169 Fun Facts About 3rd Grade

How many continents are there on Earth?

7 continents is the count most English-speaking schools teach, but much of Latin America teaches six, counting North and South America as one.

Which explorer named the Pacific Ocean, meaning 'peaceful', after finding its waters calm?

Ferdinand Magellan didn't finish the trip: he was killed in battle in the Philippines in 1521, and his crew completed the first voyage around the world.

Which is the smallest US state by area?

Rhode Island is the smallest state, and in 2020, 53% of its voters chose to drop 'and Providence Plantations' from its long official name.

Which US state is the biggest by area?

Alaska was sold to the US in 1867 for $7.2 million because its owner feared Britain would seize the hard-to-defend land in a future war.

Which is the longest river in the world?

The Nile is usually ranked the longest river, though some measurements favor the Amazon; its yearly floods left rich soil that let ancient Egyptians farm beside the desert.

What is the tallest mountain on Earth above sea level?

Mount Everest was named after George Everest, a British surveyor who never saw it and objected that local people could not pronounce his name.

Which is the largest hot desert in the world?

The Sahara was a green savanna where people and wild animals lived until about 5,000 years ago, when the rains faded and it dried into desert.

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

France paid for the statue, but Americans had to fund its pedestal; Joseph Pulitzer's newspaper raised the money by printing every donor's name, however small the gift.

The Grand Canyon is in which US state?

The Grand Canyon is in northern Arizona. The Colorado River carved it over millions of years, and it is more than a mile deep in places.

Which continent is the largest?

Asia shares one landmass with Europe, and the line between them is a tradition rather than a coastline, so some geographers count both as one continent, Eurasia.

Which continent is the smallest?

Australia is the smallest continent, and it drifts about 7 cm a year, so the country had to update its official map coordinates to keep GPS positions accurate.

Which continent is the coldest?

Antarctica is the coldest continent, and it holds so much ice that if all of it melted, the world's seas would rise by almost 60 m.

The Eiffel Tower stands in which city?

Paris got the Eiffel Tower for the 1889 World's Fair; it was meant to be temporary, but the city kept it because it proved useful as a radio station.

Giant pandas eat almost nothing but which plant?

Bamboo is nearly all a panda eats, but pandas still have a meat-eater's digestive system, so most of it passes through as waste and they must eat huge amounts.

Who was the first president of the United States?

George Washington served two terms, from 1789 to 1797, and then chose to step down, which set an example most presidents followed.

On what date was the Declaration of Independence adopted?

July 4, 1776 is when Congress approved the Declaration's final wording, but the vote for independence came on July 2, the day John Adams predicted Americans would celebrate.

Abraham Lincoln was president during which war?

Lincoln led the Union through the Civil War and was shot less than a week after General Lee's army surrendered in April 1865.

Martin Luther King Jr. is famous for which speech, given to a huge crowd at the Lincoln Memorial in 1963?

I Have a Dream was not in King's written text: soon after gospel singer Mahalia Jackson called out, 'Tell 'em about the dream, Martin!', he set his prepared text aside.

Which country's rulers sponsored Christopher Columbus's 1492 voyage across the Atlantic?

Spain's King Ferdinand and Queen Isabella sponsored the voyage after King John II of Portugal had turned Columbus down.

In 1955, Rosa Parks became famous for refusing to give up her seat on what?

Her arrest in Montgomery, Alabama, started a bus boycott that lasted more than a year.

The Wright brothers are famous for building and flying the first successful what?

The Wright brothers built their airplane while running a profitable bicycle company, and their shop mechanic, Charlie Taylor, helped build its engine.

Who was the first person to walk on the Moon?

Neil Armstrong stepped out first, Buzz Aldrin followed, and Michael Collins stayed in orbit, so Collins flew all the way to the Moon but never walked on it.

The Pilgrims sailed to Plymouth in 1620 aboard which ship?

