Summary: In this research we present the use of some technologies in problem solving activities (at different secondary school grades), aimed at finding a model for a geometric configuration, and representing this model in various ways: through a construction, through a Cartesian graph, etc. The task is part of a teaching experiment, in which students used paper and pencil, and technological tools: a sensor and a calculator (at a lower grade), GeoGebra and TI-Nspire (at a higher grade). We show results in terms of the passage from static to dynamic representations and back, to observe how technology may foster dynamic thinking for students solving mathematical problems. Data suggest that the dynamic features of technology support the genesis of conjectures, and their validation or refutation, along with the choice of independent and dependent variables. Results are used to prepare materials for teacher training in an e-learning Moodle platform (Comenius EdUmatics Project).