Earth Magnets -What are they?
One can academically appreciate the fact that every electric motor in the world works because of magnetism. One can reflect on the fact that every transformer uses it, too. Permanent magnets are used in power meters, brushless DC motors, TVs, CRT monitors, modern welding gear and various vending machines and engine ignition-timing systems. Electromagnetism plays a crucial role in making every other electronic device work.
The earth also has some magnetic force. Mainly known as neodymium iron boron (NIB) magnets, they're generally just referred to as "rare earth" or "neodymium" magnets, and this composition is both more powerful and cheaper than samarium cobalt otherwise known as king of the magnetic world.
How strong?
Well, the smallest earth magnets are a little gold-plated cylinder only 6.4 by 2.3mm in size. The field produced by these earth magnets doesn't reach far with any potency. It is due to the smaller a magnet with a specific strength, the smaller is the volume of space that it can fill with a magnetic field of a given strength. Strength of magnetic field falls as the inverse cube of the distance from the magnet, too; get double as far away and the field strength drops by a factor of about eight. So two of these little tackers can barely be noticed by each other over a distance of more than an inch. Magnetic field strength is measured with two units, the Tesla (T) and the Gauss (G). 1T means 10,000G.
The strength of earth's magnetic field is about 0.5G, depending on where you are - it's weaker at the equator and stronger at the poles. It's also lethargically declining at the moment, which is something that it does rhythmically; geological data shows that it's literally reversed several times over the planet's life. The mental giants at the Institute for Creation Research use the decline of the field strength to prove that the planet's only a few thousand years old.
The ferrite magnets are the strongest having a field potency at their poles of around 1000G. On the other hand, rare earth magnets have surface field strength of about 1T that is ten times stronger. The size of earth magnets has a lot to do with the strength of its field, though. The inverse-cube-law magnetic field strength decrease can bite into their power quite rapidly because the magnets are not at all very big in size.
For more information about magnets visit: Earth Magnets
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