What are switches used for on specific machines? Why are circuits needed to power certain devices? Questions such as these are answered as readers explore the science behind switches and circuits. Readers are given basic examples of these devices, along with simple scientific explanations of how they work. The well-researched text, detailed diagrams, and helpful fact boxes contribute to making this common science curriculum topic easily understandable for young learners. The vibrant, full-color photographs also give sharp visual depictions of the STEM concepts mentioned in the text.