The guiding question of this investigation is, How can we predict how much the temperature of 100 ml of water will change when we add different amounts of hot water to it? In this lesson, the goal is to figure out a way to predict how much the temperature of 100 ml of room-temperature water will change with different amounts of hot water added. To accomplish this goal, students need to find a pattern in the data collected and then determine a mathematical rule that can describe the pattern. The Teacher Notes provide connections to the standards, a timeline, safety notes, information on materials and preparation, and step-by-step instructions for facilitating the lesson and assessing student outcomes. After the Teacher Notes, you will find classroom-ready reproducible pages in the form of an Investigation Handout and Checkout Questions. Before you begin the lesson, we recommend reading Chapters 1 and 2, which are in this book selection. Chapter 1 provides an overview of Argument-Driven Inquiry (ADI) with an explanation of what happens during each of the eight stages of ADI, which are the same for every ADI investigation. Chapter 2 focuses on the investigations and how to use them, not to replace an existing science curriculum, but rather to function as a tool that teachers can use to integrate three-dimensional instruction into their existing curriculum. Also included in the book selection are the Table of Contents, Preface, Acknowledgments, About the Authors, Introduction, and Index.