Kids' Encyclopedia

CONTENTS

UNIVERSE Foreword by J.E. Luebering 00 • Introduction by Christopher Lloyd 00

2 The Big Bang 000 • Galaxies 000 • The Milky Way 000 • Stars 000 •
Nebulae 000 • Constellations 000 • Watching Space from Space 000
2 • Black Holes 000 • Exoplanets 000 • Our Solar System 000 • The Sun
000 • Planetary Exploration 000 • Rocky Planets 000 • Gas Giants 000
EARTH • Moons 000 • Asteroids 000 • The Kuiper Belt 000 • Rockets 000 •
Artificial Satellites 000 • Crewed Spacecraft 000 • Space Probes 000 •
50 End of the Universe 000 • Ask the Experts! 000 • The Quiz 000

3 The Earth is Born • The Earth in Space 000 • Measuring Earth 000 •
Inside the Earth 000 • The Earth’s Surface 000 • Plate Tectonics 000 •
MATTER Volcanoes 000 • Earthquakes & Tsunamis 000 • Mountains 000 • Rocks
& Minerals 000 • Giant Crystals 000 • The Earth’s Riches 000 • Fossils
98 000 • Finding Dinosaurs 000 • Fossil Fuels 000 • Water World 000 •
Ice 000 • The Atmosphere 000 • Weather 000 • Mega Storms 000 •
4 Climate 000 • Natural Climate Change 000 • Ask the Experts! 000 •
The Quiz 000
LIFE
The Atom 000 • Elements 000 • Radioactivity 000 • Compounds 000
146 • Combustion 000 • Solids, Liquids & Gases 000 • Plasma 000 • Metals
000 • Non Metals 000 • Plastics 000 • Chemistry of Life 000 • Energy
000 • Sound 000 • Electricity & Magnetism 000 • Light 000 • Speed
Demons 000 • Forces 000 • Gravity 000 • Pressure 000• Lighter than
Air • Stretching & Squashing 000 • Simple Machines 000 • Ask the
Experts! 000 • The Quiz 000

The Origin of Life 000 • Evolution in Action 000 • Classifying Life 000
• The Micro World 000 • Plants & Fungi 000 • Animals 000 • Bugs 000
• Ecology 000 • The Rain Forest 000 • The Taiga & Temperate Forests
000 • Grasslands 000 • Mount Everest 000 • Deserts 000 • Life in
Freshwater 000 • The Seashore 000 • Coral Reef Crisis 000 • The Open
Ocean 000 • The Deep Sea 000 • Ends of the Earth 000 • Shrinking Ice
000 • Urban Wildlife 000 • Harnessing Nature 000 • Ask the Experts!
000 • The Quiz 000

5 Becoming Human 000 • The Human Body 000 • DNA & Genetics 000 •
The Brain 000 • Emotions 000 • The Senses 000 • Food & Cooking 000
HUMANS • Dress & Decoration 000 • Religious Belief 000 • Conflict & War 000 •
Language & Storytelling 000 • Reading & Writing 000 • Visual Art 000 •
194 Performing Arts 000 • Calendars 000 • Money 000 • Crime & Law 000
• Education 000 • Work 000 • Games & Sports 000 • Festivals 000 •
Death Rituals 000 • Ask the Experts! 000 • The Quiz 000

6 The First Australians 000 • The Fertile Crescent 000 • Ancient
Mesopotamia 000 • Stonehenge 000 • The First Chinese Dynasties 000
ANCIENT & • Ancient Egypt 000 • Ancient Gods 000 • Andean Civilizations 000
MEDIEVAL • Settling the Pacific 000 • The Minoans, Mycenaeans & Phoenicians
TIMES 000 • The Olmecs & The Maya 000 • The Persian Empire 000 • Ancient
Greece 000 • Alexander the Great 000 • The Mauryan Empire 000 • The
242 Terracotta Army 000 • Ancient Rome 000 • The Byzantine World 000
• Ancient African Kingdoms 000 • Tang China 000 • The Golden Age of
Islam 000 • Medieval Europe 000 • Ask the Experts! 000 • The Quiz 000

7 The Renaissance 000 • African Empires 000 • Aztecs & Incas 000
• Age of Exploration 000 • The Mughal Empire 000 • Japan’s Great
MODERN Peace 000 • New Empires 000 • The British & French in North America
TIMES 000 • Slavery in the Americas 000 • Age of Revolutions 000 • Medical
Milestones 000 • The Industrial Revolution 000 • World War I 000 •
290 Votes for Women 000 • The Rise of Communism 000 • Boom & Bust
000 • World War II 000 • The Cold War 000 • Decolonization 000 •
Human Rights 000 • New Tensions, New Hopes 000 • World Map 000 •
Ask the Experts! 000 • The Quiz 000

8 One World 000 • Anything, Anywhere 000 • Inequality 000 • Feeding
the World 000 • Powering the Planet 000 • Modern Warfare 000 •
TODAY & The Mega Rich 000 • Mega Cities 000 • The Internet 000 • The Media
TOMORROW 000 • Artificial Materials 000 • Med Tech 000 • Smart Tech & AI 000
• Environmental Challenges 000 • Extinction Event 000 • Endangered
338 000 • Effects of Climate Change 000 • Stopping Climate Change 000 •
Nuclear Power 000 • Renewable Energy 000 • Cities of Tomorrow 000 •
Future Humans 000 • Ask the Experts! 000 • The Quiz 000

Source Notes 386 • Glossary 394 • The Experts 402
Index 404 • Picture Credits 414

THE SUN The surface of the Sun is
about 10,000°F (5,600°C),
The Sun is the star that powers our solar system. but its atmosphere is
It formed from a nebula of dust and gas about millions of degrees!
four billion years ago and is now a giant ball of No one is sure why
gas known as a yellow dwarf. It is 864,000 miles the atmosphere is
(1.4 million km) across and mostly made of so much hotter
hydrogen and helium, although it has heavier
metals at its core. The temperature of the core
can reach 15,000,000°C (27,000,000°F)!

