80 Fun Facts About Hard Trivia for Kids

Which planet is the hottest in the Solar System?

It is not the closest to the Sun, but its thick carbon-dioxide atmosphere traps heat until the surface reaches about 464 °C.

How many hearts does an octopus have?

One main heart pumps blood round the body and two smaller ones pump it through the gills; the main one stops when the octopus swims, so it prefers to crawl.

What is the smallest bone in the human body?

It is shaped like a stirrup and passes sound vibrations into the inner ear.

Roughly how many bones does an adult human have?

Babies are born with about 270, but many fuse together as they grow.

Which is the largest desert in the world?

A desert is defined by how little rain or snow falls, not by heat, and Antarctica gets very little. The Sahara is only the largest hot desert.

What gas makes up most of the air we breathe?

Dry air is about 78 percent nitrogen and only 21 percent oxygen.

What is the capital city of Australia?

It was purpose-built as a compromise between rivals Sydney and Melbourne and is Australia's largest inland city.

What is the smallest country in the world?

It covers only 44 hectares inside Rome and has fewer than 1,000 residents.

Which country is the largest in the world by area?

It stretches across eleven time zones and borders fourteen countries.

Which country has the most people?

Its population passed 1.4 billion in 2023, overtaking China.

How many countries are there in Africa?

That is more than any other continent; Algeria is the biggest by area and Nigeria has the most people.

Which is the longest mountain range on land?

It runs about 8,900 km down the western edge of South America.

What is the deepest known point in the ocean called?

It sits at the bottom of the Mariana Trench in the western Pacific, deeper than Mount Everest is tall.

Which is the largest and deepest ocean?

It stretches from the Arctic to the Southern Ocean and covers more area than all the land on Earth.

What is the longest river in the world?

It flows north for about 7,088 km into the Mediterranean, though the Amazon carries far more water.

Which country contains most of the Amazon rainforest?

About 60 percent is in Brazil; the forest spreads across nine countries in total.

How much of Earth's surface is covered by ocean?

That is why Earth looks blue from space and is sometimes called an ocean world.

What is the fastest land animal?

It can hit around 100 km/h thanks to a bendy spine and long legs, but only for a short sprint.

Which bird is thought to be the fastest animal of all when it dives?

Its hunting dive, called a stoop, can top 320 km/h.

What is the largest animal that has ever lived?

It can reach 30 metres and 200 tonnes and eats almost nothing but tiny krill.

What is the largest living land animal?

Bulls average over three metres at the shoulder and eat about 150 kg of plants a day.

Which is the only group of mammals that can truly fly?

The others only glide. There are at least 1,500 bat species, about a fifth of all mammals.

Which Australian mammal lays eggs?

When the first preserved one reached Europe in 1799, scientists thought it was a hoax sewn together from several animals.

What is the smallest bird in the world?

It is about 6 cm long and weighs around 2 grams, lighter than a coin.

A group of lions is called what?

A pride is mostly related females and their cubs, with one or a few adult males.

How many legs does an insect have?

Three pairs, plus a three-part body and a pair of antennae. Spiders, with eight legs, are not insects.

A shark's skeleton is made of what?

It is the same bendy stuff that is in your ears and nose, which makes sharks lighter and more flexible than bony fish.

Which is the tallest animal on land?

It is also the largest ruminant, and its closest living relative is the okapi.

Why does a sloth's fur often look green?

The algae camouflage the sloth from predators, and its hair even grows the 'wrong' way because it hangs upside down.

Honey bees tell each other where food is by doing what?

The 'waggle dance' points other workers toward flowers; a 'round dance' means the food is very close.

What is the largest organ of the human body?

It makes up about 16 percent of your body mass and would cover roughly two square metres if spread out.

What is the longest bone in the human body?

On average it is just over a quarter of your height, which lets scientists estimate a person's height from a single bone.

How many permanent (adult) teeth do humans usually have?

Children have 20 baby teeth, which are all replaced.

How many chambers does the human heart have?

Two atria on top and two ventricles below, with valves that stop blood flowing backwards.

What carries oxygen from your lungs to the rest of your body?

They are packed with an iron-rich protein called haemoglobin, which is also what makes blood red.

What does your skin make when sunlight hits it?

For most people, sunshine provides more of it than food does.

What shape is a DNA molecule?

Two long strands twist around each other like a spiral staircase, carrying the instructions for every living thing.

Which is the largest planet in the Solar System?

It is eleven times wider than Earth and has more mass than all the other planets combined, twice over.

What is the Great Red Spot, seen on the largest planet?

It has been watched since 1831 and is bigger than Earth.

Which planet is the smallest in the Solar System?

It is also the closest to the Sun, and its cratered surface looks a lot like our Moon.

Which planet could float in water, if you could find a bathtub big enough?

It is the only planet less dense than water, about 30 percent less.

Which planet spins on its side, tilted at more than 80 degrees?

It is also the coldest planet, dropping to about minus 224 °C.

Which planet has the fastest winds in the Solar System?

