English Language Learners (ELL) are capable of high levels of conceptual understanding related to science. However, traditional means of assessment do not typically reflect their understanding of science content. We found through classroom observation and analysis of student products that while ELL students have difficulty writing in English, they can speak about science with a level of sophistication not reflected on written assignments. This mismatch between assessment practices and student understanding is what motivated us as teacher researchers to assess fourth- and fifth-grade understanding of marine environments through drawings.