Cosmetic Chemistry as a Pedagogical Domain: Enhancing Pre-Service Teachers' Practical Skills and Self-Efficacy through Authentic, Scaffolded Learning

Abstract

This study examines the effectiveness of authentic, scaffolded learning implemented through a digitally supported project based approach in enhancing pre-service chemistry teachers' practical skills and self-efficacy within a cosmetic chemistry course. While project-based learning and digital tools are widely used, limited research has explored how their integration operates within domain-specific, applied contexts. Cosmetic chemistry, as a product-oriented and constraint-driven domain, offers distinct pedagogical potential for such integration. A quasi-experimental post-test-only control group design was conducted with 63 pre-service teachers. The experimental group engaged with a digitally scaffolded PjBL e-module, while the control group received conventional instruction. Practical skills were assessed through structured performance observation, and self-efficacy was measured using a validated Likert-scale questionnaire (r = 0.585-0.712; Cronbach's α = 0.852). Independent samples t-tests revealed significant differences in both practical skills and self-efficacy (p < 0.001), with large effect sizes (d = 1.24 and 1.35, respectively). The findings indicate that the intervention supported not only procedural performance but also evaluative and decision-making aspects of laboratory competence, alongside increased confidence in task execution. Importantly, the results demonstrate that cosmetic chemistry functions as a pedagogical domain that actively shapes learning through its product-oriented and constraint-based characteristics. This underscores the importance of aligning pedagogy, scaffolding, and domain-specific context in designing effective chemistry learning environments.