The Mayflower was headed for northern Virginia, but storms and shoals pushed it to Cape Cod, so before landing the Pilgrims signed the Mayflower Compact to govern themselves.

How many stars are on the flag of the United States?

50 stars stand for the 50 states, but the stripes stopped growing: after a flag with 15 stripes, an 1818 law set them back at 13.

The Sun is which kind of object?

The Sun is a star that looks so much bigger and brighter than the others mostly because it is so close: light from the next nearest star takes over 4 years to reach us.

A seesaw is an example of which simple machine?

A lever lets a small push lift a big load, which is why a lighter kid sitting far from a seesaw's middle can balance a heavier one sitting closer in.

About how many days does it take Earth to travel once around the Sun?

365 days is about how long Earth takes to circle the Sun, and seasons come from Earth's tilt, not its distance: Earth is actually closest to the Sun in early January.

In 2006, scientists reclassified which world as a dwarf planet?

Pluto was reclassified as a dwarf planet in 2006 because it has not cleared its orbit of other objects, one of the tests a planet must pass.

Which is the largest planet in our Solar System?

Jupiter is the largest planet, and it spins so fast, a day lasting under 10 hours, that it bulges out around its middle.

Which planet is nicknamed the Red Planet?

Mars looks red because rusty dust covers its surface, and its winds can whip that dust into storms that cover much of the planet.

Which planet is famous for its bright, wide rings?

Saturn's rings are made mostly of ice that is slowly raining down onto the planet, so they could be gone in under 100 million years.

A magnet will pull on objects made of which metal?

Iron is pulled by magnets, and Earth itself acts like a giant magnet because of moving liquid metal in its outer core, which is what a compass needle lines up with.

About how many bones does an adult human have?

An adult human has 206 bones, while a newborn has about 270 to 300, many of which fuse together as the child grows.

Which organ pumps blood around your body?

Your heart has its own natural pacemaker, a patch of cells that fires electrical signals, so it keeps beating without the brain having to start each beat.

Your lungs take which gas out of the air and pass it into your blood?

Oxygen is made by plants and algae, and about half of all the oxygen made on Earth comes from algae and bacteria in the ocean rather than from land plants.

At what temperature does water freeze into ice on the Celsius scale?

Water freezes at 0 °C, but very pure water can stay liquid well below that, which is called supercooling.

Plants make their own food using energy from what?

Sunlight powers photosynthesis, which feeds nearly every food chain on Earth: animals eat plants, or eat other animals that ate plants.

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

Roots take in water, which travels up through the plant and escapes into the air as vapor through tiny pores in the leaves.

A caterpillar goes into which stage before it comes out as a butterfly?

Inside the chrysalis, the caterpillar's body is almost completely rebuilt into a butterfly.

Baby frogs that hatch from eggs and swim with tails are called what?

Tadpoles breathe through gills at first, then grow legs and lose their tails as they turn into frogs.

Evaporation, clouds forming and rain falling are all steps in which natural process?

The water cycle is powered by the Sun: its heat evaporates water into the air, which later cools into clouds and falls back as rain or snow.

Which group of animals has fur or hair and feeds milk to its babies?

Dolphins are mammals too: even though they live in the sea, their calves drink their mother's milk.

What is a group of lions called?

In a pride, the females do most of the hunting, while the males take on most of the defending.

Which is the largest animal alive today?

The blue whale was nearly wiped out by whaling in the 1900s, until a worldwide ban on hunting it in 1966 gave the species a chance to recover.

Which is the fastest land animal?

A cheetah can hold its top speed only briefly, and after a chase, lions and hyenas often steal its kill.

Which is the tallest land animal?

A giraffe's neck alone can be six feet long, yet it has the same number of neck bones as you do: seven.

Spiders, scorpions and ticks all belong to which group of animals?

Arachnids have no antennae or wings, which is one quick way to tell a spider apart from an insect.

At what temperature does water boil on the Celsius scale?

Water boils at 100 °C at sea level. On a high mountain it boils at a lower temperature because the air pressure is lower.

