This chapter presents a case study on Plants That Glow using the discovery engineering process. In this lesson, students explore the process of fluorescence and learn how this light can be used to monitor the health of large numbers of plants. They learn how different organisms use fluorescence and bioluminescence and how these processes differ. They then complete a laboratory investigating fluorescence in spinach leaves. Last, students take on the role of an engineer and design a new monitoring system that is based on fluorescence to monitor the health of plants or animals. This lesson may be taught during a unit on photosynthesis and botany for beginner biology courses. A list of materials, teacher background information, teacher notes, references, resources, assessments, and standards are provided. This book selection also includes the Table of Contents, About the Authors, Acknowledgments, Introduction, and Index.