Life-giver

The Sun radiates light and heat throughout the solar system.
On Earth, we depend on this radiation to survive, but the
Sun has effects elsewhere too. It causes aurorae (luminous
streamers of light) on Jupiter and Saturn as well as Earth,
and it melts ice on Mars and Pluto too!

SLuIn SRaTysI F I E D . This is a CME, a burst
of material ejected
1. Eruptions These begin at the Sun’s core, where from the surface of
nuclear fusion joins atoms together and releases the Sun into space
vast amounts of energy.
2. Solar wind The Sun constantly emits particles in
the form of solar wind, which interacts with planets
and moons.
3. Solar flares The Sun experiences bursts of
energy called solar flares that release huge amounts
of energy into space.
4. Coronal Mass Ejections The Sun ejects large
amounts of material into space in giant “burps,”
called Coronal Mas Ejections (CMEs).
5. Light radiation Most of the light emitted by the
Sun is visible light, but it emits ultraviolet and infrared
rays too.

EXPERT: A.N. Expertname SEE ALSO: Galaxies, p.6–7; The Milky Way, p.8–9; Watching Space from Space, p.16–17; Our Solar System, p.22–23;
The End of the Universe, p.46–47; The Atmosphere, p.86–87; The Atom, p.100–01; Solids, Liquids & Gases p.110–11; Energy p.122–23

Bright flashes known
as solar flares can
affect life on Earth, for
instance, by shutting
down satellites

Magnetic fields
cause some parts of
the Sun’s surface to
appear darker

2525

EARTH (1) MARS (2) JUPITER SATURN URANUS NEPTUNE PLUTO (4)
Phobos (79 known) (82 known) (27 known) (14 known)
Moon Deimos
The diameter of Io Mimas Puck Proteus
the Earth’s Moon Europa Enceladus Miranda
Charon
is 2,159 miles Tethys Ariel
(3,474 km) Dione Triton
Umbriel Nereid
Rhea

FACTastic! Titania

The Moon is moving away from us Ganymede Oberon
by about 3.8 centimetres every
year! This is caused by tidal forces Titan Selected moons of the
from Earth making the Moon’s Hyperion Solar System to scale
orbit slightly bigger over time.
Iapetus There are 214 moons in the Solar
Callisto Phoebe System, orbiting every known planet
and dwarf planet except Mercury,
Planet Earth Venus, and Ceres. Scientists recently
Shown at the same discovered that Saturn had 20 more
scale as the moons. moons than previously thought,
bringing its total to 82—more than any
other planet in the Solar System.

MOONS

The moons of the Solar System come in all shapes
and sizes. Many are spherical, like the Moon that
orbits planet Earth. Some, like Pan, Daphnis, and
Atlas, which orbit Saturn, are shaped a bit like
ravioli. There are also some very small moons,
such as Mars’s Deimos, which is only 9 miles
(15 km) across. Jupiter’s moon Ganymede is larger
than the planet Mercury.

Exploration of Earth’s moon

The only place in space that has been visited by humans is
Earth’s moon. Twelve humans traveled to the Moon from 1969
to 1972, but no humans have gone back since. However, we
have sent lots of uncrewed landers and probes to the Moon
to study it. One of the most recent was India’s Chandrayaan-2
mission, launched in 2019.

EXPERT: A.N. Expert SEE ALSO: Our Sun, p.32–33; Asteroids, p. 42–43; Spacecraft, p. 50–51; The Elements, p. 112–13; Origin of Life 156–57; Future Humans, p. 390–91

Ejecta, a blanket of
debris excavated during
the impact of a meteor,
forms around the outer
edge of the crater.

The raised rim is
formed by rock
thrown out of the
crater during impact.

Bright streaks
called rays extend
away from the
crater for great
distances.

The walls of the Bowl-shaped or flat, Central uplifts sometimes Moon dust
crater are usually the floor is usually below occur in craters larger
steep and may ground level, unless it is than 25 miles (40km) in Called regolith, moon dust is the result
have giant stairs filled in with lava. diameter. They are caused of rocks banging into each other and
called terraces. by increase and rapid breaking down over the 4.5 billion-
decrease in pressure during year history of the Moon. It is really
the impact of a meteor. sticky and, according to the Apollo
astronauts that went to the Moon,
Anatomy of a crater smells like gunpowder.

Our Moon has many craters because there is no atmosphere
to protect it. Craters form when rocks crash into the surface,
creating large circular features. The biggest crater on the Moon
is the South Pole-Aitken basin, at 1,600 miles (2,575 km) across.
Scientists think that bits of the asteroid that formed this crater
may still lie under the surface.

