Science journals are wonderful tools. They offer a glimpse into children's science understandings, and they are both diagnostic and pedagogically informative to teachers. Examining and reflecting on children's journal work lets teachers embed assessment in curriculum and instruction; however, effectively analyzing children's journal writing and drawing takes practice. Over the past few years, as teacher-educators involved in the Children's Literacy and Science Project (CLASP), a research and professional development program funded by Toyota USA Foundation, the authors have taught teachers how to improve their understanding of children?s journal responses, what to look for in children's responses and what these responses reveal about students levels of understandings, and how these responses can guide subsequent instruction.