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Michael Faraday's World

Faraday's Inventions

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A detailed timeline of Faradays Inventions

  • Faraday's greatest work was with electricity. In 1821, soon after the Danish chemist, Hans Christian  Orsted, discovered the phenomenon of magnetism, Humphry Davy and William Hyde Wollaston tried but failed to design an electric motor. Faraday, having discussed the problem with the two men, went on to build two devices to produce what he called electromagnetic rotation which is a continuous circular motion from the circular magnetic force around a wire. A wire extending into a pool of mercury with a magnet placed inside would rotate around the magnet if charged with electricity by a chemical battery. This device is known as a homopolar motor. These experiments and inventions form the foundation of modern electromagnetic technology. Unwisely, Faraday published his results without acknowledging his debt to Wollaston and Davy, and the resulting controversy caused Faraday to withdraw from electromagnetic research for several years.

  • Ten years later, in 1831, he began his great series of experiments in which he discovered electromagnetic induction. He found that if he moved a magnet through a loop of wire, an electric current flowed in the wire. The current also flowed if the loop was moved over a stationary magnet. This was the first transformer (inductor), although Faraday used it only to demonstrate the principle of electromagnetic induction and did not realise  what it would eventualybe used for.

    His experiments established that a changing magnetic field produces an electric field. This relation was mathematically modelled by faraday's law, which afterwards became one of the four Maxwell equations. These in turn evolved into the generalization known as field theory.

    Faraday then used this principle to construct the first dynamo (in the form of a copper disk rotated between the poles of a permanent magnet), the predecessor of modern dynamos and generators.

  • In 1832, Michael Faraday reported that the quantity of elements separated by passing an electrical current through a molten or dissolved salt was proportional to the quantity of current passed through the circuit. This became the basis of the first law of electrosis. He also popularized terminology such as anode, cathode, electrode, and ion.

  • In 1845 he discovered what is now called the Faraday effeact. The plane of polarization of linearly polarized light propagated through a material medium can be rotated by the application of an external magnetic field aligned in the propagation direction. He wrote in his notebook, "I have at last succeeded in illuminating a magnetic curve or line of force and in magnetising a ray of light". This established that magnetic force and light were related.

  • In 1845 he also discovered the phenomenon that he named Diamagnetism - a very weak form of magnetism that is only exhibited in the presence of an external magnetic field. This phenomenon can can be used for levitation.

  • In his work on static electricity, Faraday demonstrated that the charge only resided on the exterior of a charged conductor, and exterior charge had no influence on anything enclosed within a conductor. This is because the exterior charges redistribute such that the interior fields due to them cancel. This shielding effect is used in what is now known as a Faraday cage.

  • Faraday also dabbled in chemistry, discovering chemical substances such as benzine, inventing the system of oxidization numbers, and liquefying gases.

fig_1_18lrg.jpg

This is a picture of the electric motor invented by Michael Faraday
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
dynamo.gif
 
 
This is a disc dynamo  like the one made by faraday
 
 
 
 
 

"Nothing is too wonderful to be true."  Michael Faraday