history.json

{
  "title": "The history of work and power",
  "tagline": "From Archimedes' lever to the star label on your AC: how people learned that force times distance is something you can measure, sell and pay for.",
  "intro": "For two thousand years people used levers and pulleys without a word for what they traded. Galileo saw that a machine gains force only by losing distance, engineers measured horses and water wheels, and in 1829 Coriolis and Poncelet gave the idea its name: work. Joule showed that work and heat are the same stuff, the watt and the joule became units, and meters began to charge homes for every kilowatt-hour.",
  "eras": [
    { "id": "machines", "name": "Machines and the golden rule", "from": -250, "to": 1640, "color": "#c49bff", "summary": "Greek engineers explain the lever and the pulley, and Galileo sees the catch: what a machine gains in force it loses in distance." },
    { "id": "measure", "name": "Measuring a day's work", "from": 1700, "to": 1790, "color": "#ffb547", "summary": "Engineers selling pumps and mills compare them with horses and measure weight raised times height, per minute." },
    { "id": "name", "name": "Work gets a name", "from": 1824, "to": 1850, "color": "#8ef0ff", "summary": "French engineers call force times distance 'travail', and Joule shows that work and heat are two faces of one thing." },
    { "id": "units", "name": "Units, meters and bills", "from": 1882, "to": 2026, "color": "#5ce1a9", "summary": "The watt and the joule become units, meters count kilowatt-hours, and star labels help families pick appliances that do the same job with less energy." }
  ],
  "events": [
    { "year": -250, "date": "c. 250 BCE", "era": "machines", "art": "scales", "key": true,
      "title": "The law of the lever", "who": "Archimedes", "where": "Syracuse, Sicily", "country": "Italy",
      "text": "In On the Equilibrium of Planes, Archimedes proved that weights balance on a lever when weight times distance from the pivot is the same on both sides. A later writer, Pappus, credits him with the boast: give me a place to stand and I will move the Earth.",
      "why": "It is the first exact rule for trading a small force for a big one.", "box": "machines", "sources": [24, 6] },
    { "year": 60, "date": "c. 60 CE (dating uncertain)", "era": "machines", "art": "scroll",
      "title": "Five machines to move a load", "who": "Hero of Alexandria", "where": "Alexandria, Egypt", "country": "Egypt",
      "text": "Hero's Mechanics lists five devices for moving heavy loads: the lever, the windlass, the pulley, the wedge and the screw. He explained them with balanced forces, but had no idea yet of work.",
      "why": "These are still the simple machines taught in school today.", "box": "machines", "sources": [25, 6] },
    { "year": 1600, "date": "c. 1600 (printed 1634)", "era": "machines", "art": "quill", "key": true,
      "title": "You can't cheat nature", "who": "Galileo Galilei", "where": "Padua, Republic of Venice", "country": "Italy",
      "text": "Teaching at Padua, Galileo wrote Le Mecaniche, a short book on levers, pulleys, screws and ramps. He showed they all follow one rule: a machine that lets a small force lift a big weight makes that force move much further. Marin Mersenne printed it in French in 1634.",
      "why": "It is the first clear statement that machines transform effort but never create it.", "box": "machines", "sources": [7, 8, 6] },
    { "year": 1637, "date": "1637", "era": "machines", "art": "inkpot",
      "title": "Weight times height", "who": "René Descartes", "where": "Dutch Republic", "country": "Netherlands",
      "text": "In a letter explaining machines to Constantijn Huygens, Descartes wrote that lifting 100 pounds one foot twice is the same as lifting 200 pounds one foot, or 100 pounds two feet. The effort of a job is weight multiplied by height.",
      "why": "It measures a machine's job the way we measure work today.", "box": "idea", "sources": [0] },
    { "year": 1702, "date": "1702", "era": "measure", "art": "piston",
      "title": "As many horses as it replaces", "who": "Thomas Savery", "where": "London, England", "country": "United Kingdom",
      "text": "In The Miner's Friend, Savery sold his steam pump for draining mines by saying how many horses it could replace. Mine owners paid for horses, so a horse was a unit they understood.",
      "why": "Comparing engines with horses led to the horsepower.", "sources": [1, 27] },
    { "year": 1759, "date": "1759", "era": "measure", "art": "gear",
      "title": "Testing water wheels", "who": "John Smeaton", "where": "London, England", "country": "United Kingdom",
      "text": "Smeaton spent seven years testing model water wheels and windmills and reported how much weight each could raise, how high, in a given time. He showed that an overshot wheel, fed from the top, does far more work than an undershot one. The Royal Society gave him its Copley Medal.",
      "why": "Measuring weight raised times height per minute is measuring power.", "sources": [13, 0] },
