Light It Up

Light It Up is a free circuit-building game. Students wire up the rooms of a house so the lamps, doorbell and heater all work, and try to do it within a budget. Behind the scenes the game solves every circuit the way an electrical engineer would, so the voltages and currents are real. Put two lamps in series and they really do glow dimmer. Draw too much current and the fuse really does blow.

How to play

The house is dark until you wire it up. Choose a part from the toolbar at the bottom, then drag along the dots on the walls to lay it: wire at first, then resistors and thick cable on later levels. Connect every lamp and appliance to the battery, and each room lights up as its lamps start working. Then press Check circuit. Turn on Numbers to see the voltage and current at every part, along with its circuit symbol, and watch the current flow around the wires.

Each level earns up to three stars: one for a circuit that works, two for staying within the budget, and three for matching the cheapest design we know.

The levels

#	Level	Years	Big idea
1	Lights On	8	A complete loop
2	Two Rooms	8	Series vs parallel brightness
3	The Hall Switch	8–9	Switches in branches
4	Twelve Volts	9	Voltage shared in series
5	Pick the Resistor	10	Ohm’s law, resistors in series
6	Two Fuses	10–11	I = P ÷ V, currents add in parallel
7	Smart Doorbell	11–13	Potential dividers and loading
8	Power to the Shed	12–13	Cable resistance and losses

Tips for teachers

• Years 8–9: before anyone presses Check, ask the class to predict which lamp will be brighter, and why. Levels 1–4 make series and parallel easy to see.
• Years 10–11: in levels 5 and 6, ask students to work out the resistor or the fuse current on paper first, then build it and check with the Numbers button.
• Years 12–13: Smart Doorbell shows why a potential divider’s output drops when you connect a load, and Power to the Shed shows why long cables waste power.

Every level ends with a short “What you learned” summary you can use as a plenary.