First Science Encyclopedia

First Science
Encyclopedia

REVISED EDITION Contents
Project editor Suneha Dutta
What is science?
Art editor Nehal Verma
Senior editor Shatarupa Chaudhuri 4–5 What is science?
6–9 Advances in science
DTP designer Bimlesh Tiwary 10–11 Being a scientist
Managing editors Laura Gilbert, 12–13 Science and everyday life

Alka Thakur Hazarika Life science
Managing art editors Diane Peyton Jones,
14–15 The living world
Romi Chakraborty 16–17 Micro life
CTS manager Balwant Singh 18–19 Fungi
Producer, pre-production Francesca Wardell 20–21 What is a plant?
22–23 How plants work
Producer Nicole Landau 24–25 Plant reproduction
Jacket editor Ishani Nandi 26–27 What is an animal?
Jacket designer Dheeraj Arora 28–29 Types of animal
30–31 Animal reproduction
Publisher Sarah Larter 32–33 Inheritance
Publishing director Sophie Mitchell 34–35 Bones and muscles
Publishing art director Stuart Jackman 36–37 Blood and breathing
38–39 The digestion ride
Consultant Jack Challoner 40–41 Health

ORIGINAL EDITION
Design team Gemma Fletcher, Hedi Gutt,

Laura Roberts-Jensen, Mary Sandberg,
Poppy Joslin

Editorial team Lorrie Mack, Alexander Cox,
Wendy Horobin, Joe Harris

Senior editors Carrie Love, Caroline Stamps,
Ben Morgan

Senior art editor Rachael Smith
Publishing manager Bridget Giles

Art director Rachael Foster
Category publisher Mary Ling
Production editor Clare Mclean
Production controller Pip Tinsley
Consultants Donald R Franceschetti,

John Farndon

First published in Great Britain in 2009
This edition first published in Great Britain in 2017

by Dorling Kindersley Limited
80 Strand, London, WC2R 0RL

Copyright © 2009, © 2017
Dorling Kindersley Limited
A Penguin Random House Company

2 4 6 8 10 9 7 5 3 1
001–280449–Jun/2017

All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted
in any form or by any means (electronic, mechanical,
photocopying, recording, or otherwise) without the prior

written permission of the copyright owner.

A CIP catalogue record for this book
is available from the British Library.

ISBN 978-0-2411-8875-0

Printed and bound in Hong Kong

A WORLD OF IDEAS:
SEE ALL THERE IS TO KNOW

2

There is a question at the bottom of each page...

42–43 Food chains 108–109 Soil
44–45 Ecosystems 110–111 Resources in the ground
46–47 Staying alive 112–113 Fresh and salt water
48–49 The Earth’s cycles 114–115 The water cycle
50–51 Carbon cycle 116–117 The atmosphere
118–119 Weather
Materials science 120–121 The energy crisis

52–53 What’s the matter? Reference section
54–55 Properties of matter
56–57 Changing states 122–123 True or false?
58–59 Amazing atoms 124–125 Quiz
60–61 Molecules 126–127 Who or what am I?
62–63 Elements 128–129 Where in the world?
64–65 Properties of elements 130–131 Glossary
66–67 Mixtures 132–135 Index
68–69 Reactions and changes 136 Picture credits
70–71 Irreversible changes

Physical science About this book
The pages of this book have special features that
72–73 What is energy? will show you how to get your hands on as much
74–75 Energy changes information as possible! Look out for these:
76–77 Electricity
78–79 Magnetism The Picture Detective
80–81 Energy waves will get you searching
82–83 Light through each section
84–85 Sound for the answers.
86–87 Heat
88–89 Forces Turn and Learn tells
90–91 Forces and motion you where to look
92–93 Machines for more information
on a subject.
Earth and space science
Every page is colour-
94–95 The Universe coded to show you
96–97 Starry skies which section it is in.
98–99 Our solar system
100–101 The Moon weird or what?
102–103 The Earth’s structure
104–105 Rocks and minerals These buttons
106–107 Shaping the land give extra weird
and wonderful

facts.

... check here for answer. 3

What is science?

What is science?

Science is the search for truth From atoms to space
and knowledge. Scientists suggest
explanations of why things are Scientists study a huge
as they are, and then they test variety of things – from the
those explanations, using tiniest atoms that make up
experiments. Some of what
science discovers can be everything around us to
applied to our everyday lives. the mysteries of space.

