Common Sense Trivia
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139 free Common Sense trivia questions with answers — trivia quiz, new questions added Oct 2026.
88 free Common sense trivia questions with answers. Common sense trivia is the stuff you are supposed to have picked up by the age of twelve: how many days are in a leap year, which way clocks go in spring, how many bones you have, why ice floats. It is also where the most stubborn myths live, so this quiz mixes the basics with the traps: the Great Wall you cannot see from space, the goldfish that remembers for months, the carrot that never helped anyone see in the dark, the peanut that is a bean and the banana that is a berry. It is built for family game night, a classroom warm-up or a bar quiz round where everyone thinks they will get 100% and nobody does. Difficulty starts very easy and climbs to a handful of genuinely tricky ones about inventors and calendars. Every answer has been checked against Wikipedia's article on the subject, and each question shows its source once you have answered, so you can settle the argument at the table.
30 of 139 questions with answers and explanations. Play the quiz
Q 01Which Roman leader gave the calendar its leap day?
Julius Caesar
Julius Caesar's calendar, drawn up with the astronomer Sosigenes, added a day every fourth year; that overshoots the true year by about 11 minutes, so a later reform had to drop three leap days every 400 years.
Q 02What shape is a standard stop sign?
Octagon
Octagon: US highway officials picked it in the 1920s so that drivers could recognise a stop sign by its outline alone, even in the dark when the lettering could not be read, and no other American road sign may use the shape.
Q 03Which kitchen measure equals three teaspoons?
A tablespoon
A tablespoon is three teaspoons, about 15 ml, in most kitchens, but measures that share a name are not quite the same size in every country, so a recipe from abroad can come out slightly wrong.
Q 04Which mountain is the tallest in the world when measured from its base rather than from sea level?
Mauna Kea
Mauna Kea stands only 4,207 m above sea level, but the Hawaiian volcano starts on the sea floor about 6,000 m down, so base to peak it measures roughly 10,210 m, well over a kilometre more than Everest.
Q 05Which continent is the smallest by land area?
Australia
Australia is the smallest continent yet one of the largest countries on Earth; Greenland, less than a third of its size, marks the cut-off and is counted as the world's largest island instead.
Q 06Roughly what share of people worldwide are left-handed?
About 10%
About 10% is the usual estimate, 10.6% in a large 2020 analysis, though the answer runs from roughly 9% to 18% depending on whether people who favour the left hand for only some tasks are counted.
Q 07How many bones does an adult human skeleton have?
206
206 is the adult count, but a baby is born with far more, roughly 270 to 300 by different counts; the number falls because many grow together and fuse as the child matures.
Q 08Which instrument's four strings are tuned G, D, A and E?
Violin
The violin's strings, tuned G, D, A, E, were traditionally made of 'catgut', which despite the name is sheep intestine and has nothing to do with cats; the viola and cello are both tuned up from a low C instead.
Q 09Which river is traditionally ranked as the world's longest, narrowly ahead of the Amazon?
The Nile
The Nile has traditionally been ranked first, but the title is disputed: in 2007 Brazilian scientists claimed the Amazon was longer after tracing its headwaters to a snow-capped mountain in southern Peru.
Q 10Which is the largest country in the world by area?
Russia
Russia covers nearly twice the territory of Canada, the runner-up, and spans eleven time zones, so when clocks in Kaliningrad say 9 pm it is already 7 am the next day in Kamchatka.
Q 11Which is the largest and deepest of Earth's five oceans?
Pacific
The Pacific covers about a third of the planet, more than all the land put together; Ferdinand Magellan gave it the name, meaning 'peaceful', in 1520 because the water was calm when his ships sailed into it.
Q 12Which fruit did the US Supreme Court rule to be a vegetable?
Tomato
Tomato importers argued in 1893 that it was botanically a fruit and so free of the vegetable tariff, but the court went by everyday use, noting that tomatoes are served at dinner and not, like fruits, as dessert.
