Impact of Inquiry-Based Labs on Secondary Chemistry Concept Mastery

Thesis Abstract

This study addresses a persistent gap in secondary chemistry education where traditional teacher-directed laboratories may inadequately develop students’ conceptual mastery of core chemistry topics. Despite policy shifts advocating inquiry-based learning (IBL) in science classrooms, empirical evidence linking IBL in lab settings to measurable gains in chemistry concept mastery at the secondary level remains inconclusive, particularly across diverse curricular contexts and assessment formats. The aim is to determine whether implementing structured inquiry-based laboratory activities enhances secondary students’ conceptual understanding of fundamental chemistry concepts compared to conventional cookbook labs. Specific objectives are (1) to quantify differences in conceptual mastery between students engaged in IBL laboratories and those experiencing traditional labs using a validated concept inventory; (2) to examine whether the impact of IBL on concept mastery is moderated by students’ prior achievement, scientific reasoning ability, and epistemological beliefs about science; (3) to explore teachers’ perceptions of feasibility, challenges, and support needs for sustaining IBL practices in routine chemistry teaching; and (4) to identify instructional features within IBL that most strongly predict conceptual gains. The methodology adopts a quasi-experimental, mixed-methods design conducted over a full academic year in three public secondary schools within a metropolitan district. The population comprises Grade 11 chemistry students (n ? 360) and their teachers. A stratified cluster sampling approach yields two matched cohorts per school an experimental group (n ? 180) receiving a sequence of eight IBL-based labs aligned to the chemistry curriculum, and a control group (n ? 180) continuing with standard inquiry or verification labs. Data collection instruments include (i) a validated Chemistry Concept Inventory (CCI) administered pre-, post-, and three-month follow-up; (ii) a standardized Chemistry Reasoning Test to assess analytical thinking; (iii) attitudinal scales measuring epistemic beliefs about science and motivation; (iv) classroom observation rubrics and teacher interviews for process data; and (v) an achievement test focusing on higher-order conceptual reasoning. Instrument validity and reliability are established through content validity checks with domain experts, Cronbach’s alpha above 0.80 for all scales, and inter-rater reliability for observational coding (Cohen’s ? > 0.75). Data analysis uses a sequential explanatory approach. Quantitative analyses include ANCOVA to compare post-test CCI scores between groups controlling for pre-test scores and covariates (prior achievement, gender, socio-economic status), hierarchical linear modeling to account for clustering at class and school levels, and multiple regression to identify moderators (prior achievement, reasoning ability, epistemic beliefs). Structural equation modeling will test a hypothesized model in which IBL influences conceptual mastery directly and indirectly through increases in scientific reasoning and epistemic growth. Qualitative data from teacher interviews and classroom observations will undergo thematic analysis, triangulated with quantitative results, and interpreted within the theoretical framework of constructivist epistemology and the Theory of Scientific Reasoning (as applied to laboratory learning). The study explicitly cites established theories, including Vygotsky’s social constructivism and the Constructivist Learning Theory, with empirical anchors from the 4E framework (engagement, exploration, explanation, and evaluation) adapted to lab pedagogy. Expected findings anticipate that students in the IBL condition will show statistically significant gains in the CCI at post-test (effect size d ? 0.40 to 0.60) relative to the control group, with sustained gains at the three-month follow-up. It is anticipated that the beneficial effects will be moderated by higher initial scientific reasoning skills and more sophisticated epistemic beliefs, suggesting differential benefits for learners. Qualitative results are expected to reveal that IBL enhances metacognitive engagement, collaborative discourse, hypothesis-driven experimentation, and reflective journaling, while teachers report improved student ownership but note implementation barriers such as time constraints, resource availability, and need for ongoing professional development. The study contributes to knowledge by providing robust, contextually grounded evidence on the effectiveness of IBL in improving secondary chemistry conceptual mastery, clarifying under what conditions and for which learners these gains are most pronounced, and detailing actionable features of IBL implementations that predict the strongest outcomes. Practical implications include guidance for curriculum designers, teacher professional development programs, and policy-makers seeking scalable, evidence-based strategies to enhance chemistry understanding. The conclusion emphasizes that well-structured IBL labs, supported by targeted teacher training and resource provision, can produce meaningful, durable conceptual gains beyond traditional lab experiences, with recommendations for staged implementation, continuous assessment, and integration of reasoning-focused objectives within the chemistry curriculum.