineering education (Crawley et al., 2007). Some of the reasons for these initiatives include ensuring that students effectively learn a set of knowledge, skills, and attitudes required for professional practice. One major challenge faced in engineering education is that students must obtain not only fundamental disciplinary knowledge and skills, but also personal and interpersonal skills that will enable them to contribute to society. One strategy for achieving the latter is to effectively implement student-centered teaching approaches in engineering curricula.

Cannon defined student-centered approaches as “ways of thinking about teaching and learning that emphasize student responsibility and activity in learning rather than content or what the teachers are doing” (Cannon et al., 2000). Teaching methods such as problem-based learning, case-based learning, project-based learning, collaborative learning, and flipped learning, among others, can be considered student-centered approaches. Kolb stated that these ways of teaching are characterized by “the strategic, active engagement of students in opportunities to learn by doing and reflecting on those activities” (Bates, 2015). This gives them the ability to use their theoretical knowledge in real-world situations both inside and outside of the classroom.

Furthermore, the teacher–student relationship is at the heart of student-centered approaches. Positive relationships, non-directivity, empathy, warmth, and encouraging thinking and learning are the specific teacher variables that are common in student-centered teaching approaches (Cornelius-White, 2007). In addition, student-centered approaches have been associated with critical and creative thinking, cognitive abilities (e.g., math and verbal achievement), participation, satisfaction, motivation to learn, self-esteem, social connection, social skills, and reductions in dropout rates (Cornelius-White, 2007).

Student-centered approaches have been contrasted with teacher-centered approaches, which are characterized by the transmission of information and the passive role of students (e.g., memorizing the content of a lecture). The focus in these approaches is on what the teacher does (e.g., the selection of content to present) (Biggs, 1999). While lectures have been found to be as effective as other methods for transmitting information (e.g., videos and reading), it is important to note that they alone are ineffective at promoting thought and changing attitudes, underscoring the need for a more engaging approach (Biggs, 1999).

Flipped learning, or the “flipped classroom”, is a student-centered teaching and learning approach in which students receive prerecorded class lectures and course materials prior to class, allowing for class time to be dedicated to collaborative group discussions and extensive problem solving (Öncel et al., 2018; Cheng et al., 2020). Flipped learning is associated with improved learning outcomes, effective project- and problem-based instruction, enhanced teacher–student and student–student interactions, active learning, and student engagement (Al Mamun et al., 2022; Beltozar-Clemente et al., 2023; Hassan et al., 2021). In addition, the flipped classroom enabled teachers to cover additional class content (Mason et al., 2013).

Nonetheless, the theoretical and conceptual underpinnings of the flipped classroom are generally only vaguely described (O’Flaherty et al., 2015; Li et al., 2021; Karabulut-ilgu et al., 2018). For example, in a review of 435 articles on flipped learning, active learning was cited as a component of the approach (Li et al., 2021). However, the term “active learning” is ambiguous and is interpreted differently by different researchers and practitioners (Prince, 2004). It is important to note that the mere fact that content is delivered outside of the classroom or is mediated by technology does not provide a comprehensive understanding of why students learn.

Few researchers have examined how learning theories guide the development of flipped learning (Li et al., 2021). Only 13 articles out of 62 published between 2000 and 2015 included references to a theoretical or conceptual framework to explain how flipped learning works. Most studies that explained why students learn better in a flipped classroom than in a lecture-based classroom used a constructivist framework to explain the learning mechanism (Karabulut-ilgu et al., 2018). Therefore, specific constructivist models that may fall under active learning, such as case-based reasoning, problem-based learning, and project-based learning, could provide a more precise direction for researchers and practitioners (Karabulut-ilgu et al., 2018).

Furthermore, instructors often find it challenging to implement the flipped classroom concept effectively in practice (O’Flaherty et al., 2015). One reason is that they must redesign their learning sequences, integrating pre-class activities into face-to-face classes using active learning methods. This is crucial for students to understand the model and motivate them to prepare for class. While the focus has been on delivering content before class, the key lies in how these resources are seamlessly integrated into the entire sequence of activities in the class. Pre-class activities that lack interactivity or are unrelated to the in-class activities are less likely to engage students in their learning process (O’Flaherty et al., 2015).

