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60 free Time trivia questions with answers — science & nature quiz, new questions added Aug 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.
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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 03How many leap seconds have been added to UTC since the system began in 1972?
27
The most recent was on 31 December 2016, and UTC now trails International Atomic Time by 37 seconds. Metrologists voted in 2022 to stop adding them by 2035.
Q 04Which year is the longest on record, at 31,622,402 seconds, because it had 366 days and two leap seconds?
1972
1972 was the first year of leap seconds and got two of them, in June and December, on top of being a leap year.
Q 05Why is Coordinated Universal Time abbreviated UTC rather than CUT?
Standards bodies wanted one abbreviation usable in every language
English speakers wanted CUT and French speakers TUC; UTC matched the existing pattern of UT0, UT1 and UT2 and satisfied nobody equally, which is how it won.
Q 06In which city did the 1884 International Meridian Conference choose Greenwich as prime meridian?
Washington, D.C.
Forty-one delegates from 25 nations attended at the invitation of the US president. Greenwich, Paris, Berlin and Washington observatories were the serious candidates.
Q 07Which country's Line Islands sit at UTC+14, the most advanced time zone on Earth?
Kiribati
UTC+13 and UTC+14 did not exist until Kiribati moved its eastern half across the Date Line at the end of 1994 so the whole country shared one date.
Q 08Which country keeps its clocks 5 hours 45 minutes ahead of UTC?
Nepal
The offset approximates Kathmandu mean time. Nepal was the last country to settle its standard offset, nudging its clocks forward 15 minutes in 1986.
Q 09Which country spans five geographical time zones yet officially observes just one, set to its capital?
China
Everything runs on UTC+8, Beijing time, so in the far west the sun can rise after 9 a.m. by the clock. Five zones were proposed in 1918 but never fully used.
Q 10Which 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 11In 1883, US and Canadian railroads switched to standard time on a telegraph signal from an observatory in which city?
Pittsburgh
The signal came from the Allegheny Observatory at exactly noon on the 90th meridian. Newspapers called it the day of two noons.
Q 12Scottish-born engineer Sir Sandford Fleming proposed worldwide time zones in the 1870s while working in which country?
Canada
Fleming also engineered much of the Canadian Pacific Railway. His 24-zone lettered scheme was never adopted directly, but the idea of hourly zones was.
Q 13Strictly speaking, 'Big Ben' is the nickname of what?
The Great Bell
Q 21In 1971 Hafele and Keating tested relativity by flying four atomic clocks around the world aboard what?
Commercial airliners
They flew eastward, then westward, and compared the travelling clocks with ones left at the US Naval Observatory. The tiny differences matched relativity's predictions.
Q 22Unix time counts seconds elapsed since midnight UTC at the start of which date?
1 January 1970
That moment is the Unix epoch. Systems storing it as a signed 32-bit number run out of room in January 2038.
Q 23The Doomsday Clock's farthest-ever setting from midnight came in 1991. How many minutes was it?
17
The name spread to the tower by extension. It probably honours Sir Benjamin Hall, the tall commissioner of works who oversaw the bell's installation.
Q 14Clockmakers fine-tune the Great Clock of Westminster by adding or removing what from its pendulum?
Old pennies
Each pre-decimal penny changes the clock's rate by 0.4 seconds a day. The clock has been famous for its reliability since 1859.
Q 15In 2012 the Palace of Westminster's clock tower was officially renamed in honour of whom?
Queen Elizabeth II
The tower became the Elizabeth Tower for the Diamond Jubilee, mirroring the renaming of the palace's west tower for Queen Victoria's jubilee. Before that it was simply the Clock Tower.
Q 16The 13.5-ton bell nicknamed Big Ben was cast by which East London firm?
Whitechapel
The same East London foundry cast Philadelphia's Liberty Bell. It closed in 2017 after more than 400 years of operation.
Q 17Who invented the pendulum clock in 1656?
Christiaan Huygens
Huygens was inspired by Galileo's work on pendulums and had clockmaker Salomon Coster build the first examples. Nothing beat it until quartz in the 1930s.
Q 18The first quartz clock was described and built in October 1927 at which organisation?
Bell Labs
Warren Marrison and Joseph Horton's clock used a crystal vibrating at 50,000 cycles per second. Quartz wristwatches took another four decades.
Q 19Which company sold the world's first commercial quartz wristwatch, the Astron, in December 1969?
Seiko
The Astron 35SQ is now an IEEE Milestone. Swiss makers had shown a rival prototype, the Beta 1, in 1967 but were beaten to market.
Q 20Which physicist built the first practical atomic clock at Britain's National Physical Laboratory in 1955?
Louis Essen
Essen worked with Jack Parry. Rabi had built the underlying atomic-beam resonance equipment in the 1930s, and an ammonia prototype ran in 1949.
The clock started at seven minutes to midnight in 1947, at the dawn of the Cold War, and by 2026 stood at 85 seconds, its closest ever.
Q 24Which 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 25Time magazine was first published in New York in 1923 by Henry Luce and which co-founder?
Briton Hadden
Hadden and Luce were Yale classmates. Hadden died in 1929, leaving Luce to build the Time Inc. empire that later included Life and Fortune.
Q 26Under the decimal time system of the French Revolution, how many hours were in a day?
10
Each decimal hour had 100 minutes and each minute 100 seconds, so a day was 100,000 decimal seconds. Midnight was called 'ten hours'.
Q 27Swatch Internet Time, launched in 1998, divides the day into 1,000 equal units called what?
.beats
Each unit lasts 86.4 seconds and there are no time zones: everyone counts from midnight in Biel, Switzerland, on what Swatch called Biel Mean Time.
Q 28The base-60 counting system behind 60 minutes and 60 seconds originated with which ancient people?
The Sumerians
It passed to the Babylonians and survives in angles and coordinates too. Ptolemy's Almagest used base 60 for fractions in the second century AD.
Q 29Which ancient civilisation divided the night into 12 parts, leading to our 24-hour day?
The Egyptians
They watched twelve constellations rise through the night. These were seasonal hours, shorter in summer and longer in winter, not the fixed hours we use now.
Q 30The Greek word clepsydra, used for a clock driven by dripping liquid, literally means what?
Water thief
From kleptein, to steal, and hydor, water. Greek and Roman versions gained gearing, feedback systems and even automata.