Effects of the iterative TIMS framework on conceptual understanding and scientific practices in Grade 11 physics

This action research examined the association between the Try–Improve–Measure–Stretch (TIMS) instructional taxonomy and Grade 11 students’ conceptual understanding and scientific practices in physics. Using a quasi-experimental mixed-methods design, 145 students in an American-curriculum school (intervention n = 87; comparison n = 58) participated in a 12-project sequence during the 2025–2026 academic year. The intervention group engaged in iterative TIMS cycles, while the comparison group completed single-cycle project-based tasks. Pre–post assessments aligned with AERO standards, artifact analysis, and student logs were analyzed. The TIMS group showed substantial improvement (Cohen’s d = 2.21; Hake’s gain = 0.59) compared with modest gains in the comparison group (d = 0.47). An ANCOVA controlling for pretest scores confirmed that post-test differences between groups remained statistically significant (F(1, 142) = 89.4, p < .001, η2 = .39). Depth of TIMS engagement correlated positively with achievement gains (r = .71, p < .01). Qualitative findings, supported by inter-rater reliability of κ = .83, indicated stronger quantitative reasoning, iterative model revision, and improved transfer to applied contexts. Stage-level analysis revealed that 91% of experimental students completed quantitative measurement tasks (Measure phase), while 68% successfully extended their models to real-world sustainability contexts (Stretch phase); the remaining 32% are discussed as evidence of the greater cognitive demands of far transfer, with implications for scaffolding. Results are interpreted as consistent with the hypothesis that structured iterative refinement is associated with enhanced inquiry-based physics learning within regular classroom settings; causal inference is constrained by the quasi-experimental design.