Structure of the Moon Silicate crust

Our Moon has different layers, just Solid silicate
as the Earth does. It has a metallic mantle
core at its center that is made
of iron and nickel. This is Partially
enclosed by a fluid outer molten core
core and then a solid
mantle layer. The KNOWN
crust, or surface, UNKNOWNS
is about 30 miles
(50 km) thick. It Could humans create a base on the
has mountains, Moon?
craters, and
flat areas It is thought that the Moon might have
called “seas,”
such as the Sea large amounts of water ice trapped
of Tranquility.
under its surface. Scientists in the US

and Europe are working on plans to

build bases where humans could use

this water to survive. However, life

would be harsh. A lunar day lasts

Crater Small iron core 14 Earth days, as does a lunar night.

Air would have to be imported. 5533

MEASURING EARTH

The Earth is a giant ball of rock. It’s round, but How much does the Earth weigh?
not quite perfectly round, and scientists now
describe its shape as “geoid,” which just means The Earth weighs more than 13 million trillion
Earth-shaped. Like a pumpkin, it’s a little flatter trillion pounds (6 million trillion trillion kg). We can’t weigh
at the poles and fatter at the equator, which is the Earth, so how do scientists know this? They can work
24,870 miles /40,024 km in circumference it out from how much Earth’s gravity pulls on neighboring
(all the way round). Satellite images also show planets. The gravity of an object is in proportion to its
that the Earth has tiny bumps here and there. mass—the amount of material that makes up that object.
These imperfections are so small they can only
be detected by accurate measuring.

Latitude and longitude Lines of latitude 0° longitude North Pole
(also called parallels) passes through
The location of any place circle the Earth Greenwich, EUROPE
on Earth can be pinpointed England ASIA
precisely using a grid of lines
of latitude and longitude. NORTH AT L A N T I C AFRICA
Lines of latitude are imaginary AMERICA OCEAN
circles drawn around the
Earth parallel to the Equator, PA C I F I C SOUTH AT L A N T I C
which is why they are often OCEAN AMERICA OCEAN
called parallels. Lines of
longitude are circles drawn ANTARCTICA
between the North and
South poles, which divide the
Earth like the segments of
an orange. Lines of longitude
are called meridians.

0° latitude passes South Pole
through the Equator

Measuring by satellite

Satellites in Space can detect tiny
differences in height on the Earth’s
surface. They can even make a map
of the seafloor by detecting little
bumps and dips in the ocean surface
(averaged out to ignore waves).
Because of the varying pull of gravity
these bumps and dips mirror the
seafloor. In this satellite map (left),
orange and red indicate areas of the
seafloor where gravity is strongest—
ridges and mountains.

EXPERT: Alex Bellos SEE ALSO: Artificial Satellites, p.40–41; The Earth in Space, p.54–55; Inside Earth, p.58–59; The Earth, p.60–61; Light p.128–29; Gravity,
p.134–35; Timekeeping, p.224–25

Where in the world The satellites transmit
data about their
The Global Positioning System (GPS) is a network of about position and the time
30 satellites orbiting the Earth whose measurements The satellite
enable users to pinpoint locations very precisely. Anyone signal travels at
with GPS—in a car SatNav, on a smart phone, or any GPS the speed of light
system—can pick up the signals beamed out by the satellites
to work out a location almost instantly.
Wherever you are on
Earth, at least four
GPS satellites have
you in their sight

The satellites are in
constant touch with
ground tracking stations

The GPS compares the
distance and time from each
satellite then works out its
position using geometry

GAME CHANGER FACTastic! 5757

ERATOSTHENES The meter measurement is based on Earth’s geometry.
Mathematician, 276–194 BCE The French invented the meter in 1791. They set it at
Ancient Greece one ten-millionth of the distance from the Equator to
the North Pole. This is why the Earth is almost
Eratosthenes worked out the 40 million meters (40,000 km)
circumference of the Earth way back round. All countries except
in 240BCE. He noticed that the the USA, Myanmar, and
Sun shone directly inside a well at Liberia use the metric system.
noon, indicating that it was directly
overhead. He then went 500 miles
(800 km) north and measured the
angle of the shadow cast by a pole
at noon. Using a type of math called
geometry, he worked out that
the Earth is about 25,000 miles
(40,000 km) all the way round.

VOLCANOES Fire fountains
shoot hot lava
We know where most volcanoes are in the world high into the air.
but not when they will erupt. Some lie inactive for
thousands of years before erupting suddenly and
violently. Volcano experts—volcanologists—look
for clues, such as movement in the rocks of the
volcano and unusual gases coming from its vent.
Drones can be flown in to measure this gas and
spot other signs of dangerous activity.

Stromboli blasts

Volcanoes erupt in different ways.
Strombolian eruptions, named after
this volcano in Italy, spray hot molten
rock called lava in a “fire fountain.”
Others ooze gently year after
year. Still others explode suddenly,
propelling gas, volcanic ash, and
fragments of bubbly solidified lava
called pumice high into the air.

The gases are a mix
of mostly water vapor,
carbon dioxide,
and sulfur.

Craters and cracks
eject spectacular
lava fountains.

Vent through
which the magma
flows out.

Fire fountains
can be a series of
short bursts or a
continuous jet.

Clouds of ash and
debris cover the
volcano’s slopes.

