Students learn by doing. Science investigation and engineering design provide an opportunity for students to do. When students engage in science investigation and engineering design, they are able to engage deeply with phenomena as they ask questions, collect and analyze data, generate and utilize evidence, and develop models to support explanations and solutions. Research studies demonstrate that deeper engagement leads to stronger conceptual understandings of science content than what is demonstrated through more traditional, memorization-intensive approaches. Investigations provide the evidence that students need to construct explanations for the causes of phenomena. Constructing understanding by actively engaging in investigation and design also creates meaningful and memorable learning experiences for all students. These experiences pique students’ curiosity and lead to greater interest and identity in science. Science is a way of knowing based on the collection and analysis of empirical data in relation to a scientific question. The growing inclusion of engineering design in K–12 classrooms presents an opportunity for students to learn yet another way of interacting with the natural and designed world around them. When investigation and design are at the center of learning, students can gather evidence and take ownership of the evidence they have gathered. This process contributes to student agency as they make sense of phenomena and designs and extend their understanding of the natural and designed world.