Everything you
see is made up of
minuscule atoms.

Life science The scientific Physical science
study of plants
How do living things survive is called botany. This science looks at
and grow, where do they live, energy and forces. There
what do they eat, and how do
their bodies work? Life science are different types of
seeks to answer such questions energy, including light,
about the living world, from heat, and sound. Forces
microscopic bacteria to plants are the things that hold
and animals – including you!
everything in place in
our world. Without the The study of
electricity is part
force of gravity, for of physical science.
example, you would

fly off into space!

The Earth

Life science studies the living What is the study of animals called?
world around us.

4

What is science?

This is NASA’s
Atlantis orbiter – part

of its Space Shuttle
programme, which

ended in 2011.

Earth and space science

The Earth is a dot in a vast
Universe filled with planets and
moons, stars and galaxies. As far
as we know, the Earth is special
because it is the only place that
supports life. Earth and space
science is the study of the structure
of our planet – and everything
that exists beyond it.

Volcanology is the scientific
study of volcanoes.

One branch of science studies Materials science All about change
how materials can change.
Our Universe is filled with atoms People always want to
and molecules, which make up make life better, and
elements, compounds, and mixtures.
Materials science is the study of that’s what puts us on
the road to scientific
these things, how they behave, discovery. Whether
how we use them, and it’s finding cures or
how they react sending rockets into
with one
another. space, science drives us
onwards, changing the

world we live in.

Pictures of the Earth
from space help scientists
understand the Earth better.

Zoology. 5

What is science?

Advances in science

Great scientists are thinkers who understand the A falling apple
world around us, provide solutions to problems, probably inspired
and create new things. This has led to many Newton to think
great inventions and discoveries.
about gravity.

Johannes Gutenberg (c.1398–1468) In a rainbow, white
light breaks up into
Gutenberg played a key role in printing. Experts seven colours.
believe he invented metal-type printing in Europe.
Gutenberg’s press was quick, accurate, and Isaac Newton
hard-wearing, compared to (1642–1727)
earlier woodblock printing.
Newton investigated forces and
Gutenberg’s first printed light. He realized there must be a
book was the Bible in 1455. force that keeps the planets in orbit
around the Sun. This force is known
as gravity. Newton also discovered
that white light is a mixture of lots
of different colours.

1400 1500 1600

Wooden replica of Galileo Galilei Replica of a
da Vinci’s Ornithopter (1564–1642) 17th-century
telescope
Leonardo da Vinci Galileo proved that the Earth
(1452–1519) moves around the Sun by
looking at the solar system
Da Vinci was a painter and inventor. through a telescope.
He drew plans for helicopters, A few wise thinkers had
aeroplanes, and parachutes. always suspected the
Unfortunately, the technology of the truth, but most people
time was not good enough to build a at the time believed
that our Earth
working model for any of these. was the centre
of everything.

6

Who invented the bifocal lens?

A kite helped did you know? Advances in science
Benjamin Franklin
More than Super inventions!
learn about 2,000 years ago, Greek Inventions and discoveries
lightning and thinker Aristotle recommended have changed the course
that people study nature, of our history.
electricity. and carry out experiments
The first known wheel
Benjamin Franklin to test the accuracy was used in Mesopotamia
(1706–1790) of ideas. around 3500 BCE.

American scientist Benjamin Louis Paper was invented in
Franklin experimented with Pasteur China around 105 CE,
lightning and electricity. (1822–1895) but kept secret for
His work in the 1700s many years.
laid the foundations for Pasteur is known
today’s electrical world. for discovering The magnetic compass
pasteurization – was first used by the
Franklin risked his life flying a kite – he a process that Chinese. It was invented
could have been struck by lightning. uses heat to destroy bacteria around 247 BCE.
in food, particularly milk.
He also discovered that The parachute was first
some diseases were caused tested in 1617 by Faust
by germs and encouraged Vrancic, centuries after
hospitals to be very clean da Vinci made his drawings.
to stop germs spreading.
The steam engine was
invented in 1804. The
earliest successful model
reached 48 kph (30 mph).

The colour photo was
first produced by physicist
James Maxwell in 1861.

