Brief History of electromagnetism

Contents 1.History 1. Ancient times. 1. Ancient times. 2. Mid-times 2. Mid-times 3. Early modern times. 3. Early modern times. 2. Unification.

Ancient times Amber Amber rubbed with fur attracts bits of dust and hairs. Static electricity - spikes on cold, dry days, lightening. Lode stone compass

Mid-times English scientist, William Giber, publishes “De Magnete” Lectures and demonstrations given by various scientists using electricity and entertain audiences

Mid-times  1700.Ben Franklin( )  Two kinds of charges: positive and negative  Like charges repel, unlike charges attract  Conservation of Charges: an isolated system has constant total charge

Mid-times  Charles Austin de Coulomb The force between two charges Q1 and Q2 is proportional to their product divided by the separation distance r squared inverse square law. The force between two charges Q1 and Q2 is proportional to their product divided by the separation distance r squared inverse square law Alessandro Volta finds chemistry acting on two dissimilar metals generates electricity. He later invents the voltaic pile-the battery.

Early Modern times Hans Christian Oersted. – electric current affects compass needle Adre Marie Ampere in Pairs finds that wires carrying current produce forces on each other Michael Faraday at royal Society develops the idea of electric field and studies the effect of currents on magnets and magnets inducing electric currents.

Early Modern times James Clerk Maxwell, a Scottish physicist and mathematician, puts the theory of electromagnetism on mathematical basis Maxwell publishes "Treatise on Electricity and Magnetism" in which he summarizes and synthesizes the discoveries of Coloumb, Oersted, Ampere, Faraday, et. al. in four mathematical equations. Maxwell's Equations are used today as the basis of electromagnetic theory. Maxwell makes a prediction about the connections of magnetism and electricity leading directly to the prediction of electromagnetic waves Hertz shows Maxwell was correct and generates and detects electromagnetic waves Guglielmo Marconi puts the discovery to practical use by sending messages over long distances by means of radio signals.radio

Maxwell’s Equations Gauss' law for electricity Gauss' law for magnetism Faraday's law of induction Ampere's law

Chaos

Order

Einstein’s Dream Is there an underlying simplicity behind vast phenomena in Nature? Einstein dreamed to come up with a unified description But he failed to unify electromagnetism and gravity (GR)

History of Unification gravity electric magnetic  -decay  -decay  -decay planets apple electromagnetiesm atoms Quantum mechanics mechanics Special relativity Quantum ElectroDynamics Weak force Strong force Electroweak theory Grand Unification? GR String theory?

The End Thank you!