The pedagogy of multiliteracies has expanded K-12 students' avenues to communicate disciplinary knowledge. Arts-based literacies, as one such channel, enhance cognitive and linguistic skills, particularly for bi/multilingual learners in science. Yet, teachers may overlook artistic responses as learning evidence, potentially marginalizing learners. This chapter explores ways to value artwork as evidence of learning in content-area classrooms by analyzing how 11 Grade 2/3 bi/multilingual children in Western Canada express their understanding of the water cycle through embodied performances and collages. Thematic and visual/multimodal analysis reveals that the children combined narrative and informational discourses to convey scientific knowledge. Through mediated interviews, science learning was assessed with probing questions connecting students' identities with content knowledge. Ultimately, the chapter underscores the power of arts-based literacies for students to express their scientific knowledge and position themselves as knowledge creators.