Electricity

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Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.

The presence of either a positive or negative electric charge produces an electric field. The motion of electric charges is an electric current and produces a magnetic field. In most applications, Coulomb's law determines the force acting on an electric charge. Electric potential is the work done to move an electric charge from one point to another within an electric field, typically measured in volts.

Electricity plays a central role in many modern technologies, serving in

active components such as vacuum tubes, transistors, diodes and integrated circuits
, and associated passive interconnection technologies.

The study of electrical phenomena dates back to antiquity, with theoretical understanding progressing slowly until the 17th and 18th centuries. The development of the theory of electromagnetism in the 19th century marked significant progress, leading to electricity's industrial and residential application by

communications, and computation, making it the foundation of modern industrial society.[1]

History

Thales
, the earliest known researcher into electricity
Main articles: History of electromagnetic theory and History of electrical engineering
See also: Etymology of electricity

Long before any knowledge of electricity existed, people were aware of shocks from

electric shocks delivered by electric catfish and electric rays, and knew that such shocks could travel along conducting objects.[3] Patients with ailments such as gout or headache were directed to touch electric fish in the hope that the powerful jolt might cure them.[4]

Ancient cultures around the

magnetic, in contrast to minerals such as magnetite, which needed no rubbing.[5][6][7][8] Thales was incorrect in believing the attraction was due to a magnetic effect, but later science would prove a link between magnetism and electricity. According to a controversial theory, the Parthians may have had knowledge of electroplating, based on the 1936 discovery of the Baghdad Battery, which resembles a galvanic cell, though it is uncertain whether the artifact was electrical in nature.[9]

A half-length portrait of a bald, somewhat portly man in a three-piece suit.
Benjamin Franklin conducted extensive research on electricity in the 18th century, as documented by Joseph Priestley (1767) History and Present Status of Electricity, with whom Franklin carried on extended correspondence.

Electricity would remain little more than an intellectual curiosity for millennia until 1600, when the English scientist

William Gilbert wrote De Magnete, in which he made a careful study of electricity and magnetism, distinguishing the lodestone effect from static electricity produced by rubbing amber.[5] He coined the Neo-Latin word electricus ("of amber" or "like amber", from ἤλεκτρον, elektron, the Greek word for "amber") to refer to the property of attracting small objects after being rubbed.[10] This association gave rise to the English words "electric" and "electricity", which made their first appearance in print in Thomas Browne's Pseudodoxia Epidemica of 1646.[11]

Further work was conducted in the 17th and early 18th centuries by

C. F. du Fay.[12] Later in the 18th century, Benjamin Franklin conducted extensive research in electricity, selling his possessions to fund his work. In June 1752 he is reputed to have attached a metal key to the bottom of a dampened kite string and flown the kite in a storm-threatened sky.[13] A succession of sparks jumping from the key to the back of his hand showed that lightning was indeed electrical in nature.[14] He also explained the apparently paradoxical behavior[15] of the Leyden jar as a device for storing large amounts of electrical charge in terms of electricity consisting of both positive and negative charges.[12]

Half-length portrait oil painting of a man in a dark suit
Michael Faraday's discoveries formed the foundation of electric motor technology.

In 1775, Hugh Williamson reported a series of experiments to the Royal Society on the shocks delivered by the

electrostatic machines previously used.[19][20] The recognition of electromagnetism, the unity of electric and magnetic phenomena, is due to Hans Christian Ørsted and André-Marie Ampère in 1819–1820. Michael Faraday invented the electric motor in 1821, and Georg Ohm mathematically analysed the electrical circuit in 1827.[20] Electricity and magnetism (and light) were definitively linked by James Clerk Maxwell, in particular in his "On Physical Lines of Force" in 1861 and 1862.[21]
: 148 

While the early 19th century had seen rapid progress in electrical science, the late 19th century would see the greatest progress in

William Thomson, 1st Baron Kelvin, Charles Algernon Parsons, Werner von Siemens, Joseph Swan, Reginald Fessenden, Nikola Tesla and George Westinghouse, electricity turned from a scientific curiosity into an essential tool for modern life.[22]

In 1887,

photocells such as can be found in solar panels
.

