98 Fun Facts About Mechanical

How many classical simple machines were defined by Renaissance scientists?

Six: lever, wheel and axle, pulley, inclined plane, wedge and screw make up the classical list, and all multiply force by trading it against distance.

What is the fixed pivot point of a lever called?

Fulcrum: the closer it sits to the load, the more a push on the long end is multiplied, so a crowbar pivoting five times nearer the rock than your hands lifts with five times your force.

The word 'lever', like 'levity', comes from a Latin adjective meaning what?

Light: Latin levis, 'light', gave levare, 'to raise', so a lever is literally a raiser; the same root gave 'levity' and 'levitate'.

In Plutarch's account, Archimedes showed off his system of pulleys by single-handedly hauling what towards him?

A fully laden ship: Archimedes had boasted to King Hiero that he could move any weight, and in Plutarch's telling he met the king's challenge with a block and tackle; Hero of Alexandria credits a windlass instead.

A screw converts rotation into what kind of movement?

Linear: each full turn advances a screw along its axis by a fixed distance called the lead, and the finer the thread, the more the turning force is multiplied.

Once a cold spray had collapsed the steam in Thomas Newcomen's 1712 engine, what force drove its working stroke?

Atmospheric pressure: the collapsing steam left a partial vacuum, and the weight of the air outside did the work, so the steam never had to be much above the air's own pressure, well within what the crude metalwork of the day could hold.

Which addition let James Watt's steam engines burn far less coal than Newcomen's?

A separate condenser: Newcomen's cylinder was chilled and reheated on every stroke, wasting heat, so Watt condensed the steam in a second vessel and kept the cylinder hot, an idea that struck him on a walk across Glasgow Green.

Which unit did James Watt fix at 33,000 foot-pounds per minute to sell his steam engines?

Horsepower: mill and brewery owners had no coal bills to compare, only horses, so Watt measured a brewery horse at work in 1782 and rated each engine by the number of animals it could replace.

Which spinning device resists any change to the direction of its axis, a property used to guide ships and spacecraft?

A gyroscope: Léon Foucault built and named one in 1852 to show the Earth turning beneath it, and the same stubborn spin now keeps the Hubble telescope and submerged submarines on course.

What did the spinning 'fly-ball' governor that James Watt fitted to his steam engines in 1788 automatically control?

Running speed: as the engine ran faster the balls swung outward and throttled the steam; James Clerk Maxwell's 1868 analysis of the device, 'On Governors', is counted as the start of control theory.

What are the four strokes of a four-stroke engine, in order?

Intake, compression, power, exhaust: only the third stroke delivers energy, so a flywheel stores part of each burst and hands it back to carry the engine through the other three.

Which German engineer built the first successful four-stroke internal combustion engine in 1876?

Nicolaus Otto's 1876 engine squeezed its fuel mixture before lighting it, but in 1886 his patent was annulled when a lawyer turned up a French patent for the same four-stroke idea, granted to Alphonse Beau de Rochas in 1862.

What ignites the fuel in a diesel engine?

The heat of compressed air: a diesel squeezes air to about a fifteenth of its volume or less, making it so hot that fuel sprayed in ignites at once, hence the name compression-ignition engine.

At the 1900 World's Fair, a Diesel engine was famously demonstrated running on which fuel?

Peanut oil: at the 1900 World's Fair a small Diesel engine was shown running on peanut oil at the request of the host government, an idea Diesel himself later championed; modern biodiesel revisits it.

Rudolf Diesel was born to Bavarian immigrants in which French city?

Paris: Diesel was born there in 1858, the son of a leather-goods maker; expelled to London when war with Prussia began in 1870, the family soon sent the boy on alone to relatives in Augsburg, where his technical schooling began.

A flywheel is a store of which kind of energy?

Rotational kinetic energy: it grows with the square of the spin rate, so carbon-fibre flywheels turning at tens of thousands of rpm store far more per kilogram than steel ones limited to a few thousand.

What does a car's differential let the two wheels on a drive axle do?

