A Jalan Besar parent weighing Primary 6 PSLE Science tuition may hear a confident prediction: reverse an electromagnet’s current and an iron pin will be repelled. The child has remembered that the poles reverse, but attached a result that does not follow for an ordinary iron pin.
This is a useful distinction to examine before choosing a weekday or weekend rhythm. The lesson needs to connect current direction, pole identity and the identity of the nearby object. A known pole of a permanent magnet and an initially unmagnetised iron pin are different comparisons, even when placed near the same electromagnet.
The examples below are illustrative paper tasks using an idealised school model and supplied pole labels. They do not ask families to wire a circuit or carry out a home experiment. Match the work to your child’s actual course, school stage and examination year; choose the schedule around the learning need that exists now.
eduKateSG · Primary 6 PSLE Science · Jalan Besar
Electromagnet reversal: identify the object and poles
Find your next step
Choose a reading route below, or open the chapter index. Each route leads to two expanded chapters; the worked example and independent check use different details.
READING ROUTE 1
Understand the prediction
Separate pole reversal from the response of an iron pin or a known magnet pole.
READING ROUTE 2
Compare lesson days
Use two separate worked comparisons and consider a weekday session.
READING ROUTE 3
Build a return routine
Consider a weekend window and keep unsupported strength claims out of the answer.
READING ROUTE 4
Check changed pole labels
Make fresh predictions and match planning to the actual PSLE course and year.
READING ROUTE 5
Choose the next step
Read the parent questions and bring two explained predictions to the programme conversation.
Open the chapter index · Try the independent check · View the Primary 6 Science programme
Full chapter index
Chapters 1–5: understand the idea and compare lesson days
Chapters 6–10: repair, check and plan the next step
CHAPTER 1 OF 10 · Understand the prediction
1. Locate the missing distinction in the prediction
Ask what object the child expects the electromagnet to repel. If the answer is an iron pin, ask whether the question identified that pin as a permanent magnet with a known pole. This checks the comparison being made before you correct the prediction.
A child may correctly state that north becomes south when current is reversed, then assume that all previous attraction becomes repulsion. The missing step is identifying what is interacting with the electromagnet. Pole reversal alone is not enough to predict the response of every nearby object.
Keep the child’s original explanation. It can show that the current-direction fact is already known while the attraction rule needs repair. A teacher can then build on the secure part rather than asking the child to relearn the entire topic as though every component were equally unclear.
CHAPTER 2 OF 10 · Understand the prediction
2. Connect current reversal to poles, then identify the other object
In the idealised school model used here, reversing the steady current reverses the electromagnet’s north and south poles. TeachEngineering’s University of Colorado electromagnet resource explains this relationship. Our paper tasks supply the resulting pole identities; they do not ask pupils to assume exact behaviour for every real core.
A known permanent magnet pole gives a pole-to-pole comparison: like poles repel and unlike poles attract. An ordinary initially unmagnetised iron pin is a different case. It is attracted near either electromagnet pole in this school model, rather than being repelled simply because the current direction changed.
The NASA magnetism explanation distinguishes attraction of ordinary iron from interactions between magnetic poles. For this guide, keep that distinction focused: identify the nearby object, identify any supplied pole labels and then choose the relevant rule.
CHAPTER 3 OF 10 · Compare lesson days
3. Compare an iron pin with a known north pole
Consider a powered electromagnet with ends P and Q. In state A, P is supplied as north and Q as south. After the current is reversed, state B has P supplied as south and Q as north. The coil, core, geometry and current magnitude are comparable between the two stated steady conditions.
In a first, separate comparison, an ordinary initially unmagnetised iron pin is brought near P. It is attracted in state A and in state B in this model. Reversal changes the pole at P; it does not turn the pin into a fixed north pole that must now be repelled.
In a second comparison, remove the pin and consider a permanent magnet’s known north pole facing P. In state A, north faces north, so repulsion is predicted. In state B, north faces south, so attraction is predicted. The second result changes because this comparison uses a known permanent magnet pole.
| Object facing P | State A: P is north | State B: P is south |
|---|---|---|
| Ordinary initially unmagnetised iron pin | Attraction | Attraction |
| Known north pole of a permanent magnet | Repulsion: like poles | Attraction: unlike poles |
| Measured force magnitude | No value supplied | No value supplied |
CHAPTER 4 OF 10 · Compare lesson days
4. Use weekday tuition to repair the exact mistaken link
A weekday lesson may suit a child who has just encountered this error in current school work. Bring the question and the original prediction. The teacher can separate what reversed, what stayed comparable and what object was nearby before asking for a revised explanation.
Check whether the child has enough attention after school to compare two cases without blending them. A focused session can examine the pin case and the permanent-magnet case separately. If the evening repeatedly produces rushed answers, the family may need a different learning window or a smaller task.
Leave time for a later return with new end letters and a different known permanent magnet pole. The child should be able to rebuild the prediction from the supplied identities. Repeating the exact north-at-P case immediately may only show memory of the teacher’s answer.
CHAPTER 5 OF 10 · Build a return routine
5. Use weekend tuition when comparison needs an unhurried window
A weekend session may help when the child needs to lay the two cases side by side and explain why their predictions differ. The teacher can keep the current reversal common while changing the nearby object, making the role of that object explicit.
