In this chapter, we first review the two dominant accounts from the 1990s of the role of writing as a learning tool in science, including relevant classroom-based research, as a basis for analysing current research agendas in this area. The increased use of new technologies to practice science and represent processes and findings, linked to recognition of the multi-modal nature of science as a discourse, has led to new accounts of the role of writing in learning science at school. Current studies have begun to shift emphasis from pedagogical conditions focused only on writing to examining how writing relates to other representational modes in the learning process. This expanded view of the role of the languages of science as learning tools requires carefully constructed research studies of appropriate pedagogical strategies to support student learning about modal interdependency.