98 Fun Facts About Simple Machines

A single fixed pulley changes only what?

Pull direction is all that changes: you haul down on the rope instead of heaving the weight up. Add a second pulley that moves with the weight, and the force needed is halved.

The ratio of a machine's output force to the force applied is called what?

Mechanical advantage need not be above 1. Tools such as tongs score less, giving up force on purpose to gain reach and speed.

A bicycle is an example of what kind of machine?

A compound machine links simple ones together, as a bicycle does with wheels, levers and pulleys. In a bench vice the long handle is a lever that turns a screw, so the jaws grip far harder than any hand could.

When several simple machines are linked in series, the overall force multiplication equals what?

The product of their ratios, not the sum: two machines that each triple your force give nine times, not six, when one drives the other.

When a machine multiplies force, what does the load give up in return?

Distance moved shrinks as force grows: to double your lifting force with a lever, your hand must travel twice as far as the weight rises.

Which medieval siege engine is a giant lever that hurls stones when its counterweight drops?

Trebuchet crews hung a great weight of stone or metal on the arm's short end; when it dropped, the long end whipped up and flung the missile. The engines stayed in use until gunpowder weapons took over.

Which machine was missing from the ancient Greeks' classic list of five?

Inclined plane: the Greeks hauled loads up ramps but left the slope off their list, probably because it just sits there while the load does the moving. It joined many centuries later.

Heron of Alexandria's list of five devices that "set a load in motion" appears in which of his treatises?

Mechanics was written in Greek but survives only in an Arabic translation. Aimed at architects, it explains how to raise heavy weights with a handful of simple machines.

Who wrote Le Mecaniche, a treatise on simple machines, around 1600?

Galileo Galilei drafted it for his private students and let it circulate in manuscript. It was a Frenchman, Marin Mersenne, who published it, bringing out his own translation in 1634.

The big wooden screw used to squeeze grapes for wine was borrowed for which 15th-century invention?

The printing press of Johannes Gutenberg, built around 1440, used the screw to squeeze paper flat against inked type. The same device had pressed grapes and olives since Roman times.

The turning effect of a force about a pivot, which a longer lever arm increases, is called what?

Torque comes from the Latin torquere, to twist, the verb the Romans also used for torture. Double the length of a spanner and the same push gives twice the twist.

The word "lever" comes from Latin levare, rooted in levis, meaning what?

Light, as in not heavy: Latin levare, to raise, grew out of it. The same Latin word gave English "elevate" and "levity", and a kindred root gave "lung", literally the light organ.

In the Egyptian Book of the Dead, a balance scale, a simple lever, weighs the dead person's heart against what?

A feather, the ostrich plume of Ma'at, goddess of truth, sits in the other pan. A heart that proved heavier was fed to the monster Ammut.

Given a place to stand, Archimedes reportedly said he could move what?

The Earth. The boast reaches us only through later writers such as Plutarch and Pappus, and it made his point that, given the right machine, a small force can move any weight at all.

Which tool is a Class II lever, with the load between the effort and the fulcrum?

A nutcracker has its hinge at one end and your hand at the other, with the nut in between, so the squeeze on the shell is far stronger than your grip.

The energy a machine passes on is measured in which unit, named after a brewer's son from Salford?

The joule honours James Prescott Joule, who ran the family brewery and did physics as a hobby. His experiments showed that heat and mechanical effort are two forms of the same thing.

A pair of tweezers, with the effort between the fulcrum and the load, is which class of lever?

Third: you squeeze partway along the arms, so your fingers move a little and the tips move more. Tweezers give up force on purpose, in exchange for reach and fine control.

Which tool is a Class I lever, with the fulcrum between the effort and the load?

A crowbar pivots on a point between your hands and the thing being prised up, so a long push on the handle becomes a short, powerful lift at the tip.

Which part of the human body is cited as a Class III lever?

The mandible (jaw) joins the forearm as one of the body's Class III levers, built for speed and range of movement instead of raw force.

Financiers took which simple-machine word for borrowing to multiply returns?

Leverage first meant the action of a lever, in the 1720s. The money sense keeps the picture: borrowed funds let a relatively small investment earn like a much larger one.

A lever multiplies force by the ratio of what?

