Abstract: Chlorine disinfection is extensively employed in tap water treatment, environmental sanitation, and food preservation owing to its potent antibacteridal properties and cost-effectiveness. However, residual chlorine often persists post-disinfection. The ingestion of such residual chlorine through food and beverages may adversely affect human health, yet public awareness of this hazard remains limited. This study presents a multi-level science communication initiative centered on residual chlorine detection. Utilizing the distinctive colorimetric transition observed in iodometric titration for chlorine quantification as a visual anchor, we developed portable demonstration kits. Supported by complementary educational materials—including pamphlets, informational displays, instructional comics, presentation slides, and versatile testing reagents—we conducted interactive science outreach activities featuring live demonstrations, theoretical explanations, and hands-on participation. Designed for diverse audiences ranging from primary students to the general public, this approach combines easily comprehensible chemical principles with portable equipment, visually striking results, and direct relevance to daily health concerns. The initiative effectively enhances public understanding of residual chlorine safety in water and food consumption, establishing a coherent cognitive framework linking experimental observations, chemical mechanisms, and practical health implications, thereby achieving optimal science communication outcomes.

Key words: Residual chlorine, Iodometric titration, Food safety, Science communication framework