Mammoth Memory

Proving which way magnetic lines on a magnet travel

If you sprinkle iron filings around a magnet, the small iron filings react to the magnetic forces and position themselves along the magnetic lines.

Iron filings sprinkled around a magnet.

To find which direction the magnetic lines travel, take a small compass and place the compass near one pole of the magnet and mark the positions of the ends N and S of the compass needle with pencil dots. Then move the compass until the end of the compass is over the second dot and mark the new position of the other with a third dot. Repeat this as many times as you can until you reach the other pole.

Magnetic lines going north to south.

Dots showing magnetic field

We can now join the dots up.

Joined up dots showing magnetic field

This shows a field line of the magnetic field.

Magnetic field lines of a bar magnet

If we keep plotting the field line around the magnet you should get the magnetic field plot above.

Magnetic field lines of a horse shoe magnet

If you plot the field lines around a horseshoe magnet you should get the magnetic field plot above.

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