99 Fun Facts About Science Trivia for Kids

Which planet is known as the Red Planet?

Mars looks orange-red from Earth because its surface is covered in iron oxide, which is the same rusty stuff you see on an old nail left out in the rain.

Which is the largest planet in our Solar System?

Jupiter is the fifth planet out from the Sun and bigger than all the other planets put together. Its famous Great Red Spot is a storm wider than Earth.

Which planet orbits closest to the Sun?

Mercury is the first planet out from the Sun and also the smallest planet in the Solar System.

What kind of object is the Sun?

The Sun is an ordinary star that happens to sit right at the centre of our Solar System. It only looks so big and bright because it is far closer to us than any other star.

Which gas do plants take in from the air to make their food?

Carbon dioxide and water, with sunlight, become sugar in photosynthesis, and the plant gives off oxygen as a leftover.

At what temperature does water freeze?

0 °C is where water turns to ice at one atmosphere, which is 32 degrees Fahrenheit; it boils at 100 °C.

What is the chemical formula for water?

Every drop of water is made of tiny molecules with two hydrogen atoms joined to one oxygen atom.

How many bones are in a grown-up person's body?

A baby is born with around 270 bones, and some of them join together as the child grows, leaving about 206 by adulthood.

Who was the first person to walk on the Moon?

Neil Armstrong stepped onto the Moon on 20 July 1969 as commander of Apollo 11. Buzz Aldrin followed him out minutes later and became the second person to walk there.

Which is the largest organ in the human body?

Your skin covers you from head to toe and makes up roughly a sixth of your whole body weight.

Which force pulls a dropped ball down toward the ground?

Gravity draws objects with mass toward each other, and it is what gives everything on Earth its weight.

Which part of a plant takes in water from the soil?

Tiny root hairs soak up water and dissolved minerals underground, and tubes inside the plant carry them up to the rest of it.

Which gas makes up most of the air we breathe?

Nitrogen is about 78 percent of dry air. Oxygen, the part our bodies actually use, is only about 21 percent.

What do we call an animal that eats only plants?

A herbivore lives mainly on leaves, fruit and seeds. Cows, rabbits and giraffes are all herbivores.

Which natural material is the hardest of all?

Diamond sits at the very top of the Mohs hardness scale, so it can scratch every other natural material but almost nothing can scratch it.

What are the three main types of rock?

Igneous, sedimentary and metamorphic rocks can each slowly turn into either of the others; geologists call that endless loop the rock cycle.

Which type of rock forms when hot melted magma or lava cools down and hardens?

Igneous rock forms when magma or lava cools and hardens; the name comes from the Latin igneus, meaning fiery. Basalt and granite are two everyday examples.

What are the flat layers that sedimentary rocks build up in called?

Strata are the flat layers, or beds, that sedimentary rock settles into over long periods. Fossils are usually found in them because the layers bury and protect whatever falls in.

Which type of rock is made when heat and pressure change an existing rock without melting it?

Marble is a metamorphic rock that started out as limestone; slate started out as shale.

The word 'fossil' comes from a Latin word meaning what?

'Fossil' comes from the Latin fossilis, meaning obtained by digging, because early finds were dug out of the ground. Fossils can be bones, shells, footprints or a bug trapped in amber.

A volcano lets lava, ash and gases escape from what underground pocket of melted rock?

A magma chamber is the underground pocket of molten rock that feeds a volcano; when pressure builds, lava, ash and gas escape through the vent. Most volcanoes on Earth are actually under the ocean.

What kind of energy waves does an earthquake send rippling through the ground?

Seismic waves are the vibrations an earthquake sends through the ground, and a seismograph records them; the magnitude 9.5 Chile earthquake of 1960 registered on instruments around the world.

Which of these metals is a magnet able to pull on?

Iron, nickel and cobalt are the classic magnetic metals; that is why a fridge magnet sticks to a steel door but not to a soda can.

Which four states of matter can you see in everyday life?

Solid, liquid, gas and plasma are the four classic states of matter. Plasma is the surprising one: lightning and the glow inside a neon sign are both plasma.

When water on the surface of a puddle turns into a gas and disappears into the air, what is that called?

Only the fastest-moving molecules escape, so evaporation cools whatever is left behind, which is why sweat cools you down.

Water vapor turning back into liquid drops on the outside of a cold glass is an example of what?

Condensation is water vapor turning back into liquid when it meets a cold surface. Clouds form the same way: air cools to its dew point and the invisible vapor becomes tiny visible droplets.

Clouds are made mostly of what?

Clouds are made of tiny water droplets and ice crystals, so light that they hang in the air; a plane can fly straight through one, and fog is simply a cloud sitting on the ground.

