True or false? 40 quiz statements with answers, and the myths behind them

A true-or-false round is the quickest format a quiz has: one sentence, two possible answers, and nobody left staring at a blank. That makes it the round that gets everyone playing, from the guest who knows nothing about football to the nine-year-old and the grandparent who does not like being put on the spot. Everyone has an opinion on whether bulls hate red, and nobody needs a name or a date to give it.

It is also the round where the answer is worth more than the question. The best statements are the ones half the room is sure of and wrong about, and the explanation afterwards (why a goldfish remembers, where the horned Viking helmet came from) is the part people repeat the next day. So read the reason out every time, not just the verdict.

Ten statements take under five minutes to read and score, which is why true or false works as an opening round while people are still arriving, and as a tiebreak at the end: read statements to the tied players in turn until one of them gets one wrong. Luck plays a bigger part in this format than in any other, and the sections after the forty statements are about keeping it in check.

• Quiz questions for a younger room

Four rounds of ten: myths people believe, science and nature, history and geography, and language, culture and everyday life. True and false are mixed in every round, roughly half and half but not the same split each time, so counting does not help. Read each statement once, give players ten seconds to commit (a show of hands, a thumb up or down on camera, or a T or an F on paper) and only then read the verdict and the reason.

Every verdict here holds without an "it depends". Where a statement needs a qualifier to be strictly true or false, such as "botanically" or "from west to east", the qualifier is part of the statement and has to be read out with it. Leave it out and you will spend the next five minutes in an argument you deserve to lose.

1. The Great Wall of China can be seen from the Moon with the naked eye. False. The Moon is about 384,000 kilometres away and the wall is a few metres wide; even from orbit, 400 kilometres up, it is hard to pick out, and China's first astronaut, Yang Liwei, said in 2003 that he had not seen it. The claim is older than spaceflight: an English antiquarian wrote it down in 1754, long before anyone could go and look.

2. Lightning can strike the same place twice. True. Tall, pointed, isolated structures are hit again and again: the Empire State Building takes around twenty strikes in an average year. The proverb is about bad luck, not about physics.

3. A goldfish can remember things for only about three seconds. False. In experiments goldfish have learned to push a lever for food or to swim to a particular sound, and still knew the trick months later. The three seconds has no known scientific source.

4. Dogs can see colours. True. They have two kinds of colour receptor where people have three, so they tell blue from yellow well and red from green hardly at all, much like a person with red-green colour blindness. The idea that dogs see in black and white was repeated for decades before experiments in the late 1980s showed otherwise.

5. Most people use only about ten percent of their brain. False. Brain scans show activity in practically every region over the course of a day, and damage to almost any small area has a noticeable effect. The idea seems to go back to the psychologist William James, who said early in the twentieth century that people use only a fraction of their mental potential; the precise-sounding ten percent was added later by popular writers.

6. Napoleon was unusually short for a man of his time. False. He was about 1.69 metres tall, average or slightly above for a Frenchman of his generation. The legend comes partly from British cartoonists, who drew him tiny, and partly from units: his recorded height of five feet two was in French feet and inches, which were longer than English ones.

7. All bats can see. True. Every one of the more than 1,400 species has working eyes, and the large fruit bats find their food mainly by sight and smell. "Blind as a bat" comes from the many smaller species that hunt in the dark by echolocation, which they use as well as their eyes, not instead of them.

8. Bulls charge at the matador's cape because the colour red enrages them. False. Cattle are red-green colour-blind, and what provokes the charge is the movement of the cloth; a bull goes for a waved cape of any colour. The cape used at the end of a bullfight is red by tradition, and because it hides bloodstains.

9. A swallowed piece of chewing gum leaves the body within a few days. True. The gum base cannot be digested, but it moves through the gut like anything else the body cannot break down; the playground version, in which it stays in your stomach for seven years, has no basis. Swallowing a lot of it in a short time can cause a blockage, which is the real reason not to make a habit of it.

