Teaching Sustainable Chemistry & Circular Economy in Lower Secondary Schools: A Comparative Study of Traditional and STEM Methods

The concepts of “circular economy” and “sustainable chemistry” cover a range of related topics, including resource efficiency, the transition to renewable resources, as well as the choice of recycling, reusing, or recovering materials. At the middle school level, the “green message” of chemistry and the circular economy can be conveyed during regular classes or optional subjects. This paper presents an experimental study conducted with middle school students, aiming to develop ecological competencies by comparing traditional educational methods of teaching–learning–assessment with modern methods. The study was conducted on a sample of 58 lower secondary students (N = 30 in class 8A—traditional methods; N = 28 in class 8B—modern/STEM-based methods), using a quasi-experimental pre-test/post-test design using a questionnaire. The results indicated a significant improvement in students’ performance, with correct response rates increasing from 17–33% in the pre-test to over 80–100% in the post-test across most items. While both traditional and modern teaching methods improved students’ theoretical understanding of green chemistry and circular economy concepts, the modern STEM-based approach facilitated higher performance in application-oriented items, critical thinking, and real-life problem-solving tasks. The study emphasizes the importance of fostering an environmentally friendly attitude among students, encouraging a commitment to sustainability, as well as their active involvement in pollution prevention. Thus, the effectiveness of the applied educational strategies in increasing ecological awareness is underlined.