EXPERT: Erik W. Klemeti SEE ALSO: Inside Earth, p.60–61; Rocky Planet, p.68–69; Solids, Liquids, Gases, p.112–13

Layers of Vent FACTastic! KNOWN
ash and Fumaroles UNKNOWN
lava Ash and lava can travel up to
430 mph (700 km/h). When Mount When will Yellowstone blow?
Vesuvius, in Italy, erupted in 79 CE,
it buried the Roman towns of The steam shooting out of cracks
Pompeii and Herculaneum under called geysers in Yellowstone
20 feet (6 m) of ash, killing people National Park in the United States
instantly. When the ash cooled is one of the reasons that scientists
it became solid, preserving the think a lot of magma lies under
positions the people were in the park. The Yellowstone volcano
when they died. erupted 640,000 years
ago, producing enough
Magma lava to fill up the Grand
chamber Canyon. Another
eruption could cover
Inside a volcano much of the western
half of the USA in
Beneath most mountain volcanoes ash at least 3 feet
there is a reservoir of molten rock (1 m) deep.
called magma. Gases may leak from
the magma chamber to the surface
through cracks called fumaroles.
Over time, magma wells up from
underneath the magma chamber
and pressure builds. Eventually, the
magma is driven out through the
vent. At this point, it becomes lava.
The temperature of lava can be up
to 2300°F (1250°C).

Ring of Fire

There is a ring of volcanoes around the Three-quarters of Hawaii Yellowstone
all the world’s active (USA) (USA)
Pacific Ocean where Earth’s tectonic volcanoes lie in the Vesuvius
Ring of Fire. (Italy)
plates—sections of Earth’s outer layer—
Stromboli
crunch together. As magma (Italy)

pushes up through cracks

in the rock, it picks up

impurities that often ASIA EUROPE
clog the volcano’s
ASIA

vent. Eventually, NORTH AT L A N T I C
AMERICA OCEAN
pressure

builds up, and AFRICA

the magma PACIFIC OCEAN

bursts out. SOUTH
AMERICA

Indonesia’s volcanoes AUSTRALIA
are the most active
in the world. Other AT L A N T I C
countries with several OCEAN
active volcanoes include
Japan and the USA. ANTARCTICA

Japan 6363

RADIOACTIVITY FACTastic!

Radioactivity is particles splitting off from the Even bananas are radioactive.
nucleus of an atom. With unstable atoms such They contain just enough
as uranium, this happens naturally—scientists
call it “radioactive decay.” Most natural particle potassium to set off some
radiation is low level and does no harm, but long- radiation alarms. So,
term exposure to it or bursts from uncontrolled scientists measure low-
nuclear reactions can kill or cause cancer. level radioactivity in food
in terms of Banana
The world’s most dangerous toy? Equivalent Doses or
BEDs. Fortunately, a BED
When radioactive materials were first discovered, people is far too weak to ever
wore watches with radium dials that glowed green in harm you, even if
the dark. Children were even given atomic energy kits you ate millions
containing uranium to play with—although not enough of bananas!
to cause harm. Still, the idea seems crazy today.

This 1950s Your own toy
Gilbert U-238 Geiger counter
Atomic Energy for measuring
Lab kit allowed the low-level
children to radiation.
create nuclear
reactions.
The kit came
complete with
four jars of
radioactive
uranium samples.

EXPERT: Cristina Lazzeroni SEE ALSO: Atomic Breakdown p.108–09; Elements, p.110–11; Periodic Table, p.112–13; Carbon and Carbon Compounds p.126–27

A PET scan of a human
brain, where high levels
of chemical activity
show up as bright spots.

High levels of
chemical activity
can be an indication
of a disease, such
as cancer.

Radioactive scanning Caught by the tusk

If you are ill, doctors may use A poacher found with a
radioactivity to find out what’s stash of elephant tusks
wrong. When patients go for a claimed they got them
PET scan, they are injected with before hunting had been
a substance that contains atoms banned. But science caught
that send out harmless radioactive them! Carbon dating
particles. The atoms gather showed the tusks contained
wherever certain chemical so much carbon-14 that the
activities are happening in the elephants could only have
body. The scanner detects the died recently.
pattern of particles
and gives doctors a Around 100 elephants
picture of what is a day are killed illegally
going on. for their ivory tusks.

GAME CHANGER Ivory is prized for
making luxury items
MARIE CURIE and souvenirs.
Physicist and chemist, 1867–1934
France (born Poland) Carbon-14 atom Carbon dating

Marie Curie and her husband Pierre The radioisotope carbon-14
were fascinated by radioactivity.
They found new radioactive (a kind of carbon atom) is
elements, which they called radium
and polonium. In 1903, they were Carbon-14 present in all living things.
awarded the Nobel Prize in physics in tusk at
for their work. Tragically, Marie died time of death The rate of When plants and animals
from cancer caused by years of decay is very
exposure to radioactive elements. slow die, particles split off from

Humanity will draw more good the carbon-14, causing it

“ ’’than evil from new discoveries. to disintegrate slowly. By

measuring the proportion

After 5,730 years the of carbon-14 isotopes left in
carbon-14 reduces by half
a well-preserved fragment,

scientists can tell how long

the plant or animal in 101505
question has been dead.

EVOLUTION Brontornis had
IN ACTION the biggest skull
of any known bird
Evolution is a change in the characteristics of and a beak designed
a species that passes from one generation to for ripping flesh
the next. The features may have been passed
on because creatures that had them survived
better than those that did not. Gradually,
useful features become more common in a
population and the species changes—a process
called natural selection.

