The Sorceress of Circuits:
A Steampunk Electricity Adventure
This is choose-your-path story you read in a browser. (The story and puzzle options are clickable.) You make choices and solve puzzles along the way, building an intuitive and conceptual understanding of the fundamentals of electricity. It’s aimed at ages 10-12.

What’s great about this format is that it gives kids instant feedback on whether they solved a puzzle correctly, which is one of the biggest things that improves learning outcomes.
This would be a great introduction to a circuits unit. You don’t need to have studied anything before you start. You can buy one copy of the game and play it again and again on as many different devices as you’d like. (So, one copy works for a full class.)
Topics Covered
Conductors and Insulators
Current, Voltage, Resistance
Lemon Batteries
Parallel and Series Circuits
How to Play
The game is an HTML file that you download and then open in your browser. It works on any laptop or desktop, but NOT tablets or phones.