The first

cat's-whisker detector" first used in the 1900s in radio receivers. A whisker-like wire is placed lightly in contact with a solid crystal (such as a germanium crystal) to detect a radio signal by the contact junction effect.[26] In a solid-state component, the current is confined to solid elements and compounds engineered specifically to switch and amplify it. Current flow can be understood in two forms: as negatively charged electrons, and as positively charged electron deficiencies called holes. These charges and holes are understood in terms of quantum physics. The building material is most often a crystalline semiconductor.[27][28]

Solid-state electronics came into its own with the emergence of transistor technology. The first working transistor, a germanium-based point-contact transistor, was invented by John Bardeen and Walter Houser Brattain at Bell Labs in 1947,[29] followed by the bipolar junction transistor in 1948.[30]

Concepts

Electric charge

Main article: Electric charge
See also: Electron, Proton, and Ion
gold-leaf electroscope
causes the leaves to visibly repel each other

The presence of charge gives rise to an electrostatic force: charges exert a force on each other, an effect that was known, though not understood, in antiquity.[23]: 457  A lightweight ball suspended by a fine thread can be charged by touching it with a glass rod that has itself been charged by rubbing with a cloth. If a similar ball is charged by the same glass rod, it is found to repel the first: the charge acts to force the two balls apart. Two balls that are charged with a rubbed amber rod also repel each other. However, if one ball is charged by the glass rod, and the other by an amber rod, the two balls are found to attract each other. These phenomena were investigated in the late eighteenth century by Charles-Augustin de Coulomb, who deduced that charge manifests itself in two opposing forms. This discovery led to the well-known axiom: like-charged objects repel and opposite-charged objects attract.[23]

The force acts on the charged particles themselves, hence charge has a tendency to spread itself as evenly as possible over a conducting surface. The magnitude of the electromagnetic force, whether attractive or repulsive, is given by

gravitational attraction pulling them together.[35]

Charge originates from certain types of

fundamental forces of nature. Experiment has shown charge to be a conserved quantity, that is, the net charge within an electrically isolated system will always remain constant regardless of any changes taking place within that system.[36] Within the system, charge may be transferred between bodies, either by direct contact, or by passing along a conducting material, such as a wire.[32]: 2–5  The informal term static electricity
refers to the net presence (or 'imbalance') of charge on a body, usually caused when dissimilar materials are rubbed together, transferring charge from one to the other.

The charge on electrons and protons is opposite in sign, hence an amount of charge may be expressed as being either negative or positive. By convention, the charge carried by electrons is deemed negative, and that by protons positive, a custom that originated with the work of Benjamin Franklin.[37] The amount of charge is usually given the symbol Q and expressed in coulombs;[38] each electron carries the same charge of approximately −1.6022×10−19 coulomb. The proton has a charge that is equal and opposite, and thus +1.6022×10−19  coulomb. Charge is possessed not just by matter, but also by antimatter, each antiparticle bearing an equal and opposite charge to its corresponding particle.[39]

Charge can be measured by a number of means, an early instrument being the

gold-leaf electroscope, which although still in use for classroom demonstrations, has been superseded by the electronic electrometer.[32]
: 2–5 

Electric current

Main article: Electric current

The movement of electric charge is known as an

electrical insulator.[40]

By historical convention, a positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part. Current defined in this manner is called

electric circuit, one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of the electrons.[41] However, depending on the conditions, an electric current can consist of a flow of charged particles
in either direction, or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation.

Two metal wires form an inverted V shape. A blindingly bright orange-white electric arc flows between their tips.
An electric arc provides an energetic demonstration of electric current.