Turn at different speeds when cornering: the outer wheel travels farther than the inner, and the differential's gears let the two half-shafts spin at speeds whose average is the input speed.

What does a crankshaft convert?

Reciprocating motion into rotation: each connecting rod pushes on a crankpin set off-centre from the shaft, so a straight shove becomes a turning force, just as a cyclist's legs drive the pedal cranks round.

In a car engine, what does the camshaft operate?

The intake and exhaust valves: lobes on the spinning shaft push each one open in turn, and because every valve opens only once per two turns of the crankshaft, the camshaft is geared to run at half its speed.

Which Greek letter usually represents torque in physics?

Tau (τ) stands for torque, a force multiplied by its distance from the pivot, which is why a longer wrench frees a stubborn bolt with the same push.

Who invented the modern steam turbine in 1884?

Charles Parsons built his first steam turbine in 1884 to drive a dynamo; in 1897 his turbine yacht Turbinia turned up uninvited at the Royal Navy's Spithead review and, at 34 knots, outpaced the fastest warships there.

Which thermodynamic cycle describes an air-breathing jet engine?

Brayton: air is compressed, heated at constant pressure and expanded through a turbine; the cycle is named for George Brayton, whose 1872 'Ready Motor' used it in a gas engine with no turbine at all, decades before the first jet.

Which English RAF officer patented the turbojet in 1930 and first ran one in 1937?

Frank Whittle's Power Jets WU first ran on 12 April 1937; Germany's Hans von Ohain, working independently, built the engine that powered the first jet flight in 1939.

The rotor of a Wankel engine is roughly the shape of what?

A Reuleaux triangle: the rotor's three tips carry seals that proved the weak point of early cars, and the generous warranty on NSU's 1967 Ro 80 helped drain the firm, which Volkswagen took over in 1969.

The hydraulic press patented in 1795 is also known by which inventor's name?

Joseph Bramah patented the press in 1795, hence 'Bramah press'; the London locksmith also offered 200 guineas to anyone who could pick his lock, a prize unclaimed for decades until an American spent 16 days on it in 1851.

The hydraulic press works on a pressure principle named after which scientist?

Pascal's principle: pressure applied to a confined fluid is transmitted undiminished throughout it, so a small force on a small plunger produces a much larger force on a large one.

What was Archimedes' screw used for in antiquity?

Lift water for irrigation: a helix turning inside a tilted tube raises water, and the device irrigated fields and drained mines and ships' bilges in antiquity; run in reverse, modern versions generate power.

The Antikythera mechanism's bronze gears were built to predict what?

Eclipses: turning its crank moved dials that tracked the Sun and Moon and flagged eclipses years ahead; sponge divers found the wreck in 1900, and no gearing so intricate is known again until medieval clocks, over a thousand years later.

What component distinguishes a Stirling engine from other closed-cycle hot-air engines?

A regenerator: Robert Stirling, a Scottish clergyman, patented his 'economiser' in 1816, a heat store between the hot and cold spaces that gives the engine its efficiency.

Hooke's law states that the force needed to stretch a spring scales how with the distance?

Linearly: F = kx, so doubling the extension doubles the force; the hairspring of a watch's balance wheel relies on this to keep a constant period.

Elisha Otis's 1850s invention did what?

Stopped an elevator falling if its cable broke: orders were few until Otis showed the brake off at New York's Crystal Palace exhibition in 1854, and in 1857 he put the first passenger safety elevator in a city store.

Jesse Reno's 'inclined elevator', an early escalator, was installed beside a pier at which seaside resort?

Coney Island: Reno's machine at the Old Iron Pier was a sloping belt with cleats for grip rather than steps; stepped machines and the name 'escalator' came from Charles Seeberger and Otis a few years later.

Otis lost its 'escalator' trademark in 1950 because the word had become what?

A generic name for a moving stairway: in Haughton Elevator Co. v. Seeberger (1950) the US Patent Office found even Otis used 'escalator' generically, and the trademark was cancelled.