Distances from the fulcrum decide it: push three times as far from the pivot as the weight sits, and the lever triples your force. Archimedes proved the rule.

Archimedes proved the law of the lever using what kind of reasoning?

Geometric: in On the Equilibrium of Planes he treats the lever like a theorem, laying down seven postulates and deducing the law from them, proposition by proposition.

An "ideal" machine is assumed to be free of what?

Friction is assumed away, along with any bending or wear in the parts, so an ideal machine passes on every bit of the effort put in. Real ones always lose a little as heat.

Several pulleys assembled to lift heavy loads with a rope form what device?

A block and tackle is riggers' language: a cased pulley is a block, and the rope run through a pair of them makes the tackle.

The ideal force multiplication of a pulley set equals the number of what?

Rope sections supporting the load share its weight equally, so with four of them each strand carries a quarter, and a quarter is all you have to pull.

According to Plutarch, Archimedes demonstrated compound pulleys by pulling what toward himself?

A fully laden ship, passengers and cargo aboard, which Plutarch says he drew in by hand while sitting far off. The king had challenged him to back up his boast that a small force could move any weight.

Besides rope and cable, what else is commonly run over a pulley's wheel to transmit power?

A chain runs on toothed pulleys called sprockets, whose teeth catch each link, as on a bicycle. A belt does the same job on a smooth wheel.

A ramp multiplies force by its sloped length divided by what?

The height it spans: to raise a 100-pound crate 2 feet, an 8-foot ramp is four times as long as it is high, so a push of about 25 pounds will do.

The steepest angle at which a load rests on a ramp without sliding is the angle of what?

Repose, as in rest: tilt the ramp any steeper and the load starts to slide. The same angle explains why poured sand always settles into a cone of the same slope.

The Diolkos, an ancient paved trackway, let crews haul ships overland across which isthmus?

Corinth: for some 650 years, from about 600 BC, the track spared ships the long and dangerous voyage around the Peloponnese.

Which ancient monuments are widely thought to have been built by hauling stones up ramps?

The Egyptian pyramids are the classic case, yet historians still argue over what form the ramps took: one long straight ramp would have needed as much material as the pyramid itself.

Ancient Greek engineers miscalculated the force needed to push a weight up a ramp; in which era were correct solutions finally published?

The Renaissance: Simon Stevin's proof of 1586 imagined a loop of beads draped over a ramp, though the 13th-century scholar Jordanus de Nemore had already got the answer right.

Roads are built with gentle slopes so vehicles can climb hills without losing what?

Traction is the grip between tyre and road, and it gives out on a slope that is too steep. Footpaths keep to gentle ramps for the same reason: shoes slip too.

A wedge multiplies force by the length of its slope divided by what?

Its width at the thick end: a long, thin wedge multiplies force more than a short, fat one, though a thin blade is also more likely to jam in the wood.

Perhaps the first wedge, the hand axe, was usually made by chipping which stone?

Flint was the usual choice. Striking flakes off both faces left a sharp two-sided edge, and tools of this design stayed in use for well over a million years.

Which everyday item acts as a wedge?

A nail is a wedge at its tip: the point forces the wood fibres apart, and the fibres then squeeze the shaft and hold it fast.

By focusing a blow on its thin edge, an axe blade greatly increases what on the wood?

Pressure: the same swing lands on a far smaller area, and the wedge-shaped head then forces the wood apart. Tearing a log in two with bare hands would take a much bigger force.

The earliest known blade, the sharp edge of a struck stone, was used to cut what?

Animal tissue: cut marks on fossil bones, such as a zebra ankle found at Gona in Ethiopia, match the marks made in butchery experiments with sharp stone flakes.

A screw is often described as a narrow ramp wrapped around what?

A cylinder: unwrap the thread and you get one long, gentle ramp, which is why each turn drives a screw in only a little way but with great force.

The distance between a screw's threads is called its what?

Pitch is the gap from one thread crest to the next. On an ordinary single-thread screw it is also how far the screw advances per turn, so a finer pitch means more force and slower progress.

The Archimedes screw is a pump that uses a rotating helical chamber to move what uphill?

Water: farmers turned it to lift river water into their fields. Tradition says Archimedes invented it on a visit to Egypt, but its origins are unknown and some historians think it is older than he was.

