Simple circuit simulator

What this simulator shows

A circuit is a complete loop that electricity can flow around. This simulator shows a series circuit: one loop with cells along the top, bulbs along the bottom and a switch on the side. You can have up to 3 cells and 1 to 3 bulbs, and you tap the switch to open or close it.

The bulbs light only when the switch is closed and there is at least one cell. The glow around each bulb also changes with the set-up: more cells make it look brighter, and more bulbs sharing the same cells make it look dimmer. A short line under the circuit says whether the switch is open or closed, how many cells and bulbs there are, and whether the bulbs are lit.

A note on words

Scientists call a single unit a cell, and two or more cells joined together a battery. In everyday speech, people call a single AA a battery too. Using "cell" in class matches the word on most worksheets and in England's science curriculum.

Why simulate before building

Real circuit kits are the best way to learn, but they come with loose wires, flat cells and bulbs that blow. A simulator lets a child test an idea in a second, reset, and test again. It is a good warm-up before hands-on work and a quick way to revisit the ideas afterwards.

It also targets the misconceptions children bring. Many think electricity flows out of the cell to the bulb and stops there, so a single wire should be enough. Opening the switch and seeing the bulb go dark shows that the loop must be complete. Others expect the bulb nearest the cell to light first or shine brightest, but in a series loop every bulb lights at the same moment and glows the same.

Where this fits in school

• England, Year 4: the national curriculum asks pupils to construct a simple series circuit, name its parts including cells, bulbs and switches, and recognize that a switch opens and closes a circuit.
• England, Year 6: pupils link the brightness of a lamp to the number and voltage of cells, and compare how components work. The curriculum notes that only series circuits are studied at this stage.
• US, grades 3 to 5: elementary science units on energy and electricity often start with getting a bulb to light and testing switches.
• US, grades 6 to 8: use the simulator as a quick model before discussing energy transfer in circuits in more detail.

A 10-minute circuits activity

• Start with 1 cell, 1 bulb and the switch open. Ask: "Will the bulb light if I close the switch?" Then close it.
• Ask the child to make the bulb go out in two different ways. Opening the switch is one; removing all the cells is the other.
• Add a cell. Ask for a prediction first, then compare the glow.
• Go back to 1 cell and add bulbs one at a time. Ask why the bulbs might look dimmer when they share one cell.
• Finish by asking the child to draw the circuit they liked best and label the cell, bulb, switch and wires.

Remind children that real mains electricity is dangerous. Safe circuit experiments use low-voltage cells, never plugs or sockets.

Learning more

Eurekami's skill map includes science alongside math and English, and its lessons draw circuits live in the browser with narration in English or Spanish. Teachers can use the class view to see which science skills need reteaching.