The original Ferris Wheel was built as a landmark for which event?

George Washington Gale Ferris Jr. designed the 80-metre wheel for the 1893 World's Columbian Exposition in Chicago as America's answer to the Eiffel Tower of 1889.

What powers a turbocharger, as opposed to a supercharger?

Exhaust gases spin a turbine that drives the compressor, where a supercharger takes its power from the crankshaft; the price is 'turbo lag', the pause while the exhaust flow builds enough to spin it up.

Two or more meshing gears together are called what?

A gear train: each meshing pair multiplies the ratio of the one before, which is how a clock's motion work turns the hour hand exactly once for every twelve turns of the minute hand.

Rack railways use a rack and pinion, with a toothed rack laid between the rails, to do what?

Climb steep gradients: a cog wheel on the locomotive engages the toothed rack so trains can climb grades far beyond what wheel adhesion allows, such as the Pilatus Railway's 48 percent.

Which shaft coupling, called a Cardan joint after a 16th-century Italian polymath, lets a drive shaft turn through an angle?

Universal joint: Cardano wrote only about gimbals, the pivoted rings behind the idea; Robert Hooke later found that a single joint makes the driven shaft speed up and slow down within each turn, so they are used in pairs that cancel it.

In a ratchet, what is the pivoting catch that stops the gear turning backwards called?

Pawl: a spring presses it against the sloped teeth, so it clicks over them one way and jams against them the other, which is how a socket wrench keeps turning a nut without being lifted off between strokes.

Which kind of bearing did Welsh ironmaster Philip Vaughan patent in 1794 to ease carriage axles?

Ball bearing: Vaughan set iron balls between axle and wheel so they rolled instead of rubbing; in 1869 a French mechanic's ball bearings were on the bicycle that won the first city-to-city road race.

The name of Hero of Alexandria's aeolipile comes from Aeolus, the Greek god of what?

Air and wind: the name means 'ball of Aeolus'; Hero's hollow sphere spun on its own jets of steam, yet as far as anyone knows it stayed a curiosity and never drove a machine.

The first practical windmills, with sails turning around an upright shaft, ground grain in which land?

Persia: there is no clear evidence of windmills anywhere before these, whose reed-mat or cloth sails spun around an upright shaft; the familiar kind with a horizontal axle appeared in northwestern Europe only in the 12th century.

Which fastener is named after a 1920s brand of rubber galoshes?

The zipper: Goodrich trademarked the word for its fastened overshoes, it is said after an executive slid the fastener up and down and echoed the sound it made, but the public soon used the word for the 'hookless fastener' itself.

Which 1793 machine by Eli Whitney used wire hooks to pull fibre through a mesh too fine for the seeds?

The cotton gin: 'gin' is short for engine, and by cleaning the fibre far faster than hands could, it made the crop so profitable that the South's demand for land and enslaved labour soared.

Which American's sewing machines, sold on instalment plans from the 1850s, made his surname a household brand?

Isaac Singer did not invent the sewing machine: Elias Howe held the lockstitch patent, won his case in 1854 and earned royalties on Singer's sales, while easy-payment plans from Singer's partner put the machines in ordinary homes.

Which mechanism shifts a bicycle's chain sideways from one sprocket to another to change gear?

Derailleur is French for 'derailer', because it knocks the chain off one sprocket and onto the next; the Tour de France allowed gear changing only from 1937, before which riders stopped and took out the rear wheel to switch gears.

In a steam engine, what does steam pressure push back and forth inside the cylinder?

A piston: in Watt's later engines steam was let in at each end of the cylinder in turn, so it pushed on both strokes instead of one, the 'double-acting' design that suited his engines to driving factory machinery.

Thomas Savery's 1702 book promoting his steam pump had what title?

The Miner's Friend: Savery promised to drain flooded mines, but suction could lift water only about 30 feet, so his engine would have had to sit deep underground; pumping deep mines had to wait for Newcomen's engine.

