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Published by pssibnusinasdm, 2022-04-11 23:05:07

DK Children’s Encyclopedia ( PDFDrive )

DK Children’s Encyclopedia ( PDFDrive )

Carbon cycle SEE ALSO
▸▸ Atmosphere p.33
Without the element called carbon, our world would be ▸▸ Climate change
frozen and lifeless. Carbon constantly moves between
living things, the atmosphere, the oceans, and the Earth p.60
below us. This movement is known as the carbon cycle. ▸▸ Elements p.90
▸▸ Fossil fuels p.110
▸▸ Gases p.117
▸▸ Pollution p.198

Carbon Carbon floats in CO2 is released into
movement the atmosphere as the atmosphere
carbon dioxide (CO₂). by factories.
Carbon is always
on the move. When Animals
it is in the air, it is breathe
combined with oxygen out CO2.
to make the gas
carbon dioxide (CO2).

Plants use sunlight Plants take
and CO2 to make in more CO2
their own food. than they

give out. Oceans take
in CO2.

17% Animals take Carbon from dead
other in carbon when sea life is released
elements they eat plants. as CO2, or forms
rocks or fossil
18% Animals release fuels such as oil.
carbon CO2 when they
die or poo. CO2 is released from fossil
65% fuels whenthey are dug
oxygen Dead plants up and burned.
rot or eventually
become fossil
fuels such as coal.

Carbon in Keeping the Sun
the human body Earth warm
Some sunlight
Almost one-fifth of the Carbon dioxide in the is reflected, and
human body is made of atmosphere acts like a some is trapped
carbon. After we die, this blanket around the Earth, as heat by CO₂.
is returned to the Earth trapping the sun’s heat.
and naturally recycled. Without it, the Earth Earth’s
would be very cold. atmosphere

49

The story of... Earth is born

Changing world Our planet was formed
when rocks orbiting the sun
Since it formed, the Earth has been crashed into each other and
covered with molten lava, bombarded stuck together. The early Earth
by rocks from space, and blanketed had a poisonous atmosphere
in ice. In 4.5 billion years, the
Earth has changed from a hot, and a volcanic landscape
lifeless planet into a watery with lots of craters.
home, full of life.
The formation
On the move of the Earth

Earth’s land is split up into Mountains are
huge chunks called continents.
Throughout Earth’s history, the created when
continents have shifted around.
continents
Today, there are seven move and hit
continents, but they have
not always looked the way each other.

they do today.

The continents were 250 million years ago
grouped together in
a “supercontinent” Life begins
called Pangaea.
At first, nothing lived on
Marrella, a life form from Earth. The earliest life
540 million years ago. forms appeared 4,600 million
years ago. Over time, more
species developed. Now there 120 million years ago
are millions of different
types of life, and over Pangaea split in two, forming
Laurasia in the north and
7.5 billion people. Gondwana in the south.

50

Under ice

For much of the last
two million years, huge ice
sheets covered large parts of
Northern Europe and North
America. We are currently
living in a warmer period.

Changing surface The Andes mountains
formed 45 million years ago.
The Earth’s surface changes
constantly. As continents crash Mammoths lived during
together or move apart, mountain the last ice age.
ranges are forced up, then worn
down. Rainforests become icy
wastelands, oceans expand and

shrink, and glaciers turn
into deserts.

The Atlantic Ocean If the sea level today
was opening, pushing was as high as it was
North America and 500 million years ago,
Europe apart. London, New York, and
Sydney would all be
Africa was moving
northward, on its way to underwater.
crashing into Europe.

Climate change

Humans have a direct impact
on Earth’s climate. We burn
fossil fuels such as coal, oil,

and gas to make power.
This releases dangerous
gases into the air, making

Earth hotter.

80 million years ago Burning fossil fuels

51

Cars SEE ALSO
▸▸ Electricity p.87
Cars are vehicles that travel on roads. The shape and
size of a car depends on its use, such as for a family or ▸▸ Engines p.92
for racing. Cars are powered by engines. Engines can
be powered by fuel such as gasoline or diesel, or by ▸▸ Fossil fuels p.110
using electricity.
▸▸ Inventions
Parts of a car pp.136—137

All cars have a strong metal frame ▸▸ Sports p.239
called a chassis. Attached to this are
all the other parts, such as the ▸▸ Transportation
engine and wheels. pp.258–259

The engine is
powered by
burning gasoline
or diesel.

This shaft takes The axle spins to
power from the move the wheels
engine to the axle. forward or backward.

The battery The front wheels are Electric car
provides electricity turned by the driver’s
to start the car and steering wheel. Today, many cars are powered by electricity.
to power the lights. Fuel-powered cars release harmful gases into
the air, but electric cars don’t. The battery in an
Formula 1 electric car is powered up at a charging point.

Some of the world’s fastest cars take part
in a racing competition called Formula 1.
They compete on special tracks and around
some city streets. The cars have long, low
shapes to help them go super fast.

1998 Ferrari F300 F1

52

Castles SEE ALSO
▸▸ Buildings p.48
Most castles were built between 1000 and 1500 ce. They ▸▸ Engineering p.91
had homes and workshops inside their walls. Kings and ▸▸ Europe p.94
wealthy people built castles as protection from enemy ▸▸ Imperial Japan
attack. Once cannons were invented, they were no longer
safe. Many fell apart over time, but some are still standing. p.131
▸▸ Knights p.142
Stone castles The bailey was The largest tower ▸▸ Homes
an open space inside in the castle was
Later castles in Europe had stone walls the castle with areas called the keep. pp.244–245
and towers. The biggest ones could hold for growing food.
hundreds of soldiers. Smaller stone Stone walls
castles were home to just were difficult for
a single family and attackers to climb.
its servants.
Sheep and other
livestock were kept
safe in the castle.

The drawbridge People kept watch Some castles had
could be lifted to for the enemy from a water-filled moat
keep the enemy tall towers. around them for
out of the castle. extra protection.

Early castles Himeji Castle in south Japan is
called “the white heron” as its
Hundreds of “motte and bailey” castles peaks look like wings flapping.
were built from 1020–1200. They had
two parts—a mound of earth Japanese fortress
(motte) topped by a tower,
and a courtyard (bailey). Castles in Japan were
designed with towers built
Many castles of both wood and stone.
were built on The central tower was used
hilltops so they as the main hideout if the
had a clear view castle was attacked.
of everything
around them.

53

Cats SEE ALSO
▸▸ Dogs p.81
The cat family are all meat-eaters. They have sharp
teeth that let them slice up their food. Cats are very ▸▸ Food chains
fast, with strong bodies that let them run, jump, p.107
and even swim.
▸▸ Habitats p.126
Cats have
good hearing. ▸▸ Pets pp.152—153

▸▸ Sight p.226

▸▸ Vertebrates
p.266

Small wild cats Whiskers help
cats sense their
Most wild cats are much smaller surroundings.
than lions. The colors of their fur
help them to be camouflaged, or
hidden, in their habitat.

Cat Pet cats Chartreux
tongues
Cats were one of the first animals that
are covered in
humans tamed from the wild to become
sharp hairs. They
pets, around 12,000 years ago.
are used to clean meat
off a bone and to Big cats

wash their The largest types of cat
fur. are known as “big cats.”
They include lions, tigers,
leopards, and jaguars.
These are the only cats
that are able to roar.

Male lions have
longer hair over
their shoulders,
called manes.

Lynx Night vision Lion
54 Leopard
Cats hunt at dawn and
dusk. Their eyes are
good at seeing when
there is not much light.
Their eyesight is six
times better than a
human’s.

Caves SEE ALSO
▸▸ Animal homes
Caves are large natural holes in the ground. They are
usually formed when rock is hollowed out by running p.23
water over millions of years. Prehistoric humans used
caves for shelter, and some people still live in caves today. ▸▸ Erosion p.93
They are also home to lots of animals, including bats.
▸▸ Glaciers p.122

▸▸ Rocks and
minerals p.214

▸▸ Homes
pp.244–245

Cave network A stream pours into A level area of
the cave through an rock without soil
Caves form when rainwater dissolves opening in the ground covering is called
the soft limestone rock in the ground. known as a sinkhole. a pavement.
They often contain fantastic rock
features, such as stalactites
and stalagmites.

