Science classes should support students' development of scientific argumentation. While previous studies have analyzed argumentative texts, they have overlooked the ways in which other types of representations, including images, affect the production of such texts. In addition, studies into the use of visual images in science education have…

In asynchronous threaded discussions, messages posted near the end of the week provide less time for students to critically examine and respond to ideas presented in the messages than messages posted early in the week. This study examined how the day in which messages are posted (early, midweek and weekend) in computer-supported collaborative…