How many sides does a hexagon have?

6 sides make a hexagon, and bees build their hexagon cells from wax that workers make in glands on their bellies.

How many minutes are in one hour?

An hour has 60 minutes and a minute has 60 seconds, a counting-by-60 system that goes back to ancient Babylon.

What is the top number of a fraction called?

The numerator is the top number, and when it is bigger than the bottom number, the fraction is worth more than one whole.

How many cents is a US quarter worth?

25 cents, and a quarter's old nickname, two bits, comes from Spanish silver dollars, whose eighths were called bits.

How many things are in a dozen?

12 things make a dozen, while a baker's dozen is 13, from bakers' old habit of adding an extra loaf when selling a dozen.

How many degrees are in a right angle?

90 degrees makes a right angle, and builders check for one with the 3-4-5 rule: a triangle with sides 3, 4 and 5 units long always has a right angle.

How many years are in a century?

100 years make a century, and because there was no year 0, the 21st century officially began on January 1, 2001, not in 2000.

A leap year adds an extra day to which month?

February gets the extra day, February 29, which keeps the calendar in step with the seasons.

In Roman numerals, what number does the letter X stand for?

10 is X, and a smaller numeral placed before a bigger one is subtracted, so IX means ten minus one.

In art class, which three colors are usually taught as the primary colors?

Red, yellow and blue are the art-class primaries for mixing paint, but TV and computer screens mix colored light from red, green and blue instead.

In the book Charlotte's Web, what is the name of the pig?

The pig is Wilbur. Charlotte the spider writes words like "Some Pig" in her web to save him from being slaughtered.

Which brother and sister travel through time in the Magic Tree House books?

Jack and Annie's author runs a literacy program that lets Title 1 schools apply for free Magic Tree House books.

Who wrote and illustrated The Cat in the Hat?

Dr. Seuss (Theodor Geisel) wrote and drew The Cat in the Hat in 1957 using only 236 different words so that first graders could read it themselves.

Author Dav Pilkey created which book series?

Dav Pilkey, who created Captain Underpants, was so disruptive in class that teachers sent him to sit in the hallway, where he drew his own comic books.

Who is the main character in Diary of a Wimpy Kid?

Greg Heffley narrates the books and insists he is writing a journal, not a diary.

Who wrote the Junie B. Jones books?

Barbara Park's Junie B. Jones books were among the most challenged in US libraries in the 2000s, largely over Junie B.'s bad grammar and back talk.

How many players does each soccer team have on the field at once?

11 players per side is the maximum, and a match cannot continue if a team is left with fewer than seven players.

In tennis, what word means a score of zero?

Love means zero in tennis, and no one is sure why; one old explanation is 'playing for love', meaning playing for no stakes.

How many keys does a modern piano have?

88 keys each move a small felt-covered hammer that strikes strings inside the piano when the key is pressed.

Which animals truly fly by flapping wings made of skin?

Bats fly with their hands: each wing is stretched over long finger bones like those of a human hand.

Which bird is the smallest kind of bird in the world?

Hummingbirds burn energy so fast that on cold nights they can slip into torpor, a deep rest that slows the body down to save energy.

Which is the biggest and heaviest bird alive today?

Ostriches don't really bury their heads in sand: to hide, they lie low with head and neck flat on the ground, which from far away can look buried.

Which big cat has stripes?

A tiger's stripes are camouflage: they help it blend into grass and forest shadows while it waits to ambush prey.

Koalas eat mostly the leaves of which tree?

Koalas eat mostly eucalyptus leaves, which give so little energy that they sleep about 20 hours a day; they are marsupials, not bears.

Sloths spend most of their lives doing what?

Sloths spend most of their lives hanging upside down in trees, and green algae growing in their fur helps them hide among the leaves.

Which is the largest animal that lives on land?

An elephant is the largest land animal, and on hot days it flaps its huge ears to cool the blood flowing through them.

To escape predators, an octopus releases a dark cloud of what?