Which engineer built the first full-scale railway steam locomotive, hauling iron in Wales in 1804?

Richard Trevithick's engine ran on 21 February 1804, pulling 10 tons of iron, 70 men and five wagons along the Pen-y-darren tramway at Merthyr Tydfil.

What kind of 1905 disaster at a Massachusetts shoe factory spurred ASME to write its landmark safety code?

A boiler explosion: an old backup boiler at the Grover Shoe Factory in Brockton blew up through the roof, killing 58; Massachusetts answered with a state boiler law, and ASME's Boiler Code followed in 1914–15.

Which machine tool spins the workpiece itself while a cutting tool is pressed against it?

A lathe turns the work, not the cutter; around 1800 Henry Maudslay's screw-cutting lathe made it possible to cut identical threads again and again, which is what made standard, interchangeable nuts and bolts practical.

Which kind of spring, among the oldest in vehicle suspension, carried horse-drawn coaches and still holds up many trucks?

Leaf spring: its stacked steel strips spread a heavy load along the chassis instead of onto one point, which is why trucks keep them; in 1804 Obadiah Elliott's patent mounted coach bodies straight onto such springs.

Which 1808 locomotive gave Londoners shilling rides around a circular track near today's Euston?

Catch Me Who Can reached about 12 mph on its ring of track, but the show closed within weeks when a rail broke beneath it and it derailed, and its builder never made another locomotive.

Cornish engineer Arthur Woolf patented which kind of steam engine, later near-universal at sea?

Compound: steam expands first in a small high-pressure cylinder and then again in a larger one, getting more work from each ton of coal; stretched to three stages, the idea was almost universal in ships after 1880.

Zhang Heng's bronze urn of 132 AD dropped a ball from a dragon's mouth to signal what?

An earthquake: the ball that fell showed the direction of the shock, and the chronicles say it once dropped when nobody at court felt a thing, days before a messenger arrived with news of a quake hundreds of kilometres away.

Al-Jazari's celebrated medieval water clock sits on the back of which animal?

An elephant: a bowl with a small hole floats in a tank hidden inside it and takes half an hour to fill and sink, and each time it goes under it releases a ball and sets the figures on the elephant's back moving.

A towering Corliss steam engine, started by President Grant, powered the machinery at which city's 1876 world's fair?

Philadelphia: at the Centennial Exposition Grant and Brazil's Emperor Pedro II set the 45-foot engine going, and through a mile of shafting it drove nearly every exhibit; it later powered George Pullman's railcar works until 1910.

A contraption that performs a simple task through an absurdly complicated chain reaction is named after which American cartoonist?

Rube Goldberg trained as an engineer and spent six months on San Francisco's water and sewer works before quitting to draw cartoons; British readers call the same sort of machine a 'Heath Robinson'.

Which TV science presenter began his career as a mechanical engineer at Boeing, designing a part for the 747?

Bill Nye invented a hydraulic suppressor tube used on 747 airplanes while working in Seattle, then left the company in 1986 to write and perform comedy.

Failure of which rubber seal in a solid-fuel booster destroyed the Space Shuttle Challenger in 1986?

O-ring seals stiffened in the record cold of launch morning and could no longer close a booster joint, a flaw that test data had been pointing to since 1977.

Which kind of business in Dayton, Ohio, paid for the Wright brothers' early flying experiments?

A bicycle shop gave the Wrights more than money: riding taught them that an unstable machine can be balanced with practice, the idea behind their flight controls.

Which household machine did Josephine Cochrane patent in 1886 and sell at first mainly to hotels?

The dishwasher came to her after heirloom dishes were chipped while being washed after a dinner party, and her hand-powered design was the first one to succeed.

Henry Ford's moving assembly line of 1913 cut the build time of which car to about 93 minutes?

Model T assembly had taken more than 12 hours before the line started at Highland Park, and the saving let the price fall within reach of middle-class families.

Denis Papin's steam digester of 1679, built to extract fat from bones, was the forerunner of which kitchen appliance?