1700 1800

William Wilhelm Conrad
Herschel Röntgen (1845–1923)
(1738–1822)
Röntgen discovered
Herschel is well electromagnetic rays –
known for his work today known as X-rays –
in astronomy (he on 8 November 1895.
was the first to This important
identify the planet discovery earned
Uranus). He also him the first
discovered infrared radiation Nobel Prize for
– this technology is used today for Physics in 1901.
wireless communications, night vision,
weather forecasting, and astronomy. X-rays allow doctors to
look inside the human body.

Benjamin Franklin. 7

What is science? Karl Landsteiner Orange juice is
(1868–1943) a good source
Movie projectors of vitamin C.
developed quickly after Austrian-born physiologist
Landsteiner discovered Albert Szent-Györgyi
Edison’s early work. that human blood can (1893–1986)
be divided into four main
Early movie groups – A, B, AB, and O. The Hungarian scientist
projector This laid the foundation of Albert Szent-Györgyi is best
modern blood groupings. known for discovering vitamin
Thomas Edison C. He also pioneered research
(1847–1931) into how muscles move and
work. In 1937, he won the
Thomas Alva Edison
produced more than 1,000 Nobel Prize for physiology
inventions, including long- and medicine.
lasting light bulbs, batteries,
and movie projectors. Blood transfusions play Red You inherit your
an important part in blood cells blood type from
1800 modern medicine. your parents.

1850

Albert Earthquakes Charles Richter
Einstein destroy homes (1900–1985)
(1879–1955) and office
buildings. Richter developed a way
German-born to measure the power of
earthquakes. He worked
physicist Albert on his scale with
fellow physicist
Einstein’s famous Beno Gutenberg.
equation E=mc2
Einstein’s equation
explained how

energy and mass

are related. It helped

scientists understand A “great” earthquake Epicentre (an
earthquake’s
how the Universe works. (8–9.9 on the Richter
scale) strikes on average point of
origin)
once a year.

8 Who was the father of the frozen food industry?

Alan Turing Tablet Advances in science
(1912–1954)
Modern inventions
During World War II, Imagine the world
Alan Turing, a brilliant without these fantastic
mathematician, helped inventions!
develop code-breaking
machines that eventually The first antibiotic,
led to the invention of penicillin, was discovered
accidentally.
modern computers.
Modern cars are driven by
The English used Turing’s An Apple internal combustion engines
machine to break German smartphone that run on petrol or diesel.
codes that were sent through
the Enigma machine during Nuclear power is
World War II. efficient, but some people
think it could harm us.
Computers (1941) Mobile phones and
tablets (1980s) Plastics technology
The first computers were is used to make many of
huge machines. They The first mobiles the things in your home.
couldn’t cope with were large and
complicated tasks, but Compact discs are
worked on only one heavy, weighing small and light, and they
thing at a time. about 35 kg store lots of information.

(77 lb). Tablet Energy-efficient light
technology has bulbs help save energy
in your home.
Today’s laptops also improved
can be lightweight drastically since
and portable.
Early computers its invention in
filled whole rooms. the late 1980s.

1900 1950

DNA profiling (1986) The Internet (1990s)

The discovery of DNA With its roots in the
(which holds information in 1960s, the Internet
(short for internetwork)
human cells) led to DNA became public during the
profiling, a huge help to the mid-1990s, and is now
police – criminals can now used for fun and education
by about 2.5 billion users –
be identified by a single 70 per cent of whom are
hair or spot of blood.
online every day.
Nuclear bombs (1945)
Before DNA profiling, police
The USA dropped two nuclear identified criminals by their
bombs on Japan in World War II, killing fingerprints. This system
nearly 300,000 people. It is the only time was developed in the 1890s.
nuclear weapons have been used in war.

Clarence Birdseye, who started a frozen food company in 1924. 9

What is science?

Being a scientist Experiments can involve toxic
fumes or chemicals that
Scientists study the world around
us. They look for gaps in existing might explode, so scientists
wear protective goggles.

knowledge and try to find the

answers. Not all scientists study

the same things – they specialize

in different areas.

Testing, testing Mixing it up

Scientists explore their ideas and theories Experimenting with chemicals and
using tests called experiments. In this their reactions can produce some
book, there are lots of experiments you
can try out for yourself. mixed results. Some mixtures can be
dangerous, while others can be the
answer the scientists are after.

