Magnetic Poles Simulation – Non contact force — Description & Class Activity
What the Simulation Does
A full-screen interactive simulation of magnetic poles with three tabs, each showing a different scenario. All magnets are draggable — grab either magnet and move it anywhere on the canvas to see the field lines update live.
🟣🔵 Unlike Poles Attract
Two bar magnets face each other with opposite poles — the S face of the left magnet meets the N face of the right magnet. The magnets animate rhythmically toward each other showing attraction. Purple field lines arc through the gap and loop around the outside, traced by real dipole field integration so they fan out naturally and never cross. Purple arrows show the attractive force pulling each magnet inward. Drag either magnet — the animation pauses and the field lines recompute live from the new positions.
🔴🔴 Like Poles Repel
Both magnets face North-to-North. They animate pushing apart. Orange field lines leave each N pole, bow outward away from the gap, loop around the magnet body and re-enter the S pole on the far side — computed from the combined field of both dipoles so the lines naturally deflect away from the opposing N pole. Orange force arrows on the outer faces show the magnets being pushed apart. Drag either magnet to explore what happens as they get closer or further apart.
🟢 Field Lines
A single bar magnet at the centre. Green field lines fan out from the N pole, arc through space and curve back into the S pole — 18 lines traced from the dipole equations. Animated arrowheads flow along the lines showing direction. Move the cursor anywhere on the canvas and a floating compass needle appears, its red N-tip aligning with the real field direction at that point, calculated live. Drag the magnet anywhere on the canvas and the field lines and compass both update instantly.
Suggested Class Activity
“Poles Apart” — Investigate & Explain KS3 Physics / AQA GCSE P7 · Magnetism · 25–35 minutes · pairs
Learning Objectives
- State the rule for magnetic poles — unlike poles attract, like poles repel
- Describe the pattern of magnetic field lines around a bar magnet
- Explain what field lines show about strength and direction
- Use a compass to determine field direction at a given point
Starter — Predict First (3 min)
Before opening the simulation, pose this question verbally or on the board:
Two bar magnets are brought toward each other. Magnet A has its North pole facing Magnet B’s North pole. What will happen? What will the space between them look like?
Students write a prediction in one sentence and sketch what they think the field lines look like.
Part 1 — Explore Each Tab (12 min)
Students work in pairs through these questions, one tab at a time:
Tab 1 — Unlike Poles Attract
- Describe what happens to the magnets. Which faces are attracted to each other?
- Sketch three field lines you can see. Mark the direction with an arrow.
- Where are the field lines closest together? What does this tell you about the field strength there?
- Drag the magnets closer together. What happens to the field lines in the gap?
Tab 2 — Like Poles Repel
- Which poles are facing each other? What happens to the magnets?
- Sketch the field lines around one magnet. Where do they start and where do they end?
- Drag the two magnets very close together. Describe what the field lines in the gap look like compared to Tab 1.
- What is different about the force arrows compared to Tab 1?
Tab 3 — Field Lines
- Move your cursor to different positions around the magnet. Which way does the compass needle point near the N pole? Near the S pole?
- Move the cursor to a position directly above the magnet, halfway along its length. Which way does the compass needle point now?
- Drag the magnet to a corner. Do the field lines still behave the same way?
- Complete this rule: Field lines leave the ___ pole and enter the ___ pole.
Part 2 — Record and Explain (8 min)
Students complete this table from memory after closing the simulation:
| Unlike poles | Like poles | |
|---|---|---|
| Force | ||
| Field lines in the gap | ||
| Field lines outside | ||
| What happens as magnets get closer |
Then write one sentence answering: Why do field lines never cross each other?
Part 3 — Challenge Questions (5 min)
“A compass needle placed between two unlike poles always points from S to N along the field line. Explain why the needle aligns this way rather than pointing in a random direction.”
“Two bar magnets are placed end to end with N facing S. A student says the field between them is twice as strong as a single magnet. Evaluate this claim using what you saw in the simulation.”
“If you cut a bar magnet in half, each piece becomes a new magnet with its own N and S pole. Explain what this tells us about magnetic poles and whether a magnetic monopole can exist.”
Part 4 — Consolidate (5–7 min)
Teacher projects the field lines tab and drags the magnet to an unexpected position — off-centre, near a corner. Asks:
- Point to where the field is strongest. How do you know?
- Place your mental compass here — which way would it point?
- What would a real compass needle do if I moved it slowly from the N pole around to the S pole?
Students then compare their original prediction sketches to what they saw and identify one thing they got right and one thing they would change.
Differentiation
| Need | Adaptation |
|---|---|
| Visual stress / Irlen | Open Accessibility → choose a colour overlay |
| Colour vision deficiency | Accessibility → Deuteranopia or Protanopia mode |
| ADHD / distractibility | Accessibility → reduce motion (freezes animation, students explore by dragging) |
| Low vision | Accessibility → high contrast + text scale to 140% |
| Dyslexia | Accessibility → dyslexia spacing + larger text |
| Lower ability | Provide a pre-drawn outline of a bar magnet and ask students to add three field lines from the simulation, labelling N, S and direction |
| Higher ability | Ask students to predict and then verify: what would the field lines look like between a N and S pole that are offset vertically rather than horizontally? (drag Tab 1 magnets to test) |