Ink forms a dark cloud that blocks a predator's view, giving the octopus a moment to jet away.

What do honey bees collect from flowers to make honey?

Nectar is mostly water, so bees fan their wings over it in the comb to dry it until it thickens into honey.

A crocodile is what kind of animal?

A crocodile is a reptile, and the temperature of its nest decides whether each egg hatches as a male or a female.

What does a tortoise use its shell for?

Protection from predators is the shell's job, and because the shell is part of the tortoise's skeleton, built around its ribs, a tortoise can't crawl out of it.

A shark is what kind of animal?

A shark is a fish, and it keeps shedding and regrowing its teeth, so some sharks go through tens of thousands of teeth in a lifetime.

A frog is what kind of animal?

An amphibian like a frog can breathe through its skin, which is one reason frogs must keep their skin moist.

A snake's body is covered in what?

A snake's body is covered in scales made of keratin, the same material as your fingernails; the snake sheds this outer skin layer several times a year.

Penguins live almost only in which half of the world?

Nearly all penguins live in the Southern Hemisphere; the Galapagos penguin is the only kind that also lives in the Northern Hemisphere.

Owls mostly hunt at what time?

Most owls hunt at night: their big eyes gather dim light, and soft-edged feathers let them fly silently toward prey.

Which bird is the national bird of the United States?

The bald eagle has been on the Great Seal since 1782, but a law making it the official national bird was not signed until December 2024.

What does a camel's hump mainly store?

A camel's hump stores fat it can live on when food is scarce, and the hump leans over and droops as that fat gets used up.

Which force makes a rolling ball slow down on a flat floor?

Friction is the force that resists motion when two surfaces rub together; it is why a rolling ball slows down and why rubbing your hands warms them.

The Sun is mostly made of which gas?

Hydrogen is the Sun's main gas; in its core, hydrogen is fused into helium, releasing the energy that becomes the Sun's heat and light.

Which US president challenged America to land astronauts on the Moon before the 1960s ended?

John F. Kennedy set the Moon goal in 1961 but was assassinated in 1963, more than five years before Apollo 11 landed in July 1969.

What is a shooting star really?

A meteor is a speck of space rock burning up in Earth's air; meteor showers happen when Earth passes through the dusty trail a comet left behind.

Which planet spins on its side compared with the other planets?

Uranus is tilted about 98 degrees, so it rolls around the Sun almost on its side, perhaps knocked over by a collision with an Earth-sized object long ago.

Which planet is closest to the Sun?

Mercury is the closest planet to the Sun, but it spins so slowly that one sunrise to the next lasts 176 Earth days, twice its 88-day year.

Which planet is the hottest in the Solar System?

Venus is the hottest planet: its thick carbon dioxide atmosphere traps heat, keeping the surface at about 465 °C, hot enough to melt lead.

Which planet is the farthest from the Sun?

Neptune is the farthest planet from the Sun, and it was found by math: its position was worked out on paper before anyone spotted it there in 1846.

What do you call a scientist who studies stars, planets and space?

An astronomer studies space; the early astronomer Galileo backed the idea that Earth circles the Sun and spent his last years under house arrest for it.

What is the name of the galaxy that our Solar System is in?

The Milky Way looks like a hazy band across the night sky because we see our flat, disc-shaped galaxy edge-on from inside it.

Thomas Edison is famous for his work on which invention?

The light bulb wasn't Edison's idea alone: inventors had built electric lamps for decades, but his team's long-lasting filament made them practical.

Alexander Graham Bell is credited with inventing what?

Bell received the first US patent for the telephone in March 1876 and days later made the famous call, "Mr. Watson, come here."

In which US state did the Wright brothers make history in 1903?

North Carolina's remote Kitty Hawk drew the Wright brothers with its steady winds and soft sand dunes.

Isaac Newton is famous for explaining which force?

Gravity, Newton showed, is one force that makes things fall on Earth and keeps the planets circling the Sun, ending the old idea that the heavens follow different rules.