10. Spinach is exceptionally rich in iron. False. Fresh spinach has about three to four milligrams per 100 grams, a decent amount for a vegetable but nothing exceptional (parsley, pulses and oat flakes have as much or more), and the oxalic acid in it means the body absorbs only a small share. The famous explanation, a nineteenth-century scientist's misplaced decimal point, has never been traced to an actual error and is a myth of its own; as far as anyone has been able to reconstruct it, the high figure that circulated was measured on dried spinach and quoted as if it applied to fresh leaves.

11. Botanically, a banana is a berry. True. To a botanist a berry is a fleshy fruit that grows from a single flower with a single ovary and usually holds several seeds, which makes bananas, grapes, tomatoes, kiwis and aubergines berries. In the cultivated banana, the seeds are the tiny dark specks in the middle.

12. Botanically, a strawberry is a berry. False. The red flesh is the swollen base of the flower, and the actual fruits are the little "seeds" on the outside, each a tiny nut-like fruit with a seed inside. Raspberries are not berries either: each one is a cluster of tiny fruits.

13. An octopus has three hearts. True. Two pump blood through the gills and the third sends it round the rest of the body. The blood itself is blue, because it carries oxygen on copper rather than iron.

14. Venus takes longer to turn once on its axis than to travel once around the Sun. True. One rotation takes about 243 Earth days, one orbit about 225. Because Venus also turns backwards, the time from one sunrise to the next is shorter, about 117 Earth days, so ask about the rotation rather than the "day" or the room will argue.

15. Mercury, the planet closest to the Sun, is also the hottest. False. Venus is hotter, at around 465 degrees Celsius by day and by night, because its thick atmosphere of carbon dioxide traps the heat. Mercury has almost no atmosphere: its day side reaches about 430 degrees and its night side falls below minus 170.

16. Sound travels faster in water than in air. True. In air it covers about 340 metres per second, in water about 1,500, more than four times as fast. Water is far harder to compress than air, so it passes a vibration on more quickly.

17. It is summer in Europe because the Earth is closer to the Sun at that time of year. False. The seasons come from the tilt of the Earth's axis, which turns each hemisphere towards the Sun for half the year. The Earth is actually closest to the Sun in early January, about five million kilometres closer than in July.

18. Honey in a sealed jar can keep for decades without going off. True. It holds so little water and so much sugar that bacteria and moulds cannot grow in it. It may crystallise or darken with age, which changes the texture but not the safety; archaeologists have found honey in Egyptian tombs that had survived for thousands of years.

19. A newborn baby has fewer bones than an adult. False. It is the other way round: a baby is born with roughly 270 to 300 bones and bony parts, depending on how they are counted, and many of them fuse during childhood, in the skull, the spine and the pelvis, leaving an adult with 206.

20. Under its white-looking fur, a polar bear has black skin. True. The hairs themselves contain no pigment at all; they are translucent and look white because they scatter light, much as snow does.

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21. Cleopatra lived closer in time to the Moon landing than to the building of the Great Pyramid of Giza. True. The pyramid was finished around 2560 BC; Cleopatra died in 30 BC, some 2,500 years later, and the Moon landing came about 2,000 years after her. To her, the pyramids were already ancient monuments.

22. Viking warriors wore horned helmets into battle. False. Not one horned helmet has been found from the Viking Age, and the best-preserved Viking helmet, found at Gjermundbu in Norway, is a plain rounded iron cap. The horns are a nineteenth-century invention, spread above all by the costumes Carl Emil Doepler designed for the first complete performance of Wagner's "Ring" cycle at Bayreuth in 1876.

23. The University of Oxford is older than the Aztec Empire. True. There was teaching in Oxford by 1096, and a university was flourishing there by the end of the twelfth century. The Mexica founded their capital, Tenochtitlan, around 1325, and the alliance usually called the Aztec Empire was formed in 1428.

24. The Hundred Years' War lasted a hundred years. False. It lasted 116, from 1337 to 1453, with long truces in between, and the name was given by later historians. The Thirty Years' War, by contrast, really did run from 1618 to 1648.

25. From west to east, mainland Australia is wider than the Moon. True. Australia measures about 4,000 kilometres across; the Moon's diameter is about 3,475. The comparison is about width only, because the Moon's surface is roughly five times the area of Australia.

