Experiential learning and geometrical thinking among grade 8 students: A quasi-experimental study

Background: Experiential learning connects concrete experience, reflection, conceptualization, and application. This approach is relevant to geometry learning because students are expected to reason about geometric properties, relationships, and applications rather than merely recognize geometric objects. Aims: This study examines differences in geometrical-thinking improvement between Grade 8 students receiving experiential learning and those receiving conventional mathematics instruction. Method: A quasi-experimental pretest–posttest control-group design was employed with 50 Grade 8 students at SMP Negeri 42 Batam, Indonesia. The participants comprised 25 students in an experimental group and 25 in a control group selected through purposive sampling within existing school-based classes. The experimental group received instruction structured around Concrete Experience, Reflective Observation, Abstract Conceptualization, and Active Experimentation, whereas the control group received conventional instruction. Data were collected using a four-item written essay test assessing geometrical thinking in learning the Pythagorean theorem. Group differences in score changes were analyzed, with baseline-adjusted analysis used as a supplementary analysis. Results: The experimental group showed greater improvement than the control group, with mean gains of 29.75 and 6.50 points, respectively, on a 0–100 scale. The between-group difference in change was significant (t(48) = 3.97, p < .001), with a large effect (Cohen’s d = 1.12). Conclusion: The findings suggest that experiential learning is associated with greater improvement in overall geometrical-thinking performance than conventional instruction. The findings should be interpreted within the limitations of the quasi-experimental design, existing class arrangements, single-school setting, and short intervention period.