The process by which electric current passes through a material is termed

electrical conduction, and its nature varies with that of the charged particles and the material through which they are travelling. Examples of electric currents include metallic conduction, where electrons flow through a conductor such as metal, and electrolysis, where ions (charged atoms) flow through liquids, or through plasmas such as electrical sparks. While the particles themselves can move quite slowly, sometimes with an average drift velocity only fractions of a millimetre per second,[32]: 17  the electric field that drives them itself propagates at close to the speed of light, enabling electrical signals to pass rapidly along wires.[42]

Current causes several observable effects, which historically were the means of recognising its presence. That water could be decomposed by the current from a voltaic pile was discovered by

resistance causes localised heating, an effect James Prescott Joule studied mathematically in 1840.[32]: 23–24  One of the most important discoveries relating to current was made accidentally by Hans Christian Ørsted in 1820, when, while preparing a lecture, he witnessed the current in a wire disturbing the needle of a magnetic compass.[21]: 370 [a] He had discovered electromagnetism, a fundamental interaction between electricity and magnetics. The level of electromagnetic emissions generated by electric arcing is high enough to produce electromagnetic interference, which can be detrimental to the workings of adjacent equipment.[43]

In engineering or household applications, current is often described as being either

battery and required by most electronic devices, is a unidirectional flow from the positive part of a circuit to the negative.[44]: 11  If, as is most common, this flow is carried by electrons, they will be travelling in the opposite direction. Alternating current is any current that reverses direction repeatedly; almost always this takes the form of a sine wave.[44]: 206–07  Alternating current thus pulses back and forth within a conductor without the charge moving any net distance over time. The time-averaged value of an alternating current is zero, but it delivers energy in first one direction, and then the reverse. Alternating current is affected by electrical properties that are not observed under steady state direct current, such as inductance and capacitance.[44]: 223–25  These properties however can become important when circuitry is subjected to transients
, such as when first energised.

Electric field

Main article: Electric field
See also: Electrostatics

The concept of the electric field was introduced by Michael Faraday. An electric field is created by a charged body in the space that surrounds it, and results in a force exerted on any other charges placed within the field. The electric field acts between two charges in a similar manner to the way that the gravitational field acts between two masses, and like it, extends towards infinity and shows an inverse square relationship with distance.[34] However, there is an important difference. Gravity always acts in attraction, drawing two masses together, while the electric field can result in either attraction or repulsion. Since large bodies such as planets generally carry no net charge, the electric field at a distance is usually zero. Thus gravity is the dominant force at distance in the universe, despite being much weaker.[35]

Field lines emanating from a positive charge above a plane conductor

An electric field generally varies in space,

direction, it follows that an electric field is a vector field.[23]
: 469–70 

The study of electric fields created by stationary charges is called electrostatics. The field may be visualised by a set of imaginary lines whose direction at any point is the same as that of the field. This concept was introduced by Faraday,[45] whose term 'lines of force' still sometimes sees use. The field lines are the paths that a point positive charge would seek to make as it was forced to move within the field; they are however an imaginary concept with no physical existence, and the field permeates all the intervening space between the lines.[45] Field lines emanating from stationary charges have several key properties: first, that they originate at positive charges and terminate at negative charges; second, that they must enter any good conductor at right angles, and third, that they may never cross nor close in on themselves.[23]: 479 

A hollow conducting body carries all its charge on its outer surface. The field is therefore 0 at all places inside the body.[32]: 88  This is the operating principal of the Faraday cage, a conducting metal shell which isolates its interior from outside electrical effects.

The principles of electrostatics are important when designing items of high-voltage equipment. There is a finite limit to the electric field strength that may be withstood by any medium. Beyond this point, electrical breakdown occurs and an electric arc causes flashover between the charged parts. Air, for example, tends to arc across small gaps at electric field strengths which exceed 30 kV per centimetre. Over larger gaps, its breakdown strength is weaker, perhaps 1 kV per centimetre.[46]: 2  The most visible natural occurrence of this is lightning, caused when charge becomes separated in the clouds by rising columns of air, and raises the electric field in the air to greater than it can withstand. The voltage of a large lightning cloud may be as high as 100 MV and have discharge energies as great as 250 kWh.[46]: 201–02 

The field strength is greatly affected by nearby conducting objects, and it is particularly intense when it is forced to curve around sharply pointed objects. This principle is exploited in the

lightning conductor, the sharp spike of which acts to encourage the lightning strike to develop there, rather than to the building it serves to protect.[47]
: 155 

Electric potential

Main article: Electric potential
See also:
Battery (electricity)
AA cells
. The + sign indicates the polarity of the potential difference between the battery terminals.