The common principle of every screw is that a rotating helix produces what?

Linear motion: every full turn moves the screw, or the nut riding on it, a fixed step along its axis. A corkscrew pulls itself into the cork the same way.

One of the first applications of the wheel and axle was a tool for doing what?

Making clay pots: a potter's wheel found at Ur in Iraq is about 5,000 years old, and spinning the clay let one potter turn out many more pots an hour.

Pictographs from the city of Uruk, among the oldest images of wheeled wagons, belong to which civilization?

Sumerian: about a thousand years after these sketches, the Standard of Ur shows Sumerian wagons rolling into battle and trampling the enemy.

Which device, a crank turning a barrel that reels in a rope, lifts buckets from wells?

Windlass: it is little more than a long handle fixed to a shaft, and probably the form in which Hero of Alexandria counted the wheel and axle among his machines for lifting weights.

The wheel and axle multiplies force by the ratio of which two measurements?

Their radii: grip the rim of a wheel ten times wider than its axle, and the axle turns with ten times the force of your hand.

Archimedes lived in which Sicilian city?

Syracuse was a Greek city then. When it fell to Rome in 212 BC a soldier killed him, the story goes, because he was too deep in a calculation to obey an order to move.

Besides the screw pump and compound pulleys, what else did Archimedes famously design for his home city?

Defensive war machines: when Rome attacked, his catapults and a crane-like claw, said to have hoisted galleys clean out of the sea, helped hold the besiegers off for about two years.

Which Pulitzer-winning cartoonist's name describes gadgets that do a simple job the hard way?

Rube Goldberg trained as an engineer and worked on San Francisco's sewers before he turned to drawing. His 1948 Pulitzer was for a political cartoon, not a gadget.

Which Italian artist drew an aerial screw, a flying machine with a corkscrew rotor, in the 1480s?

Leonardo da Vinci modelled the rotor on the screw pump, hoping it would push against air the way the pump pushes liquid. He also drew an early parachute and a hang glider.

For which impossible invention does the US patent office officially demand a working model?

Perpetual motion machines, meant to run forever with no energy supply, would break the laws of thermodynamics. So many inventors applied anyway that examiners began asking for proof.

Which unit did Scottish engineer James Watt adopt to help sell his improved steam engines?

Horsepower let buyers compare an engine with the draft horses it would replace. Watt and his partner Matthew Boulton fixed one unit at 33,000 foot-pounds a minute.

Ancient tomb murals and brick reliefs are the earliest hard evidence of the wheelbarrow in which country?

China has the oldest pictures of wheelbarrows, painted in Han dynasty tombs. With the load carried between the wheel and the handles, a barrow is a lever that rolls.

Small wheeled figures dug up at ancient sites in Mexico have been identified by archaeologists as what?

Children's toys on wheels turn up at Mexican sites, yet large-scale use of the wheel never followed before European contact. One suggested reason is the lack of large animals to pull carts.

Which part of a steamer, an improvement on the paddle wheel, do marine engineers often call a screw?

The propeller has twisted blades that drive a vessel forward as they turn, much as threads pull a screw into wood. On aircraft it is sometimes called an airscrew.

Which playground lever was set across the US-Mexico border fence in 2019 for both sides to play?

A seesaw is a beam balanced on a central pivot, with the effort on one side and the load on the other. The border set let people in two countries share one beam.

Which household tool joins two Class I levers at a shared pivot and gives each a wedge-shaped edge?

Scissors squeeze material between two sharpened wedges, with one shared pivot serving both handles. Mass production began in Sheffield in 1761.

Which people-mover, in physics terms a powered ramp, was first installed at Coney Island in 1896?

An escalator is a flight of moving steps laid on a slope, so riders gain height gradually instead of being lifted straight up. Jesse Reno built the first beside the Old Iron Pier.

The oldest wooden wheel yet found, over 5,000 years old, was dug from a marsh in which country?

Slovenia's Ljubljana Marshes Wheel was found in 2002 with its oak axle. Wedges fixed the two together, so the axle turned with the wheel instead of the wheel spinning on it.

Which device from an ancient Greek wreck, recovered in 1901, used bronze cogs to predict eclipses?