Columns form where Stalactites grow
stalactites and down from the
stalagmites join up. roofs of caves.

Stalagmites
build upward
from cave floors.

An underground river wears
away more rock, creating
chambers and tunnels.

Ice caves Biggest cave

Glaciers are rivers of ice The 40-story-high
that move very slowly. Hang Son Doong cave
Some glaciers have in Vietnam is the
caves inside them. They world's biggest cave.
are made by streams of Inside, it has a river,
water tunneling through a forest, and even its
the glacier. own clouds!

This ice cave is inside 55 A river flows through
a glacier in Iceland. part of the huge cave.

Cells SEE ALSO
▸▸ Body cells p.41
Living things are made from tiny parts that stick ▸▸ Genes p.119
together, called cells. Cells come in different shapes ▸▸ Heart p.128
and sizes depending on the job they do. They can ▸▸ Photosynthesis
divide and make copies of themselves.
p.191
▸▸ Plants p.194
▸▸ Sickness p.225

Plant cell Cell wall Cytoplasm Bacteria
The strong outer This is the liquid inside
Plant cells can collect air and make wall gives the the cell that everything Bacteria are living things
their own food from sunlight. They cell and plant else floats in. Chemicals made from just one cell.
have a strong cell wall, which gives their shape. mix together here. They can divide to make
the plant strong stems copies of themselves. This
and leaves. Cell membrane is how germs spread and
The cell membrane is make us sick.
a barrier that keeps
the cytoplasm inside
the cell.

Nucleus
The nucleus
controls the cell
and contains
instructions
called genes.

Animal cell

Animal cells use oxygen to break down
sugar and make energy. Animals get sugar
from the food they eat, while oxygen gets
to the cells through the blood.

Cell membrane

Cytoplasm
Nucleus

Mitochondrion Chloroplast Vacuole Mitochondrion
This is where energy Chloroplasts collect The vacuole is a storage
from sugar is released sunlight and use air and bubble filled with liquid
to power the different water to make food. food, water, or waste.
parts of the cell.
56

Changing states SEE ALSO
▸▸ Atoms p.34
Most materials can change between being solid, liquid, ▸▸ Gases p.117
or gas, depending on their temperature and how tightly ▸▸ Water p.120–121
packed they are. Substances such as water can change ▸▸ Liquids p.148
from one state to another and then back again. ▸▸ Solids p.234
▸▸ Temperature

p.252

Different states Liquid
Materials flow when
All substances are made from tiny they are liquid. The
particles that are arranged in different particles are close but
ways depending on whether they move past each other.
are solid, liquid, or gas.
Water vapor is
Solid Ice is water water as a gas.
Solid materials keep as a solid.
their shape. The
particles are very
close together.

Gas
Materials move in all
directions when they
are gas. The particles
are far apart.

Drinking water is
water as a liquid.

Shifting states Melting When we heat Solidifying When a liquid Evaporating When a Condensing When water
a solid, it melts and like this lava cools, liquid changes into a gas, turns from a gas back
The same material can changes to a liquid. it becomes solid. it evaporates as steam. into a liquid form, this
change from being solid is condensing.
to liquid and from liquid
to gas when it is heated,
and back again as it
cools. These changes
are called melting,
solidifying, evaporating,
and condensing.

57

Chemistry SEE ALSO
▸▸ Atoms p.34
▸▸ Body cells p.41

Chemistry is a science that looks at the smallest ingredients ▸▸ Elements p.90

of everything, called elements. It studies how elements ▸▸ Engineering p.91

react when we mix them together, and how tiny particles ▸▸ Changing states
in materials are arranged and can be rearranged. p.57

▸▸ Materials p.157

Building blocks Particles called
electrons move
around the outside.

Everything around us is made 1. Atoms
from tiny parts called atoms. Atoms are so small we can’t see them
Atoms join to each other and and they’re mostly empty space.
other types of atoms to They have even smaller particles
make arrangements called inside. The type of atom depends
molecules. These basic on the number of particles inside it.
building blocks are what
chemistry investigates.

An atom is mostly Gold
empty space. If an atom
The center is 2. Elements Antimony
was the size of a called the nucleus. Materials that that have Plutonium
football stadium, It contains particles only one type of atom
called protons are known as elements.
the nucleus would be and neutrons. Elements have just one
the size of a marble. ingredient—themselves.
Antimony, plutonium,
Chemical reaction and gold are all elements.

When two or more elements come
together to make a new compound, it
is called a chemical reaction. Reactions
can fizz, burn, or even explode when
new compounds are made.

Iron and oxygen react 3. Compounds
to form rust. Elements that have
joined together are
called compounds.
For example, water
is a compound made
from the elements
oxygen and hydrogen.

Oxygen and hydrogen combined
make the compound water.

58

Circuits SEE ALSO
▸▸ Computers p.71
A circuit is when an object that uses electricity is ▸▸ Electricity p.87
connected with wires to a power source. Circuits in our ▸▸ Light p.147
homes connect lights and appliances, like the fridge or ▸▸ Measuring
television, to electricity.
p. 159
▸▸ Television p.251

How circuits work Wires are
covered in
When a circuit is a complete plastic to stop
loop with no gaps, electricity can electricity
flow around it. We use symbols escaping.
to represent the different parts
of the circuit. Battery “cell”
Batteries are power
Electricity sources that hold
travels through electricity. Electricity
metal wires. can flow around the
circuit when we
Switch connect it to both
Electricity only flows ends of a battery.
around the circuit when
the switch closes and is Light bulbs
switched on. Once the Electricity makes the
switch is opened, light bulb switch on
the circuit breaks. and light up. Objects
in a circuit that need
electricity to work are
called components.

Crocodile clips The flow of Circuit boards
connect circuit
wires to objects. electricity Computers have tiny
boards in them called
around the circuit circuit boards. Circuit
is called the boards have lots of
wires connected up
current. to tiny components
to make the
computer work.

59

Climate change SEE ALSO
▸▸ Arctic p.25
Climate is the average weather for an area. The way we ▸▸ Carbon cycle p.49
live is changing the Earth’s climate. It is becoming warmer. ▸▸ Fossil fuels p.110
This change is causing extreme weather conditions, such ▸▸ Industrial
as long periods of little rainfall, called droughts, and huge
storms. Many countries are now trying to stop Revolution p.133
climate change. ▸▸ Pollution p.198
▸▸ Storms p.246

More than What is the cause?

39 billion tons Power stations, factories, and cars
pump gigantic amounts of the gas
(35 billion metric tons) carbon dioxide (CO2) into the
atmosphere. This gas acts like
of CO2 is released a blanket, trapping the sun’s
every year. heat and warming our planet.

Exhaust fumes from
road traffic are one of
the biggest causes
of climate change.

How is the climate changing? What can we do? Solar panels make
energy from sunlight
Climate change is making our summers hotter. Floods, We need to reduce the amount and do not release
droughts, and powerful storms are becoming more of fuels we burn that release CO2. harmful gases.
common. The ice in cold parts of the world is melting, We can do this by using sources
which is making sea levels rise. of energy that do not produce
CO2, such as sunlight, wind,
and water.

Flooding in New Orleans, Louisiana

60

Clocks SEE ALSO
▸▸ Machines p.150
A clock is a device used to keep track of time. Ancient ▸▸ Measuring p.159
civilizations measured time by falling sand, flowing water, ▸▸ Numbers p.185
or the position of the sun. Modern clocks are either digital ▸▸ The sciences
or have clockwork mechanisms.
pp.218–219
12 ▸▸ Sun p.247
▸▸ Time zones p.255

How does a 2 Clock face
clock work? 3 This part of the clock
shows the time, in hours,
Clocks make regular 4 minutes, and seconds.
movements for measuring
time. They do this using Minute hand
machinery known as The long minute hand
clockwork. The clock makes a full turn around
face has moving hands the clock every hour.
that show the hours,
minutes, and seconds. Hour hand
The short hour hand makes
Gears a complete turn around the
Gears are wheels that lock clock every 12 hours.
together. In a clock, they
make the hands turn at Second hand
different speeds. This long, thin hand makes
a complete rotation of the
clock every minute.