It is essential to have a comprehensive understanding of the flipped classroom approach, as it could be reduced to a mere ’technique’ if implemented without a full understanding of its principles (Li et al., 2021). In this study, we present a teaching strategy that aids in the effective implementation of the flipped classroom teaching approach. Our focus is on the application of a student-centered teaching approach (i.e., the ’flipped classroom’) to teach Signals and Systems, a course in the electrical engineering program at Pontificia Universidad Javeriana. This study delves into the impact of active learning pedagogies such as problem- and collaborative-based learning (in line with Prince’s definition) on learning in a flipped classroom (Prince, 2004). The aim of this article is to showcase a case in a specific setting that facilitates the design, implementation, and evaluation of a course, thereby transforming the learning experience of electrical engineering students.

This study’s primary research question is whether flipped learning enhances student comprehension of signal and system concepts. Therefore, we designed an educational environment to enhance students’ comprehension of signals and systems concepts. The objectives of this study were to (1) evaluate how well students learned signals and systems concepts using a flipped classroom design in the Signals and Systems course and (2) compare the learning outcomes of students who were taught through flipped classroom instruction to those of students who were taught using traditional instruction.

2. Description of the Course

A Signals and Systems course in the Department of Electronics Engineering at Pontificia Universidad Javeriana was used for this study. The Electronics Engineering program at the university is a four-year program that requires students to learn basic knowledge in mathematics and physics and apply it in signal acquisition, signal processing, and in the measurement of real-world physical phenomena. The course covers mathematical models and graphical representations of signals and systems both in continuous and discrete time, as well as the analysis of the frequency–time relationship using the Fourier transform technique.

The Signals and Systems course is divided into three sections taught by two different professors. One professor used a flipped learning approach and taught two sections, while the other used a traditional lecture-based approach and taught one section. All three sections shared the same learning objectives, textbook, initial diagnostic assessment, final exam, and three projects. Both professors select problems for students to solve from the textbooks by Oppenheim et al. (1983) and Soliman et al. (1990).

2.1. Lecture-Based Classroom

In the lecture-based classroom, students had to read a chapter of the book Signals and Systems authored by (Oppenheim et al., 1983) before class. During the class, the instructor presented the class content, which corresponded to the themes of the book, and after class, students had to complete some of the exercises suggested in the two textbooks. Sometimes, single students had to solve problems on the board. The instructor also implemented three projects during the semester so that students could apply the concepts they learned in the class.

2.2. Flipped Classroom

The course was redesigned to bolster student learning. As shown in Figure 1, the course instructor selected or created a series of videos and texts for students to review prior to class, as well as a test to evaluate the students’ foundational knowledge and problem-solving skills. In class, students were required to solve a series of complex problems and interact with their classmates and instructor through a variety of activities, including whole-class discussions, pair work, micro-lectures, and quizzes. During the semester, the teacher gave the students four projects to help them apply the course’s main ideas and methods.

2.3. Before-Class Activities

The course was redesigned to bolster student learning. As shown in Figure 1, the course instructor selected or created a series of videos and texts for students to review prior to class, as well as quizzes to evaluate the students’ foundational knowledge and problem-solving skills.

2.3.1. Learning Resources

A series of learning resources was developed for students, including videos developed or curated by the instructor, short readings, infographics, and presentations, with the purpose of introducing basic and complex concepts to students before class so that they could focus on the student-centered activities in class. In addition, students had a variety of learning resources to choose from based on what was best for their learning. The resources were offloaded to the university’s learning management system. The videos were no longer than seven minutes.

2.3.2. Diagnostic Assessment

An online asynchronous quiz was developed for students to answer before class. The purpose of the quiz was to assess and provide feedback to students on the basic concepts presented in the learning resources. Before class, the instructor reviewed the students’ results and decided which concepts to reinforce in class. At the beginning of the class, the instructor showed the aggregated results to the students and explained how to solve the more difficult problems, as indicated by the students and their quiz results.

2.3.3. Problem-Solving Exercises

At least once a week, students were given problems to solve by applying the concepts introduced in the learning resources. Students were able to ask questions about how to complete the exercises through the nota bene (NB) platform of the Massachusetts Institute of Technology. The instructor constantly gave them feedback.

2.4. In-Class Activities

Class activities were focused on collaborative group discussions and extensive problem solving. The groups could be established freely by students or assigned by the instructor depending on students’ answers. That is, the instructor grouped students who gave different answers on the quizzes to compare their problem-solving procedures. Students also answered questions individually.

