This article examines the ways in which four focal English Learners (ELs) in an eighth-grade sheltered science classroom used visual and written resources in a unit on watersheds. The students first recorded their observations about stream tables through open-ended drawing and writing. Their own ideas were evident in these responses, but subsequent tasks directly referenced photocopied visual material. As a result, the students directly replicated the distributed diagram and graphic organizer. This impeded conceptual cohesion across the unit as reflected in the students' visual and written responses to tasks that were based on teacher-provided resources. This article concludes that, in sheltered science classrooms, visual and written modes must be enlisted as meaning-construction resources, not simply as meaning-reproduction resources, if they are to mediate science understanding.