The Aqueous Extract of Bela Emília (Plumbago auriculata) flowers as an natural indicator of pH in Investigative Chemistry Teaching

Abstract

This work aims to contribute to the teaching and learning of Inorganic Chemistry through an investigative practice using the natural pH indicator obtained from the flowers of Plumbago auriculata (Bela Emília). The aqueous extract was tested in a range of previously known pH values, encompassing acidic, neutral, and alkaline pH. The activity was structured as a Didactic Sequence, divided into 4 moments: 1) presentation of the theme and previous discussion on acids and bases; 2) reproduction and discussion of a YouTube video on the use of acids and bases in everyday life; 3) investigative experimental part; 4) discussion and evaluation of the experiment mediated by the teacher, followed by the preparation of a final report. With the approach of the aforementioned Didactic Sequence, we hope to make the teaching of Chemistry more attractive, facilitating the guiding process of teaching and learning, and allowing the development of scientific experimentation using homemade, simple, and low-cost materials. Through this educational proposal, the teacher's approach and the involvement of the students can bring positive results, making the learning of Inorganic Chemistry (Acids and Bases) an uncomplicated and enjoyable task, as well as allowing the act of scientific experimentation in the school context, bringing Chemistry more and more into the students' daily lives.