The history
From amber that pulls on feathers to the ampere defined by counting electrons: how people learned what flows in a wire and what pushes it.
For two thousand years electricity was a curiosity of sparks and rubbed amber. Then Volta's pile made charge flow steadily, Ampère measured the flow, and the war of the currents brought AC into homes. Only in 1897 did anyone find the electrons that actually move, and today a lithium cell in your pocket and 230 V in your walls are taken for granted.
c. 600 BCE
Electric attraction recorded
Thales of Miletus (attributed), Ionia
1600
The word 'electricus'
William Gilbert, England
1747
Positive and negative charge named
Benjamin Franklin, Philadelphia
1800
First battery, first steady current
Alessandro Volta, Italy
1879
Electric light shown in India
P. W. Fleury & Co., Calcutta
1897
India's first hydroelectric station
Sidrapong, Darjeeling
1897
Electron discovered
J. J. Thomson, Cambridge
600 BCE – 1760
Rubbed amber, conductors and insulators, the Leyden jar, and Franklin's plus and minus.
600 BCE
c. 600 BCE
Rub a piece of amber with fur and it pulls on bits of straw and feathers. Later Greek writers credit Thales with noticing this, though none of his own writings survive. The Greek word for amber, elektron, gave us 'electricity'.
Why it mattered. The first recorded brush with electric charge, and the root of the word.
1600
In De Magnete, the English doctor William Gilbert showed that glass, sulphur and many gems attract things just as amber does. He called them 'electrica', from the Latin electricus, 'like amber', and built a pivoting needle to detect the pull.
Why it mattered. Electricity became a subject of its own, separate from magnetism.
1729
Stephen Gray sent the 'electric virtue' from a rubbed glass tube along hundreds of feet of thread hung on silk. Metal wire and damp thread carried it; silk did not. He had found conductors and insulators.
Why it mattered. Electricity could move from place to place: the first hint of a current.
1745
1745–1746
Two experimenters, working separately, found that a water-filled glass jar could store a large charge and release it in one painful spark. The Leyden jar became the battery of 18th-century science.
Why it mattered. For the first time, charge could be collected and let go on demand.
1747
Franklin argued that electricity is a single 'fluid'. A body with too much was 'positive' (plus), one with too little 'negative' (minus). The choice of which was which was a guess, and it is why conventional current flows from + to − while electrons go the other way.
Why it mattered. The signs on every battery, and the 'backwards' arrows on circuit diagrams, come from here.
1752
June 1752
Franklin is said to have flown a kite in a thunderstorm and drawn sparks from a key on its wet string, showing that lightning is electricity. The details come from later accounts, and he was lucky: others were killed repeating such experiments.
Why it mattered. Lightning was proved to be electric, and Franklin's lightning rod soon protected buildings.
1790 – 1835
Galvani's frog, Volta's pile, and Ørsted, Ampère, Ohm and Faraday turning current into a science.
1791
Galvani found that a dissected frog's leg twitched when touched with two different metals. He believed the electricity came from the animal itself, which he called 'animal electricity'. We now know nerves really do signal with electricity.
Why it mattered. The argument over the frog's leg led straight to the battery.
1800
20 March 1800
Volta stacked discs of zinc and copper separated by cloth soaked in brine, and got a steady flow of electricity for the first time. He described his 'pile' in a letter to the Royal Society in London. The unit of voltage, the volt, is named after him.
Why it mattered. The first steady current: electricity could now flow, not just spark.
1820
September 1820 – 1827
Within weeks of hearing of Ørsted's result, Ampère showed that two parallel wires carrying current attract or repel each other. He called the flow an electric 'current', worked out the law of the force between currents, and studied it until 1827. The unit of current, the ampere, honours him.
Why it mattered. Current became something you could measure by its force.
1827
Ohm published the rule linking the push, the flow and the resistance of a wire: current = voltage ÷ resistance. OhmsLawClear tells the full story.
Why it mattered. It tied current and voltage together with one simple rule.
1831
29 August 1831
Faraday found that a changing magnetic field drives a current in a coil: electromagnetic induction. Every generator and transformer since depends on it (see FaradayClear).
Why it mattered. It made electricity something power stations could produce in bulk.
1875 – 1900
Light bulbs, the first power stations, the war of AC against DC, and electricity arriving in India.