Pendulum 5 Then and now
Each swing of the pendulum 7
turns the gears one click, In the past, people had
usually once a second. 6 sundials, which showed
the time of day using
shadows cast by the sun.
Modern digital clocks show
time as numbers.

The first Counterweight Sundial
This weight stores energy Digital clock
pendulum clock so the clock can work
without a battery.
was made by Dutch
scientist Christiaan 61
Huygens in 1656.

The story of...

Clothing

Over time, the things we wear have changed a lot. The
clothes that people wear often reflect where they live,
what jobs they do, and how much money they have.
Clothes are generally made from woven materials such
as cotton, wool, or silk, with special designs. They are
often worn for show, but can also be practical or even
worn for fun.

First clothes This long,
embroidered
The first people wore dress is made
clothes made of animal skins of silk.
to keep out the cold and wet.
They later discovered how to
clip the wool off a sheep’s
back and spin it into a thread
that could be woven to
make material.

The Roman A toga wraps
Emperor Nero around the
wore a purple toga body and is
thrown over
and punished anyone the left
else who wore purple shoulder.

with death.

Roman clothes Court finery

The main item of clothing for In the royal courts of Europe in the
ancient Romans was a simple 1500s and 1600s, men and women
tunic. For special occasions, men wore special, expensive clothing.
wore a long piece of cloth called The women wore long, embroidered
a toga on top of their tunic. dresses, while the men wore padded

Women wore a woollen jackets with short trousers
shawl called a palla. and silk stockings.

62

A sari Traditional costume

27 ftcan be up to Around the world, people wear
(8 m) long. clothes that are unique to their
country. For traditional events,
A long cotton or silk Indian women wear saris, while
sari is wrapped
around the waist. Japanese women wear long,
decorated kimonos with wide

sleeves. A kimono is tied
at the back with an
obi, or sash.

Kimono

A padded Hats were
jacket, designed to
called a match the rest
doublet. of the outfit.

Weaving

The cotton, silk, wool, or linen
material used to make clothes
is woven on a loom. Different
colored threads can be used

to make patterns, such as
checks or stripes.

A New Look Loom
skirt was full
and long, with
a small waist.

A suit is often Traditionally, the
worn with a
shirt and tie. bottom button of

a suit jacket should

be left undone.

The New Look Smart suit

During World War II (1939–45), material All around the world,
for new clothes was in short supply. businessmen and women wear a
In reaction to this, fashion designer suit of a jacket and matching pants.
Christian Dior introduced in Paris in The suit was developed in Europe
1947 a “New Look” for women. during the 1800s and is a practical
The full skirts were shorter and
became fashionable uniform for work and other
around the world. formal occasions.

63

Clouds SEE ALSO
▸▸ Gases p.117
Clouds are made of tiny droplets of water or ice. They ▸▸ Water
form when air that contains water rises and cools. As
well as making rain, snow, and hail, clouds help control pp.120–121
our planet’s temperature. ▸▸ Storms p.246
▸▸ Temperature
Types of cloud High-level clouds
p.252
There are many different types Cirrus ▸▸ Water cycle p.270
of cloud. Some float very These wispy ▸▸ Weather p. 271
high up, while others hug clouds form very
the ground. Clouds may high up in the air. Cirrocumulus
look white and fluffy Cirrostratus clouds
or dark and stormy. sometimes break up to
form these little clouds.

Altostratus Medium-level clouds
These clouds form a thin
sheet across the sky.

Altocumulus Cirrostratus
These clouds are These thin clouds
broken into segments, are made of tiny
or “cloudlets.” ice crystals.

Stratus Low-level clouds Stratocumulus
These flat sheets These big clouds form a
of cloud can be lumpy layer in the sky.
white or gray.

Cumulonimbus Nimbostratus
Towering and huge, Tall and gray, these clouds
cumulonimbus clouds bring hours of rain or snow.
are often seen during
thunderstorms. Cumulus
These fluffy heaps of
cloud are often seen on
sunny, breezy days.

Temperature Clouds Cloud or UFO?
control reflect
heat from Clouds that do not move
Clouds reflect the the sun. can form in the sheltered
sun’s heat, stopping air behind areas of high
the Earth from getting Clouds ground, such as mountains.
too hot. They also trap trap heat They are shaped like saucers
heat below them, so a reflected or lenses and have been
cloudy night is warmer from the mistaken for unidentified
than a clear one. Earth. flying objects (UFOs)!

64

Coding SEE ALSO
▸▸ Codes p.66–67
Computers follow instructions from special programs.
These instructions are known as code, and writing ▸▸ Communication
them is called coding. Code can be written in many p.69
different coding languages.
▸▸ Computers p.71
Computer languages
▸▸ Internet p.138
Programming languages tell
computers what to do. This ▸▸ Language p.144
example shows a text-based
language called Python. ▸▸ School
pp.272–273

Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 26 2016, Hello World!
10:47:25)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on
Darwin
Type “copyright”, “credits” or “license()” for
more information.
>>>

print ( ‘Hello World!’) The first
programmer was
Input Output
Instructions are typed into a text When the program is run, it follows the Lady Ada
window. These instructions tell the typed instructions. Here, the computer Lovelace
computer to show, “Hello World!” screen shows, “Hello World!”
(1815–1852).
Learning to code
Input
Some computer In Scratch,
languages are easier coding is done by
to learn than others. putting together
Scratch uses colorful instruction blocks.
blocks of code that you
can arrange to make your
own games.

Output
The blocks control
the actions of the
characters here, on
the “Stage.”

65

The story of... Morse Code

Codes Morse Code represents
letters and numbers as
Codes are words, letters, and numbers that are dots and dashes. It was used
used to represent other words, letters, and to send messages through
numbers. People used codes to communicate wires before telephones
with each other, or to keep things secret.
Others, such as DNA, are just instructions. were invented.

The ancient Morse Code tapping machine
Egyptians used

hieroglyphics
as a writing
system

to record
their history.

Writing with pictures Bonjour Nee-how, Mandarin

The ancient Egyptians used Boh-zhoo, French
drawings to communicate, instead of
written words. These symbols are called Konnichiwa, Japanese Languages Hello
hieroglyphics. Hieroglyphics were not
understood by modern people until Merhaba The different languages English
humans speak are types
a stone was discovered with a Mehr-hah-bah, of code. Until you learn a Zdrast-wui-tyeh,
translation of hieroglyphics into Turkish foreign language, hearing Russian
someone using it to speak
Greek, allowing the “code” to or reading their writing will
be worked out. make little sense to you.

Programming Holá Jambo
Oh-lah,
Computers need Spanish Ja-m-boh, Swahili
instructions to operate.

These are created by
programmers, who use
combinations of symbols
and words. Programming
is often called coding.

Nômoshkar, Bengali
66

Codes in war This system of writing
from ancient Greece is
One of the most common still not understood.
uses for codes is to keep secrets,
especially during wartime. When Linear A tablet
commanders give orders to their
armies, they need those orders to
be kept secret from the enemy.
Code breakers try to crack the codes

and learn enemy secrets.

The Enigma Code Unbroken codes

was broken by a Some languages remain a
machine called a mystery—their writings have
been discovered but never
“bombe,” created
by Alan Turing. translated. It is likely that
we will never know
Messages what they mean.
typed here
were encoded DNA strand
by special
wheels.

DNA

DNA—short for
Deoxyribonucleic acid—is
found inside the cells of all
living things, including plants
and animals. It contains a
genetic code on how the

living thing will form.

The Enigma machine was used by Germany during World War II.

