Plantas medicinais e o ensino de Ciências Naturais

Abstract

This research aimed to arouse students' interest in chemistry, through the interaction between popular, scientific and school knowledge about medicinal plants in the teaching of Natural Sciences. Two classes of theory and experimental practice on medicinal plants and the study of phenolic substances were prepared. Classes were held with students in the ninth grade of elementary school at a state school in the city of São Gonçalo/RJ, in an urban area. The first class was theoretical, about medicinal plants and Chemistry, and a diagnostic questionnaire was applied that revealed the students' previous knowledge about the use, the name, the form of preparation and the importance of the preparation of medicinal plants. The second class was experimental and an extraction by infusion (tea) of six medicinal plants containing phenolic substances was carried out. The reaction of these substances with an aqueous solution of ferric chloride (FeCl3) forms salts with different colors, enabling a study of colors. At the end of the class, an evaluation questionnaire was applied to ascertain the receptivity of the method, its positive and negative points. The results showed that the students had knowledge about medicinal plants, brought mainly from the family within generations. The activities developed provided an opportunity to raise students' awareness of the presence of chemical substances in medicinal plants, and concepts of Chemistry, Biology and Physics.