Saturday, January 21, 2012

Magnetism: Natural Magnetism

Important Terms:
Ferromagnetic: adjective used to describe metals that are highly magnetic (such as iron, cobalt, and nickel)
Domain: a small region within a magnetic material which has uniform magnetization
Magnetic Field: region of space that will exert a force on a moving charge or magnetic field that enters the space
Field Density: how strong a magnet's magnetic field is

Important Theory/Concepts
Domain Theory: Permanent magnets are are ferromagnetic metals that have all of their domains aligned. On the other hand, non-magnetic ferromagnetic materials' domains are not aligned in any way.

Strength of magnetic forces: The force of attraction or repulsion between two permanent magnets is inversely proportional to the distance between the two.

Non-Permanent Magnets: when a permanent magnet is brought near a non-magnetized piece of ferromagnetic material, the former will temporarily align the domains in the latter, thus magnetizing latter. However, once the former is removed, the domains in the latter will removed back to being random.

Magnetic Field: each magnet has a magnetic field, which can be represented by lines of force. The more lines of force that a magnet has, the stronger it is. The arrows in the diagram represent the directions of the force that an object will experience if it is placed on a particular point in the diagram. Also, all lines of force exit from the north pole and enters the south pole.

  • the domains of a magnet become misaligned if the magnet is dropped or hit
  • when a permanent magnet is heated above the Curie point (different for each material), it'll lose its magnetic properties
  • magnetic fields tend to be strongest at the two poles of the magnet