The concept of electric potential is closely linked to that of the electric field. A small charge placed within an electric field experiences a force, and to have brought that charge to that point against the force requires

electric potential difference, and is the energy required to move a unit charge between two specified points. An electric field has the special property that it is conservative, which means that the path taken by the test charge is irrelevant: all paths between two specified points expend the same energy, and thus a unique value for potential difference may be stated.[23]: 494–98  The volt is so strongly identified as the unit of choice for measurement and description of electric potential difference that the term voltage
sees greater everyday usage.

For practical purposes, it is useful to define a common reference point to which potentials may be expressed and compared. While this could be at infinity, a much more useful reference is the Earth itself, which is assumed to be at the same potential everywhere. This reference point naturally takes the name earth or ground. Earth is assumed to be an infinite source of equal amounts of positive and negative charge, and is therefore electrically uncharged—and unchargeable.[48]

Electric potential is a scalar quantity, that is, it has only magnitude and not direction. It may be viewed as analogous to height: just as a released object will fall through a difference in heights caused by a gravitational field, so a charge will 'fall' across the voltage caused by an electric field.[49] As relief maps show contour lines marking points of equal height, a set of lines marking points of equal potential (known as equipotentials) may be drawn around an electrostatically charged object. The equipotentials cross all lines of force at right angles. They must also lie parallel to a conductor's surface, since otherwise there would be a force along the surface of the conductor that would move the charge carriers to even the potential across the surface.

The electric field was formally defined as the force exerted per unit charge, but the concept of potential allows for a more useful and equivalent definition: the electric field is the local gradient of the electric potential. Usually expressed in volts per metre, the vector direction of the field is the line of greatest slope of potential, and where the equipotentials lie closest together.[32]: 60 

Electromagnets

Main article:
Electromagnets
A wire carries a current towards the reader. Concentric circles representing the magnetic field circle anticlockwise around the wire, as viewed by the reader.
Magnetic field circles around a current

Ørsted's discovery in 1821 that a magnetic field existed around all sides of a wire carrying an electric current indicated that there was a direct relationship between electricity and magnetism. Moreover, the interaction seemed different from gravitational and electrostatic forces, the two forces of nature then known. The force on the compass needle did not direct it to or away from the current-carrying wire, but acted at right angles to it.[21]: 370  Ørsted's words were that "the electric conflict acts in a revolving manner." The force also depended on the direction of the current, for if the flow was reversed, then the force did too.[50]

Ørsted did not fully understand his discovery, but he observed the effect was reciprocal: a current exerts a force on a magnet, and a magnetic field exerts a force on a current. The phenomenon was further investigated by Ampère, who discovered that two parallel current-carrying wires exerted a force upon each other: two wires conducting currents in the same direction are attracted to each other, while wires containing currents in opposite directions are forced apart.[51] The interaction is mediated by the magnetic field each current produces and forms the basis for the international definition of the ampere.[51]

A cut-away diagram of a small electric motor
The electric motor exploits an important effect of electromagnetism: a current through a magnetic field experiences a force at right angles to both the field and current.

This relationship between magnetic fields and currents is extremely important, for it led to Michael Faraday's invention of the

permanent magnet sitting in a pool of mercury. A current was allowed through a wire suspended from a pivot above the magnet and dipped into the mercury. The magnet exerted a tangential force on the wire, making it circle around the magnet for as long as the current was maintained.[52]

Experimentation by Faraday in 1831 revealed that a wire moving perpendicular to a magnetic field developed a potential difference between its ends. Further analysis of this process, known as

Faraday's disc was inefficient and of no use as a practical generator, but it showed the possibility of generating electric power using magnetism, a possibility that would be taken up by those that followed on from his work.[53]

Electric circuits

Main article:
Electric circuit
current I around the circuit, delivering electrical energy into the resistor
R. From the resistor, the current returns to the source, completing the circuit.