10

How much bigger do things look through a microscope?

Hooke’s Modern Being a scientist
microscope
A closer look microscope Types of scientist
Almost everything
The microscope in the world is the
was developed subject of study by
by two Dutch a scientific specialist.
spectacle makers in
around 1610, and then Zoologists study
refined by Robert Hooke animals of all kinds
in England. Early models except human beings.
revealed tiny organisms in
water, while modern versions Biologists are interested
can look inside a single cell. in everything about life
and living organisms.
Inside view
Paleontologists are
When you go to a hospital, experts on fossils, and try
the doctor may send you for to learn about organisms
a body scan. Using a powerful from them.
machine, the medical team
can see what’s going on Botanists learn about
inside you. the world of plants, plant
types, and plant groups.
hands on Experiments allow
scientists to observe Chemists study elements
Fill a cup or and theorize how and chemicals, and they
vase with water, and add a things work and why. help make new substances.
few drops of food colouring. It has been found, for
Cut the end off the stem of a instance, how plants Astronomers are experts
flower and put the flower in take up food and on space, planets, stars,
the water. The petals turn water from the soil and the Universe.
and transport it up
the colour you mixed the stem. Entomologists are a
in the water. special kind of zoologists
who learn about insects.

Geologists find out about
our Earth, particularly by
studying rocks.

Archaeologists are
interested in the remains
of past peoples and lives.

Ecologists study the
relationship between
living things and
their environment.

Oceanographers
know all about oceans
and ocean life.

11
Some microscopes can magnify objects up to 2,000 times!

What is science?

Science and everyday life

Science is not just used by experts Teflon Iron
working in laboratories. It is part
of all our lives. From brushing Invented in 1938, Teflon
your teeth to setting your alarm,
science is with you all day, every was used in space suits.
day, in the form of technology.
In everyday life, it stops

stuff from

sticking

to hot Teflon pan

surfaces.

Electricity Plastic building blocks Plastic fantastic

Electricity lights up the Look around you and you will
world and gives us the see dozens of things made of
energy to run machines
and gadgets with which plastic. From containers
we can cook, travel, to toys, plastic is a
work, and play. versatile and hard-
wearing material.
Cities at night are bright Many plastics can
places, lit up by offices, now be recycled.
houses, and street lights.
Some medicines come in
plastic bottles. Sometimes
tablets are contained in plastic
packets, and sold in strips.

12

What was the first satellite in space?

Science and everyday life

Surgeons get
a helping hand
from computers.

Satellite orbiting
the Earth

In the best of health Masks, aprons, and Communications
gloves help doctors
Long ago, people relied only keep operation rooms Satellites orbit the Earth,
on herbs to cure diseases. Thanks free from infection. beaming back all sorts
to modern science, many illnesses, of information. They send
including those that were once TV signals, supply weather
untreatable, can now be information, and help us
cured or prevented. look into space.

Clothing technology From here to there

Advances in sports- Science and technology make
clothing technology have it much easier to get around.
impacted everyday clothes. Trains, planes, and cars
Breathable fabric, stretchy make the world a smaller
place and allow us to visit
spandex, and thermal exotic destinations. They
underwear were developed are also useful for getting
from specialized sportswear. to school on time.

Turn Bullet trains in
and learn Japan travel up to
300 kph (186 mph).
Health:
pp. 40-41
Electricity:
pp. 76-77

Sputnik 1, launched by the Soviet Union in 1957. 13

Life science

The living world

Our amazing world is filled with millions Dragonfly
of species, or types, of living thing.
They can be as big as elephants

Spider or so small that you have to look
through a microscope to see them.

Animals Micro-organisms

The animal kingdom is Micro-organisms are very tiny –
made up of vertebrates (animals each of them is made up
with a backbone) and invertebrates of a single cell. This
(animals without a backbone). amoeba has been
magnified more
than 100 times.

Coral reef, home Mammals, birds,
to a variety of reptiles, amphibians,
living organisms and fish are vertebrates.

Sunflower

Deer

14

Which group of animals has the most members?

Snake Insects, such as The living world
butterflies, are
Plants invertebrates. Picture detective
Look through the Life
Plants cannot move Science pages and see
around like animals. To if you can identify the
survive and grow, they pictures below.
have to make their own
food. Plants provide food
for many animals and
fungi, too.