The Antikythera mechanism was turned by hand to show where the Sun and Moon would be decades ahead. It even tracked the four-year cycle of the Olympic Games.

Which parts, first patented by Welshman Philip Vaughan in 1794, cut the drag around a turning axle?

Ball bearings swap sliding contact for rolling, which wastes far less effort. A Paris mechanic fitted them to the bicycle that won the first road race, in 1869.

Roman builders doubled a crane's lifting capacity with half the crew by swapping its winch for what?

A treadwheel is a large wooden wheel turned by men walking inside it, and its wide diameter multiplies their effort. Medieval builders used the same device to raise cathedrals.

Which type of crane takes its name from an Elizabethan executioner, by way of a gallows?

A derrick was first a kind of gallows, named after the hangman Thomas Derrick, before the word passed to hoists with a mast and boom. Oil rigs use it for their drilling towers.

Which upright drum did sailors turn by pushing on bars, multiplying their pull on heavy ropes?

A capstan stands upright so that many sailors can walk around it, each pushing a bar that works as a lever. The long bars and narrow drum trade a wide circle of walking for a short, strong haul.

Which philosopher is the traditional, though doubted, author of the Greek text Mechanical Problems?

Aristotle was named as its author for centuries, but scholars generally regard the attribution as spurious. One has proposed Archytas instead; another says only that it came from Aristotle's school.

Which irrigation tool of ancient Egypt is a pivoting pole with a bucket and a counterweight?

A shadoof lets the counterweight do most of the lifting, so a full bucket rises with an easy swing. It reached Upper Egypt sometime after 2000 BC.

Which Flemish engineer used a loop of beads to find the force holding a weight on a ramp?

Simon Stevin pictured a string of evenly spaced beads draped over a triangular prism and reasoned from how it must balance. The diagram became known as the Epitaph of Stevinus.

Which kitchen gadget combines a lever with a cutting wedge and gained its rotating wheel in 1870?

A can opener squeezes the rim between two handles while a sharp wheel wedges through the lid. The serrated second wheel that grips the rim was added in 1925.

Which tall outdoor fixture has a fixed pulley at its top, worked by a loop of cord from the ground?

A flagpole's cord, called a halyard, loops over the pulley so the person hoisting never leaves the ground. Sailors use the same word for the lines that raise sails.

Push or pull on a machine is measured in which unit, named after the author of the 1687 Principia?

The newton honours Isaac Newton, and an average apple weighs about two of them. An average adult presses down with roughly 600.

Which measure compares a machine's useful output with its input, and never reaches 100 per cent?

Efficiency is output divided by input, so a perfect machine would score exactly 1. No real one does, because some energy always escapes where parts rub.

Real machines lose some energy where moving parts rub together, and it is mostly given off as what?

Heat carries off the difference between what goes into a real machine and what comes out. In 1842 Julius Robert Mayer measured the warming of stirred paper pulp to study the effect.

Which kind of substance, found on chariot axles from 1400 BC, helps a machine's parts slide easily?

A lubricant such as oil or grease keeps surfaces from grinding against each other. The Romans used olive oil and rapeseed oil for the job.

Which clothing closure, once sold as the hookless fastener, opens and shuts by means of small wedges?

A zipper's slider holds a Y-shaped channel whose wedges mesh the two rows of teeth going one way and pry them apart going the other.

Which garden tool is a wedge when pushed into soil and a lever when its handle is pulled back?

A shovel shows how most tools combine simple machines: the blade splits the ground and the long handle pries the load free. A wheelbarrow pairs a lever with a wheel and axle in the same way.

Which building feature counts as an everyday screw in engineers' lists of simple machines?

A spiral staircase swaps a steep climb for a long, gentle walk around its post, just as a screw's thread turns many easy rotations into a small, strong advance.

Which gripping tool, perhaps descended from Bronze Age tongs, is a pair of Class I levers?

Pliers put the pivot close to the gripping end, so a modest squeeze on the long handles becomes a hard pinch at the tips.

Which lighter design, appearing around 2000 BC, made fast horse-drawn war chariots possible?

Spoked wheels cut weight without giving up strength, which allowed lighter and swifter vehicles. The oldest known wooden examples come from the Sintashta culture.

Which rotating part of a car engine turns a shaft's spin into an up-and-down push on the valves?

