The flipped classroom and challenged-based learning methods are effective at integrating sustainability in higher education

The European Union has been working to shift to a circular economy, an economic model which focuses on the entire life cycle of a product (production, consumption, waste management, etc.). The purpose of a circular economy is to receive the most utility out of the product while limiting emissions and waste. Yet, there remains skepticism about this new model, both among the general population and among specialized professionals such as technicians, engineers, and researchers. To mitigate this issue, higher education (HE) institutions are working to provide courses that focus on sustainable development and the circular economy and strive to use innovative teaching methods in these courses. The purpose of this study was to assess the effectiveness of two new classroom methodologies in educating HE students on sustainability and the circular economy in Spain.

This study integrated two innovative methods of teaching; the Flipped Classroom (FC) method and the Challenged-based Learning (CBL) method. The FC method creates an autonomous learning environment, where students are in charge of their learning process. This method encourages student motivation through adapted course structure, training materials, and resources. Students are expected to complete activities at home, then receive help or guidance from their professor when in class. While this style of teaching has shown to promote valuable skills among students, such as creativity, critical thinking, and collaborative work, it does not always include hands-on problem solving of real-world environmental issues. Flipped classrooms can be complemented with other teaching methods such as CBL to encourage additional skill development. The CBL method aims to actively involve students in real world-situations through projects. The project begins with students defining a complex challenge to society and results in students using critical thinking to find a solution and generate further questions to investigate. Previous literature has demonstrated the success of CBL in increasing various skills among students, including problem-solving, collaboration, leadership, creativity, and planning.

This study was conducted at the Universidad Politecninca de Madrid in Madrid, Spain, and was applied in three courses; Environmental Management, Environmental Engineering, and Industrial Ecology, that were taught to two engineering majors, Degree in Geomatics and Survey Engineering, and Master's degree in Chemical Engineering. The first part of the study, project 1, was called Innova-ambiental and utilized the FC method during the 2016-17 academic year with 77 student participants. Project 1 utilized a web platform, where students watched YouTube videos on various environmental topics and completed quizzes created by the professor prior to the in-class portion of the course. The in-class portion consisted of discussions, oral presentations, and experimentations. After completion of the course, professors identified that the FC method was successful in helping students acquire competencies regarding the circular economy, but student grades and satisfaction levels were not as high as expected. To mitigate that issue, the researchers implemented the second part of the study, project 2.

Project 2 was called Retoinnova-ambiental, and utilized both the FC and the CBL method during the 2017-18 academic year with 64 student participants. Project 2 included the CBL method to more actively involve students in defining a challenge and applying solutions. This was done for all courses, except for the Environmental Management course for the Geomatics and Survey Engineer majors. The students focused on the overall life cycle of pulp and paper products and worked to find creative solutions within the concept of the circular economy. Students worked in groups to solve an issue assigned by the professor, then presented their solution at the end of the course. Although project 2 involved both FC and CBL, the research looked at the two methods separately.

After the application of both methods, the researchers delivered questionnaires to students at different times of the year to gauge students' perceived knowledge on sustainable development and the circular economy. To assess the FC method, professors viewed the percentage of videos watched and students' responses to the questions. The CBL method was assessed in three ways: 1) by professors, who assessed the teamwork, interactions between groups, and proposed solutions, 2) by external experts, who attended the final presentations of groups, and 3) by students, who completed additional questionnaires to score group individuals work and issues they had with solving the proposed challenge.

Overall, the results show that both FC and CBL methodologies were effective. The researchers found that the two methodologies increased students' acquisition of and motivation to gain knowledge and skills about sustainable development and the circular economy. Despite the benefits of utilizing both methods together, the researchers found that both students and professors preferred the CBL method to FC.

The FC method created an autonomous learning opportunity for students, which left more in-class time dedicated to debates, discussions, and questions for the professor. This method allowed professors to understand students' learning styles, and they were able to adapt their teaching strategies when needed. While there were apparent benefits to the FC method, students and professors identified the additional time required for this course as the biggest disadvantage. The method required too much of student's time outside of the classroom and too much of the professors' time to create new materials and constantly regulate the online materials for the students. Additionally, certain topics did not receive the expected grades, which resulted in the need for additional classes on the topic.

The study found that the CBL method was preferred by both students and professors. Results showed that students acquired skills in group work, leadership, creativity, and planning. Although there were many benefits, the professors identified the largest obstacle for this approach was group work among students. While this was a difficulty, the CBL approach still allowed students to gain the necessary skills in group work and improve upon any issues.

This study had limitations. The small sample and specific location limit the generalization of the results of this study. Also, this study focused on Engineering majors, and may not apply to other fields of study. This study concluded that students and professors preferred the CBL method to the FC method, but only in the context of CBL being utilized in combination with FC. Employing the CBL method only in concurrence with the FC method and not independently could have impacted the results.

The researchers have various recommendations. They believe that a mixed-methods approach with FC and CBL will be the most effective for students to learn and developing skills while simultaneously catering to different learning needs. Additionally, CBL can be integrated more easily than an FC approach and can be considered for various educational programs. While FC is beneficial, programs must consider the time and effort that will be required for this approach. Lastly, programs can utilize these approaches for difficult topics as well as to build problem-solving and group work skills. Overall, the researchers suggest that using a combination of FC and CBL can increase student motivation and competencies related to sustainability and circular economy.