An electric circuit is an interconnection of electric components such that electric charge is made to flow along a closed path (a circuit), usually to perform some useful task.[54]

The components in an electric circuit can take many forms, which can include elements such as

linear: while they may temporarily store energy, they contain no sources of it, and exhibit linear responses to stimuli.[55]
: 15–16 

The

circuit theory, stating that the current passing through a resistance is directly proportional to the potential difference across it. The resistance of most materials is relatively constant over a range of temperatures and currents; materials under these conditions are known as 'ohmic'. The ohm, the unit of resistance, was named in honour of Georg Ohm, and is symbolised by the Greek letter Ω. 1 Ω is the resistance that will produce a potential difference of one volt in response to a current of one amp.[55]
: 30–35 

The capacitor is a development of the Leyden jar and is a device that can store charge, and thereby storing electrical energy in the resulting field. It consists of two conducting plates separated by a thin insulating dielectric layer; in practice, thin metal foils are coiled together, increasing the surface area per unit volume and therefore the capacitance. The unit of capacitance is the farad, named after Michael Faraday, and given the symbol F: one farad is the capacitance that develops a potential difference of one volt when it stores a charge of one coulomb. A capacitor connected to a voltage supply initially causes a current as it accumulates charge; this current will however decay in time as the capacitor fills, eventually falling to zero. A capacitor will therefore not permit a steady state current, but instead blocks it.[55]: 216–20 

The inductor is a conductor, usually a coil of wire, that stores energy in a magnetic field in response to the current through it. When the current changes, the magnetic field does too, inducing a voltage between the ends of the conductor. The induced voltage is proportional to the time rate of change of the current. The constant of proportionality is termed the inductance. The unit of inductance is the henry, named after Joseph Henry, a contemporary of Faraday. One henry is the inductance that will induce a potential difference of one volt if the current through it changes at a rate of one ampere per second. The inductor's behaviour is in some regards converse to that of the capacitor: it will freely allow an unchanging current, but opposes a rapidly changing one.[55]: 226–29 

Electric power

Main article: electric power

Electric power is the rate at which

watt, one joule per second
.

Electric power, like

work, measured in watts, and represented by the letter P. The term wattage is used colloquially to mean "electric power in watts." The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential (voltage
) difference of V is

where

Q is electric charge in coulombs
t is time in seconds
I is electric current in amperes
V is electric potential or voltage in volts

Electric power is generally supplied to businesses and homes by the

fossil fuels, electricity is a low entropy form of energy and can be converted into motion or many other forms of energy with high efficiency.[56]

Electronics

Main article: electronics
Surface-mount
electronic components

Electronics deals with

circuit boards, electronics packaging technology, and other varied forms of communication infrastructure complete circuit functionality and transform the mixed components into a regular working system
.

Today, most electronic devices use

electronics engineering.[59]

Electromagnetic wave

Main article:
Electromagnetic wave

Faraday's and Ampère's work showed that a time-varying magnetic field created an electric field, and a time-varying electric field created a magnetic field. Thus, when either field is changing in time, a field of the other is always induced.

electromagnetic wave. Electromagnetic waves were analysed theoretically by James Clerk Maxwell in 1864. Maxwell developed a set of equations that could unambiguously describe the interrelationship between electric field, magnetic field, electric charge, and electric current. He could moreover prove that in a vacuum such a wave would travel at the speed of light, and thus light itself was a form of electromagnetic radiation. Maxwell's equations, which unify light, fields, and charge are one of the great milestones of theoretical physics.[23]
: 696–700 

The work of many researchers enabled the use of electronics to convert signals into high frequency oscillating currents and, via suitably shaped conductors, electricity permits the transmission and reception of these signals via radio waves over very long distances.[60]

Production, storage and uses

Generation and transmission

Main article: Electricity generation
See also: Electric power transmission and Mains electricity
Prokudin-Gorsky
, 1905–1915).

In the 6th century BC the Greek philosopher

electrical battery, store energy chemically and make it available on demand in the form of electricity.[61]

Electrical power is usually generated by electro-mechanical

generators. These can be driven by steam produced from fossil fuel combustion or the heat released from nuclear reactions, but also more directly from the kinetic energy of wind or flowing water. The steam turbine invented by Sir Charles Parsons in 1884 is still used to convert the thermal energy of steam into a rotary motion that can be used by electro-mechanical generators. Such generators bear no resemblance to Faraday's homopolar disc generator of 1831, but they still rely on his electromagnetic principle that a conductor linking a changing magnetic field induces a potential difference across its ends.[62] Electricity generated by solar panels rely on a different mechanism: solar radiation is converted directly into electricity using the photovoltaic effect.[63]

A wind farm of about a dozen three-bladed white wind turbines.
Wind power is of increasing importance in many countries.

