Development of an inquiry-based module to teach acid-base titration concepts using green chemistry indicators in high school chemistry classrooms

Project Abstract

This study reports the design, implementation, and evaluation of an inquiry-based teaching module for acid-base titration integrated with green chemistry indicators to enhance conceptual understanding, scientific reasoning, and practical laboratory skills in high school chemistry classrooms. Grounded in constructivist learning theory and evidence from chemistry education research on inquiry-based learning and students’ misconceptions about titration, the module centers on hands-on experiences, collaborative experimentation, and reflective discourse. The module introduces students to acid-base theory, pH concepts, acid-base indicators, and stoichiometry through a sequence of guided investigations that culminate in authentic titration experiments using environmentally friendly indicators such as natural dyes and universal indicators derived from plant extracts. A mixed-methods design was employed across three urban high schools with diverse student populations to examine learning outcomes, engagement, and attitudes toward green chemistry practices. Quantitative data were collected via pre- and post-tests assessing conceptual understanding of acid-base equilibria, equivalence point determination, buffer action, and indicator colorimetric reasoning. Practical assessments evaluated procedural fluency, data interpretation, and error analysis, while a rubric measured scientific communication and collaboration in group tasks. Qualitative data included classroom observations, student think-aloud transcripts during inquiry cycles, and semi-structured interviews with teachers and students to capture affordances and challenges of implementing the module, as well as perceptions of green indicators’ reliability and sustainability. Triangulated results indicate statistically significant gains in conceptual mastery of titration concepts (p < .05) and improvements in students’ ability to justify indicator choices, interpret titration curves, and explain the role of green chemistry in reducing hazardous waste. Students demonstrated heightened inquiry skills, including formulating testable questions, designing simple experimental controls, and engaging in evidence-based argumentation during post-lab discussions. Critical factors influencing success were identified alignment of learning objectives with assessment tasks, explicit instruction on uncertainty and error analysis, collaborative structuring of inquiry cycles, and accessible scaffolds for interpreting color changes with color-blind accommodations. The use of green chem indicators enhanced student motivation and perceived relevance to real-world sustainability challenges, although variability in indicator sensitivity required careful protocol adjustments and teacher facilitation to ensure accurate interpretation of results. The module’s scalability was explored through digital simulations and reusable teacher resource packs, enabling implementation beyond the study contexts. The discussion highlights how inquiry-based approaches, when integrated with green chemistry indicators, promote deeper understanding of acid-base titration concepts, foster scientific literacy, and model sustainable laboratory practices. Recommendations for classroom implementation include phased scaffolding of inquiry, professional development on green indicators, and iterative assessment that emphasizes conceptual reasoning over procedural reproduction. The study contributes to chemistry education by providing empirical evidence and a practical framework for delivering environmentally conscious, student-centered titration instruction that aligns with modern curricular expectations and sustainability goals.

Project Overview

What This Project Is About

---

A plain-language overview of the topic and what the project investigates.

---

---

The Problem It Addresses

---

What problem or gap this project tackles and why it matters to the field or society.

---

---

Objectives of the Project

---

1. Introduce students to acid-base titration concepts using a hands-on, inquiry-based approach.
2. Evaluate green chemistry indicators as safer alternatives to traditional indicators.
3. Develop a teaching module that aligns with high school science standards and fosters critical thinking.
4. Assess student understanding before and after the module to measure learning gains.
5. Provide practical guidance for teachers on implementation and classroom management.

---

What You Will Do Step by Step

---

1. Review existing acid-base titration teaching methods and identify gaps.
2. Select safe, eco-friendly indicators and design inquiry activities around them.
3. Develop instructional materials, student worksheets, and assessment rubrics.
4. Pilot the module in a few classes and collect feedback from students and teachers.
5. Analyze data on student learning outcomes and engagement using simple statistical tools.
6. Revise materials based on results and create a final teaching package.

---

---

Expected Outcome

A ready-to-use teaching module that improves understanding of titration concepts while promoting safer, greener lab practices. The project should produce clear assessment results showing improved student proficiency and ideas for scale-up in schools.