A bulb drawn beside a cell does not necessarily form a working circuit. For families exploring schools in Bishan, a useful science task is tracing the whole conducting path and explaining why a gap matters.
Kuo Chuan Presbyterian Primary School’s Science Department describes inquiry-based learning, investigations and questioning that supports reflection. The diagram discussion here is an independent eduKateSG activity inspired by that broad approach, not a reproduction of the school’s lessons.
Keep this activity entirely on paper. Use one cell, connecting wires, one suitable filament bulb and a switch as the imagined components. No sockets, household appliances or battery experiments are needed to practise the reasoning.
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Contents
Explore, practise and connect · Four chapters
CHAPTER 1 OF 4
1. Trace the path through every component
Imagine a simple circuit where a wire connects one cell terminal to one bulb contact, and another wire connects the other bulb contact back to the other cell terminal. The route must pass through the bulb’s filament rather than merely touch its glass.
With a suitable working cell, bulb and good conducting connections, this complete circuit allows current to flow and the bulb to light. State those assumptions: a complete-looking drawing alone cannot prove that a real cell has enough energy or a real bulb is undamaged.
Draw component boxes labelled Cell, Bulb and Switch and join them in one loop. These boxes are a conceptual sketch, not standard circuit symbols. If the child already knows circuit symbols, use the symbols taught in class instead.
CHAPTER 2 OF 4
2. Explain what an open switch changes
Place the switch in the single path between the cell and bulb. When the switch is closed, its conducting contacts join the path. When it is open, a gap interrupts that path, so the bulb does not light in this simple circuit.
The everyday phrase “switch on” can confuse children who expect “open” to mean operating. In circuit language, a closed switch completes the connection; an open switch breaks it. Link the words to the drawing rather than to a door metaphor.
Ask the child to trace the loop with a finger. Where must they jump across a gap? That is the place to explain. Merely listing “cell, wires, bulb” misses the important relationship between the components.
CHAPTER 3 OF 4
3. Distinguish a complete path from a shortcut
Two wires attached to the same bulb contact do not create a path through the filament. A sketch can contain all the expected objects yet connect them incorrectly. Trace through the bulb, not just around the outside of its picture.
Likewise, directly connecting the two cell terminals with a wire is not a suitable bulb circuit. It creates a short circuit and can cause heating. Discuss this only as a diagram error; do not build or test the shortcut.
Keep claims within the one-loop model. Circuits with branches need additional reasoning because one open branch does not necessarily interrupt every other path. Do not turn “a gap anywhere stops this bulb” into a rule for all possible circuits.
CHAPTER 4 OF 4
4. Predict, then name the missing evidence
Prepare two fictional diagrams: A shows a correctly connected single loop with the switch closed; B is identical except that the switch is open. Under the stated working-component assumptions, predict that A lights and B does not.
Now add a third situation: the connections look correct, but the bulb does not light. The drawing alone cannot identify the fault. A depleted cell, faulty bulb or poor connection are possible explanations, not confirmed diagnoses.
Ask the child to complete: “My prediction is… because the path…; I am assuming…”. This joins a claim to a reason and its conditions. Any real investigation should use an appropriate school-approved low-voltage kit under adult guidance; this home exercise ends with the paper explanation.
Sources and scope
School information checked on 16 October 2026 (Singapore time): Kuo Chuan Presbyterian Primary School: Science Department. Programmes may change. Family activities are independently written by eduKateSG, not official school tasks. This article does not imply school endorsement, rank schools or guarantee admission or learning results.
For more local learning connections, explore the neighbourhood school and family learning guide.