Furthermore, the difficulty of the problems posed to students increased throughout the class. Each class began with questions or problems from the previous class. Most of the questions concerned concepts with which students were already familiar or numerical calculus. Problems, on the contrary, involve what is unknown, data, and a set of conditions or problems that comprise a hypothesis and a conclusion (Pólya, 1985).

The following sequence of activities shows how the instructor moved from fully worked-out problems, where students just choose an answer, to open-ended problems, where students could solve the problems in different ways.

• At the beginning, the instructor poses a question, and students can raise their hands to answer, or all students vote for the best answer from a series of alternatives. The instructor or the students themselves can propose alternatives. After voting, a student can explain or defend their answer. Other students can disagree with or complement the answers of their classmates. The instructor provides explanations when necessary.
• An alternative is that students write their answers on an acrylic palette and show them to the instructor. The instructor assigns groups of students who have different answers and asks them to show their peers how they reached the answer. The group must come to an agreement about a group answer. After reaching an agreement, the group presents their answer to the rest of the class. If another group disagrees, then they can explain why. The groups start to interact and discuss their procedures. The instructor intervenes and explains why he would choose or not choose a procedure when necessary.
• Finally, the instructor provides open-ended problems for students to propose solutions to. Students have two ways of participating: (1) They can solve the problem individually in their notebook and call the instructor to review it. If the instructor agrees with the solution, then the student presents it to the rest of the class and receives a bonus on the final grade. (2) A student can ask to explain the problem to the entire class. If the student solves the problem correctly, then they receive a bonus on their final grade.

The difficulty of solving an open problem usually motivates high achievers, while low achievers feel more at ease responding to structured problems. Using this strategy, the instructor can tailor their instruction for students who have diverse needs.

Micro-Lectures or Explanations

In all classes, the instructor gave micro-lectures or explanations with the purpose of reinforcing concepts that students learned during the preparation of the class or in class, and they redirected student learning by explaining the arguments that led to a solution in a certain way when needed. These micro-lectures were short (no more than three minutes), and their purpose was to give students a sense of direction when they had trouble with the activities or ideas.

2.5. After-Class Activities

2.5.1. Summative Assessment Activities

Besides the formative assessment activities described above (quizzes and projects), two scheduled examinations (each worth 20% of the final grade) and a final exam (worth 30% of the final grade) were used to assess students’ understanding of the course content and measured their ability to achieve the desired learning outcomes.

2.5.2. Course Projects

During the course, students had to complete four projects in MATLAB (Mathworks, 2020). These projects were meant to show how mathematical models, graphical representations of signals and systems, and frequency–time relationships can be used. In the first project, students become acquainted with MATLAB and the representation of continuous and discrete signals in that program. In the second project, students applied different audio signal systems to create sound effects (e.g., delay, inversion, and scaling in time). In the third project, students applied the Fourier transform technique to identify the vowels A, I, and O in an audio file. These three projects were also used in the lecture-based classroom. Unique to the flipped classroom is the fourth project, in which students used the finite-length impulse response filter and the infinite impulse response filter to remove unwanted frequencies from a song.

Students completed all projects in groups of two or three. For the first project, students chose their teammates. They had to choose new teammates for the second project, and the instructor assigned the groups for the third project. This aimed to help students get to know different classmates and develop teamwork skills. The students chose their teammates freely for the final project. At this point, they knew their classmates well and with whom they worked best so that they could pursue their best performance.

2.6. Positive Instructor–Student Relationships

The instructor also tried to build positive relationships with students by fostering a positive classroom climate, encouraging student-to-student interaction, and interacting with students (Myers et al., 2016; Cook et al., 2017). A positive classroom climate is established by creating agreements at the beginning of the class when students learn about the class schedule, assessment dates, and methodology. In addition, on the first day of class, a discussion was facilitated to identify positive behaviors and expectations that helped students feel safe, accepted, and valued. No bullying or segregation was permitted. Moreover, when students could not attend class because they were sick or had personal problems, they could watch the class online or watch the recording later. Nevertheless, attendance was over 90% every session.

