Wednesday, March 20, 2013

Magnetism




Standard 6.1: How is electricity generated by moving magnetic fields? Provide an example.


Electricity generation is based on the principle of electromagnetism, a scientific law that was discovered by British scientist Michael Faraday and American scientist Joseph Henry. The principle states that when an electric conductor, such as a copper wire, is moved through a magnetic field, an electric current will flow through the conductor.Faraday and Henry found that a moving magnet (kinetic energy)  can generate an electric current which can be transformed in to electric potential energy.

For example when a copper wire passes through a magnetic field (anywhere near a magnet) the coppers electrons all start moving in the same direction. This will be one of two directions, depending on which end of the magnet is closer. As the magnet goes by the wire, electrons are attracted by the magnet and flow down the copper wire,  creating electrical power. Say we only one side of the magnet goes by the copper wire over and over, these electrons will only move in one direction. This form of power is called direct current (Electrons are flowing only one way). If the magnet rotates, the electrons will move in both directions. This is what you get from your wall and is called Alternating current (AC). Tesla is the man responsible for this concept and much of the modern power systems.
This is an example of an Alternating Current
In our world today there are many generators that use this idea of kinetic to electric potential energy such as a Fossil Fuel Generator. A fossil fuel generator produces electricity by burning coal in a boiler to heat water in order to produce steam. This steam is then built up in order to create a tremendous amount of pressure that will flow into a turbine which spins a generator to produce electricity. After the steam is then cooled, condensed back into water, and returned to the boiler to start the process all over again.
Geothermal power plant illustration
Fossil Fuel Generator

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