The history
From a sling and a pendulum clock to cream separators, the wall of death and a spinning tether in orbit.
People always knew that a whirled stone pulls on the hand. Huygens found the rule in 1659, and Newton turned it round in 1684: circles need an inward, centre-seeking force. Coriolis explained what turning frames add, and engineers put spinning to work in dairies, labs, fairs and space.
1659
Formula for circular motion worked out
Christiaan Huygens, Netherlands
1673
'Centrifugal force' in print
Christiaan Huygens, Horologium Oscillatorium
1684
'Centripetal force' named
Isaac Newton, De motu corporum in gyrum
1835
Coriolis effect described
Gaspard-Gustave de Coriolis, France
1878
Continuous cream separator
Gustaf de Laval, Sweden
1893
Ferris wheel
George W. G. Ferris Jr., Chicago
1926
Nobel Prize for the ultracentrifuge
Theodor Svedberg, Sweden
1966
Artificial gravity made in space
Gemini 11, NASA
1644 – 1690
Descartes, Huygens, Hooke and Newton work out that circles need an inward pull, and how big it is.
1644
In his Principles of Philosophy, Descartes wrote that every moving thing tends to carry on in a straight line. A stone whirled in a sling keeps trying to fly off along the tangent, and only the sling stops it.
Why it mattered. It swapped the old idea that circles were natural for the modern one: straight is natural, turning needs a cause.
1659
Working on pendulum clocks, Huygens worked out that the outward tug on a whirled weight grows with the square of its speed and falls with the radius: in today's terms m v² ÷ r. He wrote it up as De vi centrifuga, which was only printed after his death, in 1703.
Why it mattered. It was the first correct formula for circular motion.
1673
At the end of Horologium Oscillatorium, his great book on pendulum clocks, Huygens printed thirteen theorems on 'centrifugal force' without their proofs. It is where the name first appeared in print.
Why it mattered. Scientists across Europe, including Newton, could now calculate the force needed for any circle.
1679
In letters to Isaac Newton, Hooke suggested that a planet's orbit is a straight-line motion constantly bent by an attraction towards the Sun. The inward pull, not an outward one, was the thing to explain.
Why it mattered. It pointed Newton towards thinking of an inward, centre-seeking force.
1684
In a short manuscript sent to Edmond Halley, De motu corporum in gyrum, Newton introduced vis centripeta, 'centre-seeking force', a name that mirrors Huygens's centrifugal force. He showed that an inverse-square centripetal pull gives Kepler's orbits.
Why it mattered. It turned the question round: circles need an inward pull, and gravity can be it.
1687
Principia defined centripetal force (Definition 5) and used it for the Moon, planets and tides. In one passage Newton described a bucket of water set spinning: as the water starts to turn with it, its surface climbs the sides into a curve, a sign of real rotation.
Why it mattered. It made m v² ÷ r part of one system of mechanics, and started a long argument about what 'really rotating' means.
1740 – 1860
Whirling arms, Coriolis's sideways force and Foucault's pendulum show what it means to measure from something that turns.
1742
1740s
Robins, a military engineer, built a whirling arm to swing test shapes round in a circle and measure the air's drag on them. It is often counted as the first centrifuge-like machine; engineers later used whirling arms to test wings and propellers.
Why it mattered. Spinning things fast in a circle became a way to do experiments.
1835
Studying machines with turning parts, Coriolis showed that anyone describing motion from a rotating frame must add two extra terms: the centrifugal one, and a sideways one that grows with speed. The sideways one now carries his name.
Why it mattered. It explains why winds and cyclones curve on the turning Earth.
1851
Foucault hung a heavy bob on a 67 m wire in the Panthéon. As it swung, its line slowly turned round through the day, because the floor, the Earth, was turning underneath it.
Why it mattered. It showed the Earth is a rotating frame, where Coriolis effects are real but slow.
1864 – 1930
Cream separators, giant wheels, loops, the wall of death and the ultracentrifuge put m v² ÷ r to work.
1864
Antonin Prandtl proposed spinning milk so the denser skim milk flies outwards and the lighter cream gathers in the middle. His brother Alexander showed a working machine in 1875.
Why it mattered. It was the start of the centrifuge as an everyday machine.
1878
De Laval patented a separator that took in milk and let cream and skim milk flow out non-stop while it spun. With Oscar Lamm he founded AB Separator in 1883, now Alfa Laval. Dairies everywhere still separate cream this way.