Even though it is farthest from the Sun, leftover heat from its formation powers wild weather.

Why is Mars called the Red Planet?

Its thin atmosphere is mostly carbon dioxide and its temperature can drop to minus 153 °C.

What does a light-year measure?

It is how far light travels in a year: about 9.46 trillion kilometres.

Roughly how fast does light travel?

That is about a billion kilometres an hour, and it is why the metre is now officially defined using light.

Compared with air, how does sound move through water?

Sound is slowest in gases, faster in liquids and fastest in solids like iron.

What kind of object is the Sun?

It is a ball of hot plasma powered by nuclear fusion, and it holds almost all the mass in the Solar System.

Who was the first person to walk on the Moon?

He commanded Apollo 11 in 1969; Buzz Aldrin followed him down the ladder.

Who was the first person to travel into space?

His 1961 flight aboard Vostok 1 lasted just 108 minutes and circled Earth once.

What is thought to have wiped out the dinosaurs about 66 million years ago?

The rock was 10 to 15 km wide and left the Chicxulub crater in Mexico; the dust blocked sunlight and killed off plants.

What is the hardest natural material?

It is pure carbon, the same element as pencil graphite, just with the atoms locked in a much tougher pattern.

What is the chemical symbol for gold?

It comes from 'aurum', the Latin word for gold; Ag is silver.

Which ancient people wrote with hieroglyphs?

There were more than 1,000 different symbols, and nobody could read them for centuries until the Rosetta Stone helped crack the code.

The Great Pyramid of Giza was built as a tomb for which pharaoh?

Built around 2600 BC over about 26 years, it is the only one of the Seven Wonders of the Ancient World still standing.

Which volcano buried the Roman city of Pompeii in AD 79?

It threw ash and stones 33 km into the sky and is still an active volcano near Naples today.

In which year did the Titanic sink?

She hit an iceberg on her very first voyage from Southampton to New York, and about 1,500 people died.

The Statue of Liberty was a gift to the United States from which country?

Its metal skeleton was built by Gustave Eiffel, who later built the Eiffel Tower.

Who made the first powered aeroplane flight, in 1903?

The Wright Flyer took off near Kitty Hawk, North Carolina; the Montgolfiers flew balloons and the Lumières made films.

Who was the first person to win two Nobel Prizes?

She won for physics in 1903 and chemistry in 1911, and is still the only person to win in two different sciences.

Which scientist wrote down the laws of motion and universal gravitation in 1687?

His book the Principia stayed the standard view of physics until Einstein's relativity.

Which famous composer kept writing music after losing his hearing?

His hearing began to fail around 1798, when he was still in his twenties.

Who painted the Mona Lisa?

It became world-famous partly because it was stolen from the Louvre in 1911 and not found for two years.

Big Ben in London is actually the name of what?

The tower was called the Clock Tower until 2012, when it was renamed the Elizabeth Tower.

Why does the Leaning Tower of Pisa lean?

It started tilting during construction in the 1100s and reached 5.5 degrees before engineers pulled it back to under 4.

How many rings are on the Olympic flag?

Blue, yellow, black, green and red on white; the designer said the number stood for the five parts of the world.

The Great Barrier Reef lies off the coast of which Australian state?

It is the world's largest coral reef system, over 2,300 km long with more than 2,900 separate reefs.

What is the tallest mountain above sea level?

It was measured at 8,848.86 metres in 2020 and sits on the border of Nepal and China.

What is a baby kangaroo called?

It finishes growing inside its mother's pouch, called a marsupium.

Which is the largest living bird?

It cannot fly, but it has the biggest legs of any bird and can outrun most animals.

How far away is the Moon, on average?

That is roughly 30 Earths lined up in a row, and it takes the Moon 29.5 days to go round us.

Which is the largest continent?

Africa comes second in both size and population.

Which is the only penguin that breeds during the freezing Antarctic winter?

Emperors trek 50 to 120 km over the ice to reach their breeding colonies and are the tallest and heaviest penguins alive.

About half of all chameleon species live only on which large island?

Chameleons' eyes move independently, so their brains take in two separate pictures at once until they focus forward to hunt.

Up to how many hours a day does a koala sleep?

Its eucalyptus-leaf diet is so low in energy that the koala saves strength by barely moving.

In a normal rainbow, which colour appears on the outer edge of the arc?

A fainter second rainbow sometimes appears about 10 degrees outside the first, with its colours reversed.

Which food, when stored properly, does not spoil, with ancient samples still edible after thousands of years?

Its high sugar and acidity stop most microorganisms from growing; bees make it from flower nectar.

The best-known parts of the Great Wall of China were built by which dynasty?

All the wall sections together stretch about 21,196 km, and the earliest walls date back to the 7th century BC.

Roughly how hot does the air around a lightning flash become?

That sudden heating makes the air expand with a shock wave, which is what we hear as thunder.

Who is credited with inventing the piano in Padua, Italy, around 1700?

He was an expert harpsichord maker working as Keeper of the Instruments for the Medici family.