Selective Cognitive and Affective Benefits of 3D-Printed Bacteriophage T4 Models in High School Molecular Biology Instruction: A Quasi-Experimental Study

Teaching abstract molecular concepts poses persistent challenges in high school biology education. This study evaluated a custom-developed three-dimensional (3D) bacteriophage T4 model for teaching the Hershey-Chase experiment in a Grade 11 classroom. Using a quasi-experimental design, 92 students were assigned to either model-based instruction ( n = 46) incorporating hands-on assembly of a disassemblable 3D-printed phage model, or conventional instruction ( n = 46). Pre- and post-intervention questionnaires assessed conceptual understanding and affective outcomes. ANCOVA revealed no significant overall cognitive difference between groups, F _{(1, 89)} = 1.42, p = 0.237. However, item-level analysis showed the model group significantly outperformed on structural component identification (52.2% vs 26.1%, p = 0.018, ϕ = 0.27). Affective outcomes significantly favored the model condition, including lesson enjoyment ( p = 0.038), model construction interest ( p = 0.028), perceived knowledge mastery ( p = 0.033), perceived instructional utility ( p = 0.028), and modeling skill need ( p = 0.049). These findings suggest that curriculum-aligned 3D model-based instruction selectively enhances representational competence for spatially complex concepts and improves situational affective engagement.