In accordance with Parmetros Curriculares Nacionais (PCN): ‘ ‘ The paper of Natural Sciences is to collaborate for the understanding of the world and its transformations, pointing out the man as participativo individual and integrant part of the Universo’ ‘ (BRAZIL, PCN, 2001, p.15) to reach the objectives cited for the PCN, it must beyond planning theoretical lessons, applying practical lessons that they can develop in the pupils a investigativo character in the search for the understanding of the phenomena surround that them. To apply the practical lessons, it must also be planned thus the same ones beyond awaking, keep the interest of the pupils they involve, them in scientific inquiries, and develop established scientific abilities in abilities to solve problems and to understand for itself basic concepts. It is of great importance that the education of sciences has for the pupils as feeling the understanding of the nature main and of the way where they live therefore the practical lessons have great paper in this process, therefore the understanding must be based on the notion of that all the knowledge in natural sciences if drift of the comment and the experimentation and that still it has very to be studied.
Thus, since the beginning of Basic Ensino the pupils must learn to observe, to take off conclusions, to formulate hypotheses, to try and to verify its conclusions. The natural curiosity and the creativity of the pupils must be stimulated. It is important, that the pupil understands phenomena that occur to its redor, reason for which to start for the study of the reality of the pupil is a desirable and efficient attitude. So that everything occurs in correct way and beneficial the good preparation them practical lessons must follow some basic ideas, as for example, the choice of adjusted techniques, the adequacy of the time of the lesson to its execution, the domain of the content and the technique, item these that do not have to be forgotten, moreover, the professor has the duty of with its lesson practical to provoke questionings, quarrels and reflections circa the subject of the lesson, to guide the course of the lesson, looking for not to induce the waited results, beyond knowing that the enthusiasm, the interest and the envolvement of the pupils they depend to a large extent on it.