Experimentação com viés investigativo para o ensino de cinética química

Abstract

The teaching of chemistry still values calculations and the memorization of mathematical formulas and nomenclatures of compounds, which causes a high level of rejection of Chemistry by high school students and has a negative impact on the teaching-learning process. Experimentation can contribute to making Chemistry more interesting and attractive to students and result in effective learning as long as experiments that require the active participation of students are proposed. This goal can be achieved by using an investigative experimentation approach, in which the teacher acts as a mediator of the process. Unlike traditional experiments, in investigative experimentation the student has the possibility to analyze problem situations, collect data, elaborate and test hypotheses, argue and discuss with colleagues. Chemical kinetics enables the experimental evaluation of the influence of certain factors on the speed of chemical reactions and therefore it is a content that enables an approach based on investigative experimentation. This work proposes to evaluate the use of investigative experimentation to approach chemical kinetics in high school through two carbon dioxide detachment reactions: the reaction between sodium bicarbonate and vinegar and the thermal decomposition of sodium bicarbonate. The research showed that experimentation is capable of motivating students to participate in the activity attentively and by taking detailed notes. In the diagnostic evaluation, the students presented inadequate scientific vocabulary, but were able to report the experimental observations satisfactorily. The teacher played a crucial role in directing the experiment and presenting the content after the practice. This work provided the elaboration of a didactic sequence that can be used by teachers of Basic Education in the approach of the content of chemical kinetics to students.