From TeachEngineering - During a power failure, or when we go outside at night, we grab a flashlight so we can find our way. What happens inside a flashlight that makes the bulb light up? Why do we need a switch to turn on a flashlight? Have you ever noticed that for the flashlight to work you must orient the batteries a certain way as you insert them into the casing? Many people do not know that a flashlight is a simple series circuit. In this hands-on activity, students build this everyday hou