The pressure cooker owes its safety valve to him: early digesters exploded, so Papin added a steam-release valve, and watching it rise and fall gave him the idea for a steam engine.

Which element, making up at least 10.5% of the alloy, gives stainless steel its resistance to rust?

Chromium reacts with oxygen to form an invisible film on the surface that blocks corrosion and heals itself whenever the metal is scratched.

Willis Carrier designed the first modern air conditioner in 1902 to fix humidity at what kind of business?

A printing plant in Brooklyn was so humid in summer that its paper swelled and shrank between passes, so the four coloured inks no longer lined up.

Which Japanese carmaker championed the Wankel rotary engine for decades, from the 1967 Cosmo to the RX-7?

Mazda bet on the rotary to stand apart from its bigger rivals, and the gamble peaked in 1991 when its rotary-powered 787B won the 24 Hours of Le Mans.

Which figure displayed on a petrol pump measures the fuel's resistance to knocking inside an engine?

Octane rating is set against two reference fuels: iso-octane, which resists knocking, scores 100 by definition, and n-heptane, which knocks readily, scores 0.

Brass, the metal of trumpets and door handles, is an alloy of copper and which other element?

Zinc makes up roughly a third of a typical brass, and changing the proportion shifts the colour; swap it for tin and the alloy is bronze instead.

Which mode of heat transfer needs no material to travel through, letting the Sun warm Earth across empty space?

Radiation is the reason vacuum flasks are silvered: a vacuum stops the other routes for heat, so a mirror coating is added to bounce this one back.

Which of the classical simple machines does an axe head use to split a log apart?

The wedge is in effect a portable inclined plane and one of the oldest tools known: stone hand axes were being chipped into that shape hundreds of thousands of years ago.

Which everyday object is a textbook second-class lever, with the load sitting between the pivot and the effort?

A wheelbarrow puts the wheel at one end and your hands at the other with the load in between, the same layout as a nutcracker or a bottle opener.

Which component lets a driver disconnect a car's engine from the gearbox while changing gear?

The clutch is also allowed to slip on purpose: a partly engaged one lets the shafts turn at different speeds while a car pulls away from a standstill.

Which German engineer's three-wheeled Patent-Motorwagen is widely regarded as the first practical automobile?

Karl Benz got his best field test from his wife Bertha, who in August 1888 made the first long-distance journey in a car and had a cobbler fit leather brake linings on the way.

Which SI unit of energy equals the work done when a force of one newton moves one metre?

The joule honours James Prescott Joule, a Salford brewer's son who measured how much a falling weight warmed a tank of water as it stirred it.

Which device, largely replaced by fuel injection since the 1990s, mixes air and petrol before they enter an engine?

The carburettor lives on in lawnmowers, generators and many motorcycles, but it was never fitted to diesels, which have always injected their fuel.

Chuck Hull's 1980s stereolithography, hardening liquid resin under an ultraviolet beam, launched which technology?

3D printing grew from a day job: Hull was curing tabletop coatings with ultraviolet lamps in 1983 when he saw the same trick could build solid objects in thin layers.

Which failure mode, driven by repeated cabin pressurisation, broke up two de Havilland Comet jetliners in 1954?

Metal fatigue was not fully understood at the time, and the Comet had to be extensively redesigned and reinforced before its final version entered service in 1958.

Joseph Marie Jacquard's 1804 loom wove patterns by reading which medium, later borrowed by Charles Babbage?

Punched cards were laced into a long chain, one card for each row of the design, and a silk portrait of Jacquard woven this way needed 24,000 of them.

Which heat treatment hardens red-hot steel by plunging it into water or oil to cool it rapidly?

Quenching leaves steel hard but brittle, so it is usually followed by tempering, a gentler reheating that gives up some hardness in exchange for toughness.

Which manufacturing process makes long parts of constant cross-section by pushing material through a shaped die?

Extrusion pushes the material where drawing, its close cousin, pulls it through the die, and it shapes polymers, ceramics, clay and foodstuffs as well as metals.

