What is Magnetic field?
{{Electromagnetism}} '''The magnetic field''' is the area around a [[magnet]] in which there is [[magnetic force]]. Moving [[electric charge]]s can make magnetic fields. Magnetic fields can be illustrated by [[magnetic flux line]]s. At all times the [[direction]] of the magnetic field is shown by the direction of the magnetic flux lines. The strength of a magnet has to do with the spaces between the magnetic flux lines. The closer the flux lines are to each other, the stronger the magnet is. The farther away they are, the weaker. The flux lines can be seen by placing [[iron]] filings over a magnet. The iron filings move and arrange into the lines. Magnetic fields give power to other [[particle]]s that are touching the magnetic field. In [[physics]], the magnetic field is a field that passes through space and which makes a magnetic force move electric charges and magnetic [[Dipole|dipoles]]. Magnetic fields are around electric currents, magnetic dipoles, and changing electric fields. When placed in a magnetic field, magnetic [[dipole]]s are in one line parallel with the field lines, as can be seen when iron filings are in the presence of a magnet. Magnetic fields also have their own energy and momentum, with an energy density proportional to the square of the field intensity. The magnetic field is measured in the units of [[tesla (unit)|teslas]] ([[SI unit]]s) or [[gauss (unit)|gauss]] (cgs units). There are some notable kinds of magnetic field. For the physics of magnetic materials, see [[magnetism]] and [[magnet]], and more specifically [[diamagnetism]]. For magnetic fields made by changing electric fields, see [[electromagnetism]]. The electric field and the magnetic field are [[wikt:component|components]] of the electromagnetic field. Research on magnetic fields began in 1269 when French scholar [[Petrus Peregrinus de Maricourt]] mapped out the magnetic field on the surface of a spherical magnet using iron needles. He said magnets always have both a north and south pole, no matter how finely one slices t