When one decides to design on-line educational materials, he have to bear in mind multiple dimensions, such as the non-linearity of the hypertext, the use of embedded multimedia languages and the interactivity between learners and educational tools. The Internet and the Information and Communication Technologies provide a challenge to develop all these dimensions in order to enhance web-based learning. The AFINET project (Learning of Physics through the Internet) is intended to know which transformations of a classic linear text on Physics education need to be done to develop hypertextual materials.