This study focuses on how the combined use of graphic calculators with connectivity software promotes the social construction of mathematical knowledge. Particular emphasis is placed on the aspects related to design, development, implementation, and evaluation of didactic activities that integrate these technologies. We use Didactical Engineering (DE) and Realistic Mathematics Education (RME) as frames of reference. Twenty, eighth grade students from a private institution in the metropolitan area of San Juan, Puerto Rico participated. The topics discussed were those related to the conic sections as geometric loci. The results show that the careful planning of graphing calculator integrated with a system of connectivity in the classroom promotes the discussions and reflections of students. These reflections provide insight as to how students engage in the social construction of mathematical knowledge. In addition, students showed that they could reflect on powerful mathematical ideas and acquire meaningful knowledge.