Signs of life

Living things share some
characteristics. They all

need food and water. They
also grow, reproduce, and
adapt to their environment.

Fungi Tree frog

Fungi (like toadstools,
mushrooms, and moulds)

are neither plants nor
animals, but they’re more
like plants than animals.

Fungi

Turn
and learn

How plants work:
pp. 22-23

Types of animal:
pp. 28-29

Invertebrates – they make up 97 per cent of all animal species. 15

Life science Petri dish

Micro life Bacterial colonies
Thin hairs attach
Most living things are Each spot on the bacterium to
made up of just one cell, this petri dish a surface.
and are too small to see. is a colony
To study them, we must made up of
use powerful microscopes. thousands
of bacteria.

Bacteria Whip-like structures
push the bacterium
Bacteria are single-celled life forms.
They are found in the ocean, in the along. They spin
air, and even in our bodies. They can round like screws.
reproduce very quickly by splitting
into two. Some bacteria can make
energy from sunlight. However, most
feed on dead plants and animals.

Model of a bacterium

Harmful bacteria The cell is full of a DNA inside the
jelly-like substance bacterium acts
Some bacteria can cause like a control
serious illnesses such as that helps it to centre.
cholera and tetanus. Good work and grow.
sanitation and antibiotic
drugs help fight diseases The cell wall holds the
caused by harmful bacteria. bacterium together
and protects it.

Bacteria may be shaped like rods, Good bacteria
spirals, or spheres.
Some bacteria are helpful
to humans. Bacteria in

our guts protect us from
illnesses. Other bacteria
are used to make foods
such as yoghurt and cheese.

16

How many copies can a single bacterium make of itself in 24 hours?

Micro life

Protective
protein coat

Model of Viruses
a virus
Viruses are much, much smaller than bacteria.
They are shaped like spheres or rods. Viruses
are not really alive, because they are not
made of cells. They only become active
when they invade a cell. They copy
themselves by taking over the cell
and turning it into a virus factory.

DNA or Plant viruses
RNA strand
Plant viruses can change the way
Vaccinations that plants develop. For example,
one virus affects the pigment in
Vaccinations can help to tulips’ petals. It stops the pigment
protect people from harmful
diseases. A person is injected from working in
with a weakened form of some places. This
a virus or bacterium. This makes the petals
prepares the immune system look stripey.
for the real thing.
A virus has
made light
patches appear

on these
leaves.

Harmful viruses The streaked patterns
Viruses can cause on this tulip are caused
different illnesses. by a virus.

Chickenpox is easy to Other tiny cells
catch. The main symptom
is itchy spots. Like bacteria, another
group of organisms called
Rabies is a fatal virus archaea are all single-
that is common in animals celled. There are also some
such as dogs. single-celled organisms,
such as amoebas, algae,
Colds are viruses and can and yeasts, that are closely
bring on a sore throat, related to animals, fungi,
runny nose, and cough. and plants.

Microscope photograph of algae

It can make 4,000 million million million copies. 17

Life science Bread mould

Fungi

Mushrooms, toadstools, yeasts, and Warm,
moist bread
moulds are kinds of fungi. Fungi
Moulds
are neither animals nor plants. They
Moulds are microscopic fungi
feed on living or dead animals or which grow in long strands
called “hyphae”. They feed
plants, and absorb their nutrients.
on dead organic matter – like
Mushrooms our food – by making it rot.

Many fungi are hidden in the soil,
Gills or inside food sources like trees.

They only become visible when
they grow mushrooms.

Stem Mushrooms scatter
spores, which will
grow into new fungi.

The gills release Athlete’s foot
spores into the air.
Athlete’s foot is a disease
Picking wild mushrooms caused by ringworm fungi

Many wild mushrooms are not only edible, growing on human feet.
but also delicious. However, some are highly It makes the skin between
poisonous! Harmful mushrooms are often called your toes turn red and flaky.
toadstools. They sometimes have bright colours
that warn animals not to eat them. Jelly antler fungus

Wood blewit mushroom Fly agaric
mushrooms
Penny bun
mushroom

18

How big is the world’s largest fungus?

