Teaching Magnetism (Grades 7-9): Field Lines, the Compass, and Simple Experiments

Magnets fascinate, and they are perfect for discovery learning. This in-depth guide shows how to teach magnetism in grades 7 to 9 with simple experiments, from poles and forces through field lines and Earth's field to the domain model, with ready material at the end.

Poles and forces

First, students clarify which materials a magnet attracts: ferromagnetic materials, above all iron, also nickel and cobalt. Then comes the force rule: like poles repel, unlike poles attract. A nice aha moment: break a bar magnet and you get two whole magnets, each with a north and south pole; a single pole (monopole) does not exist.

Making the field visible

Iron filings make the invisible field visible. Students draw field lines and discover the rules: outside the magnet they run from north to south; where they are dense (at the poles) the field is strong; and they never cross. The field-line picture is thus a precise tool to represent the field's strength and direction.

Earth's field and the compass

Why does a compass needle point north? Because Earth itself is a giant magnet. The freely turning needle aligns along Earth's field. This connection links physics with geography and navigation and is highly motivating, for example with the question of how sailors once found their way.

The domain model

The domain model explains magnetizing clearly: imagine many tiny magnets in the material. Disordered, their effects cancel and the material is unmagnetic. Align them (by stroking with a strong magnet) and the material becomes a magnet. Strong heating or hammering scrambles the domains, and the material is demagnetized.

Experiments that stick

• Test materials with a magnet (what is attracted?).
• Make field lines visible with iron filings and draw them.
• Find directions with a compass.
• Magnetize a paper clip and demagnetize it again.

Safety and material tips

Bar magnets, horseshoe magnets, compasses, and iron filings (best in a tray or sleeve) are enough for impressive experiments. Use strong neodymium magnets with care, pinch risk, and keep them away from devices.

Ready material

The complete unit includes a workbook, a jigsaw, picture cards, a slide deck, and an answer key:

• Magnetism: Poles, Magnetic Field, Compass & Domains
• Part of the Electricity & Magnetism bundle (12 lessons)

Frequently asked questions

Which experiments are essential? Iron filings for the field lines and a compass for Earth's field.

Are neodymium magnets suitable? Only with care, pinch risk, and keep away from devices.

What comes after magnetism? Logically electromagnetism: current makes magnetism.

Why does heating weaken a magnet? The aligned domains scramble and their effects cancel again.

How do you explain that there is no single pole? Through the break test: one magnet becomes two whole magnets.

Can this be cross-curricular? Yes, with geography (navigation, aurora) and history (compass and seafaring).