    { "year": 1782, "date": "1782–1783", "era": "measure", "art": "horse", "key": true,
      "title": "One horsepower", "who": "James Watt and Matthew Boulton", "where": "Birmingham, England", "country": "United Kingdom",
      "text": "Watt watched mill horses turn a wheel of 12 ft radius 144 times an hour, pulling with about 180 pounds-force. That came to about 32,600 foot-pounds a minute. In 1783 he and Boulton rounded it up to 33,000: one horsepower, today 745.7 W.",
      "why": "It gave buyers a number for how fast an engine could work.", "box": "people", "sources": [1, 2] },
    { "year": 1824, "date": "1824", "era": "name", "art": "flame",
      "title": "The motive power of fire", "who": "Sadi Carnot", "where": "Paris, France", "country": "France",
      "text": "Carnot asked how much work a steam engine could possibly get from its fuel. He found a limit set by how hot and how cold its two ends are, so no heat engine can turn all its heat into work.",
      "why": "It explains why a petrol engine is only about 30% efficient.", "box": "machines", "sources": [23] },
    { "year": 1829, "date": "1829", "era": "name", "art": "block", "key": true,
      "title": "Travail: work gets its name", "who": "Gaspard-Gustave Coriolis", "where": "Paris, France", "country": "France",
      "text": "In Du calcul de l'effet des machines, Coriolis called force times distance moved 'travail', work. He also put the half into ½ m v², showing that the work done on a body equals the change in its energy of motion. He even proposed a unit, the dynamode, 1,000 kilogram-metres, which never caught on.",
      "why": "Work became a precise, measurable quantity for engineers.", "box": "idea", "sources": [9, 10, 11, 0] },
    { "year": 1829, "date": "1826–1829", "era": "name", "art": "wrench",
      "title": "Mechanics for the factory", "who": "Jean-Victor Poncelet", "where": "Metz, France", "country": "France",
      "text": "Teaching engineers and workers at Metz, Poncelet used 'mechanical work' as the key idea for judging machines, independently of Coriolis. His Introduction à la mécanique industrielle came out in 1829, and he also designed better water wheels.",
      "why": "He made work the everyday language of engineering.", "sources": [12, 0] },
    { "year": 1845, "date": "1845", "era": "name", "art": "thermometer", "key": true,
      "title": "The paddle wheel", "who": "James Prescott Joule", "where": "Manchester, England", "country": "United Kingdom",
      "text": "Joule let falling weights spin a paddle wheel in an insulated can of water and measured how much the water warmed. The same amount of work always gave the same amount of heat: 819 foot-pounds per British thermal unit in 1845, refined to about 772 by 1850.",
      "why": "It proved that work and heat are both energy, which is why the unit of work is the joule.", "box": "limits", "sources": [14, 15] },
    { "year": 1882, "date": "August 1882", "era": "units", "art": "bolt",
      "title": "A unit called the watt", "who": "C. William Siemens", "where": "Southampton, England", "country": "United Kingdom",
      "text": "In his presidential address to the British Association, Siemens proposed naming the practical unit of electrical power after James Watt.",
      "why": "It joined the steam age and the electric age in one unit.", "sources": [2] },
    { "year": 1888, "date": "1888", "era": "units", "art": "coil", "key": true,
      "title": "A meter for AC", "who": "Oliver B. Shallenberger", "where": "Pittsburgh, USA", "country": "United States",
      "text": "Working for Westinghouse, Shallenberger noticed a loose spring turning in the magnetic field of an AC lamp. He turned the idea into a meter that measured how much alternating current a customer used. About 120,000 were sold within ten years.",
      "why": "Homes could now be charged for the energy they used, not a flat fee per lamp.", "box": "bill", "sources": [5, 4] },
    { "year": 1889, "date": "31 August 1889", "era": "units", "art": "plug",
      "title": "The joule and the watt made official", "who": "International Electrical Congress", "where": "Paris, France", "country": "France",
      "text": "Meeting during the Paris World's Fair, the congress adopted the joule for work and the watt, one joule per second, for power. Joule died in October that year, weeks after his unit became official.",
      "why": "Scientists and engineers everywhere could now use the same words for work and power.", "sources": [3, 21, 2] },
    { "year": 1889, "date": "autumn 1889", "era": "units", "art": "motor",
      "title": "The kilowatt-hour meter", "who": "Ottó Bláthy, Ganz Works", "where": "Budapest, Hungary", "country": "Hungary",
      "text": "Bláthy's induction meter, shown at the Frankfurt Fair, used a spinning disc to add up power over time and show kilowatt-hours. The same principle ran most electricity meters for the next hundred years.",
      "why": "The kilowatt-hour became the unit on every electricity bill.", "box": "bill", "sources": [4, 28, 26] },
