This article presents a tool that teachers can use to support children in planning science investigations. Using an extended example from a second-grade investigation into seed dispersal, we describe strategies for structuring conversations that anchor investigations in phenomena and provide opportunities for students to be involved in making decisions about what materials to use in an investigation, how to use materials, and what to look for or count as evidence. These teaching strategies can support children to engage deeply in science practice, while also keeping activity manageable for students and their teachers. Our goal is that this article will provide teachers and curriculum designers with a tool that they can use to support children to engage in joyful, meaningful, and productive science investigations.