Harnessing the Electron


In 1821, following the discovery of electromagnetism by a Danish physicist named Hans Christian Ørsted, Michael Faraday designed a device that harnesses this energy and transforms electrical current into mechanical energy. That device being the first rudimentary homopolar motor(left), which now known as a Faraday Motor.
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The Faraday Motor works because as the electrons flow through the wire and through a conductive liquid (in Faraday's case it was Mercury) the wire become an electromagnet. This electromagnet experiences a force that is directly perpendicular to the flow of the electrons and to the attraction of the regular magnet placed in the center. This force, or torque is what causes the wire to move in a circular motion around the magnet. 

A Scientific Dynamo

Ten years after Faraday was able to harness electrons for mechanical energy with the first electric motor his research lead him to discover a process known as electro-magnetic induction. Induction is a process where a conductor placed in a changing magnetic field (or a conductor moving through a stationary magnetic field) causes the production of a voltage across the conductor. In Faraday's case we see a liquid battery (right) being used to provide a current to Coil A. Coil A (the conductor) is then moved inside of Coil B (the stationary magnetic field). The inducted current in Coil B is then measured by a galvanometer(G). 

With this realization Faraday established that a changing magnetic field produces an electrical field. This discovery lead  Faraday to construct the first electric dynamo, the precursor to the modern generator.

Faraday's Law


​Following Faraday's discovery of electro-magnetic induction, Scottish scientist James Clerk Maxwell (who was also a gifted mathematician) was able to model how exactly a changing magnetic field produces an electric field. This model eventual became known as one of the four Maxwell equation which largely govern a portion of science known as field theory.
In it's most basic form Faraday's Law states:
"The electromotive force around a closed path is equal to the negative of the time rate of change of the magnetic flux enclosed by the path."
,We see that Faraday's law is clearly described with the equation on the left, wherein E, the electromotive force is equal to the negative partial derivative of magnetic flux taken with respect to time. With the equation on the right Maxwell describes how the magnetic flux through a surface can be modeled by a surface integral of function B which models the magnetic field.