    { "year": 1960, "date": "1960", "era": "units", "art": "scales",
      "title": "Joule and watt join the SI", "who": "11th General Conference on Weights and Measures", "where": "Sèvres, France", "country": "France",
      "text": "The new International System of Units, the SI, made the joule (a newton times a metre) its unit of energy and work, and the watt (a joule per second) its unit of power.",
      "why": "One set of units now serves physics, engineering and your electricity bill.", "sources": [2, 22] },
    { "year": 1975, "date": "1975", "era": "units", "art": "magnet",
      "title": "Weighing with watts", "who": "Bryan Kibble", "where": "Teddington, England", "country": "United Kingdom",
      "text": "At the National Physical Laboratory, Kibble designed a balance that compares mechanical power, a mass moving in gravity, with electrical power in a coil. It was called the watt balance.",
      "why": "Power became precise enough to define the kilogram itself.", "sources": [16] },
    { "year": 1979, "date": "12 June 1979", "era": "units", "art": "plane",
      "title": "Pedalling across the Channel", "who": "Bryan Allen, Paul MacCready's team", "where": "Folkestone, England to Cap Gris-Nez, France", "country": "United Kingdom",
      "text": "Cyclist Bryan Allen pedalled the Gossamer Albatross 35.7 km across the English Channel in 2 hours 49 minutes, producing about 300 W, just enough to keep the ultralight plane in the air.",
      "why": "It shows how much a fit person can do with a few hundred watts.", "box": "people", "sources": [17] },
    { "year": 2006, "date": "18 May 2006", "era": "units", "art": "acunit", "key": true,
      "title": "India's star labels", "who": "Bureau of Energy Efficiency", "where": "New Delhi, India", "country": "India",
      "text": "Under the Energy Conservation Act 2001, the BEE launched its star labels: one to five stars showing how many units a year an appliance needs. From 7 January 2010 labels became mandatory for frost-free fridges, room ACs, tube lights and distribution transformers.",
      "why": "Families could compare the energy bill before buying, not after.", "box": "bill", "sources": [18, 19, 20] },
    { "year": 2019, "date": "20 May 2019", "era": "units", "art": "scales",
      "title": "The kilogram, by way of the watt", "who": "General Conference on Weights and Measures", "where": "Sèvres, France", "country": "France",
      "text": "The kilogram stopped being a metal cylinder in a vault. It is now fixed by the Planck constant, and Kibble balances, renamed after Bryan Kibble in 2016, realise it by balancing mechanical and electrical power.",
      "why": "A unit of mass now rests on measuring watts.", "sources": [16, 22] }
  ],
  "firsts": [
    { "label": "Law of the lever proved", "value": "c. 250 BCE", "who": "Archimedes, Syracuse" },
    { "label": "Machines trade force for distance", "value": "c. 1600", "who": "Galileo Galilei, Padua" },
    { "label": "Horsepower fixed at 33,000 ft·lbf/min", "value": "1783", "who": "James Watt and Matthew Boulton, Birmingham" },
    { "label": "'Work' (travail) named", "value": "1829", "who": "Gaspard-Gustave Coriolis, Paris" },
    { "label": "Work turned into a measured amount of heat", "value": "1845", "who": "James Prescott Joule, Manchester" },
    { "label": "Joule and watt adopted as units", "value": "1889", "who": "International Electrical Congress, Paris" },
    { "label": "Appliance star labels in India", "value": "2006", "who": "Bureau of Energy Efficiency, New Delhi" }
  ],
  "people": [
    { "name": "Archimedes", "life": "c. 287 – c. 212 BCE", "role": "Mathematician and engineer", "from": "Syracuse, Sicily", "note": "Proved the law of the lever." },
    { "name": "Hero of Alexandria", "life": "c. 10 – c. 70 CE", "role": "Engineer and mathematician", "from": "Egypt", "note": "Listed the five machines for moving loads." },
    { "name": "Galileo Galilei", "life": "1564 – 1642", "role": "Physicist and astronomer", "from": "Italy", "note": "Showed that every simple machine gains force only by losing distance." },
    { "name": "John Smeaton", "life": "1724 – 1792", "role": "Civil engineer", "from": "England", "note": "Measured the work of water wheels and windmills by experiment." },
    { "name": "James Watt", "life": "1736 – 1819", "role": "Engineer and inventor", "from": "Scotland", "note": "Defined the horsepower; the unit of power is named after him." },
    { "name": "Sadi Carnot", "life": "1796 – 1832", "role": "Engineer and physicist", "from": "France", "note": "Found the limit on how much work a heat engine can give." },
    { "name": "Gaspard-Gustave Coriolis", "life": "1792 – 1843", "role": "Mathematician and engineer", "from": "France", "note": "Named work 'travail' and wrote kinetic energy as ½ m v²." },
    { "name": "Jean-Victor Poncelet", "life": "1788 – 1867", "role": "Engineer and mathematician", "from": "France", "note": "Made mechanical work the language of industrial engineering." },
