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50 free Measurement trivia questions with answers — science & nature quiz, new questions added Aug 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 50 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 50 questions with answers and explanations. Play the quiz
Q 01How many base units does the International System of Units (SI) have?
Seven
They are the second, metre, kilogram, ampere, kelvin, mole and candela; everything else is derived from them.
Q 02Which SI base unit measures luminous intensity?
Candela
Its name is Latin for candle, and an ordinary wax candle gives out roughly one of them.
Q 03Since 2019, how is the metre defined?
By the distance light travels in a vacuum in a fraction of a second
All three distractors were earlier definitions: the pole-to-equator fraction in 1791, the bar from 1799 and krypton light in 1960.
Q 04The 1791 metre was defined as one ten-millionth of the distance from the equator to where?
The North Pole
That set Earth's quarter-meridian at exactly 10,000 km, at least on paper.
Q 05How was the kilogram originally defined in 1795?
As the mass of one litre of water
The modern definition, fixed to the Planck constant, still agrees with that litre of water to within 0.003%.
Q 06Why was the International Prototype of the Kilogram retired as the standard in 2019?
Its mass had drifted from its replicas
The kilogram is now defined by fixing the Planck constant, so any lab with a Kibble balance can realise it.
Q 07The SI second is defined by a transition frequency of which element's atoms?
Caesium
The number is 9,192,631,770 cycles of caesium-133 radiation per second.
Q 08How many seconds are there in a day?
86,400
24 hours times 60 minutes times 60 seconds; the day-based second is still used by the UT1 time system.
Q 09On 20 May 2019, four SI base units were redefined in terms of physical constants. Which four?
Kilogram, ampere, kelvin and mole
The date was the 144th anniversary of the Metre Convention; the metre, second and candela had already been redefined earlier.
Q 10How many elementary entities are in one mole?
About 6.022 x 10^23
That is the Avogadro number, roughly 602 sextillion.
Q 11On Anders Celsius's original 1742 scale, what temperature did 0 degrees represent?
The boiling point of water
His scale ran backwards; it was flipped after his death, with Linnaeus among those credited.
Q 12What was the Celsius scale commonly called in English before 1948?
Centigrade
From the Latin centum and gradus, meaning 100 steps.
Q 13According to Fahrenheit's original paper, 0 °F was the freezing point of what?
Salty ice brine
His upper point was his estimate of human body temperature, first 90 then 96 degrees.
Q 21How many pounds are in a stone, the unit still used for body weight in Britain and Ireland?
14
Historic European 'stones' ranged anywhere from about 5 to 40 local pounds.
Q 22Why is the pound abbreviated 'lb'?
From the Roman libra
The £ sign for pounds sterling has the same Roman ancestor.
Q 23A troy ounce, the standard for precious metals, weighs about how many grams?
31.1
It is heavier than the avoirdupois ounce, but a troy pound of 12 troy ounces is lighter than a normal pound.
A carat, used for gemstones, is equal to how many milligrams?
Q 14How do you convert a temperature in degrees Celsius to kelvins?
Add 273.15
The Kelvin scale starts at absolute zero, so it has no negative values.
Q 15How many feet are in a mile?
5,280
That is 1,760 yards; since 1959 the mile has been exactly 1,609.344 metres.
Q 16Since 1959, the inch has been defined as exactly how many millimetres?
25.4
The word comes from the Roman uncia, meaning a twelfth, and the unit was long tied to a thumb's width.
Q 17What fraction of an inch is a barleycorn, the unit still behind shoe sizes?
One third
A medieval statute defined the inch as 'three barleycorns, dry and round'.
Q 18A furlong is what fraction of a mile?
One eighth
That's 220 yards; the unit survives mainly in horse racing.
Q 19An acre was traditionally the area one man could plough in a day with how many oxen?
Eight
Formally it is one chain by one furlong, or 43,560 square feet.
Q 20How many square metres are in a hectare?
10,000
That is a square with 100-metre sides, roughly 2.47 acres.
200
The metric carat was fixed in 1907 and is divided into 100 'points' of 2 mg each.
Q 25How many feet are in a fathom?
Six
Originally the span of a man's outstretched arms, it was the English-speaking world's standard for water depth.
Q 26The international nautical mile is defined as exactly how many metres?
1,852
It began as one minute of latitude, so the Earth's polar circumference is close to 21,600 nautical miles.
Q 27A knot is a unit of speed equal to one nautical mile per what?
Hour
A ship doing 1 knot along a meridian covers about one minute of latitude in an hour.
Q 28The 'hand', used to measure horses, is standardised at how many inches?
Four
Its subdivisions are in quarters, so 15.2 hands means 15 hands and 2 inches, not 15.2 in decimal.
Q 29A light-year is a unit of what?
Distance
It is about 9.46 trillion km, the distance light travels in one Julian year of 365.25 days.
Q 30A parsec is approximately how many light-years?
3.26
It is the distance at which one astronomical unit subtends an angle of one arcsecond; Proxima Centauri is about 1.3 parsecs away.