67

Comets SEE ALSO
▸▸ Asteroids p.30
Comets are objects in the solar system made of ice, ▸▸ Gases p.117
dust, and rock. They have a hard core and long tails of ▸▸ Gravity p.125
gas and dust. Every now and again they appear within ▸▸ Meteorites p.164
sight of Earth, before disappearing into deep space. ▸▸ Solar system

p.233
▸▸ Sun p.247

Dust tail Gas tail

Two tails The tails Circling the sun
start to
When a comet gets close to the get shorter. Comets move around the sun.
sun, its ice melts and two tails Their tails always point away
form: one made of gas and one 68 from the sun, but in slightly
made of dust.
different directions. The tails
Halley’s Comet get longer as the comet
gets closer to the sun.
Halley’s Comet makes
one full circle around the The tails start
sun every 75 years, and to get longer.
it has been recorded by
historians for more than
2,000 years. The Bayeux
Tapestry, which tells the
story of the Battle of
Hastings, shows it
moving across the sky
in the year 1066.

Communication SEE ALSO
▸▸ Codes pp.66–67
The different ways people keep in touch are all ▸▸ Computers p.71
forms of communication. People have many ways ▸▸ Internet p.138
of communicating, such as talking to each other or ▸▸ Satellites p.215
writing letters. Most modern communication other ▸▸ Games
than talking is done using mobile phones.
pp.240–241
Mobile phones ▸▸ Telephones

Mobile phones are very useful, p.250
as they let people communicate
in many different ways. Video calling
This type of call lets
Email you see the person
Email lets us send you are speaking to.
written messages.
It is much faster Gaming
than sending a letter People can chat
through the mail. and talk to one
another while
Photo Telegraph they play games.
messaging In the early 1800s, messages
Photos can be taken were sent in a series of dots Internet
and then shared and dashes (called Morse The internet
with other people. Code) over a thin wire. lets people find
out information
Phone 69 very quickly.
Using a phone lets
you talk to others Texting
around the world. Texts are short
written messages.
Past and future Texting is a popular
way to communicate.
People have always
found clever ways to HoloLens
communicate. The first This is a computer you
humans drew pictures for can wear. It displays 3-D
each other on cave walls. objects that the wearer
Modern communication is can interact with.
becoming more high tech.

Compass SEE ALSO
▸▸ Ancient China
A compass is a simple instrument that helps people
find their way around by showing directions. It is usually p.16
round and contains a freely rotating, magnetic needle
that always points north–south. This lets you work ▸▸ Inside Earth
out other directions. p.135

▸▸ Magnets p.151

▸▸ Maps p.155

▸▸ Navigation p.182

How to use a compass Directions
The main directions are
When using a compass, lay it flat and north (N), east (E), south (S),
then turn it until the north end of the and west (W). They are called
needle is above north on its base. Now the cardinal directions.
you know which direction is north, you
can find the other directions. Finer directions
Between the four cardinal
Direction hand directions are more precise
This hand can be turned to ones, such as northeast (NE)
mark the direction that you and southwest (SW).
want to travel toward.
Needle
Compass rose The magnetic needle
The base of the compass detects Earth’s magnetic
shows all the different field and lines up with
directions and is known north–south. The end of the
as the compass rose. needle pointing to north is
usually colored or marked.

A compass on a phone
shows which direction
the phone is pointing in.

Directions can 21st-century
be written as compass
angles. For example,
southwest is 225º. Many of today’s phones
contain a device called a
Walking compass magnetometer. It detects
the Earth’s magnetic field
A walking compass has and lets you use your
a see-through back so phone as a compass.
that it can be used on
top of a map. This lets
you work out where you
are and which direction
you want to go in.

70

Computers SEE ALSO
▸▸ Coding p.65
Computers are machines that store information and can be ▸▸ Codes pp.66—67
programmed to perform tasks. Many show information on ▸▸ Communication
a screen, such as on a mobile phone or a laptop. Others are
hidden inside objects to make them work. p.69
▸▸ Internet p.138
Screen ▸▸ Machines p.150
Words and images are ▸▸ Robots p.212
displayed on the screen.
USB port
How computers work Work can be saved and
moved between devices on
Computers are programmed a tiny hard drive, called a
in code to perform different USB. It is plugged in here.
tasks. This is called software.
The programs are stored and
run by the parts, or hardware,
of the computer.

Battery Keyboard
Computers need Words typed on
electricity to work. The the keyboard
battery provides and appear on
stores the electricity. the screen.

Processor Motherboard RAM Hard drive
This part performs the This connects everything, so This part stores information, This stores information
calculations that make that different parts of the but only while the computer even when the computer
the computer work. computer can communicate. is switched on. is switched off.

How we use Traffic lights Video games Industrial robot
computers Computers control Game consoles are computers
when the lights that let you play games on a Computers tell big
Computers are found change color. television screen. machines what to do—
inside many everyday often the same thing
objects. Computers let us 71 over and over again.
program these machines to
perform specific tasks.

Conservation SEE ALSO
▸▸ Climate change
Conservation is the protection of habitats and the
plants and animals that live in them. This is important p.60
because human activity, such as cutting down trees ▸▸ Farming p.98
and throwing away garbage, destroys animal homes. ▸▸ Forests p.109
▸▸ Habitats p.126
Habitats Forests ▸▸ Pollution p.198
Animals live in People cut down trees ▸▸ Zoo p.281
areas we call habitats. for wood and to make space
When people damage for farms. Some wood is In danger
habitats, they threaten Many animals are
many animals and plants. used to make paper. in danger of dying out.
Wildlife reserves protect Recycling paper helps When a type of animal has
habitats and the animals completely died out, we say
that live in them. save trees. it is extinct. National parks
and laws try to stop

animals from
becoming extinct.

Under threat

Here are some of the
ways humans have affected
animals and their habitats, or
homes. We can help protect

animals by making small
changes in our
everyday lives.

Pollution Fishing
Pollution happens People have caught so
when people release many fish from the sea
dirty or harmful that many species are
substances into the world becoming rare. We can now
around them. It can kill choose to eat farmed fish
wildlife. Reusing and instead, leaving wild
recycling things reduces
fish alone.
the amount we
throw away. 72

Constellations SEE ALSO
▸▸ Ancient Greece
Ancient civilizations looked at the night sky and
grouped stars into patterns or constellations to p.18
represent heroes, creatures, and objects. As the Earth
moves, the constellations appear to move across the sky. ▸▸ Galaxies p.116
The stars are all at different distances from the Earth.
▸▸ Myths and
legends p.178

▸▸ Navigation p.182

▸▸ Seasons p.221

▸▸ Stars p.242

Modern constellations This star is called
Menkent, meaning
Astronomers today look at 88 “shoulder of
constellations. Some can be seen from the Centaur.”
both the north and south parts of the
world, others from only one or the other.

This star
is called
Mizar.

Ursa Major Betelgeuse is a red Centaurus
Also known as the Big Dipper, supergiant star. This constellation
Ursa Major (“great bear”) can represents a half-man,
only be seen from the northern half-horse creature
half of Earth. from Greek myth. It is
only visible from the
southern half of Earth.

Navigation

Ancient sailors used the constellations to find
where they were. By looking at the pattern of stars
they could work out where they were on Earth. One
key signpost was Polaris, the North Star.

Orion’s Over thousands of
belt years, stars shift and

constellations
change their
shape.

Orion
The hunter, Orion, is one of the
most well-known constellations.
Three bright stars line up to make
Orion’s belt.

73

Coral reefs SEE ALSO
▸▸ Animal homes
Coral reefs are underwater structures where many plants
and animals live. They are made by tiny animals called p.23
corals that grow hard shells. When they die, the shells
remain and new corals grow on top of them. Some coral ▸▸ Fish p.101
reefs can grow very big.
▸▸ Invertebrates
p.139

▸▸ Oceans and seas
p.187

▸▸ Vertebrates p.266

Coral reef Trigger fish eat coral, Green sea turtles Great Barrier Reef
using strong teeth that have sharp beaks This reef is home to more than 1,500
Coral reefs cover only a tiny crush the corals’ shells. to break off different types of fish. It is the
part of the ocean, but are seagrasses to eat. longest reef in the world and is
home to nearly a quarter of found off the east coast of Australia.
all ocean life. The reefs are
full of food for sea creatures.

