Answering a question or proposing an explanation based on evidence gathered from observations and measurements is at the heart of scientific inquiry. To develop this ability, teachers should provide repeated opportunities for students to generate questions, figure out what data must be collected, decide what tools they must use to gather it, and determine the best way to organize and display it. The activities in this issue of Scope will show your students how to properly represent and analyze the data they collect firsthand and to examine and use existing databases and images to craft explanations and make important decisions.