    { "name": "James Prescott Joule", "life": "1818 – 1889", "role": "Physicist and brewer", "from": "England", "note": "Measured how much heat a given amount of work makes." },
    { "name": "Oliver B. Shallenberger", "life": "1860 – 1898", "role": "Electrical engineer", "from": "United States", "note": "Invented the AC electricity meter for Westinghouse." },
    { "name": "Ottó Bláthy", "life": "1860 – 1939", "role": "Electrical engineer", "from": "Hungary", "note": "Built the induction kilowatt-hour meter." },
    { "name": "Bryan Kibble", "life": "1938 – 2016", "role": "Metrologist", "from": "England", "note": "Invented the watt balance that now helps define the kilogram." }
  ],
  "series": [],
  "facts": [
    "Watt measured about 32,600 foot-pounds a minute for a mill horse, then rounded up to 33,000, perhaps so that buyers of his engines would never feel short-changed.",
    "Europe and India often quote engines in metric horsepower (PS), 735.5 W, about 1.4% smaller than Watt's 745.7 W.",
    "One kilowatt-hour, a single unit on your bill, is 3.6 million joules: enough to lift a 1,000 kg car about 367 m.",
    "Joule died on 11 October 1889, weeks after the unit named after him was officially adopted.",
    "Coriolis also proposed a unit of work, the dynamode, 1,000 kilogram-metres. Nobody used it."
  ],
  "sources": [
    { "title": "Work (physics)", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Work_(physics)" },
    { "title": "Horsepower", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Horsepower" },
    { "title": "Watt", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Watt" },
    { "title": "Joule", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Joule" },
    { "title": "Electricity meter", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Electricity_meter" },
    { "title": "Oliver B. Shallenberger", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Oliver_B._Shallenberger" },
    { "title": "Simple machine", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Simple_machine" },
    { "title": "Le Mecaniche", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Le_Mecaniche" },
    { "title": "“It Is Impossible to Deceive Nature”: Galileo’s Le mecaniche", "publisher": "Philosophia Scientiae", "url": "https://journals.openedition.org/philosophiascientiae/1242?lang=en" },
    { "title": "Gaspard-Gustave de Coriolis", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Gaspard-Gustave_de_Coriolis" },
    { "title": "Du calcul de l'effet des machines (Coriolis, 1829)", "publisher": "Gallica, Bibliothèque nationale de France", "url": "https://gallica.bnf.fr/ark:/12148/bpt6k1068268" },
    { "title": "Gaspard-Gustave de Coriolis, biography", "publisher": "MacTutor History of Mathematics, University of St Andrews", "url": "https://mathshistory.st-andrews.ac.uk/Biographies/Coriolis/" },
    { "title": "Jean-Victor Poncelet", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Jean-Victor_Poncelet" },
    { "title": "John Smeaton", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/John_Smeaton" },
    { "title": "James Prescott Joule", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/James_Prescott_Joule" },
    { "title": "Mechanical equivalent of heat", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Mechanical_equivalent_of_heat" },
    { "title": "Kibble balance", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Kibble_balance" },
    { "title": "MacCready Gossamer Albatross", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Gossamer_Albatross" },
    { "title": "BEE Star Label", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/BEE_Star_Label" },
    { "title": "Standards and Labelling", "publisher": "Bureau of Energy Efficiency, Government of India", "url": "https://beeindia.gov.in/show_content.php?lang=1&level=1&ls_id=372&lid=322" },
    { "title": "BEE Energy Star Labelling Programme: a case study", "publisher": "CUTS International", "url": "https://cuts-ccier.org/pdf/Case_Study-Bee_Energy_Star_Labelling_Programme.pdf" },
    { "title": "International Electrical Congress", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/International_Electrical_Congress" },
    { "title": "The International System of Units (SI Brochure, 9th edition)", "publisher": "BIPM", "url": "https://www.bipm.org/en/publications/si-brochure" },
    { "title": "Nicolas Léonard Sadi Carnot", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Nicolas_L%C3%A9onard_Sadi_Carnot" },
    { "title": "Archimedes", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Archimedes" },
    { "title": "Hero of Alexandria", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Hero_of_Alexandria" },
    { "title": "Kilowatt-hour", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Kilowatt-hour" },
    { "title": "Thomas Savery", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Thomas_Savery" },
    { "title": "Ottó Bláthy", "publisher": "Wikipedia", "url": "https://en.wikipedia.org/wiki/Ott%C3%B3_Bl%C3%A1thy" }
  ]
}