This work is a part of a PhD thesis with main purpose the consideration of effective educational strategies and curricular changes. In this paper we describe the results on the implementation of web based applications which include inquiry-based methods, educational software, interactive spreadsheets, parametric simulations and quizzes in order to check Lyceum students' ability to relate diagrammatical, graphical, mathematical and verbal representations. The educational and pedagogical value of quizzes and collaborative testing is considered. The design of web based applications is assessed. Finally, educational strategies and curricular changes that support modelling instruction are proposed.