THE IMPORTANCE OF PRACTICAL CLASSES IN CHEMISTRY EDUCATION: AN APPROACH USING ACID-BASE INDICATORS

Abstract

This article reports on an experimental activity involving acid-base indicators, conducted with first-year high school students at the Colégio Estadual de Tempo Integral Professora Elineuza da Silva Ferreira in Belo Campo, Bahia. The activity served as a strategy to relate concepts of acids, bases, and pH indicators to the students' everyday lives. This qualitative experience report details a two-stage process: the first stage involved using red cabbage extract as a natural indicator to analyze various household and laboratory substances; the second stage featured the "Devil's Blood" experimental demonstration, using phenolphthalein as an indicator. Throughout the activities, students formulated hypotheses, observed color changes in the solutions, and discussed the underlying chemical phenomena. Analysis of the reports produced at the end of the activity revealed that the majority of students correctly identified the behavior of the acid-base indicators and grasped concepts related to pH variations. The study concludes that the use of simple, accessible, and contextualized experiments fosters the integration of theory and practice, encourages active student participation, and contributes to a more dynamic and meaningful teaching-learning process.