DISCOVERY OF ELECTRICITY

HISTORY:

           About 600 BC Greek philosopher Thales observed that if AMBER (a type of resin of pine) is rubbed with fur  then it attracts paper cut into pieces.It was not then understood that why this happen?But in no time man started application of it.They found it a great way to stick balloons on the wall. Pet cats were then a useful fellow for their hairy body.

EXPLANATION

             The fact was explained later in the 17th century AD. The observation of Thales was explained as statical electrification.All matter consists of atoms.Atom contains two types of charged particle Protons and Electrons and neutral particles the Neutrons and a few elementary particles.Protons and Neutrons forms the center, the Nucleus and the Electrons moves round the nucleus in orbits.Fur the position of electron from the nucleus less the force of attraction, due to the nucleus, is on it.Thus the electrons at the furthest orbit are very loosely bounded to the atom.If we rub any matter with then these electrons may free from atom due to mechanical energy.The free electrons are received by one of the materials that were rubbed; thus both of them becomes electrified.Electrified materials can attract oppositely charged materials or neutral materials.So they attracts pieces of paper, pith ball etc.

         

             If the material that is rubbed is an insulator then the charged developed can not move through it stays there for a long time.Hence this is called STATICAL ELECTRICITY. If we rub a Conductor with wool or fur then we never see such things; because they conducts the charge developed due to rubbing.

VOLTA'S  DISCOVERY    :

              Scientist Volta was the first to develop current electricity.He did it by using 'oil of vitriol' and two types of metallic plates - one of copper (Cu) and the other zinc (Zn).  He made multiple layer of Zinc and Copper by placing one after another and separating them by  cloth and felt wet in 'oil of vitriol"  (Sulfuric Acid ) .This led to invent the first electric cell, called the Simple Voltaic Cell.

FURTHER DEVELOPMENT :

  

         
      Then as time passes more developed cells were designed. A few of them are The Leclance cell, Lead Acid cell etc.But with these cells we cannot fulfill the great requirement of electricity.

FARADAY'S DISCOVERY :

     Michael Faraday discovered that "If there is relative motion in between a magnet and a closed loop then electric current is generated in the loop.The magnitude of the current increases with velocity of movement , number of turns of the loop.

                   DYNAMO:

                             Dynamo is a device designed to generate current electricity.There is a rectangular coil      made of insulated copper wire and a strong magnet.The magnet actually forms the armature of the device.If the Armature is rotated around its axis then we get current electricity.Following is a simple diagram of a Dynamo.

              Here we get AC current.The magnitude of voltage (also current) changes sinusoidally with time.This happens because the number of the lines of force of the magnet that passes through the coil changes with time (As the is rectangular and the magnet is in circular motion).

   

             In power generation centers we actually revolve the shaft i.e. the armature of a dynamo.If we do that by Heat Then it called Thermal Power, If by Water flow then Hydel Power , If by Atomic Energy to Heat to Electric Energy then Atomic Power.