This study offers important insights into the coexistence of multiple discourses and the link between these discourses and science understanding. It offers concrete examples of students’ movement between multiple discourses in sixth-grade science fair presentations, and shows how those multiple discourses in science practices illuminate students’ understanding of science and offer insights into how they engage in the complex thinking and communication of the New Literacies. The findings suggest that classroom teachers should recognize and incorporate students’ everyday science talk as a useful tool in instilling basic scientific concepts. Teachers should also help students develop awareness of the value and appropriateness of drawing on life circumstances in talking about science and the benefit of knowing and talking about scientific phenomena along a continuum of science understanding. Teachers should also build their own understandings of the value of discourse in encoding students’ science understandings.