Comparing School Science Explanations in Books and Computer-Based Formats: The Role of Images, Image/Text Relations and Hyperlinks

This paper focuses on the significance for reading practices of differences and similarities in types of images and image-text relations in conventional book and computer-based texts as well as the types of hyperlinks in electronic texts. Explanations of 'the greenhouse effect', 'the water cycle' and 'sound waves' suitable for older elementary and junior high school students were collected from trade books, high school textbooks, CD ROMs and websites. The number and types of images and image-text relations were analyzed for two texts on each topic from each of the four text formats - a total of twenty four texts. Trade books and websites included more images than CD ROMS, and some websites and CD ROMs compositionally foregrounded images as the point of departure for the explanations. There was a marked difference in the use of language within images across the book and electronic versions, while image-'main text' relations seemed to be more influenced by topic. Problematic aspects of the visual modeling of scientific concepts were addressed through the analyses, as were practical pedagogical issues such as the complementarity of dynamic and synoptic representations in images in computer-based texts. Variation in the nature and role of hyperlinks in CD ROM and website contexts are reported and implications for understanding strategic practice in reading to learn from electronic texts are discussed.