Wings were small and could be
used as stabilizers while running,
and when flapped, they could have
been part of a courtship display

The terror bird Long powerful legs The Brontornis stood
with formidable claws 9.2 feet (2.8 m) tall and
Birds are living dinosaurs. could kick and hold weighed up to 880 lb
They escaped the mass down prey. Brontornis (400 kg), making it the
extinction of dinosaurs was probably a walking third heaviest bird that
that occurred 66 million years bird rather than a runner ever lived
ago, and some evolved into Astrapotherium resembled a cross
ferocious monsters such as the between an elephant and a tapir,
Brontornis terror bird. Taking but was related to neither. It lived
over places left vacant by their at the same time as Brontornis
extinct relatives, terror birds and could have been its prey
were South America’s top
predator for 60 million years.

EXPERT: Michael D. Bay SEE ALSO: Fossils, p.76–77; Dinosaur Excavations, p.78–79; The Origin of Life, p.148–49; Classifying Life, p.152–53; Ecology p.162–63;
Domesticating Plants & Animals, p.190–91; Extinction Event, p.370–71

Newest Changing color
rocks
Peppered moths are normally white with black speckles.
This means that birds can’t see them on the bark of birch
trees, their natural habitat. Some moths, however, are black.
In 19th-century Britain, when soot from coal fires covered
the trees, the pale moths were eaten while black moths
survived and their numbers increased.

Black moths thrived
in soot-filled British
cities during the
industrial revolution
because birds could
not see them easily

Oldest
rocks

Time The number of white
moths recovered in the
Evidence for evolution mid-20th century when
there was less pollution
By comparing the fossils of ancient
creatures in old and young rocks FACTastic!
scientists can see how a species
might have evolved over time. Hard More than 99 percent of species
parts of an animal, such as bones, that ever lived are now extinct. Some
fossilize well but soft parts, such disappeared because of competition
as flesh, do not. Scientists look at for food, others because their habitat
modern species to work out how changed. Most dinosaurs were wiped
their extinct ancestors out when an asteroid hit the Earth.
may have looked The woolly mammoth became extinct
when they lived. around 5,000 years ago, partly
because it was hunted by humans.
GAME CHANGER
KNOWN 151151
CHARLES DA WIN UNKNOWNS
Naturalist and geologist 1809–82
United Kingdom Could dinosaurs come back?

In 1858, British scientists Charles If scientists could find dinosaur DNA,
Darwin and Alfred Russel Wallace they may be able to create a dinosaur.
shocked the world by claiming Some thought they might find
that all living things, including dinosaur DNA inside ancient blood-
humans, had evolved though natural sucking mosquitoes preserved in lake
selection. This, they said, explained sediments. So far, they haven’t found any
the diversity of life on Earth. The but some people continue to look for it.
next year, Darwin published On the
Origin of Species. The book upset
many people who believed that God
had created all living things in their
present-day form.

BUGS ARE KING!

A whopping 80 percent of all known species

on Earth are insects. They include butterflies,

ants, flies, bees, wasps, grasshoppers, as well

as many other creatures. Beetles form the

largest insect group, with about 360,000

known species and as many as 700,000

that we haven’t yet discovered.

One beetle expert once

found 1,200 species of

beetles in a single Long-horned beetle
rain forest tree!
Most numerous in the tropics, long-

horned beetles can be up to 6½ inches

(17 cm) long, excluding their antennae.

They are members of the Cerambycidae

family, which has about 25,000 species.

Adults feed on flowers and leaves, while

the larvae eat wood.

jointed legs, an external skeleton, and

y, six Antenna feel

All insects have a three-part bod Front Head ers. They usually also have wings
wing Eye

Back Thorax
wing Abdomen

Leg

Design of a honeybee

The honeybee has two pairs of wings, which
are joined by tiny hooks. Honeybees beat
their wings more than 200 times a second
and not only use them for flying but also
as fans to cool down their hive. They
also flex their flight muscles to
warm up when the weather
gets too cold.

EXPERT: Dino Martins SEE ALSO: Classifying Life, p.152–53; Plants, Animals & Fungi, p.156–57; Majesty of Trees, p164-65; Extinction Event, p.370–71;
Climate Change, p.372–73

The antennae, sometimes
called feelers, are often
longer than the body. They
are used to detect smells
and to seek out mates.
Working like a bank of TV
cameras, compound eyes
allow the beetle to see a
mosaic of images. Each eye
is made up of tiny ommatidia
(simple eyes) , which send
messages to the brain.
A beetle’s front wings are not
used for flying. They have
become hard wing cases,
or elytra. They protect the
beetle’s delicate back wings,
which are tucked underneath
when the beetle is not in flight.
Mandibles are hard,
jaw-like mouthparts that
are used for chewing. The
female beetle also uses
them to create a place
where she can lay her
eggs in the bark of trees.

Like other arthropods,
beetles have jointed legs.
The tarsi at the end have
special claws for gripping.

161161

The tallest THE RAIN FOREST
trees are
called Rain forests are found in parts of the world that
emergents. are very wet. They absorb carbon dioxide from
The thick the atmosphere and produce oxygen. Tropical
forest canopy rain forests such as the Amazon rain forest are
blocks out hot and humid, while temperate rain forests are
sunlight. cooler and often next to the coast. More than
half of the world’s species of plants and animals
The understory live in rain forests, where food is plentiful.
has small trees
and bushes. Strangler figs Layered habitats
climb the tree
and compete Tropical rain forests have distinct layers, which are
for resources. determined by the amount of light and moisture
available. The tallest trees can achieve heights over
200 feet (60 m). They emerge from the dense canopy
layer, where the leaves of the trees have “drip tips” to
drain away water. This helps stop algae from forming. In
the dark understory below, the plants have large leaves
to capture the little light that gets through the canopy.

