Abordagem do ciclo do nitrogênio nas aulas de ciências : o livro didático e as necessidades do professor

Abstract

The science curriculum has undergone great changes in the past decades due to the constant transformations of the society and its consequent scientific advance. It is possible to perceive, in this current panorama, that as to ideas there is an evergrowing evolution, however, as to actions much remains to be done. This study focuses as a topic on the existing teacher`s dependence on the textbook to approach a certain subject matter in the classroom, being the focus of this paper on the Nitrogen Cycle. Its main purpose is to know if science textbooks have an adequate approach to the aforementioned cycle, so that it meets the teacher`s needs. This subject matter was select based on the uderstanding that its study is of the utmost importance, since the energetic balance in nature, the maintenance of nutrients in the soil and the formation of nitrogenous compounds vital to the organic structure of living beings depend on such a cycle. In the classroom, the study makes understanding such phenomena possible, but the teacher should above all, identify the relations between different scientific concepts of diferrente areas involved in this cycle. The research work was carried out at first, through the analysis of the science textbooks recommended by the Textbooks Guide 2005, considering that, supposedly, upon being apprived and suggested by the National Textbooks Program, they are already qualified to be adopted by teachers. Finally, teachers thoughts were analyzed through written comments on statements related to the subject. From this research we reached the conclusion that there are different limits to approach the Nitrogen Cycle, both in textbooks and in teachers presentation. However, this conclusion is not enough to solve a real problem; it is believed, however, that becoming aware of the existence of this set of problems and understanding what brought it about tend to make a possible solution to this question less distant and less conflictive.