Electronic textiles (e-textiles) weave computational and electronic components into fabric, enabling students to design and build fabric-based projects that interact with their surroundings. This meshing of physical hardware and virtual software can be difficult for students to untangle when debugging. Is an LED failing to light up because of an error in the circuit, the code, or some combination of the two? Answering this question of hardware vs software can be challenging for students relying on traditional debugging techniques. This is why I developed Circuit Check, an interactive debugging tool that enables students to debug through system exploration and tinkering. In this dissertation I present the development process for Circuit Check, a set of design guidelines for novice-friendly debugging tools, and a framework (Productive Debugging) for evaluating the support a debugging tool provides to both students and their teacher. These three contributions where each evaluated within a formal and informal educational settings, including summer camp programs and high school classrooms. Through qualitative analyses of student observations, I demonstrate the benefits of and need for debugging tools, like Circuit Check, which are designed around the needs of novice students and their teachers. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]