What is the lowest layer of Earth's atmosphere, where most weather happens, called?

The troposphere is the lowest layer of the atmosphere, only about 10 to 15 km thick, yet nearly all clouds, rain and storms happen inside it.

Which part of the upper atmosphere soaks up most of the Sun's harmful ultraviolet light?

The ozone layer, high in the stratosphere, absorbs most of the Sun's ultraviolet light. French physicists Charles Fabry and Henri Buisson discovered it in 1913, and the 1987 Montreal Protocol phased out the chemicals thinning it.

Which gas, lighter than air and unable to burn, is used to fill party balloons?

Helium is the second-lightest element and cannot burn, which is why it replaced explosive hydrogen in balloons and airships; the Sun makes helium by fusing hydrogen.

Which instrument measures how hot or cold something is?

A thermometer measures temperature; Daniel Fahrenheit made the first reliable mercury thermometer in 1714, and most countries read temperature on the Celsius scale, named after Anders Celsius.

Roughly how fast does sound travel through air at room temperature?

Sound moves through air at about 343 meters per second, roughly a kilometer every three seconds, which is why you see lightning before you hear thunder; count the seconds and divide by three for the distance in kilometers.

In a rainbow, which color is on the outer edge of the arc?

Red is on the outer edge of a primary rainbow and violet on the inside; the colors appear because sunlight bends and splits apart inside millions of raindrops.

A compass needle is a small magnet that always turns to point which way?

A compass needle lines up with Earth's magnetic field and points toward magnetic north. The Chinese invented the compass more than 2,000 years ago, at first using it for fortune-telling rather than finding the way.

What is the fixed point that a lever turns on called?

A seesaw is a lever with the fulcrum in the middle; a wheelbarrow is a lever with the fulcrum at the wheel.

Which simple machine is a ramp that helps push a heavy box to a higher place?

A ramp is an inclined plane: you push with less force but over a longer distance, and that trade-off is the same for all six classic simple machines.

Which simple machine is a wheel with a rope running over it, used to lift things like a flag up a pole?

Pulleys were being used in ancient Egypt around 4,000 years ago; several together make a block and tackle that can lift huge weights.

Rubbing two sticks together can start a fire because of which force?

Friction turns motion into heat; the same force is what makes your hands warm when you rub them together.

How many chambers does the human heart have?

The two upper rooms are the atria and the two lower ones are the ventricles; the whole thing is about the size of your closed fist.

Which large muscle under your lungs does most of the work when you breathe?

When it tightens and flattens, your lungs get bigger and air rushes in; hiccups are the diaphragm twitching.

Which animal group has three body parts, six legs and a pair of antennae?

Insects have three body parts, six legs and a pair of antennae, and more than a million kinds are known. Spiders have eight legs and two body parts, so they do not belong.

What are baby frogs called while they swim in water breathing with gills?

Tadpoles are the swimming, gilled larvae of frogs and toads. Frogs, toads, salamanders and worm-like caecilians are all amphibians, a name that means 'both lives': water and land.

Which feature do all mammals share?

Feeding their young with milk is the one trait every mammal shares, from a mouse to a whale; whales and bats are mammals too, even though they swim or fly.

Which is the only animal group that has feathers?

Birds are the only living animals with feathers; they also have no teeth and lay hard-shelled eggs. Feathers are made of keratin, the same protein as your fingernails.

A caterpillar changing into a butterfly is an example of what process?

Metamorphosis, Greek for 'transformation', is the dramatic change of body form between young and adult; frogs, beetles and even some fish go through it too.

In a food chain, what do we call a living thing like grass or algae that makes its own food?

Every food chain starts with a producer and often ends with an apex predator such as a killer whale or a grizzly bear.

Fungi and bacteria that break down dead organisms and recycle nutrients are called what?

Decomposers such as fungi and bacteria pour digestive juices onto dead material and soak up the results instead of swallowing it, which is why a fallen log slowly turns to mush.

Bees carrying pollen from one flower to another is called what?

Wind, water, birds and bats do the job too; without pollination most flowering plants could not make seeds.

Which creatures pass the winter in a deep sleep with a slow heartbeat and low body temperature?

Hibernating animals such as ground squirrels slow to just a few heartbeats a minute and let their body temperature fall; the summer version of the trick is called aestivation.

What is the trick called when a leopard's spotted coat helps it hide?

Camouflage is coloring or patterning that helps an animal blend into its surroundings; in the open ocean, with nothing to hide against, fish use silvery scales and see-through bodies instead.

Animals with a backbone, like fish, birds and mammals, are called what?