1879
24 July 1879
The first public demonstration of electric light in India took place in Calcutta. Twenty years later, in 1899, the Calcutta Electric Supply Corporation opened the city's first power station.
Why it mattered. Electric light reached India within months of Edison's lamp.
1879
October 1879
Edison's team and Joseph Swan in England each made practical carbon-filament light bulbs. A good lamp gave people a reason to want electricity in every home.
Why it mattered. The light bulb created the demand for electricity supply.
1881
September 1881
Delegates from many countries agreed on practical electrical units, naming them after scientists: the volt, the ampere, the ohm, the coulomb and the farad.
Why it mattered. Engineers everywhere could now measure current and voltage the same way.
1882
4 September 1882
Edison's Pearl Street Station began supplying direct current (DC) to customers in lower Manhattan. DC could not easily be changed in voltage, so it only reached about a mile from the station.
Why it mattered. The start of electricity supplied from a central station.
1888
1886–1893
Westinghouse backed alternating current (AC), using transformers to send high voltages far and step them down for homes, and bought Nikola Tesla's AC motor patents in 1888. Edison campaigned that AC was deadly. AC lit the 1893 Chicago World's Fair and in 1895–96 carried power from Niagara Falls to Buffalo.
Why it mattered. It is why the socket in your wall gives AC.
1897
10 November 1897
The Sidrapong hydel station, with two 65 kW generators driven by mountain streams, began supplying Darjeeling. It is the oldest hydroelectric station in India and is still preserved.
Why it mattered. One of the first public electricity supplies in Asia.
1897 – today
The electron is found, lithium-ion batteries power phones and cars, and every Indian village is connected.
1897
30 April 1897
Thomson showed that cathode rays are streams of tiny negatively charged particles, far lighter than atoms. They were soon called electrons: the charges that actually move in a wire.
Why it mattered. A century after Franklin, the thing that flows in a current was finally identified.
1985
Whittingham made the first lithium battery in the 1970s and Goodenough found a better cathode in 1980. Yoshino replaced the dangerous lithium metal with carbon, making a safe rechargeable cell; Sony sold the first ones in 1991.
Why it mattered. The battery in every phone and electric car.
2018
28 April 2018
The government declared every inhabited village in India electrified when Leisang in Manipur was connected. A village counted as electrified once its public places and at least 10% of its homes had power; connecting every household took longer.
Why it mattered. A milestone 139 years after Calcutta's first electric light.
2019
20 May 2019
The SI units were redefined. The ampere is now set by fixing the charge of one electron at exactly 1.602176634 × 10⁻¹⁹ coulombs, so one amp is about 6.24 × 10¹⁸ electrons a second.
Why it mattered. Current is now defined by counting electrons, just as chapter 1 does.
2019
9 October 2019
The three chemists shared the Nobel Prize in Chemistry. At 97, Goodenough became the oldest Nobel laureate ever.
Why it mattered. The prize recognised the battery that made portable electronics and electric cars possible.
Did you know?
The word 'electricity' comes from elektron, the Greek word for amber.
Electrons in a torch wire drift at about a tenth of a millimetre per second, slower than a snail.
One ampere is about 6.24 billion billion electrons passing every second.
Conventional current flows from + to − only because Franklin guessed which charge was which in 1747.
In 2022 lightning killed about 2,900 people in India, more than any other force of nature.
The people
1544 – 1603 · Physician and natural philosopher · Colchester, England
Named electric attraction after amber.
1666 – 1736 · Dyer and astronomer · Canterbury, England
Showed that charge travels along conductors.
1706 – 1790 · Printer, scientist and statesman · Boston, United States
Named positive and negative charge and invented the lightning rod.
1737 – 1798 · Physician · Bologna, Italy
Made frogs' legs twitch with metals: 'animal electricity'.
1745 – 1827 · Physicist · Como, Italy
Built the first battery; the volt is named after him.
1775 – 1836 · Physicist and mathematician · Lyon, France
Founded electrodynamics; the ampere is named after him.
1856 – 1943 · Inventor and engineer · Smiljan (now Croatia)
Designed the AC induction motor that Westinghouse used.
1856 – 1940 · Physicist · Manchester, England
Discovered the electron.
1922 – 2023 · Materials scientist · Jena, Germany
Found the cathode that made lithium-ion batteries powerful.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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