50 Fun Facts About Simple Machines

How many classical simple machines did Renaissance scientists define?

The list is the lever, wheel and axle, pulley, inclined plane, wedge and screw.

Which of these is NOT one of the six classical simple machines?

Gears are combinations of wheels; later engineers such as Franz Reuleaux catalogued hundreds of such "machine elements".

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

Ignoring friction, the work done on the load equals the work done by the applied force.

A bicycle, which combines wheels, levers and pulleys, is an example of what?

Simple machines are the building blocks from which more complicated machines are built.

A machine built from several simple machines multiplies force by what, relative to its parts?

Two machines that each double force, chained together, quadruple it.

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

You push a smaller force over a longer distance; the total work stays the same.

The idea of simple machines originated with a Greek philosopher of which century BC?

Archimedes studied the lever, pulley and screw and discovered the principle of force multiplication in the lever.

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

Heron of Alexandria listed the lever, windlass, pulley, wedge and screw; the ramp joined the list later.

Heron of Alexandria's list of five mechanisms that "set a load in motion" appears in which work?

He also described how each was built and used, including a tap for cutting screw threads.

Who worked out the complete dynamic theory of simple machines in 1600 in Le Mecaniche?

He showed the underlying mathematical similarity of all the machines as force amplifiers.

By the late 1800s, who had identified hundreds of "machine elements" he called simple machines?

His catalogue went far beyond the classical six of the Renaissance.

The Greeks understood the statics of simple machines but lacked which concept?

Their theory covered balance of forces but not the trade-off between force and distance.

A lever pivots on a fulcrum; what is the force it works against usually called?

The input force is the effort, and the positions of fulcrum, load and effort define the three classes.

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

Light as in "not heavy" — the lever makes heavy things feel light.

The earliest known use of the lever, in Egypt around 5000 BC, was in which device?

Around 3000 BC Mesopotamia added the shadouf, a crane-like lever for lifting.

The earliest surviving writings about levers date from which century?

They are attributed to Archimedes, who promised to move the world given a long enough lever.

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

Wheelbarrows, bottle openers and a car's brake pedal work the same way.

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

Nutcrackers, bottle openers and a car's brake pedal work the same way.

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

Fishing rods, tongs, hoes and the human jaw are also Class III levers.

Which of these is a Class I lever?

Its fulcrum sits between the hand and the load, like a seesaw.

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

The jaw muscles apply effort between the joint and the teeth that do the work.

The mnemonic "FRE 123" tells you which element is in the middle of each lever class. What is R?

Fulcrum in the middle for class 1, resistance for class 2, effort for class 3.

A lever multiplies force by the ratio of what?

A longer input arm and a shorter output arm turn a small push into a big lift.

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

He is credited with claiming he could move the whole world given a place to stand.

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

It also has no power source and is built of rigid bodies that do not bend or wear.

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

One block is fixed to a mounting point and the other moves with the load.

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

If four rope parts hold the moving block, each carries a quarter of the weight.

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

The ship seemed to glide through the water as if by magic, silencing his doubters.

Besides rope and cable, which of these can drive a pulley system?

Belts and chains are common drive elements alongside ropes and cables.

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

A longer, gentler ramp means a smaller push over a greater distance.

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

Also called the angle of friction, it equals the arctangent of the coefficient of static friction.

The Diolkos, a 6 km paved ramp, let the Greeks drag ships across which isthmus?

It saved a long and dangerous voyage around the Peloponnese.

Which ancient monuments are believed to have been built using earthen ramps?

The stones of Stonehenge are thought to have been set in place the same way.

Heron and Pappus of Alexandria tried to calculate the force needed on a ramp. How did they fare?

The correct analysis had to wait until the Renaissance.

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

Pedestrian paths use the same idea so walkers keep their footing.

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

The narrower the tip angle, the greater the splitting force.

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

Chipping both faces produced a sharp bifacial edge.

Which of these everyday items works as a wedge?

Forks, knives, axes, chisels and plows all split material the same way.

Wedges, saws and chisels cut hard materials with less force and waste than what method?

Crushing applies the same force over a wider area and is far less precise.

The earliest known blade, a sharp flint edge, was used to cut what?

It let humans cut meat and fibres with far less force than tearing by hand.

Geometrically, a screw is described as a narrow ramp wrapped around what?

Heron of Alexandria defined it exactly that way in the first century AD.

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

The smaller the pitch, the greater the force multiplication.

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

Records suggest the water screw was used in Egypt before Archimedes described it around 234 BC.

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

That is why a turning wood screw drives itself forward into the timber.

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

True free-spinning potter's wheels were developed in Mesopotamia by 4200–4000 BCE.

Clay-tablet pictographs of wheeled wagons from Uruk, c. 3700–3500 BCE, belong to which civilization?

Uruk lay in Mesopotamia, where true potter's wheels had appeared centuries earlier.

Which device, a crank turning a barrel to wind a rope, lifts buckets from wells?

Hero of Alexandria identified the wheel and axle in this form as a machine for lifting weights.

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

A big wheel turning a small axle turns a gentle push into a strong pull.

Archimedes lived in which Sicilian city?

He was killed there by a Roman soldier during the siege of 212 BC.

Besides the screw pump and compound pulleys, what did Archimedes design to protect his home city?

Legend credits him with a giant claw that lifted Roman ships out of the water.