Tiny clown fish This red coral forms These hawkfish hide
live among the a branchlike shell. among the coral,
tentacles of swimming out to grab
anemones. The organ pipe small fish and shrimp.
coral has feathery
tentacles that The shells of these
trap food. corals are covered in
small black spines.
Anemones have
swaying tentacles Banded coral shrimp
that sting fish if they are small animals that
get too close. feed by cleaning the
skin of fish.

Blue corals join If threatened by other Fan corals bend and Many small animals
together to form animals, reef crabs sway in the water, use the seagrasses
columnlike groups. pretend to be dead. catching food. as hiding places.

74

Crafts SEE ALSO
▸▸ Ancient Rome
A craft is something done by hand, often with a lot of skill.
People have always used natural and artificial materials, p.20
such as clay or glass, to make things. Craft objects can ▸▸ Art p.28
be for everyday use, such as plates for eating, or for ▸▸ Books p.44
decoration, such as jewelry. ▸▸ Clothing

Pottery pp.62–63
▸▸ Inventions
Potters use clay from the ground to
make things such as plates, bowls, pp.136–137
cups, and vases. They shape the clay,
then put it in a special oven called a kiln Glass
to heat it up and make it hard. Roman

jug

African
wooden
figure

Woodcarving Glasswork

Woodworkers shape When sand is heated
wood into different to a very high
things. They can make temperature, it
furniture, bowls, and other becomes liquid glass.
useful or decorative items. This can be shaped
and cooled into solid
Native American woven rug objects such as jugs.

Red terra- Ancient Egyptian vase Beads are made
cotta in different sizes
clay and shapes.

Weaving Beading

Weavers bring together wool, Materials such as glass -Eastern beads
can be made into beads.
silk, or cotton threads to make Beads can be threaded
material. This can be used for onto string to make
jewelry, or sewn
many things, such as clothes, onto clothing.
rugs, and wall decorations.
Ancient Middle

75

Dance SEE ALSO
▸▸ Clothing pp.62–63
Moving your body in time to a beat is called dancing. ▸▸ Music
People dance to music to enjoy themselves, to be close
to their friends, and to show their skills. Dances can be pp.176–177
very formal with set movements to follow, or much ▸▸ Festivals
more casual and relaxed.
pp.206–207
Fans used ▸▸ Religion p.208
in dance ▸▸ Sports p.239
▸▸ Theater p. 253
Arms above
the head Elegant arm
positions

Traditional dance Feet lift high Religious dance
Many countries or regions have off the ground Some people in the Islamic religion
their own dances, called traditional dance by spinning around in
dances. Korean fan dancing Tribal dance circles. This is called Sufi whirling
involves making shapes with fans. Many African tribal dances follow and helps them feel closer to God.
drum beats and have strong
rhythms. The historical dances of
tribes can include whole crowds.

Acrobatic
moves

Bollywood dance
Bollywood films from India
are famous for their dance
routines. Often, the whole
cast perform exciting
dances with precise
arm movements
and footwork.

Precise Ballet
hand Ballet is a formal
shapes dance style with
graceful and
Complicated strong moves.
footwork Ballet dancers
use a series of
Street dance Latin dance precise steps,
Street dance often involves Latin dance began in Latin leaps, and lifts.
dancers making up their America. Dances such as the
own moves to hip-hop tango involve two people Pointed toes
music. They usually do dancing close together, as
flips and spins. if they are in love.

76

Day and night SEE ALSO
▸▸ Earth p.83
Day and night are times of light and darkness that ▸▸ Light p.147
occur because the Earth spins, or rotates. One full ▸▸ Moon p.171
day-and-night cycle is called a “day” for short. The half ▸▸ Seasons p.221
of the spinning Earth that faces the sun has daylight, ▸▸ Solar system p.233
and the half facing away from the sun is in darkness. ▸▸ Sun p.247
▸▸ Tides p.254
What makes Earth spins on
day and night? its axis, which is The sun is where
an imaginary line Earth’s light and
As the Earth spins round, that goes through heat come from.
parts of it move in and out the North and
of the sun’s light. The South poles.
light parts are in day
and the dark parts
are in night.

It takes the Earth
24 hours to make
one rotation.

Half of the Earth Light from The Earth
is in darkness. the sun
used to spin
Half of the much faster in the
Earth is in light.
distant past, and the

days were much
shorter.

Moving sun Eclipses

The sun appears to move across the sky during the day The moon circles the
as the Earth spins around it. It rises in the east and sets Earth. Occasionally, it
in the west. In the summer, the sun is higher in the sky blocks our view of the
than in the winter. sun during the day, and
the sky darkens for a
few minutes. This event
is called a solar eclipse.
If the moon blocks all of
the sun, it is called a
total eclipse, and stars
can be seen in the sky.

Total eclipse

77

Deserts SEE ALSO
▸▸ Africa p.12
The world’s driest areas are deserts. They have less than ▸▸ Antarctica p.24
10 in (25 cm) of rain a year. Deserts can be sandy, rocky, or ▸▸ Habitats p.126
even icy. Most deserts have hot days and cold nights. Some ▸▸ Mountains p.172
animals survive here by getting water from plants or by ▸▸ Plants p.194
only moving around after sunset. ▸▸ Reptiles p.210
▸▸ Weather p.271

Desert living Golden eagles have Egyptian vultures use
good eyesight to the hot air that rises
Animals and plants living in deserts look for food from from the desert to
must be able to survive with little a long way up. soar high in the sky.
water. In hot deserts, animals are
active at night. During the day, they Sand dunes are hills of Camels store fat
retreat under the sand to stay out sand that are created in their hump.
of the hot sun. by strong winds. They They can go for
move in the wind. days without
Acacia trees have water or food.
long roots to reach Cheetahs get water
deep underground from the blood of
to find water. their prey.

Most of the desert
is made of rocks and
gravel, not sand.

Horned vipers Deathstalker
hide under the scorpions have
sand. deadly poison
in their tails.

Agama lizards warm Peyote cactuses
up in the sun, then Sahara frogs store water in
hide under rocks to stay near any their thick stems.
keep cool. pools of water.

Jerboas get all Scarab beetles
the water they eat animal waste.
need from the
seeds they eat. Sahara Desert
The Sahara Desert is in the north of
Sahara ants have long Africa. It is the world’s largest hot
legs to keep their desert. The Sahara is spread across
bodies off the hot sand. many different areas, including
mountain ranges and sand dunes.
78

Digestion SEE ALSO
▸▸ Food p.106
Digestion is when we eat food and it gets broken down
and used by our bodies to give us the energy we need to ▸▸ Eating
move and stay healthy. Your digestive system starts with pp.104—105
your mouth and ends at your bottom.
▸▸ Human body
Esophagus p.130

▸▸ Lungs p.149

▸▸ Taste p.249

Food journey Stomach
Inside the stomach,
Once it has been swallowed, food liquid chemicals are
passes into the stomach. From here, added to the food
it moves through the intestines and and churned around.
is then pushed out of the body.

Small intestine A large meal takes
After passing
through the stomach, one to three days
the mushed-up food
liquid travels through to pass through the
the small intestine. digestive system.

Digestive system

In the mouth

When we chew, food is broken and mixed
with saliva. Different teeth do different jobs.
When the chewed food is swallowed, it goes
down a tube called the esophagus.

Esophagus Sharp
incisors
cut food.

Large intestine Pointed Flat molars
The waste parts of canines crush food.
food stay in the large tear food.
intestine until they
are pushed out as poo.