On Christmas night during the Revolutionary War, George Washington led his troops across which icy river?

The Delaware crossing let Washington surprise Hessian troops at Trenton the next morning, a much-needed win after months of defeats.

Abraham Lincoln was born in a one-room log cabin in which state?

Kentucky was Lincoln's birthplace, but his family left for Indiana when he was seven, chiefly over shaky land titles and partly, he wrote, because of slavery.

Who was the main writer of the Declaration of Independence?

Thomas Jefferson wrote the draft, and John Adams and Benjamin Franklin made only a few changes; Congress later cut his passage blaming King George III for the slave trade.

Which document begins with the words "We the People"?

The Constitution's 1787 draft began 'We the people of the States of' and named all 13; the final version said 'of the United States' instead.

Harriet Tubman helped enslaved people escape using a secret network called what?

The Underground Railroad was a secret network of safe houses and guides; Tubman made about 13 trips into Maryland and later said she never lost a passenger.

Who was the first American woman to fly in space, in 1983?

Sally Ride flew on the shuttle Challenger in 1983, and later she was the only person to serve on the panels investigating both the Challenger and Columbia disasters.

What was the first permanent English settlement in North America?

Jamestown nearly failed: after the 1609–10 'Starving Time', its few survivors were sailing home when a new governor's supply ships arrived and turned them back.

What lies at the feet of the Statue of Liberty as a sign of freedom?

Broken chains lie at Liberty's feet for the end of slavery and oppression, but they are half hidden under her robes.

In which city can you see the Liberty Bell?

The Liberty Bell in Philadelphia cracked on its first test ring, so two local metalworkers melted it down and cast a new one.

What is the street address of the White House?

1600 Pennsylvania Avenue is the White House's address; British troops set the house on fire in 1814, during the War of 1812, and it had to be rebuilt.

Mount Rushmore is in which US state?

Mount Rushmore in South Dakota was carved mostly with dynamite, yet in 14 years of dangerous work not a single worker died.

Which is the largest of the Great Lakes?

Lake Superior is the largest Great Lake, and its storms can be deadly: the freighter Edmund Fitzgerald sank there in 1975 with all 29 crew.

Which river forms much of the border between the United States and Mexico?

The Rio Grande shifted south after floods in the 1860s, moving Mexican land to the El Paso side, and a 1963 treaty handed land there, the Chamizal, back to Mexico.

Old Faithful, a famous geyser, is in which national park?

Yellowstone's Old Faithful can be forecast because its eruptions follow a pattern: the longer one eruption lasts, the longer the wait before the next.

Mount Everest is part of which mountain range?

The Himalayas are young mountains, still being pushed higher today as two of Earth's tectonic plates keep colliding.

Which is the largest country in the world by area?

Russia is so wide that when it is 8 p.m. in Moscow, it is already 5 a.m. the next day on the Kamchatka Peninsula.

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

Queensland's Great Barrier Reef struck Captain James Cook's ship Endeavour in 1770, and the crew threw guns overboard and beached her for repairs.

What is the capital city of Canada?

Ottawa, Canada's capital, clears 7.8 km of its Rideau Canal when winter is cold enough, turning it into a skating rink through the city.

What is the capital city of China?

Beijing's imperial palace is called the Forbidden City because ordinary people were forbidden to enter it without the emperor's permission.

What is the capital city of Japan?

Tokyo was called Edo until 1868, when it was renamed 'Eastern Capital' and the emperor moved there from Kyoto.

As of 2020, what was the capital city of Egypt?

Cairo was Egypt's capital and largest city in 2020, but its government has since moved to a newly built city, the New Administrative Capital.

Brasília replaced which city as Brazil's capital?

Rio de Janeiro was Brazil's capital until 1960, when the government moved inland to Brasília, a new city built to help develop the country's interior.

The Colosseum, an ancient arena, is in which city?