Demand for electricity grows with great rapidity as a nation modernises and its economy develops.[64] The United States showed a 12% increase in demand during each year of the first three decades of the twentieth century,[65] a rate of growth that is now being experienced by emerging economies such as those of India or China.[66][67]

solar have become cost effective, speeding up an energy transition away from fossil fuels.[68]

Transmission and storage

The invention in the late nineteenth century of the

electrical transmission meant in turn that electricity could be generated at centralised power stations, where it benefited from economies of scale, and then be despatched relatively long distances to where it was needed.[69][70]

Normally, demand of electricity must match the supply, as storage of electricity is difficult.[69] A certain amount of generation must always be held in reserve to cushion an electrical grid against inevitable disturbances and losses.[71] With increasing levels of variable renewable energy (wind and solar energy) in the grid, it has become more challenging to match supply and demand. Storage plays an increasing role in bridging that gap. There are four types of energy storage technologies, each in varying states of technology readiness: batteries (electrochemical storage), chemical storage such as hydrogen, thermal or mechanical (such as pumped hydropower).[72]

Applications

resistance
generating heat.

Electricity is a very convenient way to transfer energy, and it has been adapted to a huge, and growing, number of uses.[73] The invention of a practical incandescent light bulb in the 1870s led to lighting becoming one of the first publicly available applications of electrical power. Although electrification brought with it its own dangers, replacing the naked flames of gas lighting greatly reduced fire hazards within homes and factories.[74] Public utilities were set up in many cities targeting the burgeoning market for electrical lighting. In the late 20th century and in modern times, the trend has started to flow in the direction of deregulation in the electrical power sector.[75]

The resistive

heat pumps).[81][82]

The effects of electromagnetism are most visibly employed in the

pantograph. Electrically powered vehicles are used in public transportation, such as electric buses and trains,[83] and an increasing number of battery-powered electric cars
in private ownership.

Electricity is used within

Optical fibre and satellite communication
have taken a share of the market for communications systems, but electricity can be expected to remain an essential part of the process.

Electronic devices make use of the transistor, perhaps one of the most important inventions of the twentieth century,[85] and a fundamental building block of all modern circuitry. A modern integrated circuit may contain many billions of miniaturised transistors in a region only a few centimetres square.[86]

Electricity and the natural world

Physiological effects

Main article:
Electric shock

A voltage applied to a human body causes an electric current through the tissues, and although the relationship is non-linear, the greater the voltage, the greater the current.[87] The threshold for perception varies with the supply frequency and with the path of the current, but is about 0.1 mA to 1 mA for mains-frequency electricity, though a current as low as a microamp can be detected as an electrovibration effect under certain conditions.[88] If the current is sufficiently high, it will cause muscle contraction, fibrillation of the heart, and tissue burns.[87] The lack of any visible sign that a conductor is electrified makes electricity a particular hazard. The pain caused by an electric shock can be intense, leading electricity at times to be employed as a method of torture.[89] Death caused by an electric shock—electrocution—is still used for judicial execution in some US states, though its use had become very rare by the end of the 20th century.[90]

Electrical phenomena in nature

Main article:
Electrical phenomena
The electric eel, Electrophorus electricus

Electricity is not a human invention, and may be observed in several forms in nature, notably

Jacques Curie. The effect is reciprocal: when a piezoelectric material is subjected to an electric field it changes size slightly.[92]

Some organisms, such as

electrocytes.[3][4] All animals transmit information along their cell membranes with voltage pulses called action potentials, whose functions include communication by the nervous system between neurons and muscles.[94] An electric shock stimulates this system, and causes muscles to contract.[95] Action potentials are also responsible for coordinating activities in certain plants.[94]

