What Makes a Circuit Work
Three parts covering everything a simple circuit actually needs, in the order the ideas depend on each other. Start with the loop, because nothing works until the path closes and comes back. Then find out what that loop has to be made of, using the one test that decides every material — including the surprise that pure water insulates. Finish with the battery, which turns out to hold chemicals rather than electricity, and to be finished rather than empty when it dies.
CodePLU Goal
Upgrading Human Mental Models
Learn how to think in Workflows
Why Must an Electric Circuit Be a Complete Loop?
A bulb lights only when charge has an unbroken path back to the battery. Build that loop yourself and find out exactly what one small break does.
What Lets Electricity Through, and What Blocks It?
Conductors and insulators are not about what a material is made of but about whether anything inside it is free to move. Sort four materials by that test.
What Does a Battery Actually Do?
A battery does not store electricity waiting to be used up. It holds chemicals, and it pushes. Build a battery down to what it does at each moment.