Time Trivia
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54 free Time trivia questions with answers — science & nature quiz, new questions added Sep 2026.
57 free trivia questions about time, with answers and sources. Time is the one thing everyone measures and almost nobody thinks about, so this quiz digs into where the pieces came from: why an hour has 60 minutes, who first divided the night into twelve, what a second actually is now that it is defined by an atom, and how railways, telegraphs and a conference in Washington turned thousands of local noons into the time zones we live by. There is a round on famous clocks (Big Ben and its pennies, the Prague Orloj, the 10,000-year clock inside a Texas mountain), a round on the odd corners of the map (the country that skipped a Friday, the one that runs 45 minutes off everyone else, the islands that ring in every New Year first), and a round on time in science and culture, from Hafele and Keating flying atomic clocks around the world to the Doomsday Clock, Y2K and the Times Square ball. Roughly a third of the questions are easy, a third medium, and the rest will stretch even people who read about horology for fun. Every answer has been checked against a reference page and shows its citation once you have answered, so you can settle the argument about who invented the pendulum clock without another search.
30 of 54 questions with answers and explanations. Play the quiz
Q 01Since 1967 the second has been defined by the radiation frequency of an atom of which element?
Caesium
The definition counts 9,192,631,770 periods of caesium-133 radiation. Optical clocks based on strontium and aluminium ions are now more precise, so the definition may change again.
Q 02The name for the 60th division of a minute comes from the Latin pars minuta secunda, meaning what?
Second small part
The minute was the pars minuta prima, the first small division of the hour into 60 parts; dividing again by 60 gave the second small part.
Q 03Leap seconds are added to Coordinated Universal Time to keep it in step with what?
Earth's rotation
Earth's rotation. It varies unpredictably, and the extra second added in June 2012 locked up servers at sites including Reddit.
Q 04Why is Coordinated Universal Time abbreviated UTC rather than CUT?
A compromise between English and French
A compromise between English and French: English speakers would say CUT and French speakers TUC, so one code was chosen for every language.
Q 05In which city did the 1884 International Meridian Conference choose Greenwich as prime meridian?
Washington, D.C.
Washington, D.C. France abstained from the vote, and Paris mean time stayed its legal time until a 1911 law.
Q 06Which country's Line Islands sit at UTC+14, the most advanced time zone on Earth?
Kiribati
Kiribati. Until the end of 1994 its eastern islands were a day behind its capital, so it moved the Date Line around itself to share one date.
Q 07Which country keeps its clocks 5 hours 45 minutes ahead of UTC?
Nepal
Nepal. It kept India's UTC+5:30 until 1986, then pushed its clocks 15 minutes ahead.
Q 08Which country spans five geographical time zones yet officially observes just one, set to its capital?
China
China. In far-western Xinjiang, many people unofficially keep Xinjiang Time, two hours behind Beijing, so times often need clarifying.
Q 09Which company was the first to standardise its timetable on Greenwich Mean Time, in November 1840?
Great Western Railway
Before 'railway time', towns kept their own local mean time, and Bristol ran about ten minutes behind London. Britain did not legislate a single standard time until 1880.
Q 10In 1883, US railroads reset their clocks on a signal from the Allegheny Observatory in which city?
Pittsburgh
Pittsburgh. The observatory's director, Samuel Langley, helped fund it by selling time signals to railroads and cities.
Q 11Scottish-born engineer Sir Sandford Fleming proposed worldwide time zones in the 1870s while working in which country?
Canada
Canada. A timetable mix-up that made him miss a train reportedly helped inspire his search for a simpler way to keep time.
Q 12Strictly speaking, 'Big Ben' is the nickname of what?
The Great Bell
The Great Bell. It kept ringing throughout the Blitz, even as bombs fell on London.
Q 13Clockmakers fine-tune the Great Clock of Westminster by adding or removing what from its pendulum?