Only 1 percent of light Buttress roots help Lowland gorilla
reaches the ground, so support the tree.
there are few plants. The western lowland gorilla lives in the Congo rain forest,
the second largest rain forest on Earth. It lives in small
family groups led by a male, the silverback, and eats
mostly plants. Even though the gorilla is large and heavy,
it is a good tree-climber. The loss of its forest habitat and
poaching are threatening its existence.

EXPERT: Greg Nowacki SEE ALSO: Plants, Animals, and Fungi, p.164–65; Bugs are King, p.168–69; Environmental Challenge, p.374–75;
Climate Change, p.380–81

Pool of rainwater The tadpoles feed High and mighty
at the center of on infertile eggs.
the bromeliad. The biggest trees in the world are the redwoods and giant
sequoias that live in rain forests along the West Coast of
the USA. They are the tallest trees, and their trunks have
some of the largest diameters. The tallest living tree is
currently a redwood called Hyperion—the “High One”—
in Redwood National Park, which is 380 feet (116 m) tall.

HYPERION
380 feet (116 m)

Poison frogs The lower trunk
has no branches
South American poison frogs live mostly on the forest because of the
floor and in the understory plants of the Amazon rain lack of light.
forest. Their bright colors warn birds and monkeys that
they are highly poisonous. They are good parents. The
female lays her eggs on land. When the tadpoles hatch,
the male carries them on his back up to the high forest
canopy. There he puts them in tiny pools that form on
plants called bromeliads and protects them as they grow.

FACTastic!

The golden poison frog, only about 2 in (5 cm) long,
is one of the most poisonous animals on Earth. The
skin secretions from a single frog could kill 10 people.
Frogs reared in captivity tend not to be poisonous.
Scientists believe this is because the frog does not
make its own poison but acquires the chemicals from
its natural food—tiny beetles and ants.

A giraffe is
17 feet (5.2m) tall
on average, so
Hyperion is as tall
as 22 giraffes.

161565

THE DEEP SEA

The ocean is the planet’s largest habitat, most of which is deep LAYERS OF THE SEA
sea, yet scientists have explored only a fraction of the deep sea
floor. In fact, we know more about the surface of the moon Scientists divide the ocean into layers
than we do about the deepest ocean. The invention of new according to depth, pressure, and
underwater vehicles called submersibles is changing all that, how much sunlight they receive.
revealing many kinds of strange and fascinating creatures. In the deep trenches, the pressure
is enormous. Each square inch is
crushed by the weight of an elephant.

Sunlight Zone (Epipelagic), 0–656 ft (0–200 m) The top layer of the ocean is the euphotic zone (receives
Pressure 0 to 20 times that at the surface sunlight). Photosynthesis is only possible in this layer
Twilight Zone (Mesopelagic) 656–3,281 ft (200–1,000 m) The area below the top layer of the ocean is the
Pressure 20–100 times that at the surface disphotic zone (receives little sunlight)

Midnight Zone Dumbo octopus
(Bathypelagic)
3,281–13,124 ft This species reaches the greatest
(1,000–4,000 m) depth of any known octopus. It is
Pressure 100–400 8–12 inches (20–30 cm)
times that at high and gets its name
the surface from its flap-like fins,
Abyssal Zone which resemble the ears
(Abyssopelagic) of Disney’s Dumbo.
13,123–19,685 ft
(4,000–6,000 m) Tripod fish
Pressure 400–600
times that at The 12–15 inches- (30–40 cm) long tripod
the surface fish stands on stilts formed by its pelvic
and tail fins. It is then at the right height to
catch passing prey swimming in the current.

Hadal Zone The lower layers of the ocean
(Hadalpelagic) are the aphotic zone (receive
19,686–36,037 ft no sunlight)
(6,000–10,984 m)
Pressure 600-1100 Snailfish
times that at
the surface The snailfish is
6–12 inches (15–
30 cm) long. In 2017,
Japanese scientists filmed
a snailfish 26,831 feet (8,178 m)
deep in the Pacific Ocean in the Mariana
Trench—the deepest place on Earth.

EXPERT: Monika Bright SEE ALSO: Inside Earth, p.58–59; Plate Tectonics, p.62–63; Earthquakes & Tsunamis, p.66–67; Pressure, p.136–37;
The Open Ocean, p.180–81;

Glow-in-the-dark Female anglerfish are
7 inches (18 cm) long.
Many animals in the deep sea are bioluminescent: they Males are much smaller at
light up in the dark . They can do this because of a chemical just 1 inch (2.5 cm) long
reaction in their bodies or in bacteria that they host. Female
deep sea angler fish, which live in the twilight and midnight
zones, have a bioluminescent bacteria-filled lure on the end
of a long fin like a fishing rod. The light attracts
prey toward its tooth-filled mouth.

