Saturday, 13 December 2008
Magnetism
I've been shopping at Wiki again, exploring ideas on magnetism, and magnetic charge. I quote: "A magnet (from Greek μαγνήτης λίθος, "Magnesian stone") is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other magnetic materials and attracts or repels other magnets." Ferromagnetic (iron) materials are the only ones strongly enough attracted to a magnet to be commonly considered 'magnetic'.
Convention states that the magnetic field lines emanate from the north pole of the magnet, and re-enter the magnet through the south pole. Some think of magnetic field lines being created by the planet in the same way. This is an assumption that magnetic field lines travel in one direction, but surely, both opposite poles are attracted to each other? Two poles that are alike will repel each other; north will repel north, and south shall repel south. On a bar magnet it would appear that the energy does not simply emanate from the north pole and move to the south pole. The energy moves out from both poles. Are the forces which move from a bar magnet completing a circuit of some type?
The geographic north pole is a magnetic south pole. On a compass, it's the north pole of the needle which is attracted to the magnetic south pole. We might forget perhaps that the south pole of the needle is also attracted to the magnetic north pole.
The movement of any charged particle will produce a magnetic field. In previous posts, we have seen how charges are attracted from a higher potential to the lower potential. We also suspect that there are charges which are attracted from the lower potential to the higher potential. New research on lightning shows not only a strike reaching down from clouds (higher potential), but that it is met halfway by a strike from the ground ( lower potential). A typical bolt bridges a potential difference (voltage) of several hundred million volts.
The movement of charges in the magnetic fields suggests that there is a difference of potential in the ends of a bar magnet. This idea is a little hard to confirm because magnetic fields are invisible. We can spread iron filings over a piece of paper on top of a bar magnet, and this will give us some idea of the shape which the magnetic field lines take. Unfortunately, the iron filings do not reveal from which direction the lines emanate.
Ultimately, magnetic fields can produce electric currents, and electric currents produce magnetic fields. If an electrical cable acts as an antenna for an ELF wave - what then is at work with an ordinary bar magnet? There's something special about iron, and it's natural magnetism. Does the iron act as an antenna for an ELF wave? If it did, the relatively weak magnetic forces of iron without an induced electric current, would imply we are looking for a frequency at the lower end of the ELF spectrum. A frequency perhaps, which permeates everything .
Many thanks:
http://en.wikipedia.org/wiki/Magnet
http://www.intuitor.com/resonance/radioTVres.html
http://science.howstuffworks.com/magnet1.htm
http://science.nasa.gov/newhome/headlines/essd18jun99_1.htm
http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/lightning2.html
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