79

Dinosaurs SEE ALSO
▸▸ Asteroids p.30
Dinosaurs are reptiles that lived on Earth for 160 million ▸▸ Birds p.39
years, about 225 million years ago. Some were fierce ▸▸ Fossils p.111
meat eaters, others gentle plant eaters. Scientists have ▸▸ Prehistoric life
learned about dinosaurs from studying the fossils left
behind when the dinosaurs died. p.202
▸▸ Reptiles p.210
Ceratopsians Triceratops’s ▸▸ Rocks and minerals
frill was used to
Ceratopsians were plant-eating protect the neck p.214
dinosaurs. They had a protective during fights.
frill around their head. The horns
were used for
Dinosaur fossils defending itself
against other
The remains of dinosaurs dinosaurs.
have been preserved in rock.
Some even show the Dinosaur remains
dinosaur’s last meal have been found on
still inside them.
every continent,

including Antarctica.

The sharp beak
was used for
tearing pieces
off tough
plants.

Archaeopteryx fossil The legs had A long neck let
to be strong, Brachiosaurus
as Triceratops reach leaves
weighed the at the top of
same as four cars. tall trees.

Triceratops
(try-SER-uh-tops)

Tyrannosaurus rex Sauropods
(TIE-ran-oh-SORE-us rex)
Sauropods were
Sharp teeth let T. rex enormous plant-
tear meat off bones. eating dinosaurs.
They had to eat all
Theropods The long tail the time to fuel their
was used for huge bodies.
Theropods were fierce meat- balance.
eating dinosaurs. They lived in Brachiosaurus
what is now North America. (brack-ee-oh-SORE-us)

80

Dogs SEE ALSO
▸▸ Animal families
Dogs are meat-eaters with sharp teeth and excellent
senses. They include wild jackals, foxes, and wolves, as p.21
well as the tame dogs we keep as pets in our homes. Wild ▸▸ Cats p.54
dogs hunt for food or eat animals that have already died. ▸▸ Deserts p.78
▸▸ Hearing p.127
Pet dogs ▸▸ Pets pp.152—153
▸▸ Work p.274
There are lots of different types of
dogs. Some are friendly and make good
pets. Some are strong and loyal to their
owners and are good at guarding things.

There are Beagle Lhasa Apso

300more than
different
types of pet
dog.

Irish Wolfhound

Grey Fennec fox Working dogs
wolf
Foxes For thousands of years,
Wolves dogs have been known
These pointy-eared animals can as man’s best friend.
The grey wolf is the most be found in deserts, icy locations, This is because they
closely related animal to mountains, and even cities. The work closely with
pet dogs. Wolves live and fennec fox is the smallest fox. people. Dogs work in
hunt in groups called packs. the fields, hunt, and
even sniff out people
who have been buried
in rubble or snow.

81

Early humans SEE ALSO
▸▸ Africa p.12
The first humans were similar to apes, such as gorillas and
chimpanzees. Over millions of years, they learned to walk ▸▸ Evolution p.95
on two legs and got smarter as their brains grew larger.
They also lost most of their body hair, slowly becoming ▸▸ Fossils p.111
more like the humans we are today.
▸▸ Monkeys
and apes p.170

▸▸ Exploration
pp.180–181

▸▸ Stone Age p.243

Ancient humans 7 million Hominins 4 million
years ago Early humanlike years ago
There were many different species, called hominins,
types, or species, of human developed from apes.
relatives. Some of them lived They spent a lot of their
at the same time and may have time in trees, and began
met each other regularly. walking on two legs.

First toolmakers Basic rock Prehumans
Homo habilis was one Australopithecus
2 million of the first species to tool 3 to 2.5 is a species of
years ago use stone tools to million hominin that
help with work. The years ago learned to walk
tools made it easier fully upright, like
for them to get food. humans do today.

First fire-makers 200,000 Modern humans
Human relatives became years ago Modern humans appeared in
steadily more clever and Africa. The tools they made
ate more meat. Homo Hand axe helped them adapt to other
erectus may have been environments. They spread
using fire to cook food across the world, while other
over a million years ago. humanlike species died out.

Human evolution How do we know?

The first humanlike animals were short, had Ancient humans left behind
small brains, and lived mostly in trees. Over bones and tools. Scientists
many years, they began spending more study the bones to learn
of their lives on the ground. everything from how ancient
humans walked to what they
ate and what diseases they Ancient skull
had. Their tools can reveal
information about daily life.

82

Earth SEE ALSO
▸▸ Atmosphere p.33
Earth is the planet we live on. It is the third planet away ▸▸ Earth’s surface
from the sun and the largest rocky planet in the solar
system. Earth is about 4.5 billion years old. At the moment p.84
it is the only planet known to support life. ▸▸ Gases p.117
▸▸ Water pp.120–121
Earth has seven ▸▸ Solar system
large land masses
called continents. p.233
▸▸ Sun p.247
Our home
After seeing the
Earth has all the right first pictures from
conditions for life. It is just space, scientists
nicknamed Earth
“the blue marble.”

the right distance from
the sun, it has oceans

of liquid water, and a
blanket of gases called

an atmosphere that
protects it from

outer space.

Earth’s atmosphere
is mostly made of
two gases, nitrogen
and oxygen.

About

70 percent

of the Earth’s
surface is

covered in
liquid water.

Habitable The white swirls
are clouds. Thick
patches of white
are storms.

Too cold Too hot Earthrise

Safe zone Earth is here On Earth, we see a
83 sunrise and a moonrise
Earth orbits the sun in what is known as the as the sun and moon
habitable zone (in green), where liquid water become visible in the sky.
can exist. Closer to the sun, it is too hot, and When astronauts orbited
farther away it is too cold. the moon in 1968, they
saw our own planet
rising in the sky.

Earth’s surface SEE ALSO
▸▸ Earthquakes p.85
The outer layer of the Earth is called the crust. It is
made up of many pieces, called tectonic plates, which fit ▸▸ Inside Earth
together like a giant, ball-shaped jigsaw. Tectonic plates p.135
move very slowly, just a few centimeters each year.
▸▸ Mountains p.172

▸▸ Oceans and seas
p.187

▸▸ Volcanoes p.268

▸▸ World p.275

Many volcanoes Tectonic plates KEY
are found on the meet at plate Plate boundary
Ring of Fire. boundaries.
Ring of Fire
Earthquakes are very Mountains
common along the San Volcano
Andreas Fault, a part of the The Himalayas are a mountain
Ring of Fire in California. range in Asia at the boundary
between two tectonic plates.
Pacific Ocean The range formed over millions
of years as the plates pushed
Earth’s tectonic plates into each other, forcing the
ground up. The mountains
Earth’s surface has seven giant are still rising by about 1/5 in
tectonic plates and several smaller (5 mm) every year.
ones. The largest plate is below the
Pacific Ocean. It covers more than 84
one-fifth of the Earth.

Ring of Fire

Volcanic eruptions
and earthquakes
are common at the
plate boundaries
around the Pacific
Ocean. This is known
as the Ring of Fire.

Earthquakes SEE ALSO
▸▸ Buildings p.48
An earthquake is when the ground shakes. ▸▸ Changing world
Earthquakes happen along cracks in the Earth’s
crust, known as faults. Small earthquakes can pp.50–51
barely be felt by humans, but the biggest can ▸▸ Earth’s surface
cause enormous damage.
p.84
What causes A fault is a crack in ▸▸ Inside Earth p.135
an earthquake? the rocks that form ▸▸ Rocks and
the Earth’s crust.
An earthquake happens when minerals p.214
two huge areas of the ground
jerk past one another, making Powerful shaking
the ground shake. The crack causes buildings to
between them is called a fault. collapse, breaks up
roads, and brings
down power lines.

The point on the ground
directly above where
the earthquake starts
is called the epicenter.

The ground on either Earthquake waves
side of the fault moves travel fast outward
in opposite directions. in all directions, making
the ground shake.
The point in the ground
where the earthquake Giant waves Waves can
starts is called the focus. be taller than
The biggest earthquakes happen buildings
San Andreas Fault under the sea. They make the sea
bulge upward, forming dangerous giant
The San Andreas Fault is a waves, known as tsunamis.
large crack in the ground that
slices through California. It Sea surface
marks the join between two lifts
huge pieces of the Earth’s
crust, called plates. Big
earthquakes happen on the
fault about every 10 years.