Vertebrates are less than five percent of all animal species; the other 95 percent, like insects and worms, have no backbone at all.

Which SI unit is used to measure force?

It is named after Isaac Newton, and one newton is roughly the weight of a small apple.

Which SI unit is used to measure energy?

The joule, named after English physicist James Prescott Joule, is the SI unit of energy; lifting a small apple one meter takes about one joule.

Density is found by dividing an object's mass by what?

Density is mass divided by volume, so a material with more mass packed into the same volume is denser. Ice is less dense than liquid water, which is why ice cubes float.

A material like rubber or glass that does not let electricity flow through it easily is called what?

An insulator such as rubber or glass holds its electrons tightly to their atoms, so current cannot flow easily; the plastic around a wire is there to keep the current inside the copper.

Which instrument would you use to look at something far too small to see with your eyes?

The first and most common kind uses glass lenses and light; electron microscopes can even show single atoms.

How long does the Moon take to go once around the Earth and return to the same phase?

The Moon takes about 29.5 days to return to the same phase, which is why a full moon comes roughly once a month; the word 'month' actually comes from 'moon'.

Which three renewable energy sources are used the most around the world?

They are called renewable because sunshine, wind and flowing water keep coming back, unlike coal, which takes millions of years to form.

What is it called when wind or water carries broken rock pieces away?

The Grand Canyon is erosion on a giant scale: the Colorado River has been carrying rock away for millions of years.

Which blood cells fight germs and infection in your body?

White blood cells are the body's defenders: they surround and destroy bacteria and make antibodies. A healthy adult has roughly 4,000 to 11,000 of them in every microliter of blood.

Which planet has the hottest surface in the Solar System?

Venus is not the closest planet to the Sun, but its thick carbon dioxide atmosphere traps heat so well that the surface reaches about 464 °C, hot enough to melt lead.

Which pigment gives plant leaves their green colour?

Chlorophyll's name comes from Greek words meaning 'pale green' and 'leaf'; it absorbs red and blue light for photosynthesis and reflects the green, which is why leaves look green.

Which planet has the largest and most easily seen rings?

Saturn's rings are the only ones bright enough to spot through a small backyard telescope, and they are made mostly of ice chunks.

Which animal is the largest known to have ever lived?

A blue whale can stretch about 30 metres and weigh up to 200 tonnes, heavier than any dinosaur found so far. Its heart alone is roughly the size of a small car.

Which animal is the fastest runner on land?

A cheetah can sprint at around 93 to 104 km/h thanks to long legs, a bendy spine and powerful back muscles, though it can only keep that pace up for a short burst.

Which is the tallest animal living on land today?

A giraffe's neck has the same number of bones as a human neck, seven, but each one is greatly stretched. Giraffes are also the largest ruminants, or cud-chewing animals.

How many hearts does an octopus have?

An octopus has three hearts: one main heart pumps blood around the body, while two smaller gill hearts push blood through the gills. Its blood is blue because it uses copper instead of iron to carry oxygen.

Spiders are not insects, so which animal group do they belong to?

Spiders are arachnids, with eight legs and two body sections, unlike insects with six legs and three; scorpions, ticks and mites are arachnids too.

Which is the heaviest and largest living bird?

The ostrich can weigh up to 145 kg and cannot fly, but it can run faster than any other bird.

Which species is the smallest bird in the world?

Found in Cuba, it is only about 5 to 6 cm long and weighs less than a coin. It has even been called the smallest living dinosaur, since birds descend from dinosaurs.

Which Australian mammal has a duck-like bill and lays eggs?

European scientists who first saw a preserved specimen thought it was a hoax. A female platypus lays eggs yet still feeds her young with milk, as all mammals do.

Which animals are the only mammals that can truly fly?

Flying squirrels and sugar gliders only glide. A bat's wing is a thin skin membrane stretched over very long finger bones, which lets it twist and turn more nimbly than most birds.

How many permanent (adult) teeth does a person usually have?

Adults usually have 32 permanent teeth, replacing the 20 baby teeth of childhood; the last four, the wisdom teeth, often do not appear until the late teens or twenties.

Which is the hardest substance in the human body?

Tooth enamel is about 96 percent mineral, which makes it tough but also means it cannot grow back once it wears away; that is why cavities need fillings.

Which is the smallest bone in the human body?

The stapes is shaped like a tiny stirrup, which is what its Latin name means; with the malleus and incus it passes sound vibrations from the eardrum to the inner ear, and it is only about 3 mm long.

Which planet is the farthest known planet from the Sun?

Neptune was found in 1846 after mathematicians predicted where it should be. It takes about 165 Earth years to orbit the Sun once.

