Permanent and Induced Magnetism, Magnetic Forces and Fields

• the poles of a magnet are the places where the magnet forces are strongest - when 2 magnets are brought close together they exert a force in each other - 2 like poles repel, 2 opposite poles attract (attraction and repulsion between 2 magnetic poles are a non contact force)
• a permanent magnet produces its own magnetic field
• what is an induced magnet

  material that becomes a magnet when it's placed in a magnetic field - induced magnetism always causes a force of attraction, when removed from the magnetic field an induced magnet loses most/all of its magnetism quickly
• what is a magnetic field

  the region around a magnet where a force acts on another magnet or a magnetic material
• examples of magnetic materials

  • iron
  • steel
  • cobalt
  • nickel
• the force between a magnet and a magnetic material is always one of attraction
• the strength of the magnetic field depends on the distance from the magnet - the field is strongest at the poles of the magnet
• the direction of the magnetic field at any point is given by the direction of the force that would act on another north pole placed at that point - the direction of a magnetic field line is from the north (seeking) pole of a magnet to the south (seeking) pole of the magnet
• a magnetic compass contains a small bar magnet - the earth has a magnetic field - the compass needle points in the direction of the earths magnetic field