Only female angler Like many deep sea fish,
fish have a light- the angler has a soft body.
producing lure Some species of male angler
fish latch on to the body of a
The large mouth has female with their teeth. They
long sharp teeth, giving eventually fuse with her for
the angler fish a fierce the rest of their life
reputation. They eat other The angler fish has no scales
deep-sea fish and shrimps and does not have a fin on
the underside of its body
Angler fish can inflate their
stomachs to incredible Note from the e
sizes. This allows them to xpert!
consume prey far bigger
than themselves

Deep-sea exploration MONIKA BRIGHT

Underwater vehicles called Marine Biologist
submersibles are specially University of Vienna
strengthened to resist high
pressures at great depths. Living in a landlocked country her
This enables scientists to first encounters with the ocean
see deep-sea animals. were during vacations to the
Scientists sometimes Mediterranean Sea. Most fascinated
bring creatures to the by the high diversity of animals in
surface in cooled and the sea she studied zoology and
pressurized tanks so that marine biology.
they can study them in
the laboratory. “ Only when you fly with a 181833

These scientists sit in a submersible to the bottom of the
spherical capsule with
all-round views ocean do you start to understand

”how huge this habitat is.

SHRINKING ICE The polar bear is the largest
of the bears. It is classified
The amount of ice in the Arctic Ocean over the as a marine mammal, as it
summer months is becoming less and less because of spends most of its life on the
global warming. This affects polar bears, which travel sea ice or swimming in the sea
over the ice in search of ringed seals. Faced with going
hungry, most polar bears head for land and survive on
birds’ eggs, berries, and seaweed, but bears in Hudson
Bay, Canada, have learned to stand on rocks and catch
belugas as they swim in on by the tide.

Like dolphins, belugas belong
to a group of aquatic mammals
called toothed whales. Unlike
the dolphin, it has no dorsal
(top) fin, as this could get
trapped under the ice

EXPERT: Michael D. Bay SEE ALSO: Ice, p.84–85; Climate Change, p.94–95; Evolution in Action, p.150–51; Ecology, p.162–63; The Open Ocean, p.180–81;
Ends of the Earth, p.184–85; Climate Change and Manmade Causes, p.372–73; Stopping Climate Change, p.374–75

energy and need regular meals of energy-rich b
Bears use huge amounts of lubber from seals to survive
Heading for extinction?

The Arctic is warming faster than almost
anywhere else on the planet. This means
that ice breaks up earlier in spring and
freezes later in the fall. Without the
ice, polar bears cannot ambush seals at
breathing holes, and many bears and
their cubs starve to death.

Baby belugas stay close to their Summer visitors 181787
mothers. Belugas communicate
by calling to each other like Each summer, belugas visit the Seal Estuary in Hudson
birds, so are sometimes known Bay, where they molt (shed their outer layer of skin) and
as “sea canaries” give birth. The water here is slightly warmer than in the
bay, so it makes a good nursery for the newborn beluga.

1
2

4
3

5

7
6

89

12

EXPERT: Jane Long SEE ALSO: Ancient Greece, p.268–69; Golden Age of Islam, p.284–85; Age of Exploration, p.298–99

THE RENAISSANCE

With roots in 14th-century Italy, the
Renaissance, meaning “rebirth,” revived
interest in the art of ancient Greece and
Rome. Philosophy was a key theme of the
period, along with theology and beauty. The
movement spread across Europe, thanks in
part to the creation of the printing press. It led
to some of the most magnificent works of art,
literature, and scholarship in European history.

The School of Athens (1509–1511)

This fresco was one of three painted by the Italian
Renaissance artist Raphael for the Room of the
Segnatura, inside the Vatican, Rome. It features key
cultural and artistic themes of the era and includes a
self-portrait of Raphael himself. He is the figure wearing
a black hat on the far right, looking out at the viewer.

1 Renaissance architects admired the “harmonious” proportions of
ancient Greek buildings.

2 Parallel lines in the painting meet at a “vanishing point” to
create the illusion of depth on a flat surface.

10 3 Many figures in the painting represent ancient Greek
11 philosophers. Socrates, pictured, would have been well known.

4 Aristotle and Plato: The two most famous ancient Greek
philosophers are central to the work.

5 Contemporary artists feature in this painting. Here, famous
Renaissance artist Leonardo da Vinci represents Aristotle.

6 Raphael hints at the influence of Islam’s Golden Age by including
the Muslim philosopher Averroes in the work.

7 Francesco Maria della Rovere, Duke of Urbino. Apart from the
artist himself, he is the only person who looks out of the painting.

8 Many Renaissance scholars were scientists, sculptors, artists,
and writers—all at the same time.

9 The contemporary artist Michelangelo was also working in Rome
at this time, painting the Vatican’s Sistine Chapel.

10 A globe represents world expansion and the recent discovery of
new continents, such as North and South America.

11 Mathematical instruments represent the huge interest in the
sciences that arose at this time.

12 The doorway that leads into the Room of the Segnatura, and
above which the fresco was painted.

332193

US Civil Rights Movement whites had. After World War II, African Americans
organized the Civil Rights movement to demand that they
The Civil War ended slavery, but it didn’t make African be treated equally. African Americans and their white allies
Americans equal with whites in the US. In the South, staged peaceful protests around the country (including
legal segregation kept black citizens from living, working, the 1963 March on Washington shown here). They fought
playing, shopping, or going to school alongside white for their rights in court and won important changes. The
people. State and local laws made it difficult for African Supreme Court declared segregation illegal, and Congress
Americans to vote. Even in the North, African
Americans weren’t given the same opportunities passed a series of law protecting voting rights.

