This research focuses on knowledge and ways in which knowledge may be constructed in the learner's mind. Specifically, it addresses the Web as a cognitive supporter for learning, organising and constructing a new domain of knowledge. In particular, the research analyses student reflection on constructing web sites. The analysis is based on an ongoing reflection of 40 prospective and in-service teachers who took a course on educational computational environments. The students were asked to choose a complex topic and to document the process of constructing a web site that would present their chosen topic. They were to reflect upon the process with regard to their decision making, difficulties encountered, ways of thinking, considerations and insights. Student reflection is analysed from two perspectives: the first perspective examines how the task of constructing a web site contributes to student learning of complex topics, the second perspective views the students as teachers who explore how constructing a web site contributes to their understanding of learning processes.