# Magnetic Field Lines around a Magnet

1. May 13, 2014

### Jimmy87

Hi, please could someone explain why the magnetic field is stronger at the poles of a magnet. I know that the field line density is strongest at the poles and more spaced out in the middle. I get that. I just wanted to know why the magnetic field is stronger at the poles than the middle of a magnet.

Thanks for any help offered.

2. May 13, 2014

### UltrafastPED

If you have a bunch of small magnets you can test this: stack the magnets end-to-end so that they form a single magnet. What happens when you bring iron filings near by? Are the field lines the same as for the individual magnets, or are they stronger? What about the body of the magnet?

3. May 15, 2014

### Dannypeng

I think it's because the direction as magnetic field has direction, from north to south. On the poles, the force is towards or from the surface of the magnets, so you can feel it. In the middle, the force is parallel to the surface, it's from the poles and both poles are kind of far from the middle. Hope this will help you.

4. May 17, 2014

### enorbet

Greetz
If we are talking about so-called permanent magnet like the common bar magnet, total field strength is quite constant, assuming stable temperature. The variation in intensity at different locations depends on the geometry of that field. In a single magnet system the lines of force are concentrated to nearly a point at the poles, whereas in the "equatorial area" where the lines have ballooned out, they are more diffuse.

This geometry and resulting intensity can be altered by introducing a second magnet, where pole orientation can either increase or decrease apparent intensity by further concentration or diffusion.

5. Sep 22, 2015

### magnetics

I would have thought this had more to do with homogeneous and inhomogeneous magnetic fields.

Near the middle of the shaft of a long magnet, the field lines are straight and parallel and field is homogeneous. At this point along the magnet, the magnetic field is only going to exert a torque on a magnetic dipole to align its direction with the field lines. Whereas at the ends of a magnet the filed lines are curved where the magnetic field is inhomogeneous and at this point the magnetic field will exert a translatory force on a magnetic dipole.

I'd be interested in hearing how a physicists describes this??