The aim of the study is to develop a Web-based teaching material according to “Hypermedia Design Model” which is based on the constructivist approach in the unit “The States of Matter and Heat” taught in Grade 8 and to receive views of students and teachers about the material and Web-based teaching. First of all the educational attainments of the study unit in the new Science and Technology Curriculum were examined. A teaching plan was developed by reviewing literature. Considering the finding from literature a Web-based teaching material was designed. 5 Teachers‟ and 12 students‟ views are taken on the developed Web site. From the research findings, it can be declared that the prepared Web site is sufficient with its forums, sharing documents, online messaging and visuality. Most of the students assessing the Web material agree that the materials which take place in material are adequate especially in terms of visual quality and content. It is stated by the students that they are satisfied and pleased with the activities, experiments, games, animations and such items taken place in the content a lot since that they love to use computer.