Student–student interaction was stimulated by using an icebreaker. On the first day of class, students introduced themselves and shared information about their hobbies, personal achievements, and academic strengths and weaknesses. Incorporating collaborative learning into classroom activities increases student engagement and peer support. Additionally, students collaborated on projects and presentations, which promoted interaction among them. The instructor tried to engage students by being approachable and personable, allowing students to contact the instructor, chatting with them before, during, and after class, generally caring about their well-being, using students’ names, and encouraging them to ask questions.

3. Materials and Methods

As described in Section 2, we used a “flipped classroom” strategy to teach signals and systems in the field of electronic engineering.

3.1. Research Design

This study employs a quasi-experimental design with a non-equivalent control group post-test only to compare the effectiveness of traditional lecture-based instruction versus flipped classroom teaching methodologies. Since our primary interest was in teaching methodology rather than instructor effect, we pooled data from the two flipped classrooms taught by the same professor for comparison with the lecture-based group taught by another professor.

Students from the three sections of the course completed the final exam at the same time and had the same amount of time to answer the questions. In addition, we evaluated the effectiveness of the flipped classroom by comparing students’ final exam performance and perceptions of teaching between the two groups.

At the end of all courses, we administered an anonymous survey of students’ perceptions of teaching. Students were asked to rate statements about preparing for class, learning activities, receiving feedback, educational resources, interactions between students and instructors, learning outcomes, and motivation to learn on a five-point Likert scale.

3.2. Course Intervention

The course was evaluated during the Spring 2023 semester by comparing three sections of the Signals and Systems course. Two sections were taught by the same professor using a flipped classroom approach (with 31 and 30 students initially enrolled), while the third section followed a traditional lecture-based format (30 students enrolled).

In the lecture-based section, 27 students completed the course. In the flipped sections, 26 of the 31 students finished in one section and 25 of the 30 completed the other. Two students from the flipped sections did not take the final exam on the scheduled day and were excluded from the analysis to avoid potential bias.

All sections met twice a week for a total of four hours per week over a 16-week semester.

Both professors consistently receive high student evaluations, averaging 5.6 out of 6.0 on the university’s faculty evaluation scale (range: 1–6) for this course. To minimize selection bias, the university’s registration system conceals instructor names during the initial enrollment period, when students choose courses based solely on scheduling. After instructor names are revealed in the second enrollment period, no significant changes were observed in group composition or enrollment numbers, indicating minimal self-selection effects.

3.3. Participants

All participants were undergraduate engineering students at a Hispanic-Serving Institution, aged 18–21 years. The two flipped classroom sections included 51 students (8 women, 43 men), while the traditional lecture-based section contained 27 students (3 women, 24 men). The three groups had similar racial/ethnic compositions (predominantly Hispanic) and comparable academic backgrounds based on prerequisite course performance.

3.4. Preliminary Analysis

Given that our primary interest was in comparing two teaching methodologies rather than three individual class sections, we used an independent-samples t-test for the statistical analysis. This approach allowed us to directly compare the pooled flipped classroom group (Professor A’s two sections) with the lecture-based group (Professor B’s section). We did not treat the two flipped classroom sections as independent samples, as both were taught by the same professor using the same methodology and materials and with similar student groups.

All students were given the same quiz at the beginning of the course to assess their prior knowledge of function graphs, complex numbers, and basic integrals. Quiz scores ranged from 0 to 5.

Table 1. Grades on quiz 1 assessing students’ previous knowledge.

	N	Mean	Standard Deviation	Median	Minimum	Maximum
Flipped	61	2.46	1.36	2.6	0.0	5.0
Lecture-based	30	2.31	1.41	2.2	0.2	4.7

presents the results. The average score for the flipped classroom group was 2.5 (SD = 1.4), while the lecture-based group had a mean score of 2.3 (SD = 1.4). The minimum and maximum scores were 0.0 and 5.0 for the flipped group and 0.2 and 4.7 for the lecture group, respectively, indicating similar prior knowledge across groups.

Tests for statistical assumptions confirmed that the data were suitable for t-test analysis. A Shapiro–Wilk test indicated that both distributions were normal (Flipped: W (61) = 0.969, p = 0.126; Lecture: W (30) = 0.934, p = 0.064). A visual inspection of QQ plots supported this conclusion. Levene’s test confirmed the assumption of equal variances (F = 0.64, p = 0.21).

The independent-samples t-test showed no significant difference in quiz performance between the flipped and lecture-based groups: t (89) = 0.5, p = 0.62.