Which joining process, the standard way to fix components to a circuit board, melts a filler metal but never the parts?

Soldering bonds the filler to both surfaces, so the joint conducts electricity and is gas-tight; brazing is the same idea run at a higher temperature for more strength.

What was the profession of Robert Stirling, the Scot who patented his hot-air engine in 1816?

A church minister by calling, Stirling was licensed to preach in 1816, the very year of the patent, and joined a parish in Kilmarnock that September.

Which phenomenon, reportedly set off by marching soldiers, collapsed England's Broughton Suspension Bridge in 1831?

Resonance from the troops' rhythmic steps took the blame, and the British Army responded with a standing order to break step whenever soldiers cross a bridge.

Isambard Kingdom Brunel's SS Great Britain was the first large ocean-going ship to combine an iron hull with what?

A screw propeller and an iron hull made her the largest passenger ship in the world from 1845, the year she became the first iron steamer to cross the Atlantic.

Which English joiner turned clockmaker solved the problem of finding longitude at sea with his marine chronometers?

John Harrison was chasing rewards of up to £20,000 offered under the 1714 Longitude Act, but the official prize was never awarded to anyone; Parliament paid him a separate £8,750 when he was 80.

Which locomotive won the 1829 Rainhill Trials, held to pick engines for the Liverpool and Manchester Railway?

Rocket was the only locomotive to complete the trials, taking the £500 prize and settling the argument that moving engines could beat stationary winding ones.

Which American self-taught chemist developed vulcanised rubber, patenting the sulphur-and-heat process in 1844?

Charles Goodyear did not found the tyre company that bears his name, which was only named in his honour, and the panic of 1837 had once left him penniless.

Which German physicist introduced the concept of entropy in 1865, naming it after a Greek word for transformation?

Rudolf Clausius had already set out the basic ideas of the second law of thermodynamics in 1850, in a paper on the moving force of heat.

Which thermodynamic cycle, named after a Glasgow professor, describes how steam power stations make electricity?

The Rankine cycle boils water into high-pressure steam, spins a turbine with it, then condenses the steam and pumps the water back round to the boiler.

Which word, coined by Peter Jost in 1966 from the Greek for rubbing, names the science of friction and wear?

Tribology got its name centuries after the work began: Leonardo da Vinci had noted the two basic laws of friction as far back as 1493.

Which English toolmaker devised a standard system of screw threads in 1841, fixing the thread angle at 55 degrees?

Joseph Whitworth learned precision while helping to build Charles Babbage's difference engine, and later designed a rifle so accurate it is counted among the first sniper weapons.

Which 1963 program by Ivan Sutherland is considered the ancestor of modern computer-aided design software?

Sketchpad was written for Sutherland's PhD thesis and let a user fix the length of a line or the angle between two; it helped earn him the Turing Award in 1988.

What was the name of the first industrial robot, which joined a General Motors assembly line in New Jersey in 1961?

Unimate weighed 4,000 pounds and took over a job that endangered workers, carrying die castings off the line and welding them onto car bodies.

Which mechanism turns steady rotation into the stop-start motion that advances film through a movie projector?

The Geneva drive takes its name from the mechanical watches popularised in that Swiss city, its earliest use, and a four-spoke version looks like a Maltese cross.

Which Belgian-born inventor patented a coal-gas internal combustion engine in 1860 and soon sold well over a hundred?

Étienne Lenoir also fitted his engine to a carriage he called the Hippomobile, which in 1863 made a test drive from Paris to Joinville-le-Pont in about three hours.

Which railway pioneer founded Britain's Institution of Mechanical Engineers at a Birmingham hotel in 1847?

George Stephenson became its first president; his biographer claimed the body grew out of outrage that the Institution of Civil Engineers had asked him for a probationary essay.

Which American engineer helped develop both leaded petrol and Freon refrigerants, two products later banned?

Thomas Midgley publicly insisted that leaded petrol posed no health hazard, although the people developing tetraethyl lead knew it to be acutely toxic.