Sequência de ensino investigativa no ensino de soluções químicas

Abstract

The teaching of Chemistry should enable high school students to have a comprehensive and integrated understanding of the chemical transformations that occur in the physical world. To achieve this, it is necessary to prioritize the teaching-learning process in a contextualized, problematizing, and dialogical manner, stimulating students' reasoning and helping them recognize the importance of Chemistry in the social context. Since Chemistry is essentially an experimental science, experimentation can be used as a way to motivate students to learn the content of this discipline, although it is not always easy to promote it due to the lack or poor condition of laboratories in the school environment. Experimental activities in Chemistry classes can be organized and proposed with different objectives, and although all may be valid, the choice of a specific type will mainly depend on the goals to be achieved. Investigative practical activities must have some significance for the student, avoiding "practice for practice's sake." 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 investigative practical activities for teaching Chemical Solutions in high school. The activities can be conducted in the classroom and involve the use of simple materials or substitutes in case there is no laboratory or equipment available. The didactic sequence aims to answer, through an active methodology such as the Investigative Teaching Sequence (ITS), grounded in experimental activities with different levels of openness, the research question: "Is determining the average solubility of potassium chloride at the temperatures of our region, which is rich in vineyards, important for farmers and consequently for the local economy? Therefore, what is the solubility of potassium chloride between 5 ºC and 15 ºC? How can these low temperatures affect the purpose of fertilization?" Finally, considerations on the success of the investigative approach reveal that the methodology helped promote students' curiosity and engagement, understanding of the concepts involved in solutions, use of chemical language, and comprehension of quantitative aspects. Furthermore, reinforcing activities that promote molecular visualization, such as computational simulations and graphical representations, can be an effective strategy to overcome the learning difficulties still observed in understanding the microscopic levels of molecules in this study and reported in the literature. [resumo fornecido pelo autor]