# The Naked Scientists Forum

### Author Topic: What causes magnetic fields?  (Read 7381 times)

#### The Scientist

• Sr. Member
• Posts: 286
• Its great to be me!
##### What causes magnetic fields?
« on: 19/12/2010 11:16:00 »
Thanks people!

#### graham.d

• Neilep Level Member
• Posts: 2208
##### What causes magnetic fields?
« Reply #1 on: 19/12/2010 12:19:56 »
Magnetic force is caused by the movement of charge. However, it is more fully described as a manifestation of a single electromagnetic field. This field can appear as an elctrostatic field or a magnetic field depending on one's frame of reference. The properties are described by Maxwell's equations and these equations are invariant under a Lorentz transformation and so are consistent with special relativity.

I'm not sure whether a simpler or a more thorough explanation is required.

#### Foolosophy

• Sr. Member
• Posts: 218
##### What causes magnetic fields?
« Reply #2 on: 19/12/2010 12:54:19 »
Magnetic force is caused by the movement of charge. However, it is more fully described as a manifestation of a single electromagnetic field. This field can appear as an elctrostatic field or a magnetic field depending on one's frame of reference. The properties are described by Maxwell's equations and these equations are invariant under a Lorentz transformation and so are consistent with special relativity.

I'm not sure whether a simpler or a more thorough explanation is required.

are there moving charges in a permanent magnet?

#### graham.d

• Neilep Level Member
• Posts: 2208
##### What causes magnetic fields?
« Reply #3 on: 19/12/2010 13:32:42 »
Yes, there are moving charges in a permanent magnet. Atoms themselves can be visualised as electrons rotating about a positive nucleus and they can have a dipole magnetic field associated with them. If you can align these atoms in a similar orientation then there can result a significant magnetic field. In permanent magnets atoms get aligned in this way.

The structures can be more complicated as groups of material with a statistical imbalance of alignments (producing a magnetic field) may be forced into alignment with other "domains" with a similar orientation by mechanical or outside magnetic forces.

#### The Naked Scientists Forum

##### What causes magnetic fields?
« Reply #3 on: 19/12/2010 13:32:42 »