26. Greenland is roughly the same size as Africa. False. Africa is about fourteen times larger. The two look similar on many world maps because the common Mercator projection stretches land more and more the further it lies from the equator.

27. Russia spans eleven time zones. True. When it is eight in the morning in Kaliningrad on the Baltic, it is six in the evening in Kamchatka. Counted with its overseas territories, France has even more: twelve.

28. Woolly mammoths were still alive when the Great Pyramid was built. True. A small population survived on Wrangel Island, off the north-east coast of Siberia, until about 4,000 years ago, several centuries after the pyramid was finished.

29. Most educated people in medieval Europe believed the Earth was flat. False. Scholars had known the Earth was a sphere since antiquity, and medieval universities taught it from standard textbooks. The story that Columbus had to convince flat-earthers spread mainly in the nineteenth century, not least through Washington Irving's popular biography of him, published in 1828.

30. The Eiffel Tower was meant to stand for only twenty years. True. It was built for the 1889 World's Fair in Paris on a twenty-year permit, and was saved mainly because it proved useful as a radio aerial. While it was still going up, a group of well-known artists had published a protest against it.

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31. The word "dollar" comes from German. True. It goes back to the "Thaler", short for "Joachimsthaler", a silver coin minted from the early sixteenth century in Joachimsthal in Bohemia, now Jáchymov in the Czech Republic. The name reached English by way of the Dutch "daalder".

32. When John F. Kennedy said "Ich bin ein Berliner" in 1963, the crowd laughed because he had called himself a doughnut. False. The crowd cheered. The sentence is correct German for declaring yourself one of them, Berliners call that pastry a "Pfannkuchen" anyway, and the doughnut story only took hold in English-language retellings decades later.

33. Santa Claus wears red because Coca-Cola's advertising dressed him that way. False. He appeared in red on magazine covers and in other companies' adverts years before 1931, when the illustrator Haddon Sundblom painted his first Santa for Coca-Cola. Those adverts did much to fix the image of a jolly, round-faced Santa, but they did not invent the colour.

34. Bluetooth is named after a king. True. Harald "Bluetooth" Gormsson ruled Denmark in the tenth century and is remembered for uniting it, which seemed a fitting name for a technology meant to connect devices; the logo combines the runes for his initials, H and B.

35. Gummy bears were invented in Germany. True. Hans Riegel, a confectioner in Bonn, made the first ones in 1922 and called them dancing bears. His company's name, Haribo, is built from the first letters of HAns RIegel BOnn.

36. The Bavarian beer purity law of 1516 allowed four ingredients: water, barley, hops and yeast. False. The text names only three: barley, hops and water. Yeast is missing because nobody yet understood its part in fermentation; that came in the nineteenth century.

37. The word "hat-trick" comes from cricket. True. In 1858 the English bowler H. H. Stephenson took three wickets with three consecutive balls, and a collection among the spectators bought him a hat. Football and other sports borrowed the term later for three goals by one player.

38. "Wi-Fi" is short for "wireless fidelity". False. The name was invented by a branding agency in 1999 as a catchy play on "hi-fi" and never stood for anything. A slogan mentioning "wireless fidelity" was used briefly afterwards, which is where the confusion comes from.

39. The Mona Lisa is painted on canvas. False. Leonardo painted it in oils on a panel of poplar wood, and because wood reacts to humidity it now sits in a climate-controlled case. It became world-famous not least because it was stolen from the Louvre in 1911 and stayed missing for more than two years.

40. In Japan, the number four is often avoided because it can sound like the word for death. True. One way of reading 4 is "shi", which is also how the word for death is pronounced, so some hospitals and hotels leave out fourth floors or room numbers containing a four. The other reading, "yon", is used much of the time precisely to avoid it.

• General knowledge questions with answers

Write the false ones first, and write them from what people actually believe. A false statement nobody would believe ("Paris is the capital of Spain") is a free point; a false statement half the room grew up with is a question. The best sources are the things you were told as a child, the things you have heard repeated with great confidence, and near misses: the war that lasted 116 years, the famous fact with one detail wrong.