Which of these can sound NOT travel through?

Sound is a vibration that needs matter to pass through, so it cannot cross a vacuum such as empty space; it actually travels faster through water and steel than through air.

What is the chemical symbol for gold?

Au comes from aurum, the Latin word for gold. Ag is silver, from the Latin argentum, which is why the two are easy to mix up.

Which of Earth's oceans is the largest and deepest?

The Pacific covers more area than all of Earth's land put together. Its Mariana Trench drops nearly 11 km below the surface, deeper than Mount Everest is tall.

Which mountain is the highest above sea level?

Everest sits on the border of Nepal and China and stands about 8,849 m tall. It is still growing a few millimetres a year as tectonic plates push together.

How many arms does a classic symmetrical snowflake have?

The six-sided shape comes from how water molecules lock together in ice crystals. Fewer than 0.1 percent of real snowflakes are perfectly symmetrical, though.

Thunder is the sound made by what?

A lightning bolt heats the air around it so fast that the air expands explosively, making a boom. You see the flash first because light travels far faster than sound.

Isaac Newton used which glass object to split white light into a rainbow of colours?

Newton's prism, a triangular block of glass, bends each colour by a different amount, fanning white light out into a spectrum; his experiments of 1666 showed white light is a mixture of all the colours.

Roughly what percentage of Earth's surface is covered by ocean?

Oceans cover about 71 percent of Earth's surface, which is why the planet looks blue from space and is sometimes called the 'Blue Planet'; most of the land sits in the Northern Hemisphere.

How much of an iceberg typically floats above the water?

Only about one-tenth of an iceberg shows above the water, because ice is only slightly less dense than seawater; that is where the saying 'the tip of the iceberg' comes from.

About how long ago did the non-bird dinosaurs die out?

The non-bird dinosaurs died out about 66 million years ago, when a space rock around 10 km wide slammed into what is now Mexico, leaving the Chicxulub crater; birds are the one dinosaur group that survived.

Alexander Fleming found which germ-killing medicine growing as a mould in 1928?

Penicillin came from a stray Penicillium mould that Fleming noticed had killed the bacteria around it on a dish; the discovery led to the first antibiotics and a shared Nobel Prize in 1945.

How many chemical elements does the periodic table contain as of 2020?

Oganesson, element 118, completed the table's seventh row when IUPAC recognized it in 2016; elements heavier than uranium are made in laboratories, apart from tiny natural traces of neptunium and plutonium.

What is actually stored inside a camel's hump?

A camel's hump stores fat, an energy reserve it can live off when food is scarce; camels cope with thirst in other ways, such as drinking huge amounts quickly when water is found.

Where do flamingos get their pink colour from?

Chicks hatch greyish and turn pink from pigments called carotenoids in the tiny shrimp and algae they eat. Zoo flamingos fade to pale pink if their diet lacks those pigments.

In which fish does the male carry the eggs in a pouch until they hatch?

A male seahorse carries up to 1,500 eggs that the female places in his pouch, for up to 45 days; the babies come out tiny but fully formed.

The leaves of which tree make up most of a koala's diet?

Eucalyptus leaves are tough and low in energy, which is one reason koalas sleep up to 20 hours a day; koalas are marsupials, not bears, despite the nickname 'koala bear'.

A shark's skeleton is made of which flexible material instead of bone?

Cartilage, the same bendy stuff in your nose and ears, is far lighter and softer than bone, which is why shark fossils are usually just teeth, which are much harder.

Which body part does a jellyfish NOT have?

Instead of a brain, a jellyfish has a simple ring of nerves that lets it sense and move. Some jellyfish also have no heart and no bones, and are about 95 percent water.

Which mosquitoes bite people to drink blood?

Females need the protein in blood to make their eggs. Males, and females when not laying, feed on nectar from flowers instead.

Gravity on the Moon's surface is what fraction of Earth's?

The Moon's surface gravity is about one-sixth of Earth's, which is why Apollo astronauts could bounce along in heavy spacesuits; a 60 kg person there would weigh what about 10 kg does on Earth.

What does a barometer measure?

Falling pressure often means rain or storms are coming, while rising pressure usually brings fair weather. The first one was built in 1643 using a tube of mercury.

What shape is a molecule of DNA, the instruction code inside living cells?

DNA is a double helix: two long strands twisting around each other like a spiral staircase. Stretched out, the DNA in one of your cells would be about two metres long.

Which sea animal can regrow a lost arm?

Some can even grow a whole new body from a single arm. Starfish are not fish at all; they have no backbone, fins or gills and move on hundreds of tiny tube feet.