Argumentation is now seen as a core practice for helping students engage with the construction and critique of scientific ideas and for making students scientifically literate. This article demonstrates a negotiation model to show how argumentation can be a vehicle to drive students to learn science's big ideas. The model has six phases: creating a testable question, conducting an investigation cooperatively, constructing an argument in groups, negotiating arguments publicly, consulting the experts, and writing and reflecting individually. A fifth-grade classroom example from a unit on the human body serves as an example to portray how argumentation can be integrated into science classrooms.