Who Discovered Electromagnetism? Delve into the electrical world with kites, frog's legs and radio

The history of electromagnetism, namely electricity and magnetism combined, dates back to the dawn of time with the human observation of lightning and other unexplainable occurrences, such electric fish and eels. Humans knew there was a phenomenon, it remained shrouded in mysticism until the 1600s when scientists started digging deeper into theory.

Building on the shoulders of giants, many scientists, inventors and theorists worked together to collectively lead the charge for discovering electromagnestism.

Ancient Observations

Michael Faraday: Inventor of the Electric Motor

Amber rubbed with fur attracts bits of dust and hairs that created static electricity. Ancient Greek philosopher, mathematician and scientist Thales' writings around 600 BC noted his experiments rubbing fur on various substances such as amber. The Greeks found that if they rubbed the amber for long enough they could even get an electric spark to jump.

The magnetic compass is an ancient Chinese invention, likely first made in China during the Qin dynasty, from 221 to 206 B.C. The underlying concept may not have been understood, but the ability of the compass to point true north was clear.

Founder of Electrical Science

Toward the late 16th century, English scientist William Gilbert publishes "De Magnete." A true man of science, contemporary Galileo thought that Gilbert was impressive. Gilbert earned the title of the "founder of electrical science." Gilbert undertook a number of careful electrical experiments, in the course of which he discovered that many substances were capable of manifesting electrical properties.

Gilbert also discovered that a heated body lost its electricity and that moisture prevented the electrification of all bodies. He also noticed that electrified substances attracted all other substances indiscriminately, whereas a magnet only attracted iron. 

Franklin's Kite Lightning

American founding father Benjamin Franklin is famous for his extremely dangerous experiment of having his son fly a kite through a storm-threatened sky.

A key attached to the kite string sparked and charged a Leyden jar, thus establishing the link between lightning and electricity. Following these experiments, he invented a lightning rod.

Franklin discovered there are two kinds of charges, positive and negative. Like charges repel and unlike charges attract. Franklin also documents conservation of charge, the theory that an isolated system has a constant total charge.

Coulomb's Law

In 1785, French physicist Charles-Augustin de Coulomb developed Coulomb's law, the definition of the electrostatic force of attraction and repulsion. He found that the force exerted between two small electrified bodies varies inversely as the square of the distance. A large part of the domain of electricity became virtually annexed by Coulomb's discovery of the law of inverse squares. He also produced important work on friction.

Galvanic Electricity

In 1780, Italian professor Luigi Galvani (1737-1790) discovers electricity from two different metals causes frog legs to twitch. He observed that a frog's muscle, suspended on an iron balustrade by a copper hook passing through its dorsal column, underwent lively convulsions without any extraneous cause.

To account for this phenomenon, Galvani assumed that electricity of opposite kinds existed in the nerves and muscles of the frog.

Galvani published the results of his discoveries, together with his hypothesis, which engrossed the attention of the physicists of that time.

Voltaic Electricity

Italian physicist, chemist and inventor Alessandro Volta (1745-1827) discovers that chemicals acting on two dissimilar metals generate electricity in 1790. He invents the voltaic pile battery in 1799, credited as the invention of the first electric battery.  He was a pioneer of electricity and power. With this invention, Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings. Volta's invention sparked a great amount of scientific excitement and led others to conduct similar experiments which eventually led to the development of the field of electrochemistry.

Magnetic Field

Danish physicist and chemist Hans Christian Oersted (1777-1851) discovers in 1820 that electric current affects a compass needle and create magnetic fields. He was the first scientist to find the connection between electricity and magnetism. He is remembered today for Oersted's Law.

Electrodynamics

Andre Marie Ampere (1775-1836) in 1820 finds that wires carrying current produce forces on each other. Ampere announced his theory of electrodynamics in 1821, relating to the force that one current exerts upon another by its electromagnetic effects.

His theory of electrodynamics states that two parallel portions of a circuit attract one another if the currents in them are flowing in the same direction, and repel one another if the currents flow in the opposite direction. Two portions of circuits crossing one another obliquely attract one another if both the currents flow either towards or from the point of crossing, and repel one another if one flows to and the other from that point. When an element of a circuit exerts a force on another element of a circuit, that force always tends to urge the second one in a direction at right angles to its own direction.

Electromagnetic Induction

In 1820, English scientist Michael Faraday (1791-1867) at the Royal Society in London develops the idea of an electric field and studies the effect of currents on magnets. It was by his research on the magnetic field around a conductor carrying a direct current that Faraday established the basis for the concept of the electromagnetic field in physics. Faraday also established that magnetism could affect rays of light and that there was an underlying relationship between the two phenomena. He similarly discovered the principles of electromagnetic induction and diamagnetism, and the laws of electrolysis.

Basis of Electromagnetic Theory

In 1860,  James Clerk Maxwell (1831-1879), a Scottish physicist and mathematician bases the theory of electromagnetism on mathematics. Maxwell publishes "Treatise on Electricity and Magnetism" in 1873 in which he summarizes and synthesizes the discoveries of Coloumb, Oersted, Ampere, Faraday into 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.

In 1885, German physicist Heinrich Hertz proves Maxwell's electromagnetic wave theory was correct and generates and detects electromagnetic waves. Hertz published his work in a book, "Electric Waves: Being Researches on the Propagation of Electric Action With Finite Velocity Through Space." The discovery of electromagnetic waves led to the development to the radio. The unit of frequency of the waves measured in cycles per second was named the "hertz" in his honor.

Invention of the Radio

In 1895, Italian inventor and electrical engineer Guglielmo Marconi puts the discovery of electromagnetic waves to practical use by sending messages over long distances by means of radio signals, also known as the "wireless." He was known for his pioneering work on long-distance radio transmission and for his development of Marconi's law and a radio telegraph system. He is often credited as the inventor of radio, and he shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy."

Continue > History of Electromagnetism

Source :thoughtco.com

Posted By ZaptaiLo.BlogSpot.Com