Principia

@principiah.bsky.social

Stories of physics and the cosmos. A documentary series on how humanity discovered electricity, one experiment at a time, with the physics computed, not just told. New episode every week. https://www.youtube.com/@principiah

6 August 1890, Auburn Prison. William Kemmler is strapped into an oak chair wired to a second-hand alternating dynamo its maker refused to sell. Seventeen seconds; the doctors call it; his chest heaves. The war of the currents at its ugliest. Ep. 9 of How Humanity Discovered Electricity #histsci

Tesla vs Edison: The War That Ended in an Electric Chair (1890) | Electricity, Ep. 9

Pearl Street, the transformer, Tesla's rotating field, Harold Brown's dog, Kemmler's chair, Frankfurt and Niagara: the war of the currents, with the numbers that decided it.

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April 1820. During a lecture, Ørsted brings a compass next to a wire carrying current and the needle swings sideways: not towards the wire, not away from it, across it. Within weeks Ampère measures the force between two currents. Ep. 5 of How Humanity Discovered Electricity #histsci #physics

The Needle That Moved: Ørsted, Ampère and the Birth of Electromagnetism | Electricity, Ep. 5

Ørsted's needle, Ampère's forces and the birth of electromagnetism. Principia, 15 min.

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1800. Volta stacks discs of zinc and silver with brine-soaked cloth between them and gets, for the first time, a current that does not stop: the battery. It began with Galvani's frog legs twitching on a balcony in Bologna. Ep. 4 of How Humanity Discovered Electricity #histsci #physics

The Frog, the Battery and the First Electric Current | How Humanity Discovered Electricity, Ep. 4

Galvani's frog, Volta's pile and the first continuous current. Principia, 15 min.

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1785. Coulomb hangs a needle from a silver wire so fine that one degree of twist measures a force of a few billionths of a newton, and finds that the force between charges falls with the square of the distance. Franklin's rod came first. Ep. 3 of How Humanity Discovered Electricity #histsci

Franklin, the Lightning Rod and Coulomb's Law | How Humanity Discovered Electricity, Ep. 3

Franklin, the lightning rod and Coulomb's torsion balance. Principia, 15 min.

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1746. Pieter van Musschenbroek charges the water in a glass jar and touches the wire. The shock is so violent he writes that he would not take it again for the kingdom of France. The Leyden jar: the first device to store electricity. Ep. 2 of How Humanity Discovered Electricity #histsci #physics

The Jar That Nearly Killed Its Inventor (1746) | How Humanity Discovered Electricity, Ep. 2

The Leyden jar, from a Dutch physics cabinet to the shock felt across Europe. Principia, 15 min.

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1600. William Gilbert carves a lodestone into a sphere, moves a small needle over it and watches it dip exactly as compass needles dip at sea. The Earth is a magnet. Six hundred pages of experiments: De Magnete, the first modern book of physics. Ep. 1 of How Humanity Discovered Electricity #histsci

The Earth Is a Magnet. One Man Proved It in 1600 | How Humanity Discovered Electricity, Ep. 1

Gilbert, the terrella and the first experimental book of physics. Principia, 13 min.

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1861. Maxwell works out how fast a disturbance travels through his model of empty space: 310,740 km/s, a number two Germans had measured five years earlier with a Leyden jar and a magnetic needle. Fizeau's speed of light: 314,858 km/s. Ep. 8 of How Humanity Discovered Electricity #histsci #physics

The Speed of Light Was Hiding in a Jar of Electricity (1861) | Electricity, Ep. 8

Maxwell, Weber and Kohlrausch, Fizeau and Hertz: how the speed of light turned up in a jar of electricity, and how an invisible wave was measured with a tape. Principia, 16 min.

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