Ancient Egyptians observed shocks from electric fish as early as 2750 BC. Thales of Miletus documented static electricity from rubbing amber in 600 BC. Experimentation continued through the Middle Ages and Renaissance with discoveries of electricity from various substances and bodies. The 18th century saw advancements in generating electricity through friction and improvements to electrostatic machines. Michael Faraday's discovery of electromagnetic induction in the 1830s was a major breakthrough.
3. Ancient Egyptians were aware of shocks when
interacting with electric fish such as the electric
catfish or other animals such as electric
eels. The shocks from animals were apparent to
observers since pre-history by a variety of
peoples that came into contact with them. Texts
from 2750 BC by the ancient Egyptians referred
to these fish as "thunderer of the Nile" and saw
them as the "protectors" of all the other fish.
4. Thales of Miletus, writing
at around 600 BC, noted
that rubbing fur on
various substances, such
as amber would cause
them to attract specks of
dust and other light
objects. Thales wrote on
the effect now known
as static electricity. The
Greeks noted that if they
rubbed the amber for long
enough they could even
get an electric spark to
jump.
5. Archbishop Eustathius of Thessalonica, Greek
scholar and writer of the 12th century, records
that Woliver, king of the Goths, was able to
draw sparks from his body. The same writer
states that a certain philosopher was able while
dressing to draw sparks from his clothes, a
result seemingly akin to that obtained
by Robert Symmer in his silk stocking
experiments, a careful account of which may be
found in the 'Philosophical Transactions,' 1759.
6. Toward the late 16th century, a physician of Queen
Elizabeth's time, Dr. William Gilbert, in De
Magnete, expanded on Cardano's work and invented
the New
Latin word electricusfrom ἤλεκτρον (elektron), the Greek
word for "amber"Gilbert undertook a number of
careful electrical experiments, in the course of which he
discovered that many substances other than
amber, such as sulphur, wax, glass, etc.,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, due to the now well-known fact that moisture
impaired the insulation of such bodies. He also noticed
that electrified substances attracted all other substances
indiscriminately, whereas a magnet only attracted iron.
7. Robert Boyle (1627—1691), in
1675, stated that electric
attraction and repulsion
can act across a vacuum.
One of his important
discoveries was that
electrified bodies in a
vacuum would attract
light substances, this
indicating that the
electrical effect did not
depend upon the air as a
medium. He also added
resin to the then known
list of electrics.[
8. This was followed in 1660 by Otto von
Guericke, who invented an
early electrostatic generator. By the end of the
17th Century, researchers had developed
practical means of generating electricity by
friction with an electrostatic generator, but the
development of electrostatic machines did not
begin in earnest until the 18th century, when
they became fundamental instruments in the
studies about the new science of electricity.
9. The electric machine was subsequently improved by Francis
Hauksbee, Litzendorf, and by Prof. Georg Matthias Bose, about
1750. Litzendorf substituted a glass ball for the sulphur ball
of Guericke. Boze was the first to employ the "prime conductor" in
such machines, this consisting of an iron rod held in the hand of a
person whose body was insulated by standing on a block of
resin. Ingenhousz, during 1746, invented electric machines made
of plate glass. Experiments with the electric machine were largely
aided by the discovery of the property of a glass plate, when
coated on both sides with tinfoil, of accumulating a charge of
electricity when connected with a source of electromotive force.
The electric machine was soon further improved by Andrew
Gordon, a Scotsman, Professor at Erfurt, who substituted a glass
cylinder in place of a glass globe; and by Giessing of Leipzig who
added a "rubber" consisting of a cushion of woollen material. The
collector, consisting of a series of metal points, was added to the
machine by Benjamin Wilson about 1746, and in 1762, John
Canton of England (also the inventor of the first pith-ball
electroscope) improved the efficiency of electric machines by
sprinkling an amalgam of tin over the surface of the rubber.
11. n 1729, Stephen Gray conducted a series of experiments that
demonstrated the difference between conductors and non-
conductors (insulators), showing amongst other things that
a metal wire and even pack thread conducted
electricity, whereas silk did not. In one of his experiments he
sent an electric current through 800 feet of hempen thread
which was suspended at intervals by loops of silk thread.
When he tried to conduct the same experiment substituting
the silk for finely spun brass wire, he found that the electric
current was no longer carried throughout the hemp
cord, but instead seemed to vanish into the brass wire. From
this experiment he classified substances into two categories:
"electrics" like glass, resin and silk and "non-electrics" like
metal and water. "Electrics" conducted charges while "non-
electrics" held the charge.
12. In 1732, C. F. du Fay began to conduct several
experiments. In his first experiment, Du Fay
concluded that all objects except
metals, animals, and liquids could be electrified
by rubbing and that metals, animals and
liquids could be electrified by means of an
electric machine, thus discrediting Gray's
"electrics" and "non-electrics" classification of
substances.
13. The Leyden jar, a type of capacitor for electrical energy in large
quantities, was invented independently by Ewald Georg von
Kleist on 11 October 1744 and by Pieter van Musschenbroek in
1745—1746 at Leiden University (the latter location giving the
device its name).[35] William Watson, when experimenting with
the Leyden jar, discovered in 1747 that a discharge of static
electricity was equivalent to an electric current. Capacitance was
first observed by Von Kleist of Leyden in 1754. Von Kleist
happened to hold, near his electric machine, a small bottle, in the
neck of which there was an iron nail. Touching the iron nail
accidentally with his other hand he received a severe electric
shock. In much the same way Musschenbroeck assisted by
Cunaens received a more severe shock from a somewhat similar
glass bottle. Sir William Watson of England greatly improved this
device, by covering the bottle, or jar, outside and in with tinfoil.