Earthquake
pushes the seabed up

85

Eggs SEE ALSO
▸▸ Amphibians p.15
Some young animals grow and develop inside round ▸▸ Birds p.39
objects called eggs. There are different types of eggs. ▸▸ Fish p.101
The size of the egg and the length of time it takes to ▸▸ Life cycle p.146
hatch depends on the size of the animal that laid it. ▸▸ Mammals p.154
▸▸ Metamorphosis

p.163

Ostrich eggs are Bird eggs
the largest in
the world. Bird eggs are hard and
waterproof. They are kept
Egg-laying warm, or incubated, by one
mammals of the parents. Most bird
eggs are kept safe in a nest.
Most mammals give birth to
live babies. Only one group, It takes 42 days for
called monotremes, lay eggs. an ostrich chick to
The monotreme shown here be ready to hatch.
is called an echidna.

Ostrich chick

Tortoise hatchlings
are male or female
depending on how
warm the egg
was kept.

Dogfish eggs look like
leathery bags, which
are sometimes called
“mermaid’s purses.”

Fish eggs Leopard tortoise hatchling Frogspawn

Most fish produce lots of eggs Reptile eggs Amphibian eggs
and don’t look after them. But
they do lay the eggs in places like Reptile eggs are soft and Amphibians such as frogs and
sea grasses to keep them safe. leathery. The mother buries toads lay wet eggs in water.
them in the ground and leaves When they are ready, the eggs
them to hatch on their own. hatch and tadpoles come out.

86

Electricity SEE ALSO
▸▸ Atoms p.34
Electricity is the flow of tiny charged particles called ▸▸ Circuits p.59
electrons. It is used to power lights and electrical ▸▸ Energy pp.88–89
appliances, such as kettles and televisions, in our homes, ▸▸ Materials p.157
at school, and all around us. ▸▸ Metals p.162
▸▸ Television p.251

Lightning

Lightning is a type of natural
electricity called static electricity.
Tiny bits of ice in the clouds rub
together, charging up electricity
until a big spark of lightning occurs.

Making Using electricity A toaster
electricity needs
Appliances like coffee electricity
We make electricity pots and televisions in to heat up.
from different types our homes work when
of energy. One example we press a switch The light
is how solar panels to connect them to bulb in this
change the sun’s light electricity. Electricity lamp uses
energy into electricity. flows through them to electricity.
Also, wind turbines make them function.
change the wind’s Wind turbines
movement energy into A laptop charges up
electrical energy. using electricity.

87

The story of... Fossil fuels

Energy Fossil fuels are made
from dead plants and animals
Energy is power to make things squashed underground millions
happen. It is everywhere around us. of years ago. Coal, oil, and gas
Heat, light, and movement are types are fossil fuels. We burn these
of energy. We need energy to make
our bodies work and it’s what we use fuels to release heat and
to make electricity and power our this makes electricity in
homes. Energy can be stored and it
can change from one form to another. power stations.

Running Our bodies

Your body needs energy
to move, grow, keep warm,

and stay alive. The food
you eat gets digested and

changes inside you to
give you the energy

you need.

Movement The fastest roller Roller coaster
coaster is Formula
Movement is a type of Rossa in the United
energy. When, for example, a Arab Emirates. It
roller coaster is pulled to the travels at 150 mph
top of a hill, it has lots of stored
(241 kph).
energy. Then as it moves
downward, the roller coaster

gets faster, as stored
energy changes to
movement energy.

88

Early steam Food chain Plants
engine Deer

Plants take energy from

the sun’s light and convert it

into sugar, a type of stored

energy in plants. In this example,

the deer eats the stored energy in

the plants, which gives the deer

Industrial Revolution energy. The lion eats the deer,
and this food gives the

From the late 1700s, people lion energy.

began to use energy in new ways,

Burning coals creating huge industrial growth.

Movement energy from water turned

wheels to drive machines to weave

textiles in mills. Heat energy

from steam engines drove

trains and machines The first steam
in factories. engine was

developed in the
1760s by Scotsman

James Watt.

The sun The sun Lion
Wind turbines
Most of the energy we Renewable
use is from the sun. The
sun’s light energy changes to Renewable energy is
heat energy, warming planet energy made from sources
Earth. Light helps plants grow that won’t run out, such as
and plants provide animals sunlight, wind, and water. For
example, we can use a wind
with energy. turbine or a water wheel to

The wind turns turn movement energy
the blades of into electricity.
the turbine.

89

Elements SEE ALSO
▸▸ Atoms p.34
An element is a material that can’t be broken down ▸▸ Electricity p.87
into other materials. All objects are made from ▸▸ Gases p.117
tiny particles called atoms, which usually ▸▸ Liquids p.148
join together in groups. Elements are ▸▸ Metals p.162
pure materials, which means they are ▸▸ Gold pp.200–201
made from only one type of atom. ▸▸ Solids p.234

Elements everywhere Calcium Helium
The metal calcium is The gas helium is used in
Three-quarters of the elements are part found in rocks, living party balloons because it
of a group called metals. They are usually things, and milk. It helps is lighter than air, so it
solids that conduct electricity. Non-metal make bones, teeth, and floats. Helium is made
elements include gases, such as hydrogen animal horns. inside stars.
and oxygen, and solids, such as carbon
and sulfur.

Aluminum
The soft, light metal
aluminum can be
made into foil, cans,
and airplane parts.
It doesn’t rust like
some metals.

The periodic table Nitrogen Gold
has the The valuable
The periodic table lists all symbol Ni. metal gold is found
the known elements in the in its pure form in
universe. There are more than Uranium nature. It can be
100 chemical elements and we has the hammered into
keep finding more. All the symbol U. shapes without
elements have a symbol and snapping.
are placed in groups according The first periodic table, written by Mendeleev
to how they behave and how Mercury is the
many particles they have
inside them. only metal that
is liquid at room

temperature.

90

Engineering SEE ALSO
▸▸ Bridges p.46
Engineers use math and science to solve problems. ▸▸ Buildings p.48
They invent and create machines, buildings, tools, and ▸▸ Factories p.97
other useful inventions that make our lives easier. ▸▸ Inventions
There are different types of engineers that specialize
in different areas. pp.136–137
▸▸ Machines p.150
▸▸ Materials p.157

Civil Chemical
Civil engineers Chemical engineers
design and build turn materials into
structures such as
buildings, bridges, useful products,
including medicines.
and roads.

Electrical Mechanical
Electrical engineers Mechanical engineers

create parts for study movement,
devices such as heat, and energy to
computers, tablets, help them design new
and mobile phones. machines and tools.

Engineering process 3D printer

Engineers develop older technology to make Engineers can now use
new, better designs. An invention like the wheel computer-aided design
has changed over time from the earliest version (CAD) programs to make
to a hi-tech modern one. three-dimensional (3-D)
models of their designs.
one ood bber and metal The 3-D printer creates
St the model using layers
W of plastic.
Ru

3-D printer at work

91

Engines SEE ALSO
▸▸ Aircraft p.13
Engines power machines by turning fuel into movement. ▸▸ Cars p.52
Coal, oil, or electricity is heated to create energy. The ▸▸ Factories p.97
energy is then used to turn wheels or parts that move the ▸▸ Forces p.108
machine forward. There are three main types of engines. ▸▸ Machines p.150
▸▸ Ships p.224
▸▸ Trains p.260

Steam engine Steam and smoke 2. Steam 1. Fire A supply of coal
escape through The heat from the Coal is burned in a is stored behind
The first steam engine the chimney. fire turns the metal firebox to the engine.
was built in 1712 to water from liquid make a hot fire.
pump water out of into steam.
mines. Steam engines
were used to power
factories and trains.

3. Piston
Steam flows into
this tube where it
pushes a moving
part called a piston.

4. Movement
The piston drives
the train’s wheels
forward.

Car engine Jet engine

Car engines burn gasoline or diesel. There are four Jet engines are used for aircraft. They work by squashing,
moving parts called pistons, which move up and down, heating, and speeding up air. This hot air is blasted out
making the car’s wheels turn. backward, pushing the aircraft forward.

