Proposta de uma atividade prática investigativa de química orgânica para o ensino médio

Abstract

Chemistry teaching should enable high school students to have a comprehensive and integrated understanding of the chemical transformations that take place in the physical world. For that, it is necessary to prioritize the teaching-learning process in a contextualized, problematizing and dialogic way, stimulating the students' reasoning and leading them realize the importance of Chemistry in the social context. As Chemistry is essentially an experimental science, experimentation can be used to motivate students to learn the contents of this discipline, although it is not always easy to promote it due to the lack or precariousness of laboratories in the school environment. Experimental activities in Chemistry classes can be organized and proposed with different objectives and, although all of them can be valid, the choice of a specific type will depend, mainly, on the objectives to be achieved. Practical investigative activities must have some meaning for the student, avoiding the realization of “practice just for the sake of practice”. Although this type of activity is not easy to plan, it provides remarkable development for students who play an active role in the teaching-learning process. This work aimed to develop and apply a didactic sequence consisting of three practical investigative activities for teaching Organic Chemistry in High School. The activities can be carried out in the classroom and involve the use of easily accessible and inexpensive food dyes and materials to approach: mixtures and substances; homogeneous and heterogeneous mixtures; solute and solvent; concentrated and diluted solutions; ways to express the concentration of a solution (% and mol/L); organic compounds; structural and molecular formulas; capillarity; intermolecular forces (cohesive forces); attractive forces between solids and liquids (adhesion forces); solubility, polarity and organic functions. Due to the Covid-19 pandemic, only the first proposed activity was applied with students entering a Chemistry Degree course in the virtual learning environment, and the results are presented in this work. For the other two activities, proposals are presented for their adaptation and application in the virtual environment.