Old pennies
Old pennies. Each coin lifts the pendulum's centre of mass so it swings faster, and one penny changes the clock's rate by 0.4 seconds a day.
Q 21Why will some computers that store Unix time in 32 bits fail in January 2038?
Their seconds counter runs out
Their seconds counter runs out. Unix time counts seconds from 1970, and after 19 January 2038 a signed 32-bit count wraps round to 1901.
Q 22Which publication maintains the Doomsday Clock?
The Bulletin of the Atomic Scientists
The clock first appeared on the June 1947 cover, drawn by artist Martyl Langsdorf, whose husband had worked on the Manhattan Project.
Q 23Which American envoy joked in 1784 that Parisians could save candles simply by getting up earlier?
Benjamin Franklin
Q 14In 2012 the Palace of Westminster's clock tower was officially renamed in honour of whom?
Queen Elizabeth II
Queen Elizabeth II. MPs backed the change for her Diamond Jubilee; the palace's west tower already honoured Queen Victoria, the only earlier British monarch to reign 60 years.
Q 15Which foundry cast the giant hour bell for the Great Clock of Westminster in 1858?
Whitechapel
Whitechapel. The bell cracked months after it first rang in 1859, and the foundry blamed a hammer over twice the specified weight.
Q 16Which scientist invented the pendulum clock in the 1650s?
Christiaan Huygens
Christiaan Huygens. He had clockmaker Salomon Coster build it, and its far better accuracy made pendulum clocks spread quickly across Europe.
Q 17The first quartz clock was described and built in October 1927 at which organisation?
Bell Labs
Bell Labs. Quartz clocks went on to replace precision pendulum clocks as the standard timekeepers for science and industry.
Q 18Which company sold the world's first commercial quartz wristwatch, the Astron, in December 1969?
Seiko
Seiko. Its launch began the quartz crisis, in which electronic watches drove Switzerland's mechanical watchmakers into steep decline.
Q 19Which physicist built the first practical atomic clock at Britain's National Physical Laboratory in 1955?
Louis Essen
Louis Essen. A master of precise timekeeping, he was also a persistent critic of Einstein's relativity and rejected time dilation.
Q 20In 1971 Hafele and Keating tested relativity by flying four atomic clocks around the world aboard what?
Commercial airliners
Commercial airliners. As predicted, the clocks flown eastward lost time and those flown westward gained it, compared with clocks left on the ground.
Benjamin Franklin. His satirical letter proposed taxing window shutters and firing cannons at sunrise to wake the sluggards.
Q 24Swatch Internet Time, launched in 1998, divides the day into 1,000 equal units called what?
.beats
.beats. Swatch pitched it so internet users worldwide could share one time, with no time zones to juggle.
Q 25The base-60 counting system behind 60 minutes and 60 seconds originated with which ancient people?
The Sumerians
The Sumerians. Nobody knows for sure why they chose 60, but it divides evenly by every number from 1 to 6, which makes fractions easy.
Q 26Which ancient civilisation divided the night into 12 parts, leading to our 24-hour day?
The Egyptians
The Egyptians. Astronomers timed the dark by watching 12 stars appear in turn, so the hours stretched and shrank with the seasons.
Q 27The Greek word clepsydra, used for a clock driven by dripping liquid, literally means what?
Water thief
Water thief. The name joins Greek words for 'steal' and 'water', and in Athenian courts one timed how long each speaker could talk.
Q 28Many churches once kept an hourglass in view to time what?
Sermons
Sermons. After about 1500, smaller spring-driven clocks began pushing sandglasses out of everyday use.
Q 29Cuckoo clocks were popularised and exported to the world from which region of Germany?
The Black Forest
The Black Forest. Yet the first known cuckoo clock, described in 1629, stood in a Dresden collection, before any clockmakers worked in the Black Forest.
Q 30The first telephone speaking clock service was launched on 14 February 1933 in which country?
France
France. The Paris Observatory built it because so many callers asked for the time that its only phone line was always busy.