Rome's Colosseum lost part of its outer wall to an earthquake, and for centuries people used it as a quarry, reusing its stone in churches and palaces.

The Taj Mahal is in which country?

The Taj Mahal is a tomb: Mughal emperor Shah Jahan built it in India for his beloved wife, Mumtaz Mahal, after she died.

The Great Wall was built against raiders from which present-day country?

Mongolia's steppe was home to nomads such as the Mongols, whom Chinese dynasties built the Great Wall to keep out.

Why does the Leaning Tower of Pisa lean?

Soft ground under a shallow foundation let the tower start sinking and tilting while it was still being built.

Big Ben hangs in a tower renamed in 2012 for which queen?

Elizabeth II is honored in the tower's name, and while the tower was repaired from 2017 to 2022, Big Ben rang only on special occasions.

Which animals alive today are actually a kind of dinosaur?

Birds are living dinosaurs: the mass extinction that wiped out all the other dinosaurs spared one group of birds, the ancestors of every bird today.

What does the name Triceratops mean?

Three-horned face is what Triceratops means, yet paleontologist Othniel Marsh first mistook its horns for a bison's.

What is the hot melted rock that pours out of a volcano called?

Lava is magma that has broken through the surface, and lava pouring into the sea from Hawaii's Kilauea volcano has built new land.

Thunder is the sound of air doing what?

Expanding air makes thunder: lightning heats the air so suddenly that it bursts outward, sending out a shock wave we hear as a boom.

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

Red is on the outside of a rainbow and violet on the inside, but in the fainter second arc of a double rainbow the order is reversed.

How many degrees do the three angles of a triangle add up to?

180 degrees, the angle of a straight line: draw a line through one corner parallel to the opposite side, and the three angles sit side by side along it.

What shape is a US stop sign?

An octagon marks the highest-danger sign, and US stop signs were yellow until 1954, when fade-resistant red finishes arrived.

The Pentagon is the headquarters of which US department?

Defense Department staff work in the Pentagon, which was shaped to fit its first planned site; the building moved to a new spot, but the design stayed.

Which part of speech are the words 'I', 'you' and 'we'?

A pronoun like 'I', 'you' or 'they' stands in for a noun, and 'they' has been used for a single person for more than 600 years.

Words that mean the same or almost the same thing are called what?

Synonyms like 'big' and 'large' mean nearly the same, yet few are perfect swaps: trading one for another can shift a sentence's meaning.

In Charlotte's Web, what kind of animal is Templeton?

Templeton is the greedy barn rat who helps find words for Charlotte's web, but only when there is food in it for him.

Who wrote the children's book Matilda?

Roald Dahl wrote Matilda, whose headmistress, Miss Trunchbull, hates children and punishes them with the dreaded Chokey.

In The BFG, what is the name of the girl the giant befriends?

Sophie is snatched from her bed by the Big Friendly Giant, and together they get the Queen of England to trap the man-eating giants.

In Charlie and the Chocolate Factory, who runs the chocolate factory?

Willy Wonka runs the factory, but the Golden Ticket tour is really a test to find an heir, and at the end he hands the factory to Charlie.

In the first Harry Potter book, Harry gets his Hogwarts letter on which birthday?

Uncle Vernon kept the Hogwarts letters from Harry for days, so Hagrid delivers one at midnight on his eleventh birthday.

Who is the main character in The Hobbit?

Bilbo Baggins is the hobbit Gandalf picks as the dwarves' burglar, sent ahead to face the dragon Smaug and win back their treasure.

In Where the Wild Things Are, what costume does Max wear?

Max makes mischief in his wolf suit and is sent to bed without supper, then sails off to where the wild things are.

Who wrote and illustrated The Very Hungry Caterpillar?

Eric Carle made The Very Hungry Caterpillar from painted collages and cut real holes in its pages, so children can poke their fingers where the caterpillar ate.

In Green Eggs and Ham, which character keeps pestering someone to try the dish?