92

Erosion SEE ALSO
▸▸ Caves p.55
Erosion is the natural movement of rocks, tiny pieces of ▸▸ Deserts p.78
loose rock, and soil, over long distances. Many different ▸▸ Glaciers p.122
things can cause erosion, including wind, rivers, ice, ▸▸ Mountains p.172
oceans, and landslides. ▸▸ Rivers p.211
▸▸ Rock cycle p.213
▸▸ Weather p.271

On the move Rain, snow, Landslides happen Massive flows of
and ice wear when loose mountain mountain snow,
Erosion moves huge amounts of rock away rock. slopes collapse. called avalanches, carry
and soil, and shapes our landscape. It is loose rocks with them.
fastest in mountains, where there is
lots of rain and snow, and slowest
in dry places such as deserts.

Glaciers remove Rivers eat into valleys
loose rock and and carry pieces of rock
carry it down from downstream.
high mountains.
Coastal cliffs are
The roots broken up and
of plants can washed away by
crack rock. powerful waves.

Rock particles
carried in the wind
can wear away at
the landscape.

Wind sculptures Wind-carved rock Glacier power

Over a very long period of Glaciers are rivers of ice
time, tiny pieces of rock that move down from high
carried by strong winds in mountains very slowly. As
deserts can sandblast rocks, they move, they pick up
wearing them away into rocks that scrape away
amazing shapes. at the landscape, carving
steep-sided valleys and
hollows in the ground.

93

Europe SEE ALSO
▸▸ Ancient Greece
The continent of Europe is surrounded by ocean, except in
the east, where it is joined to Asia. Much of Europe is flat, p.18
but there are several high mountain ranges, including the
Alps, Pyrenees, and the Carpathians. ▸▸ Ancient Rome
p.20

▸▸ Asia p.29

▸▸ World War I p.276

▸▸ World War II
p.277

About Although it is the This powerful
Europe meat-eater is
second smallest the biggest
Population: member of the
743.1 million continent, Europe weasel family.

contains nearly 50
countries.

Highest point: Wolverine
Mount Elbrus
Eyjafjallajökull Ferry Oil Gas Beneath the
Lowest point: Coal domes of this
Caspian Sea In 2010, ash from this Njupeskär cathedral in
volcano in Iceland waterfall Rhythmic Moscow are
Biggest desert: stopped more than gymnastics ten separate
Oltenia Sahara 100,000 airline flights. churches.

Longest river: Brown bear
Volga
Giant’s European Grass
Causeway bison snake

Stonehenge Little St Basil’s
Mermaid Cathedral

Tulips Malbork Castle

The building Eiffel Golden St Sophia’s Cossack
of this cathedral Tower eagle Cathedral dancing
began in 1882.
It is due to Dobšinská
finish in 2026. Ice Cave

Flamenco Sagrada Leaning Dalmatian Eiffel Tower
dancing Familia Tower of pelican
cathedral This iron tower in Paris
Pisa Mount is 1,063 ft (324 m) high. It
Olympus was completed in 1889 and is
the most visited monument
Mount Etna in the world.

Giant’s Causeway The tower is made
up of more than 18,000
The Giant’s Causeway is an area of pieces of cast iron.
hexagonal columns made of ancient
volcanic rock. It is on the coast of
County Antrim in Northern Ireland.

94

Evolution SEE ALSO
▸▸ Dinosaurs p.80
In order to survive, an animal needs to change when ▸▸ Dogs p.81
the weather and food around it changes. This is called ▸▸ Fossils p.111
adaption. The theory of evolution is that lots of these ▸▸ Genes p.119
tiny changes over millions of years create new types ▸▸ Life cycle p.146
of living things. ▸▸ Prehistoric life

Fossils p.202

Fossils are the remains of Charles Darwin
living things that were alive
millions of years ago. We Scientist Charles Darwin came
study them to see how up with the theory of evolution
life has changed. while traveling around the world
investigating living things.

Ammonite fossil Taller giraffes
can reach
more food.

Giraffe Natural selection Mammals first
appeared and
When an animal passes on began evolving
something useful on to its
children, those children are 220 million
more likely to survive. This is years ago.
called natural selection.

Selective breeding

Humans can create different
shapes, colors, sizes, and
personalities of baby animals by
choosing their parents carefully.

Labrador Poodle Labradoodle
(Mother) (Father) (Child)

95

Explorers SEE ALSO
▸▸ Europe p.94
Explorers travelled to new places to meet different people, ▸▸ Maps p.155
find goods for trade, or just to see what was there! They ▸▸ Exploration
came from all over the world and faced big challenges on
their journeys. Some were successful, such as Chinese pp.180–181
explorer Zheng He, who reached Madagascar in the 1420s. ▸▸ Navigation p.182
Others did not complete their missions. ▸▸ Ships p.224
▸▸ Trade p.257

Frobisher tried to Europe Age of Exploration
reach the Pacific, Africa
but ended up in Between 1450 and 1800, new
North America. navigation tools and types of
ships allowed Europeans to make
Atlantic Ocean long sea voyages. This period is
known as the Age of Exploration.
Columbus
North America reached Asia
America.
Pacific Ocean Pacific Ocean
Magellan
led the first South Da Gama
trip around America brought Indian
the world. spices back to
Portugal.
Australia
Indian Ocean

Cook went KEY Martin Frobisher in 1576
around South Christopher Columbus in 1492 James Cook in 1770
America to get Vasco da Gama in 1498
to Australia Ferdinand Magellan from 1519 to 1521
and claim it
for Britain.

Trade Cinnamon Magellan

Explorers discovered items Spanish sailor Ferdinand
they had never seen before. Magellan set out in 1519
Merchants then traded these to find a new route to
goods, such as food, spices, Asia. He left with five
and precious metals. ships and 270 men,
Pepper, for example, but only one ship and
spread from India 18 men made it back.
around the world.

Black pepper Gold
96

Factories SEE ALSO
▸▸ Cars p.52
Factories are places where people and machines work ▸▸ Engineering p.91
to make things. When factories make many identical ▸▸ Machines p.150
things at the same time, it is called mass production. ▸▸ Robots p.212
Almost everything we have, use, and wear comes ▸▸ Transportation
from a factory.
pp.258–259
Assembly line 2. Inside and outside ▸▸ Work p.274
The frame of the car goes
Things with many parts and different 3. Finished car
materials are put together at various to the painting station. The completed car
workstations in a factory. This is called The outside is painted, is identical to the others
an assembly line. and the seats and other on the assembly line. They
are all made in the same
parts are put inside. way and have the

1. Bodywork same parts.
Factory workers and
robotic machines start
building a new car by
joining separate metal
parts together to build

a frame.

Bottling factories The oranges The juice is put
are squeezed. into bottles.
Drinks are made and
bottled in factories. The 97
same ingredients and
processes are used to fill
thousands of bottles
every day.

Oranges enter the
factory.

Farming SEE ALSO
▸▸ Fish p.101
Farming is growing plants and raising animals, usually
for food. Common crops include cereals, fruit, and ▸▸ Eating
vegetables. Farm animals include cows, sheep, pigs, pp.104–105
chickens, and even fish. As well as their meat, cows
are farmed for their milk and chickens for their eggs. ▸▸ Food p.106

Cereal farming ▸▸ Fruit and seeds
Cereal crops such as p.115
wheat, corn, and barley
are grown in large fields. ▸▸ Incas p.132
Rice is also a cereal. It is
grown in hot countries in ▸▸ Plants p.194
water–covered areas
called paddy fields.

Animal farming
Farmers raise pigs,
cows, and chickens in
large sheds or outdoors
in fields. Sheep, goats,
and llamas are often

kept on rough or
higher ground.

Fruit and
vegetable farming
Crops such as pineapples
and potatoes are grown
outside. Others, such as
strawberries and peppers,
are grown all year round

in glasshouses or
plastic tunnels.

Fish farming
Much of the fish we eat,
such as salmon and cod,

is now farmed rather
than caught in the wild.
The fish are kept in net
pens or cages in lakes,

rivers, or the sea.

98


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