Why do magnets attract or repel each other?
Short answer: every magnet has a north and a south pole. Opposite poles (north facing south) attract each other, while like poles (north-north or south-south) repel each other. When attracting, the magnetic field lines of one magnet continue into the other; when repelling, the fields push against each other. Both forces become rapidly stronger as the magnets get closer together.
Attraction or repulsion: overview
| Combination | Result |
|---|---|
| North – south | attract |
| North – north | repel |
| South – south | repel |
| Magnet – steel (any pole) | always attract |
Steel is attracted by every pole because it temporarily becomes a magnet with an opposite pole. See how does a magnet work? Repulsion is therefore the only real proof that something is a magnet.
Why does the force become so much stronger so quickly?
A magnet's field decreases rapidly with distance. At close range, the force between two magnets is therefore many times greater than at a distance of a few centimetres. This is why magnets feel nothing until they are just a few centimetres apart, at which point they snap together with force. With large neodymium magnets, this can pinch fingers and cause the magnets to shatter.
How do you find the north and south poles?
- With a compass: the north end of the compass needle points to the south pole of the magnet.
- With a marked magnet: a known north pole repels the north pole of another magnet.
- With a smartphone: a magnetometer app shows whether the field is positive or negative.
No hassle with poles? We supply these magnets with countersunk holes in north-pole and south-pole versions. Combine one of each and they will always attract each other, even when screwed together.
Holding force approx. 5.2 kg per piece, with 2 countersunk holes for screws.
Tip: mark the poles with a marker before gluing magnets in. A magnet glued in backwards will repel instead of attracting.
Repulsion in practice
- Magnetic levitation experiments: a magnet does not remain stable above another magnet on its own (Earnshaw's theorem). Guidance, rotation, or control is always required.
- Maglev trains and magnetic bearings: use controlled electromagnets or superconductors.
- Electric motors: operate by alternating attraction and repulsion between permanent magnets and coils.
- Damping and springs: repelling magnets act as a contactless spring.
Frequently asked questions
Is repulsion as strong as attraction?
At the same distance, approximately yes. At very close range, strong magnets can partially demagnetise each other, especially when heated.
Can you make a separate north or south pole?
No. If you break a magnet in half, you get two magnets, each with its own north and south pole. A separate magnetic pole (monopole) has never been found.
Why does a magnet turn when I move it towards another magnet?
Like poles push each other away. If the magnet can turn, it will rotate until the opposite poles face each other and snap into place.
Read also
Need help choosing? Use the Magnet Advisor or contact us.
