Measurement Trivia
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100 free Measurement trivia questions with answers — science & nature quiz, new questions added Oct 2026.
42 free Measurement trivia questions with answers. Measurement is where science meets everyday life, and it is full of odd stories: a metre once defined by a bar in Paris, a kilogram cylinder that slowly lost mass, a temperature scale that was upside down when its inventor died, and a Mars probe destroyed because one team used pounds. This measurement trivia quiz covers the seven SI base units, the imperial and US customary systems, temperature scales, units for land, sea, sky and gemstones, and the units named after people. The 100 questions run from easy (how many feet in a yard?) to hard (which unit is 1/3 of an inch?), so it works for classrooms, families and pub quizzes. Every answer is checked against the official definitions and documented history of each unit.
30 of 100 questions with answers and explanations. Play the quiz
Q 01Which of the seven SI base units measures amount of substance?
The mole
The mole lost its link to a lump of matter in 2019: once pegged to 12 grams of carbon-12, it is now simply a fixed number of particles.
Q 02Which SI base unit measures luminous intensity?
Candela
Candela is Latin for candle, and the name is honest: an ordinary wax candle shines with roughly one candela.
Q 03Since 1983 the metre has been defined by fixing the value of which constant of nature?
The speed of light
The speed of light in a vacuum is fixed at exactly 299,792,458 metres per second, so a metre is simply how far light gets in one 299,792,458th of a second.
Q 04The 1791 metre was defined as one ten-millionth of the way from the equator to where?
The North Pole
The North Pole. To pin the length down, two astronomers spent some seven years surveying the line from Dunkirk to Barcelona.
Q 05The gram was first defined in 1795 as the mass of one cubic centimetre of what?
Water
Water, at the temperature of melting ice. That is why a litre of it still weighs almost exactly one kilogram, two centuries of redefinitions later.
Q 06Why was the International Prototype of the Kilogram retired as the standard in 2019?
Its mass had drifted from its replicas
Its mass had drifted from its replicas by perhaps 50 millionths of a gram in a century, and no one could say why, so in 2019 the unit was tied to a constant of nature instead.
Q 07The SI second is defined by a transition frequency of which element?
Caesium
Caesium took over from astronomy as the world's timekeeper in 1967: Earth's rotation wobbles and slows, while a caesium clock keeps a steady beat. It counts 9,192,631,770 oscillations to the second.
Q 08How many seconds are there in a day?
86,400
86,400 is 24 times 60 times 60, but now and then a day officially lasts 86,401 seconds: a leap second is added because Earth's rotation is irregular.
Q 09Since 2019 the kilogram has been defined by fixing the value of which fundamental constant?
The Planck constant
The Planck constant, the tiny number at the heart of quantum physics, took over on 20 May 2019 from a metal cylinder that had defined the unit since 1889.
Q 10Chemistry's famous number, about 6.022 x 10^23, is named after which Italian scientist?
Amedeo Avogadro
Amedeo Avogadro never knew the number: his 1811 idea about gases was ignored for half a century, and the name was coined in 1909, long after his death.
Q 11Anders Celsius's 1742 scale ran backwards, with 0 as the boiling point; which naturalist is among those credited with flipping it?
Carl Linnaeus
Carl Linnaeus flipped the scale soon after Celsius's death, for the thermometers in his greenhouses, though he is only one of several people credited with the switch.
Q 12What was the Celsius scale commonly called in English before 1948?
Centigrade
Centigrade, from the Latin for a hundred steps, was dropped in 1948 partly because in some languages the word already meant a hundredth of a gradian, a unit of angle.
Q 13According to Fahrenheit's original paper, 0 °F was the freezing point of what?
Salty ice brine
Q 21Which unit of 14 pounds is still used for body weight in Britain and Ireland?
The stone
The stone owes its 14 pounds to the wool trade: a statute of Edward III fixed it in 1350, when local stones ran anywhere from about 5 to 40 pounds.
Q 22Why is the pound abbreviated 'lb'?
From the Roman libra
From the Roman libra, short for libra pondo, 'a pound by weight': English took the word from pondo but the abbreviation, and the pound sign, from libra.
Q 23Which system of weights, with an ounce of about 31.1 grams, is the standard for gold and silver?
Troy
Troy ounces are heavier than kitchen ones, yet a troy pound, at only 12 ounces, is lighter than the ordinary pound of 16.
Salty ice brine, a slush of ice and ammonium chloride, settles at one steady temperature, which gave him a zero anyone could reproduce. His upper mark was body heat, at 96.
Q 14How do you convert a temperature in degrees Celsius to kelvins?
Add 273.15
Add 273.15: a kelvin is the same size as a Celsius degree, but the scale starts at absolute zero, the coldest anything can get, so it never goes negative.
Q 15How many feet are in a mile?
5,280
5,280 feet has been the mile since a 1593 Act of Parliament. The Roman original was a round 5,000 Roman feet, stretched to fit the lengths English farmers already used for their fields.
Q 16Since 1959 the inch has been defined as exactly 25.4 of which metric unit?
Millimetres
Millimetres: since 1959 the inch has officially been a metric quantity, 25.4 of them exactly, even though its name is Latin for a twelfth of a Roman foot.
Q 17Which grain gives its name to an old unit of a third of an inch, the step between English shoe sizes?
Barley
Barley: a medieval English statute made three grains of it, dry and round, the length of an inch.
Q 18Which unit, an eighth of a mile, still measures horse races?
The furlong
The furlong is a 'furrow long': the length of one ploughed furrow in a medieval common field, later fixed at 220 yards.
Q 19An acre was traditionally the area one man could plough in a day with a team of which animals?
Oxen
Oxen are hard to turn with a heavy plough behind them, which is why the acre began as a long, thin strip: 220 yards by just 22.
Q 20How many square metres are in a hectare?
10,000
10,000 square metres, a square 100 metres on a side. The name says as much: a hect-are is a hundred ares, the are being a 10-metre square.
Q 24The carat, a gem weight, is named after the seeds of which tree?
Carob
Carob seeds served as jewellers' weights because they were believed to vary very little; the modern metric carat, agreed in 1907, is exactly 200 milligrams.
Q 25Which six-foot unit is used for depths at sea?
Fathom
The fathom gave English a verb: sailors fathomed the sea with a weighted line, and to fathom something still means to get to the bottom of it.
Q 26The nautical mile began as one minute of arc of what?
Latitude
Latitude, and there lay a snag: Earth is slightly flattened, so a minute of latitude is not the same length everywhere. In 1929 the mile was fixed at exactly 1,852 metres.
Q 27A knot is a unit of speed equal to one nautical mile per what?
Hour
Hour: the name comes from the knots tied along a ship's log line, which sailors counted as it ran out behind them to judge their speed.
Q 28Which four-inch unit still measures the height of horses?
The hand
The hand counts in quarters, not tenths: a horse of '15.2' stands fifteen hands and two inches, which is fifteen and a half.
Q 29Despite the 'year' in its name, a light-year is a unit of what?
Distance
Distance: it is how far light travels in a year, about 9.46 trillion kilometres. The nearest star beyond the Sun is some 4.2 of them away, so its light reaches us over four years old.
Q 30Which unit, about 3.26 light-years, do astronomers prefer?
Parsec
The parsec is 'parallax of one second' squeezed into a word in 1913: from that far away, the gap between Earth and the Sun spans just one arcsecond of sky.