Penicillin Fungi

In 1928, the Scottish scientist Penicillin on
Sir Alexander Fleming made a petri dish
an important discovery.
He realized that the mould The bacteria have
Penicillium notatum makes a retreated from the
chemical that kills bacteria. penicillin, leaving
That chemical, called penicillin, a clear ring.
is used today as a medicine
to treat many illnesses. Uses of fungi
Fungi have many
Sir Alexander Fleming (1881–1955) uses in the home
and in industry.
Truffles
Medicinal fungi can
Truffles are strong-smelling be used to cure many
fungi that grow underground. diseases that were
They are a delicacy used once fatal.
in cookery. Truffle hunters Wine is made from grape
use pigs and dogs to sniff juice when yeast turns
them out. the sugar in the juice
into alcohol.
White truffle Yeast
Blue cheese is made
Black perigord Yeast are microscopic, with a mould called
single-celled fungi. When Penicillium roquefortii.
truffle they feed, they turn sugar
into the gas carbon dioxide Soy sauce is made
and alcohol.Yeast plays an by adding fungi and
important part in bread- yeast to soy beans
making. As it releases gas, and roasted wheat.
it makes bread rise. Pesticidal fungi can
be an environmentally
Pig sniffing out mushroom friendly way of killing
insects or weeds.

Shaggy parasol Shaggy cap Common Chicken of the
mushroom mushroom chanterelle woods mushroom
mushroom

A mushroom in the Malheur National Forest, USA, covers 8.9 sq km (3.4 sq miles). 19

Life science

What is a plant?

Plants make their own food from the

Sun’s rays. Most have leaves that reach

outwards to capture sunlight, and roots

that dig deep for nutrients and stability.

Seaweed

Seaweed looks like a

Plant parts plant, but is an alga.

There are lots of different plants. It doesn’t have roots,

But most are made of the same so it has to stick to rocks

vital parts – roots, stems, or float with the tide.

leaves, and flowers.

The petals attract
insects and birds
that collect pollen.

Stems The stamen and
carpels form the
Stems support the leaves reproductive organs
and flowers, and allow of a plant.

water and food to flow from Flowers
the roots to the leaves.
Flowers are key to plant

reproduction. They make

pollen, and develop seeds

and fruit.

Roots Leaves

These are the foundations These are the work factories
of the plant. They dig deep
of the plant and capture the
into the soil, providing
stability, as well as Sun’s energy.

sucking up nutrients. Water lily weird or what?

20 The water lily’s flat leaves The Venus flytrap
float on the pond surface, doesn’t get its energy
as its roots sink into just from the Sun. It
the pond bed. also lures and feeds

on unsuspecting
insects. Yum!

What plant has the largest leaves?

What is a plant?

Types of plant Most conifer
trees keep their
Have a look around you. Not all
plants are the same. But some leaves all
plants are more similar than others. year round.

Fern leaves unfurl Ferns
as they grow.
Ferns love damp and
shady areas. They have
prong-like leaves and
spread using spores.

There are about Conifers The sequoia is
12,000 species of moss. the largest tree
Conifer trees grow cones in the world.

that store their seeds.

Most conifers have

needle-shaped leaves.

Moss

Mosses love moisture Leaves Ash leaf
and grow in clumps.
They don’t have roots You can identify

or grow flowers. a tree by the shape

of its leaves. In most

plants, leaves are

Flowering plants broad and flat.

This is the biggest group of plants. Maple leaf
They produce flowers, fruits and
seeds, which mainly grow in Scarlet
seasonal cycles. oak leaf

Rainforest

These warm and
wet forests are
home to nearly
half the world’s
plant species.

Deciduous

Deciduous plants

shed their leaves to

survive drier seasons.

The raffia palm has leaves that grow up to 24 m (79 ft) long. 21

Life science The Sun’s energy
is trapped in the
How plants work leaves, and helps

Plants have an amazing make food.
system for making
and transporting Cross-section
food to all their of a leaf vein
different parts.

Photosynthesis A waste product Food is moved from leaves
of photosynthesis to roots and growing tips
Leaves have a green pigment is oxygen, which along a set of tubes called
called chlorophyll, which animals need phloem vessels.
absorbs energy from sunlight. to survive.
This energy is used to change Some water evaporates through
water and carbon dioxide tiny holes, called stomata, on
into sugar. the surface of the leaf. This
process is called transpiration.
Veins carry water
around the leaf. Tiny tubes, called xylem vessels,
carry water up the stem from
the roots to the leaves.

