The purpose of this article is to explore the way in which the argumentative discourse promotes the comprehension that children of ages 8 to 10 have about variables inherent to the physical phenomenon of bouncing. From a social perspective, it is recognized that peer interaction allows boys and girls to contrast other people’s beliefs with their own ideas and reach agreements that contain validity clauses for all the participants in the situation. Discursive analysis shows how argumentative discourse generates knowledge that rather than being shared, recognizes the convergence of different styles of thought and builds new ways for explaining the physical phenomena.