Keep the target narrow enough to assess. This comparison does not require a home circuit, calculations of magnetic field strength or a full account of real-core magnetic history. The useful school reasoning is to apply supplied pole labels and distinguish an iron object from a known permanent magnet pole.
Plan a short weekday check after the session. If the child predicts that every attraction switches to repulsion, return to object identity before adding harder questions. If the distinction holds with new labels, the teacher can move on to another current learning need.
CHAPTER 6 OF 10 · Build a return routine
6. Do not turn a polarity question into an unsupported strength claim
Current direction and magnetic strength are related topics, but this paper question asks about pole identity and the type of interaction. The supplied comparable conditions support the stated polarity comparison. They do not provide a measured force value for the pin or permanent magnet.
A pupil should therefore avoid adding that the pin experiences exactly the same measured force in both states unless the question supplies suitable evidence. Likewise, the number of pins lifted is not an exact force measurement by itself. A correct attraction prediction does not require either additional claim.
Teach the child to stop where the evidence stops. A concise answer identifying the poles and predicting attraction or repulsion is stronger than an expanded answer containing an unsupported equality. This habit also helps with other PSLE questions that distinguish a trend from a precise numerical relationship.
CHAPTER 7 OF 10 · Check changed pole labels
7. Try a changed comparison independently
The check below changes the end letters and uses a known south pole in the permanent-magnet comparison. Cover the worked case first. Ask your child to identify the relevant object and facing poles before writing the prediction.
Look for two separate explanations. The iron-pin response should not be justified by pretending the pin has a supplied fixed pole. The permanent-magnet response should explicitly compare the known south pole with the electromagnet end named in each state.
Record any prompt that was needed. If an adult has to say ‘like poles’, the result is supported practice rather than independent retrieval. That is still useful information: the next lesson can work on choosing the rule from the objects and labels without that cue.
Independent check
In an idealised paper model, end R of an electromagnet is south in state 1 and north in state 2 after steady current reverses. Other stated conditions are comparable. First consider an ordinary initially unmagnetised iron pin near R. Predict attraction or repulsion in each state. Separately, remove the pin and consider the known south pole of a permanent magnet facing R. Predict its interaction in each state and explain.
Checking notes
The ordinary iron pin is attracted near R in both states in this school model. Separately, the permanent magnet’s south pole is repelled in state 1 because south faces south, and attracted in state 2 because south faces north. Reversal changes R’s pole; the appropriate prediction also depends on which object is facing it. No exact force values are supplied.
CHAPTER 8 OF 10 · Check changed pole labels
8. Fit the rhythm to the actual PSLE course and year
For the 2026 Standard PSLE Science syllabus, the paper is 1 hour 45 minutes: Booklet A has 30 multiple-choice questions worth 60 marks, and Booklet B has 10–11 structured questions worth 40 marks. All questions are compulsory. Confirm the child’s actual course and year rather than applying this Standard format to Foundation Science or assuming later years are identical.
The presence of PSLE in a programme title does not establish that an examination is still ahead for a particular child. At a later school stage, discuss the learning need that exists now. Avoid building a schedule around an invented countdown or treating every Primary 6 enquiry as the same examination situation.
For this example, progress means a new prediction supported by the correct object and pole comparison. Use the planning table to compare the attention and recall opportunities in your week. Confirm actual lesson availability directly; the guide does not state local venue or timetable details.
| Learning need | Weekday option | Weekend option |
|---|---|---|
| Repair a recent error | Use the marked answer while context is fresh | Bring the original answer to preserve context |
| Keep the two objects separate | Use a focused pair of cases | Allow an unhurried side-by-side comparison |
| Check independent transfer | Return on another day with changed labels | Plan a short weekday check |
| Match current stage | Confirm actual course and year | Apply the same course-and-year check |
Does reversing current make an iron pin repel? Not in the supplied school-model comparison with an ordinary initially unmagnetised iron pin. The electromagnet’s poles reverse, but the pin is attracted near either pole.
Why can the permanent magnet result change? Its known pole allows a like-pole or unlike-pole comparison. If that fixed pole faces an electromagnet end whose identity reverses, the comparison can change from like to unlike, or vice versa.
Must my child work out a real core’s exact strength? No. These tasks supply idealised steady-state pole identities and ask for the interaction type. Exact measured forces and the behaviour of every real core are outside the information provided.
CHAPTER 10 OF 10 · Choose the next step
10. Bring two predictions to the tuition conversation
Bring one original answer and one later attempt with changed labels. Include separate predictions for the pin and the permanent magnet. That gives the teacher a clear way to see whether the child is confusing object identity, misreading a pole label or applying the right rule inconsistently.
In a 3-pax setting, each learner should make and explain a prediction before the group settles on an answer. Discussion can expose useful differences, but a shared final response does not prove individual understanding. Ask how the teacher will check each child with a new comparison afterwards.
See Primary 6 PSLE Science tuition for programme information. Use the eduKate Singapore enquiry page to discuss the actual course, year, current work and family rhythm. Confirm arrangements directly and choose a schedule that supports precise reasoning and independent recall.
Chapter index ↑ · Previous chapter · Programme information →
For a wider comparison of lesson timing and recall, read the weekday versus weekend Science learning-rhythm guide.