Sam-I-am keeps pestering until the narrator, after refusing again and again, tries green eggs and ham and likes them.

Which is the smallest string instrument in an orchestra?

The violin is the smallest of the orchestra's bowed strings, which is why it plays the highest notes.

The composer Beethoven came from which country?

Beethoven came from Germany, and by the premiere of his last symphony he was so deaf that a performer had to show him the audience was cheering.

Which famous artist painted the Mona Lisa?

Leonardo da Vinci's Mona Lisa grew far more famous after it was stolen in 1911 and stayed missing for over two years.

The painter Vincent van Gogh came from which country?

Vincent van Gogh was born in the Netherlands and was seen as a failure in his lifetime, but after his death he became world-famous.

How often are the Summer Olympic Games held?

Every four years: the Winter Games shared the same year until 1992, then moved to 1994 so the two now alternate.

How many players from each team are on a basketball court at one time?

Five a side came later: when James Naismith invented basketball in 1891, each team had more players and shot at peach baskets.

How many players are on a baseball team on the field?

Nine players take the field, but since 2022 every MLB team can use a designated hitter who bats in place of the pitcher and never fields.

In which sport do players hit a shuttlecock over a net?

Badminton's feathered shuttlecock is built to slow down fast: its feathers create so much drag that it always turns to fly cork-first.

Golf was first played in the 15th century in which country?

Scotland's King James II banned golf in 1457 because it distracted men from practicing archery for war.

Who built the first printing press with movable type in Europe, around 1440?

Johannes Gutenberg borrowed heavily to build his press, and his investor Johann Fust later sued him and took over the printing workshop.

Oranges and other citrus fruits are famously rich in which vitamin?

Oranges and other citrus fruits are rich in vitamin C; without enough of it people develop scurvy, which once plagued sailors on long voyages.

Which blood cells help your body fight germs?

White blood cells fight infections, so doctors often count them in a blood test to help spot an infection.

What is the name for a word like 'sizzle' or 'hiss' that imitates the sound it describes?

Onomatopoeia differs from language to language, even for the same sound: a dog's 'woof' in English is 'bau' in Italian.

Table salt is made mostly of which chemical compound?

Sodium chloride joins two dangerous elements, sodium, a metal that reacts violently with water, and chlorine, a poisonous gas, into the salt we eat.

What is the chemical symbol for gold?

Gold's symbol is Au, from its Latin name aurum, which comes from an old root meaning 'to shine'.

Sound travels fastest through which of these?

Steel carries sound about 17 times faster than air, but in space sound cannot travel at all, because nothing is there to carry it.

DNA, found in living things, has a twisted shape called what?

DNA is a double helix of two twisted strands, a shape Watson and Crick modeled partly from Rosalind Franklin's X-ray photo, shared with them without her permission.

The imaginary line around the middle of Earth is called what?

The equator is where Earth's surface spins fastest, so rockets launched near it, like Europe's from Kourou, get a free speed boost.

Which scientist is famous for the idea of evolution by natural selection?

Charles Darwin sat on his theory for about 20 years and rushed to publish only after Alfred Russel Wallace sent him an essay with the same idea in 1858.

What is the hardest natural material on the Mohs scale?

Diamond is the hardest, but hard is not tough: a hammer blow can split a diamond along one of its weak planes.

Which is the smallest and shallowest of the world's five oceans?

The Arctic Ocean covers about 14 million square kilometres around the North Pole, is mostly under sea ice in winter, and averages only about 1,000 m deep.

Which bird is often called the fastest animal on Earth because of its high-speed dive?

The peregrine falcon nearly disappeared from much of the US because the pesticide DDT thinned its eggshells, and it came back after DDT was banned.

What is a baby kangaroo called?

A joey is born smaller than a cherry and climbs through its mother's fur into her pouch, where it keeps growing for months.

Which muscle does most of the work of breathing?

The diaphragm, the muscle at the base of the lungs, pulls air in as it tightens, and a sudden spasm of it is what causes hiccups.