Cultural perception

It is said that in the 1850s, British politician

William Gladstone asked the scientist Michael Faraday why electricity was valuable. Faraday answered, "One day sir, you may tax it."[96][97][98] However, according to Snopes.com "the anecdote should be considered apocryphal because it isn't mentioned in any accounts by Faraday or his contemporaries (letters, newspapers, or biographies) and only popped up well after Faraday's death."[99]

In the 19th and early 20th century, electricity was not part of the everyday life of many people, even in the industrialised Western world. The popular culture of the time accordingly often depicted it as a mysterious, quasi-magical force that can slay the living, revive the dead or otherwise bend the laws of nature.[100]: 69  This attitude began with the 1771 experiments of Luigi Galvani in which the legs of dead frogs were shown to twitch on application of animal electricity. "Revitalization" or resuscitation of apparently dead or drowned persons was reported in the medical literature shortly after Galvani's work. These results were known to Mary Shelley when she authored Frankenstein (1819), although she does not name the method of revitalization of the monster. The revitalization of monsters with electricity later became a stock theme in horror films.

As the public familiarity with electricity as the lifeblood of the

Charles Steinmetz or Nikola Tesla—were popularly conceived of as having wizard-like powers.[100]
: 71 

With electricity ceasing to be a novelty and becoming a necessity of everyday life in the later half of the 20th century, it required particular attention by popular culture only when it stops flowing,[100]: 71  an event that usually signals disaster.[100]: 71  The people who keep it flowing, such as the nameless hero of Jimmy Webb's song "Wichita Lineman" (1968),[100]: 71  are still often cast as heroic, wizard-like figures.[100]: 71 

See also

Notes

  1. ^ Accounts differ as to whether this was before, during, or after a lecture.
  2. ^ Almost all electric fields vary in space. An exception is the electric field surrounding a planar conductor of infinite extent, the field of which is uniform.
  1. ^ Jones, D.A. (1991), "Electrical engineering: the backbone of society", IEE Proceedings A – Science, Measurement and Technology, 138 (1): 1–10,
    doi:10.1049/ip-a-3.1991.0001
  2. JSTOR 1311732
  3. ^ a b c Bullock, Theodore H. (2005), Electroreception, Springer, pp. 5–7,
    ISBN 978-0-387-23192-1
  4. ^ a b Morris, Simon C. (2003), Life's Solution: Inevitable Humans in a Lonely Universe, Cambridge University Press, pp. 182–85,
    ISBN 0-521-82704-3
  5. ^ a b Stewart, Joseph (2001), Intermediate Electromagnetic Theory, World Scientific, p. 50,
    ISBN 981-02-4471-1
  6. ^ Simpson, Brian (2003), Electrical Stimulation and the Relief of Pain, Elsevier Health Sciences, pp. 6–7,
    ISBN 0-444-51258-6
  7. ^ Diogenes Laertius, R.D. Hicks (ed.), "Lives of Eminent Philosophers, Book 1 Chapter 1 [24]", Perseus Digital Library, Tufts University, archived from the original on 30 July 2022, retrieved 5 February 2017, Aristotle and Hippias affirm that, arguing from the magnet and from amber, he attributed a soul or life even to inanimate objects.
  8. ^ Aristotle, Daniel C. Stevenson (ed.), "De Animus (On the Soul) Book 1 Part 2 (B4 verso)", The Internet Classics Archive, translated by J.A. Smith, archived from the original on 26 February 2017, retrieved 5 February 2017, Thales, too, to judge from what is recorded about him, seems to have held soul to be a motive force, since he said that the magnet has a soul in it because it moves the iron.
  9. ^ Frood, Arran (27 February 2003), Riddle of 'Baghdad's batteries', BBC, archived from the original on 3 September 2017, retrieved 16 February 2008
  10. ^ Baigrie, Brian (2007), Electricity and Magnetism: A Historical Perspective, Greenwood Press, pp. 7–8,
    ISBN 978-0-313-33358-3
  11. ^ Chalmers, Gordon (1937), "The Lodestone and the Understanding of Matter in Seventeenth Century England", Philosophy of Science, 4 (1): 75–95,
    S2CID 121067746
  12. ^
    S2CID 34246664
  13. ^ Srodes, James (2002), Franklin: The Essential Founding Father, Regnery Publishing, pp. 92–94,
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References

External links

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