3.5. Data Analysis

Students’ scores on the final exam were analyzed using a Kolmogorov–Smirnov test to determine whether the data were normally distributed. The Kolmogorov–Smirnov test was used for sample sizes larger than 50. For samples smaller than 50 participants, the Shapiro–Wilks test was used. The results of the Kolmogorov–Smirnov test indicate that the scores in the final exam in the flipped classroom sample were normally distributed (D (49) = 0.12, p = 0.07). The results of the Shapiro–Wilks test indicate that the scores in the final exam in the lecture-based classroom were normally distributed (W (27) = 0.95, p = 0.16), and the inspection of a Quantile–Quantile (or QQ) plot seemed to be normal. The results of Levene’s test indicated that the variances in scores between the flipped classroom and the lecture-based classroom were equal (F = 0.71, p = 0.40). Thus, an independent-samples t-test was used to test the differences between group means. We also compared the percentage of correct answers in the final exam for each topic to deeply understand the student learning outcomes. Lastly, we compared students’ perceptions of teaching in the two courses using an independent-samples t-test. The purpose of this test was to determine whether the samples were different from each other.

4. Results

4.1. Test Achievement in Lecture-Based Versus Flipped Classrooms

Students in both groups were administered the same final exam (maximum possible rating = 5 and minimum possible rating = 0). The results show that the mean performance on the test scores was higher for the flipped classroom (M = 2.8, SD = 1.0) than for the traditional lecture classroom (M = 1.9, SD = 1.2). Moreover, the minimum grade in the flipped classroom was 1.2 versus 0.1 in the lecture classroom, and the maximum grade was 5 versus 4.8 in the lecture classroom.

On the final exam, the 49 participants in the flipped class outperformed the 27 participants in the lecture-based classroom (t (74) = 3.35, p =< 0.001, d = 1.09). The Cohen’s D value indicated a large effect size.

4.2. Comparison of Exam Questions by Topic

Table 2. Comparison of exam results between the two groups by topic.

Topic	Flipped Class Percentage of Correct Answers n = 49	Lecture-Based Class Percentage of Correct Answers n = 27	Percentage Difference
Signal parameters and transformations of the independent variable	63.1%	44.4%	18.7%
Systems properties	74.9%	56.7%	18.2%
Laplace transform	60.0%	56.3%	3.7%
Resistor-capacitor filter—RC filter	57.0%	23.4%	33.6%
Sampling	52.8%	37.3%	15.5%
Z transform and digital filters	64.5%	61.9%	2.6%
Fast Fourier transform (FFT)	34.5%	22.6%	11.9%

shows that students in the flipped classroom had better learning outcomes than those in the lecture-based classroom on all topics.

Table 2 shows that, in both groups, the lowest scores were for the FFT topic, with only 34.5% of the students in the flipped classroom and 22.6% in the lecture-based classroom obtaining a full score on that topic. The best result for the flipped classroom was 74.9% for system properties, and the best result for the lecture-based classroom was 61.9% for the Z transform and digital filters. The greatest difference in results between the two groups corresponded to the RC filter topic. Finally, in the flipped classroom, four of the seven subjects assessed obtained a percentage above 60%, but just one of the seven subjects assessed scored higher than 60% in the lecture-based classroom.

4.3. Student Perceptions of Teaching

Students completed a survey about their perceptions of class preparation, educational resources, learning activities, assessments, instructor–student interactions, perceived learning, and motivation.

Table 3. Comparison of course evaluation responses between the traditional and flipped classrooms.