Watch the absolute words. "Always", "never", "only" and "all" are the classic giveaway: experienced players know that sweeping claims are usually false and hedged ones ("can", "some", "often") are usually true. Either keep both kinds out, or deliberately include a true statement with an "all" in it, like the bats above, so that nobody can play the wording instead of the facts.

Avoid negatives. Answering "false" to "bats are not blind" means saying bats are blind, and half the room will press the wrong button for the right reason. Write every statement as a positive claim and let the verdict carry the "not". For the same reason, test one fact per statement: "The Eiffel Tower, built for the 1900 World's Fair, is 330 metres tall" is false because of the date, true because of the height, and unfair either way.

Keep the true ones honest too. A true statement needs a qualifier only where it would otherwise be arguable, and then the qualifier has to be read out. Players also notice that true statements tend to come out longer, because the writer kept adding words until they were exactly right; trim them until the true and the false ones are about the same length.

Balance the round without being mechanical. Five true and five false every time is a pattern, and a player who counts gets the last two free. Vary the split between four and six, never announce it, and do not let three of the same verdict in a row become a habit. Finally, write the explanation together with the statement: if you cannot say in a sentence why it is true or false, you do not know it well enough to ask it.

• How to write quiz questions that hold up

Every true-or-false statement can be answered by a coin. Over a round of ten, someone who knows nothing will score five on average, and in a group of six people guessing blind, one of them will typically reach seven or more. That is fine for a warm-up and a problem for anything that decides a winner. There are three remedies, and they combine well.

Take points off for wrong answers. A point for a right verdict, a point off for a wrong one and nothing for a pass: now a blind guess is worth zero on average, and answering only pays when you are more sure than not. Players start passing on the statements they really do not know, which is exactly the information the format was missing.

Ask for the reason. Give one point for the verdict and a second for saying why ("false, it is the movement of the cape"), and a lucky guess is worth half as much as knowing. It slows the round down, so keep it for the last round or the tiebreak, and agree beforehand that the quizmaster decides whether a reason is close enough.

Let players stake their points. Some quizmasters have players bet one, two or three points on each statement before the reveal, and win or lose that amount. It rewards knowing how sure you are, which is a skill of its own, and it makes the last statement of the evening matter.

• Round formats and scoring for a quiz night

The neatest fix is to follow each statement with a number. "The Hundred Years' War lasted a hundred years: true or false?" And then: "How many years did it last?" The verdict is half the answer and the estimate shows who actually knew. A player who guessed "false" by luck has nothing to go on for the number, while a player who knew it has 116 ready.

Several of the forty above work this way straight away: the Great Wall and the distance to the Moon (about 384,000 kilometres), Venus and how long it takes to turn once (about 243 Earth days), Australia and the Moon's diameter (about 3,475 kilometres), sound in water and its speed (about 1,500 metres per second). Score the verdict as usual and the estimate by who came nearest; how to set a fair range is in the estimation guide.

• Estimation questions with answers, and how to score them

The simplest way needs no preparation at all. Open a room, share the six-character code, switch on voice or video if you like, and read the statements aloud while everyone shows a thumb up or down on camera or writes a T or an F on paper. Up to ten people fit in one room.

To have the scoring done for you, put the statements into a community quiz in the editor. Multiple-choice questions there have four answer options, so a bare true-or-false statement does not fit as it is, but two adaptations work well. The first is "three truths and a myth": take four short statements, make them the four options and ask "Three of these are true. Which one is the myth?" The guessing odds drop from one in two to one in four, and because the question says plainly what it wants, nobody is caught out by a hidden "not". The second turns the statement into an ordinary question with the myth as one of the wrong answers ("How many hearts does an octopus have?" with one, two, three and four as the options), which keeps the surprise and loses the coin flip. The number half of the combination above goes in as an estimation question, which is scored by distance.

Scoring on omequiz pays for correct answers and for speed and never takes points away for a wrong answer, so in the app guessing is always worth it; the deduction rule above is for rounds on paper. If you would rather play the question bank, a room can mix up to three of the nine categories, among them science, history and geography. And for five minutes in between, there is the daily round of five questions.

• How scoring works on omequiz
• Today's five questions