Q 13The peanut is not a true nut but which of these?
A legume
A legume, like peas and beans: the peanut's pods ripen underground, and bacteria in its roots feed nitrogen into the soil, which is why farmers value it as a crop to plant in rotation.
Q 21Which is the largest living bird?
Ostrich
The ostrich cannot fly, so it runs instead, in bursts of up to about 70 km/h, the fastest of any animal on two legs, and when cornered its kick is powerful enough to kill a lion.
Q 22Which is the longest bone in the human body?
Femur
The femur, or thigh bone, is also among the body's strongest bones, so it takes great force to break one: a snapped femur usually means a serious accident such as a car crash.
Q 23Which continent is the driest and windiest on average?
Antarctica
Antarctica gets so little snow that most of it counts as a polar desert, and its fierce winds are katabatic: cold, heavy air sliding downhill off the ice cap under gravity.
Q 14Which of these fruits is botanically a berry?
Banana
Banana: to a botanist a berry is a fleshy fruit formed from a single ovary, which fits bananas and grapes, while a strawberry's flesh grows from another part of the flower altogether.
Q 15Which structure is falsely said to be visible to the naked eye from space?
The Great Wall of China
The Great Wall of China is long but narrow and close in colour to the land around it; China's first astronaut, Yang Liwei, came back in 2003 and admitted he had not been able to see it.
Q 16The Latin name of the Canary Islands means islands of which animal?
Dogs
Dogs: the Latin name Canariae Insulae means 'islands of the dogs', though why the Romans called them that is uncertain, and the songbird was later named after the islands, not the reverse.
Q 17Which colour did Isaac Newton add to his rainbow to make seven?
Indigo
Indigo was added because Newton wanted seven colours, to match the seven notes of a musical scale.
Q 18Which planet is closest to the Sun?
Mercury
Mercury has almost no atmosphere to hold the heat it gets, so its surface swings from about 430 °C in daylight to around -180 °C at night.
Q 19Which food, properly stored, essentially never spoils?
Honey
Honey holds too little water and too much sugar and acid for microbes to grow, and bees add an enzyme that makes hydrogen peroxide; left unsealed, though, it soaks up moisture from the air and can spoil.
Q 20Which sea animal has three hearts and blue blood?
Octopus
The octopus has two hearts that pump blood through its gills and a third that sends it round the body, and the blood is blue because it carries oxygen with copper rather than iron.
Q 24A light-year is a unit of what?
Distance
Distance: a light-year is how far light travels in a year, about 9.46 trillion km, so the glow we see from the nearest star beyond the Sun set out more than four years ago.
Q 25Roughly how hot does the air around a lightning bolt get?
30,000 °C
30,000 °C is about five times hotter than the surface of the Sun, and the air heats so fast that it expands explosively, sending out the shock wave we hear as thunder.
Q 26Roughly what fraction of an iceberg is above the water?
One-tenth
One-tenth is the usual figure, which is where the phrase 'tip of the iceberg' comes from; the hidden bulk below the waterline is why icebergs are treated as a serious hazard to shipping.
Q 27What is the fastest land animal?
Cheetah
The cheetah can go from a standstill to nearly 100 km/h in three seconds, but it can keep that pace for only a few hundred metres, so a hunt is won or lost in one short sprint.
Q 28Which are the only mammals capable of true, sustained flight?
Bats
Bats fly by flapping wings of skin stretched over long finger bones, much like a hugely stretched human hand, whereas flying squirrels and the other so-called fliers can only glide.
Q 29Wisdom teeth are the last of which kind of tooth to come through?
Molars
Molars: wisdom teeth are the third molars, named for arriving so late, usually in the late teens or twenties; many jaws have no room for them, so they get stuck and are often taken out.
Q 30What is the largest organ of the human body?
The skin
The skin covers up to two square metres on an adult and never stops rebuilding itself, shedding dead cells constantly so that its surface is renewed every few weeks.