Induced magnetism: iron and steel sim
Lower a bar magnet onto a soft-iron or a steel bar held in a clamp, dip the bar in a dish of paper clips and count the chain it holds, lift the magnet away and count again, read the bar's induced pole on a plotting compass, then magnetise the bars (stroking, d.c. coil), weaken them (hammering) or demagnetise them (heating, a.c. coil) and test them, in a table of your own counts.
Magnetism: induced magnetism, temporary and permanent magnets · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model (chosen, not a measured law). The bar's lower end has a strength set by its material and the magnet's gap, falling as (1 − gap ÷ 60 mm)³ as the magnet is lifted; the end nearest the magnet's pole is the opposite pole. What each bar keeps when the magnet goes, and what each treatment does, are chosen numbers given on the page once your readings open those boxes. Clips held: 10 per unit of strength with a seeded scatter of up to ±(0.3 + 5 %), whole clips, at most 12. The compass sees the bar's lower end as one point pole plus the Earth's field. Nothing runs on its own: every change is one click or drag.
- The bar in the clamp (soft iron or steel): drag it to dip it in the clips
- Bar magnet (N red, S blue), retort stand and clamps, dish of clips, plotting compass, coil and supply, hammer
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
Need a version for your exact set-up? Have one made: US$49 a figure in an order of 5.
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