Wednesday, March 20, 2013

Magnetism

Standard 6.3: Explain how objects like the earth and metals can be permanent or temporary magnets.

      The earth itself has a very large magnetic field which is caused by the molten iron/nickel core that is always moving. Although the earth has many permanent magnets, the planet itself is not one. The most common example of a permanent magnet would be a regular fridge magnet. These magnets are permanent (always magnetic) because they have tiny magnetic domains that line up and point in the same direction. Most objects have these domains, but they are all scattered and point in different directions, making them non-magnetic objects.

      A temporary magnet on the other hand is basically a magnet that can be turned on and off. It requires a flow of electrical current to create a magnetic force for the metal to exert. Electromagnets are the best examples because all they're really made of is metal and coiled wire. When an electrical current flows through those wires the metal becomes magnetic, thus allowing the magnet to be turned on or off with the flip of a switch.

(Nail Electromagnet)


      

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