Argumentation on tasks of Biology and Geology Portuguese textbooks

Argumentation is a transversal dimension to the process of constructing scientific knowledge, which is recognized as increasingly important. The Portuguese official curricula, such as the syllabus of the subject of biology and geology, from secondary education, in recognition of this situation, predicted the involvement of students in learning contexts capable of promoting the development of skills inherent to the process of scientific argumentation. Being the textbooks a mediator of teaching action, it becomes relevant to understand how they may (or may not) contribute to the creation of learning situations that lead students to engage in argument activities in science classes. Thus, hereby we present and discuss the analysis performed on tasks, of two textbooks, one of biology and another of geology, from the 11th grade, adopted at a school where one of the authors teach and the way in which they seek to promote the development of scientific argumentation competencies. The results show some significant differences between the two books reviewed, mainly about how they approach the different themes of the syllabus and the way they try to promote the development of scientific argumentation competencies in students.