Item	Flipped Class Mean (SD) n = 51	Lecture-Based Class Mean (SD) n = 22	Mean Difference	p-Value
Class preparation
I had to prepare for class to be successful.	4.2 (1.1)	4.0 (1.2)	0.1	0.32
Resources
Learning materials and resources in this class supported my learning process.	4.5 (1.0)	3.4 (1.2)	1.1	<0.001
Learning activities
The activities of the class prompted understanding and application of concepts.	4.4 (1.0)	3.4 (1.3)	1.0	<0.001
The activities of the class improved my problem-solving skills.	4.2 (1.0)	3.5 (1.3)	0.7	0.01
The activities of this class allowed me to collaborate with my peers.	4.1 (0.9)	3.5 (1.3)	0.5	0.05
The class projects inspired me to learn about signals and systems.	4.3 (1.0)	3.6 (1.2)	0.6	0.01
Assessment
The feedback I received in this class was timely.	4.4 (1.0)	3.6 (1.4)	0.8	0.01
The feedback in this class allowed me to know what I should improve on.	4.3 (1.0)	3.7 (1.4)	0.6	0.04
The feedback in this class allowed me to know how to improve.	4.2 (0.9)	3.7 (1.2)	0.5	0.03
Interaction with the instructor
The interaction with my instructor was enough to facilitate my learning process.	4.4 (1.0)	3.3 (1.4)	1.1	0.002
The instructor generated a positive climate that fostered student participation.	4.7 (0.9)	3.6 (1.4)	1.0	0.002
Learning outcomes
I am confident in my ability to apply the knowledge and skills developed in this course.	4.1 (0.9)	3.1 (1.1)	1.0	<0.001
This course allowed me to learn to argue in my discipline.	4.1 (1.0)	3.3 (1.2)	0.9	0.001
Learning motivation
This course motivated me to learn.	4.4 (1.0)	3.5 (1.2)	0.9	<0.001
Total mean	4.3	3.5	0.8

shows the means and standard deviations for each class and the p-value.

Table 3 shows that students in the flipped classroom perceived the learning resources and activities, assessments, interactions with the instructor, learning outcomes, and motivation to be significantly better than in the lecture-based classroom. The only item that was not significantly different between both classrooms was “I had to prepare for class to be successful”.

5. Discussion

The results of this investigation indicate that the students in the flipped classroom outperformed those in the lecture-based classroom. On average, the students in the flipped classrooms performed better on the final exam and had a higher course-passing rate than the students in the traditional lecture-based classroom. Although there were no significant differences between the two classes’ final exam scores for the Laplace transform and Z transform topics, which are typically the course’s easiest topics, there were significant differences between their exam scores for topics that students typically find to be challenging, such as signal parameters and transformations of the independent variable, RC filter, sampling, and FFT. This could be explained by the fact that students in the flipped classroom had class preparation materials available and were aware of the topic’s difficulty in advance, and thus were able to receive additional aid on the topic from their teacher.

In both groups, the lowest performance was in the FFT area, which is usually a difficult subject for students. However, the flipped classroom students performed better than their peers in the traditional lecture-based classroom. In the lecture-based classroom, students had a deep understanding of the Laplace transform and the Z transform. The only specific subject in which the students in the lecture-based classroom obtained higher scores than the students in the flipped classroom was the question related to the stability of a system. This could be due to the emphasis that the lecture-based teacher put on this topic during the class because it was also related to another class that he teaches.

The instructors of both courses considered that the most important reason for student difficulties in the class was deficiencies in their mathematical foundations, which are critical to understanding some of the signals and systems concepts. For example, some students have difficulties understanding complex numbers and simple integrals.

Students in the flipped classroom gave significantly higher ratings to the statement “Learning materials and resources in this class supported my learning process” than students in the lecture-based classroom. This finding is consistent with those of previous research concerning the strength of the flipped classroom in providing students with course materials before class so that class time can be dedicated to collaborative discussions and extensive problem-solving (Cook et al., 2017; Foldnes, 2016; Kanelopoulos et al., 2017; Yelamarthi et al., 2016). Another explanation of the advantages of the flipped classroom is that it enables students to learn at their own pace and puts some of the responsibility for learning on the students so they can become aware of how they learn (O’Flaherty et al., 2015).

In addition, students in the flipped classroom perceived that the learning activities in the class fostered their understanding and application of concepts, improved their problem-solving skills, enabled them to collaborate with their peers, and motivated them to learn more about the subject than the students in the lecture-based classroom, discoveries that align with earlier research (Baig & Yadegaridehkordi, 2023).

Moreover, students in the flipped classroom perceived receiving better feedback about their learning process than those in the lecture-based classroom. In the flipped classroom, the learning activities which were designed to foster a supportive learning community included collaborating with peers; discussions with peers provided students with feedback that the instructor supplemented if necessary. Furthermore, the teacher designed the course projects to enable students to apply mathematical models to signal processing, and the projects enabled the instructor to check student’s understanding of specific concepts and procedures. The instructor also complemented these activities with frequent formative assessments.