A cam is a shaped piece whose spinning outline nudges a follower back and forth. Washing machine timers once used rows of them to switch each stage on and off.

Which device, a toothed wheel with a catch called a pawl, lets a socket wrench turn only one way?

A ratchet clicks because the pawl rides up each sloped tooth and snaps into the gap behind it, then jams if the wheel tries to run backwards.

Which part of a bicycle has a reverse screw thread to keep it from shaking loose?

The left pedal would slowly unscrew under an effect called precession if its thread ran the usual way, so makers cut it in reverse.

Which hillside railway, named from the Latin for rope, links two counterbalanced cars by cable?

A funicular lets the descending car help haul the rising one, so the engine only makes up the difference in passenger weight. It is a ramp and a pulley sharing one job.

Which farm tool for turning soil before sowing is, in physics terms, a wedge dragged along?

A plough parts the soil the way an axe parts wood: a narrow edge enters first, then the widening blade forces the dirt aside.

Which American showed a New York crowd in 1854 a hoist that stopped safely when its rope broke?

Elisha Otis built a brake that halts the car automatically if the hoisting rope fails. Demand for his lifts rose after the demonstration at the Crystal Palace exhibition.

Which workshop tool has wedge-shaped cutting edges at its tip and a helix to clear the waste?

A drill bit does its cutting at the tip, while the twisted grooves behind carry the chips up and out of the hole as it turns.

Which roadside tool pairs a lever with a screw in engineers' lists of everyday machines?

A car jack turns many easy sweeps of its handle into a slow, powerful lift along a threaded rod. The word jack for a lifting machine is first recorded in 1679.

A stage crane in ancient Greek theatre gave rise to which Latin phrase for a sudden plot rescue?

Deus ex machina means god from the machine, a Latin copy of a Greek stage term. The machine was a crane that swung an actor in from above to settle the plot.

Which 1963 board game, an early mass-produced 3D design, has players build a working contraption?

Mouse Trap has players cooperate at first to build the gadget piece by piece, then turn against each other to spring it. The original edition left them almost no decisions to make.

Which science of rubbing and wear between surfaces was named in a 1966 report by Peter Jost?

Tribology takes its name from a Greek verb meaning to rub. The 1966 report that coined the word set out what worn and corroded machinery was costing the UK economy.

Which Roman weighing device has unequal arms and a counterweight that slides along the longer one?

A steelyard is a lever with its pivot very close to one end, so a small weight slid far along the beam balances a heavy load on the short side.

Which German, often called the father of kinematics, catalogued hundreds of machine elements?

Franz Reuleaux held that any machine could be reduced to sequences of elementary links he called kinematic pairs. American mechanical engineers made him an honorary member of their society.

Which Roman architect's De architectura describes hoists, pulleys, catapults and a screw pump?

Vitruvius wrote as a former army engineer who had built artillery for sieges. His book also explains sundials and an early steam toy, the aeolipile.

Which property, also called non-overhauling, means a screw stays put when the effort is removed?

Self-locking machines hold their load unaided: a wood screw does not spin back out when the driver lets go. It happens mainly in screws, ramps and wedges, where large surfaces slide on each other.

Which linkage of hinged bars, used by Christoph Scheiner in 1603, copies a drawing to a new scale?

A pantograph is built from parallelograms, so a pen at one corner mimics whatever a pointer traces at another. Its name comes from Greek words for all and write.

In Britain, an overcomplicated contraption is named after which cartoonist, a usage dating to 1917?

W. Heath Robinson drew whimsically elaborate machines for simple ends. During the Second World War a codebreaking machine at Bletchley Park was named after him.

Which construction vehicle appears on engineers' lists of everyday wedges?

A bulldozer drives its blade into a heap of soil, sand or rubble and forces the material up and aside. Strictly, the name covers only a motorised unit with a pushing blade.

Which piece of cutlery, besides the knife, appears on engineers' lists of everyday wedges?

A fork has tapered tines that push food apart as they sink in, the same splitting action an axe uses on a log.

Which household wedge is meant to stay jammed in place instead of splitting anything apart?

A doorstop turns the push of a swinging door into a hard squeeze against the floor, which pins it in place. Engineers use wedges the same way to hold engine valves.