Why it mattered. Continuous spinning made centrifuges practical for industry.
1893
21 June 1893
Built for the World's Columbian Exposition, Ferris's wheel stood 80 m high with 36 cars that each held up to 60 people. It turned slowly, about 9 minutes for a non-stop turn, so riders barely felt the circle.
Why it mattered. It started the giant wheels found at every mela and fair.
1895
1895 and 1901
The Flip Flap Railway at Sea Lion Park had a perfectly circular loop, and riders complained of neck injuries from the high g-force. In 1901 Prescott's Loop the Loop used a taller, teardrop-shaped loop to ease it.
Why it mattered. Engineers learned that a round loop is the worst shape for riders.
1911
1911 onwards
The first carnival motordrome, a steep wooden bowl, appeared at Coney Island in 1911; vertical-walled versions followed by about 1915. The show spread round the world, and in India it became the maut ka kuan of village melas.
Why it mattered. It is circular motion as a show: the wall's push lets friction hold the rider up.
1924
1924; Nobel Prize 1926
Svedberg built centrifuges that spun samples so hard, many thousands of g, that big molecules settled out and could be watched and weighed. He showed that proteins such as haemoglobin have definite sizes, and won the 1926 Nobel Prize in Chemistry.
Why it mattered. Spinning became one of biology's main tools for sorting molecules and cells.
1950 – 1980
Dreams of spinning stations, India's dairy revolution, the bathtub vortex, a tether in orbit and gentler loops.
1952
In Collier's magazine von Braun described a wheel about 75 m across, spinning slowly so its crew would have about a third of normal gravity. Artists painted it, and it shaped how films showed space stations for decades.
Why it mattered. It made artificial gravity by spinning a familiar idea.
1955
31 October 1955
Prime Minister Jawaharlal Nehru opened Amul's new dairy, which made butter and milk powder from buffalo milk, a world first. Like every butter dairy, it depends on centrifugal separators to take the cream off the milk.
Why it mattered. India's co-operative dairies grew into the world's largest milk industry, with centrifuges at their heart.
1962
Shapiro filled a round tank about 2 m across, let it stand still for a day, then pulled the plug. Only then did the Earth's tiny Coriolis effect show, as a slow anticlockwise swirl. A team in Sydney repeated it in 1965 and saw a clockwise swirl.
Why it mattered. It proved the effect is real, and also that it is far too weak to steer an ordinary sink.
1966
September 1966
The Gemini 11 crew tied their capsule to an Agena rocket with a 30 m tether and fired thrusters to set the pair slowly turning like a bola. It made about 0.00015 g, the first artificial gravity created in space.
Why it mattered. It showed spinning spacecraft could make gravity, though a useful amount needs a big, fast ring.
1976
The Revolution was the first modern steel coaster with a vertical loop. Its designer Werner Stengel shaped it as a clothoid, tight at the top and wide at the bottom, so riders never feel the 6 g of a round loop.
Why it mattered. Almost every looping coaster since uses the same curve.
Did you know?
A washer drum at 1,200 rpm pushes on clothes about 400 times harder than gravity.
The tip of a mixer grinder blade at 18,000 rpm moves at about 200 km/h.
The 1893 Ferris wheel took about 9 minutes per turn, so riders felt less than a thousandth of g from the circle.
In a sink, the Earth's Coriolis effect is about a millionth of g: far too weak to choose which way it drains.
Gemini 11's spinning tether in 1966 made about 0.00015 g, the first artificial gravity in space.
The people
1596 – 1650 · Philosopher and mathematician · France
Said moving things go straight unless stopped, using the sling as his example.
1629 – 1695 · Physicist, astronomer and clockmaker · Netherlands
Found the rule for centrifugal force and named it.
1635 – 1703 · Natural philosopher · England
Saw an orbit as a straight path bent by a pull to the centre.
1643 – 1727 · Mathematician and physicist · England
Named centripetal force and built it into his laws of motion.
1792 – 1843 · Engineer and mathematician · France
Worked out the extra forces seen from a turning frame.
1845 – 1913 · Engineer and inventor · Sweden
Invented the continuous cream separator and founded AB Separator.
1859 – 1896 · Bridge engineer · USA
Built the first Ferris wheel for Chicago's 1893 fair.
1884 – 1971 · Chemist · Sweden
Built the ultracentrifuge and weighed proteins with it.
1916 – 2004 · Fluid engineer · USA
Caught the Earth's Coriolis effect in a carefully stilled tank.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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