A life of leadership King’s dream Support from clergy
John Lewis was a seasoned protest The Reverend Dr. Martin Luther King, Jr. Many religious groups joined in the
leader and chair of the Student led the 1963 March on Washington, where Civil Rights movement. Eugene Carson
Nonviolent Coordinating Committee he gave his famous “I Have a Dream” Blake was the executive director of the
at the time of the march. He went speech. In it he said that he dreamed his United Presbyterian Church in the US.
on to spend his whole adult life children would live to see a world where Joachim Prinz (two people to the right
advocating for equality, including as people “are judged not by the color of their of Blake) was president of the American
a congressman from Georgia. skin but by the content of their character.” Jewish Congress.

CIVIL RIGHTS Take a knee

Civil rights are an important part of society. Since August 2016,
They include the right to vote, the right to some US athletes have
a fair trial, and the right to an education. protested police violence
In many societies, minority groups are and racism by kneeling during
discriminated against, meaning they do not the national anthem before
have the same rights as others. This could
be because of their gender, race, religion, or a game. Not standing for
other factors. In the 20th and 21st centuries, the anthem is considered
many groups around the world have taken part disrespectful, so kneeling
in movements to demand their civil rights. draws attention to their
message. Football star Colin
Kaepernick (pictured) was
the first to use this form of
nonviolent protest.

EXPERT CONSULTANT: A.N. Expertname SEE ALSO: Religious Belief, p.212–14; Slavery in the Americas, p.308–09; Women’s Suffrage, p.318–19;
World War II, p.324–25

Indigenous rights

Indigenous people in the Americas, Australia, Africa, Asia, and
Europe have long struggled for equal treatment in their ancestral
homes and respect for their sacred places. The Australian Anangu
people won a major victory in 2019, when the government agreed to
allow them to keep tourists off Uluru, a sacred rock formation.

FACTastic! 100%
90%
World War II fueled the American 80%
Civil Rights movement. Some 70%
1.2 million African Americans served 60%
in segregated units during the war— 50%
many with distinction. The Tuskegee 40%
Airmen flew 1,578 missions, 30%
destroyed 261 enemy aircraft, and 20%
won more than 850 medals. After 10%
the fight to end Nazi racism, racism
at home seemed crueler 41% 58% 64% 66%
than before and
more important Have no access Have homes with Have no access Have no toilet in
to stop. to power mud floors to water their home

GAME CHANGER India’s Scheduled Caste

NELSON MANDELA India’s Hindu caste system splits society into five groups. Members of
First black president of South the lowest-ranking group, the Scheduled Caste, are known widely as
Africa, 1918–2013 Dalits. Dalits have historically been treated as inferior and allowed to
South Africa work in only the lowest level jobs. Although discrimination was made
illegal in 1950, it continues. There are more than 200 million Dalits in
Nelson Mandela spent almost 30 India, and many have poor living standards.
years in prison fighting against
apartheid in South Africa. Apartheid Rights for LGBTQ+ 333131
was a government policy that
separated people of different races. LGBTQ+ people have been fighting
After being freed from prison, he for their rights since the 1970s.
became the first black president of There has been some progress over
South Africa. the years, particularly in Western
countries. Victories include the right
If needs be, it is an ideal for to love, marry, and adopt children.
Every year, in many cities, an event
“ ’’which I am prepared to die. called “Pride” celebrates LGBTQ+
freedoms and demands the rights that
the community is still fighting for.

WHAT WE KNOW & WHAT WE DON’T “A book of wonders
and a wonderful book.”

ANTONY HOROWITZ – author of the Alex Rider series

Description Biographical notes
Earth! Space! Animals! History! STEM! The All New Christopher Lloyd began his career as a journalist at the
Britannica Children’s /Kids Encyclopedia has them all. A Sunday Times in London and is now a bestselling author of
must-have addition to every family reference shelf and more than 15 books on history, science, and nature, including
library collection, this sumptuously illustrated, 416-page What on Earth Happened? (Bloomsbury), the series of What on
compendium of facts provides hundreds of hours of fun Earth Timeline Wallbooks, Absolutely Everything! and more. He
learning for curious children/kids and their families. is in great demand as a lecturer and public speaker throughout
the world, including at TEDx talks, conferences, educational
In keeping with Britannica’s extremely high standards seminars, museums, festivals and schools. Christopher Lloyd
for accuracy, every fact in this book has been lives in Tonbridge, UK.
authenticated by an expert. In addition, quotes from
the experts throughout reveal what makes their jobs J.E. Luebering is the Executive Editor of Encyclopaedia
exciting, modeling a life of continuous learning. Britannica. He lives in Chicago.
Britannica Group is a global education leader with over 250
Special features highlight some of the most intriguing years of dedication to seeking out facts and providing insight
unsolved puzzles in science, archaeology, history, into the mysteries of the universe. Its beloved Encyclopaedia
engineering, and more. And a fun quiz at the end Britannica is the world’s oldest English-language general
of each chapter promotes repeat reading. encyclopedia, first published in 1768 in Edinburgh, Scotland.
Today, Britannica continues to create innovative and engaging
Selling points learning experiences through books, digital content and
• 416 pages, 70+ experts, and 1,000+ illustrations educational tools. Over three thousand expert contributors
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• Very broad topic coverage is divided into chapters by and the joy of learning helps build the world’s future thinkers
subject: Universe, Earth, Matter, Life, Humans, Ancient & and innovators.
Medieval Times, Modern Times, and Today & Tomorrow.
• Britannica’s triumphant return to printed books in Edited by: Christopher Lloyd
partnership with What on Earth Publishing will be a Foreword by: J.E. Luebering
major publishing event, including a comprehensive Ages: 8–12
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