Multiple factors may contribute to the effectiveness of the flipped classroom. Firstly, the instructor adapted the content to meet the diverse needs of students, helping them better understand the material before class. The use of video lectures allowed for the students to control the pace of their learning, and formative quizzes provided before class offered opportunities for feedback and self-assessment.

Secondly, the flipped classroom emphasized collaborative problem-solving, which enabled students to support one another in understanding class material. Thirdly, the success of group work depended on effective communication and peer support, both of which were actively fostered by the instructor. These efforts helped build positive relationships among students and contributed to a supportive classroom environment.

While we adhered to the flipped classroom definition, future work could more explicitly isolate the influence of each instructional component—such as video lectures, formative assessments, and peer collaboration—within both flipped and traditional models.

The tension between the delivery of content and the development of skills is constant in the conversations of the electrical engineering faculty. It also reflects the contrast between teacher-centered and student-centered teaching approaches. Signals and Systems is a course that was taught in two different courses, and, due to curricular changes, the content of the two courses was reduced to a single course. The flipped classroom was effectively used to introduce content to students and provide them with feedback prior to class. Class time was focused on understanding students’ difficulties understanding the content, and after-class activities were focused on students’ applications of concepts and procedures in projects where they could experience the implications of that knowledge. The main advantage of focusing on students’ comprehension in class is that it is possible to understand how well they are appropriating the mathematical models through their application and argumentation of the procedures they followed. By performing the latter, students came to understand what they thought they knew, but in fact did not know how to apply. This understanding enabled them to process additional content because they could assimilate it with what they already knew or deepen their understanding of a specific model or procedure. The students in the flipped classroom completed four projects, while the students in the lecture-based classroom only completed three projects.

In addition, flipped classroom students gave significantly higher ratings to the statements “The instructor generated a positive climate that fostered student participation” and “The interaction with my instructor was enough to facilitate my learning process” than their peers in the lecture-based class. Both statements refer to the quality of the instructor–student interactions. These findings align with those of previous research that linked the flipped classroom to improved teacher–student interactions (Güler et al., 2023). The reason for this is that, in the flipped classroom, the transfer of information happens outside the classroom and class time is used to solve problems in a collaborative way.

Another issue to consider is the relevance of a positive classroom climate to students’ development. Positive perceptions of classroom climate were associated with higher perceptions of fundamental engineering skills (Hankey et al., 2019). A positive classroom climate has also been found to be associated with high retention rates in engineering programs (Geisinger et al., 2013).

6. Conclusions

In a signals and systems course in electrical engineering, the flipped classroom positively impacts performance scores, students’ perceptions of the usefulness of learning materials, learning and assessment activities, motivation to learn, and instructor–student interactions. We came to that conclusion by comparing a flipped classroom with a lecture-based classroom in the same program. The flipped classroom instructor’s carefully crafted activities before, during, and after class were strategically and consistently focused on improving students’ understanding, providing a reassuring sense of the flipped classroom’s effectiveness.

However, there are some limitations to this investigation. The first limitation is the limited number of participants. A larger sample size can be more representative of the population. A student’s performance on a test can be explained by the student’s prior knowledge, motivation to study the discipline, and learning habits. Due to the impossibility of randomizing this intervention, the results of this study may have been influenced by the aforementioned variables. In addition, it is important to consider that teaching success may rely on different teaching competencies, especially since the two courses were taught by different instructors. Finally, future research should investigate whether the observed benefits stem primarily from the flipped classroom structure itself or from specific instructional practices—such as formative assessment, collaborative learning, or self-paced study—that might also enhance outcomes in traditional settings.

The findings of this study add to the body of evidence on the effectiveness of the flipped classroom method. Nevertheless, it cannot be stated that flipped learning works because students engage in “active learning”. Specific learning activities should be designed to assess the method’s soundness. It also cannot be argued that the method’s principal feature is the distribution of course materials prior to class because this is a feature of many teaching methods. Students do not learn simply because they are given content prior to class; rather, they learn because that content is articulated through the other activities in the classroom.

In this study, we describe a collaborative, problem-based learning strategy for the flipped classroom, complete with diagnostic, formative, and summative assessments and projects in MATLAB in which students must apply theoretical content. In addition, we underlined the instructor–student relationship as one aspect of the flipped learning approach that has not been studied in previous research. Educators may find this study applicable to how they design and implement the flipped classroom approach in their practice.