This piece of electrical apparatus will be easily recognized as the
well-known Leyden jar, so called by the Abbot Nollet of
Paris, after the place of its discovery.
14. Benjamin Franklin (1706-
1790)
His kite experiment
demonstrated that lightning
is electricity. He was the first
to use the terms positive and
negative charge.
Franklin was one of seventeen
children. He quit school at
age ten to become a printer.
His life is the classic story of
a self-made man achieving
wealth and fame through
determination and
intelligence.
15. About 1784 C. A. Coulomb, after
whom is named the electrical unit of
quantity, devised the torsion
balance, by means of which he
discovered what is known
as Coulomb's law; — The force
exerted between two small electrified
bodies varies inversely as the square of
the distance; not as Aepinus in his
theory of electricity had
assumed, merely inversely as the
distance. According to the theory
advanced by Cavendish "the particles
attract and are attracted inversely as
some less power of the distance than the
cube." A large part of the domain of
electricity became virtually annexed
by Coulomb's discovery of the law
of inverse squares.
16. In 1800 Alessandro
Volta constructed the first
device to produce a large
electric current, later
known as the electric
battery. Napoleon, inform
ed of his
works, summoned him in
1801 for a command
performance of his
experiments. He received
many medals and
decorations, including
the Légion d'honneur.
17. Andre Marie Ampère who shortly
thereafter (1821) announced his
celebrated theory of
electrodynamics, relating to the force that
one current exerts upon another, by its
electro-magnetic effects, namely
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.
18. Georg Simon Ohm did his
work on resistance in the
years 1825 and 1826, and
published his results in 1827
as the book Die galvanische
Kette, mathematisch bearbeitet.
He drew considerable
inspiration from Fourier's
work on heat conduction in
the theoretical explanation of
his work. For experiments,
he initially used voltaic piles,
but later used
a thermocouple as this
provided a more stable
voltage source in terms of
internal resistance and
constant potential difference.
19. Michael Faraday (1791-1867) an
Englishman, made one of the
most significant discoveries in
the history of electricity:
Electromagnetic induction. His
pioneering work dealt with how
electric currents work. Many
inventions would come from his
experiments, but they would
come fifty to one hundred years
later.
Failures never discouraged
Faraday. He would say; "the
failures are just as important as
the successes." He felt failures
also teach. The farad, the unit of
capacitance is named in the
honor of Michael Faraday.
20. In 1853 Sir William
Thomson (later Lord Kelvin)
predicted as a result of
mathematical calculations the
oscillatory nature of the electric
discharge of a condenser circuit.
To Henry, however, belongs the
credit of discerning as a result of
his experiments in 1842 the
oscillatory nature of the Leyden
jar discharge. He wrote:[93] The
phenomena require us to admit the
existence of a principal discharge in
one direction, and then several
reflex actions backward and
forward, each more feeble than the
preceding, until the equilibrium is
obtained.
21. James Maxwell (1831-
1879) a Scottish
mathematician translated
Faraday's theories into
mathematical expressions.
Maxwell was one of the
finest mathematicians in
history. A maxwell is the
electromagnetic unit of
magnetic flux, named in
his honor.
Today he is widely
regarded as secondary
only to Isaac Newton and
Albert Einstein in the
world of science.
22. Nikola Tesla was born of
Serbian parents July
10, 1856 and died a broke
and lonely man in New
York City January 7, 1943.
He envisioned a world
without poles and power
lines. Referred to as the
greatest inventive genius
of all time. Tesla's system
triumphed to make
possible the first large-
scale harnessing of
Niagara Falls with the first
hydroelectric plant in the
United States in 1886.
23. Heinrich Hertz (1857-
1894) a German
physicist, laid the ground
work for the vacuum tube.
He laid the foundation for
the future development of
radio, telephone, telegrap
h, and even television. He
was one of the first people
to demonstrate the
existence of electric
waves. Hertz was
convinced that there were
electromagnetic waves in
space.
24. Hendrik Lorentz introduced
a strict separation between
matter (electrons) and ether,
whereby in his model the
ether is completely
motionless, and it won't be
set in motion in the
neighborhood of ponderable
matter. Contrary to other
electron models before, the
electromagnetic field of the
ether appears as a mediator
between the electrons, and
changes in this field can
propagate not faster than the
speed of light.
25. Henri Poincaré between
1895 and 1905 formulated
on many occasions
the Principle of
Relativity and tried to
harmonize it with
electrodynamics. He
declared simultaneity only
a convenient convention
which depends on the
speed of light, whereby
the constancy of the speed
of light would be a
useful postulate for
making the laws of nature
as simple as possible.
26. The first formulation of
a quantum theory describing
radiation and matter
interaction is due to Paul
Adrien Maurice
Dirac, who, during 1920, was
first able to compute the
coefficient of spontaneous
emission of an atom. Paul
Dirac described the
quantization of
the electromagnetic field as
an ensemble of harmonic
oscillators with the
introduction of the concept
of creation and annihilation
operators of particles