For a long time improving learning and thinking has been an aim of the educational community. Therefore, the VTB project of Midden-Limburg intensively studies the benefits of technological computer applications.The research concerns computer applications which are specified as mindtools. A mindtool is software that delivers knowledge representations of its users mind. The educational value of a mindtool is the possibility to stimulate learners’ generic critical thinking skills while developing content based knowledge and skills. In our opinion, ED is such a mindtool.