Cross-section
of a stem

ound.
Roots suck water up from the gr

22

Are plants the only organism to use photosynthesis?

New growth How plants work

Plants use sugar and starch Desert plants
as fuel. The fuel is transported
to cells where it is burnt to Plants that live in dry
release energy, which is used areas such as deserts have
to grow new cells and repair to save their water. Many
old ones. have leaves that are thick
and covered in wax to stop
Wilting leaves transpiration. Cacti have
spines rather than leaves,
On warm, sunny days, plants and thick stems in which
lose a lot of water from their they can store water.
leaves. If they lose too much,
their leaves collapse. This is
called wilting. If plants don’t
get enough water, their leaves
will shrivel and die.

The fruit acts as
a store of sugar
and water.

Root Storing food

Carrot plants Spare food is stored for future
store food in use. Plants such as hyacinths
store food in the base of their
their roots. leaves. This makes the leaves
swell and form a bulb. The
Bulb bulb survives the winter and
in spring it sprouts new leaves.

weirTdhe or slwughat?

sea

Elysia chlorotica uses

photosynthesis. The slug

eats algae that it doesn’t

fully digest. The remains in

its system continue to

photosynthesize the

food and provide

energy.

No, many bacteria also make food by photosynthesis. 23

Life science

Plant reproduction

Most plants start life as seeds. Stamen Ovary Petal
When the conditions are
right, they start to grow.
As fully grown plants,
they make new seeds
and the cycle starts
again.

Pass the pollen Fertilizing flowers

Pollen plays a vital part A flower has female
in plant reproduction. parts that make eggs,
It looks like tiny pieces or ova, and a ring of
of dust and can be blown male parts, called
from flower to flower. stamens, which make
It also sticks to insects pollen. Seeds develop
and birds and gets when pollen fertilizes
flown to new flowers. the female ova on
another flower. This
24 is called pollination.

Waving in the wind

A catkin is the flower of
the willow tree. In catkins,
the male and female parts

are on separate flowers.
Catkins move in the wind
and release a lot of pollen,

which then pollinates
the female flowers.

Bees carry
pollen in sacs
on their legs.

What is a spore?

Plant reproduction

Fruits and seeds Pear Nectarine
Plum
When a plant has been
fertilized, the ovary swells
up and becomes a fruit.
There are many different
types of fruit. Some are
fleshy and sweet tasting,
and others are dry and hard.

Fig Seeds are enclosed
within a fruit
New life
Scattering seeds
Plants scatter their seeds Seeds contain
in different ways. everything needed
to grow a new plant.
Dandelions have seeds With enough food,
with tiny parachutes that water, and light the
are carried by the wind. seed sprouts a root
and baby stem,
Sycamore seeds have a known as a shoot.
wing that allows them
to glide to the ground. Shoot

Burrs become attached
to animal fur and get
carried far away.

Animals eat fruits Root
and drop the seeds
on the ground.

Seed Seed begins to grow New plant forms

Running away get mucky

Not all new plants grow Make your
from seeds. The strawberry own small garden
plant produces long stems, inside a jar or tin. Fill it
called runners, that grow with some soil, then
along the ground. When plant some seeds. Water
the runner touches the them and watch
ground, a new plantlet
takes root and becomes them grow!
a new plant.

It is similar to a seed and plays the same role in fungi and algae life cycles. 25

Life science

What is an animal?

A key definition of an animal, as opposed to a
plant, is that most animals can move voluntarily.

Animals must also eat other living things
to survive. Let’s take a look at some
of the things animals do.

Bald eagle Food is fuel

Getting around All animals have to find and
Many animals have eat food to survive. Carnivores
muscles, which allow
them to move in a are animals that eat meat.
variety of ways. Herbivores eat mainly
plants. Omnivores are
Birds fly by flapping creatures that eat both
wings or gliding on plants and meat.
currents of hot air.
Squirrels eat seeds, nuts,
Animals like fish swim fruits, and fungi.
by moving their bodies
and fins. What a nerve!

Some snakes wriggle, Animals have
others raise and flatten nerves, which carry
their bodies. information from
their sense organs.
Many animals walk and Most animals
run using their legs. have brains to
monitor this
Sea anemones reach information.
out their tentacles The nerves also
to sting prey. carry orders from
the brain to the
organs and muscles –
such as instructions
to stay still, attack,
or run away!

26

How many species of animal are there on the Earth?

Pythons can go without food What is an animal?
for months after one big meal!
Do animals talk?
Making babies
Many animals are able to
Most animals reproduce when a communicate with each other
female egg is fertilized by a male using either sounds or signals.
sperm. Some animals give birth
to babies, while others lay eggs. Most beetles will send “messages” to other
beetles using special chemicals.

Birds lay hard-shelled Baby birds have to break out Honey bees constantly communicate. They
eggs, which hatch into of the egg on their own. give directions with a special dance.
chicks or ducklings.
Monkeys scream
at each other to
sound an alarm.

Giraffes have seven
vertebrae in their necks –
the same as most other
mammals. They are
just much longer.

Nobody knows, but there are probably about 8 million. 27

Life science

Types of animal

There are many different types, Lizard
or species, of animals. Scientists
put them in groups based on Tortoise
their similar characteristics.
Mammals, birds, reptiles, Reptiles
amphibians, and fish are
vertebrates. Creepy-crawlies Most reptiles have dry, scaly
are invertebrates. skin. They mainly live on land.
Nearly all reptiles lay eggs, but

some give birth to babies.

Mammals

Mammals usually have babies,
which feed on their mother’s milk

when they’re born. Mammals
often have fur on their bodies.

Humans are mammals.

Zebra

Wolf Deer fawn

28 Mouse Lion cub

Which is the only mammal that can fly?

Birds Types of animal

All birds have wings, and Spineless creatures
most (but not all) can fly. Animals without
They have feathers and backbones are called
a beak. Baby birds hatch invertebrates. There
from eggs. are several types
of invertebrate.
Parrot
Insects, spiders, and
Ostriches can run fast Frog crustaceans are part of
but can’t fly. the largest animal group.

Amphibians Snails and slugs are
part of an invertebrate
Amphibians live both in group called gastropods.
water and on land. They
usually have slimy skin. Worms have long,
Baby amphibians hatch soft bodies and no legs.
from jelly-like eggs. They like damp areas.

Jellyfish, starfish, and
sponges are invertebrates
that live in water.

Octopus and squid
live in the sea. They
have eight arms.

Butterfly

Salamander

Fish Insects Ladybird

Fish need to live There are more types
in water. They
breathe through of insect on the Earth than
gills, and most
are covered in any other animal. There are
scales. Fish use
their fins to move species of insects living almost
through water.
everywhere. They have six legs

and bodies with three sections.

The bat. 29

Life science

Animal reproduction

Every kind of animal has young – A mother
this is called reproduction. macaque
Usually, it happens after males
and females mate. holding
her baby

Mammal reproduction

After animals mate, egg cells

develop inside the mother. With

mammals, the eggs develop Helpless creatures
fully into babies before the

mother gives birth. Monkeys and apes need years

inside its mother of nurturing before they can

Znebrealmeopthheraannd tbabdy evelops for two look after themselves.

years!

A Family ties

Elephants look after

their young longer

than any other

animal apart

from humans.

Like all mammal
babies, elephants
drink milk from
their mother.

Turn
and learn

Plant reproduction:
pp. 24-25
Inheritance:
pp. 32-33

30

Which animal lays the largest egg?

Babies from eggs Animal reproduction

Most birds, fish, insects, Change and grow
and reptiles lay eggs. Some animals, like
The number of eggs butterflies, change
they lay can range enormously during
from one to millions! their life cycle.

A baby crocodile hatching A butterfly begins its life
out of its egg as an egg, which hatches
into a tiny caterpillar.

Young and free The caterpillar attaches
itself to a twig and forms
Once hatched in the a hard outer shell.
sand, baby turtles
have to find their own Inside the shell, the
way into the sea. caterpillar changes
and grows.

Pouch babies The shell, which is often
camouflaged, eventually
A female kangaroo has splits open.
a pouch on its tummy.
After it’s born, the tiny A butterfly emerges.
baby crawls into the This process is known
as metamorphosis.
pouch, where
it stays for
around three
more months,
feeding and
growing.

Family ties

Female elephants stay
with their family their
whole lives. Males
leave when they are
around 13 years old.

Male emperor penguins
look after the young
while the females
search for food.

The ostrich. 31

Life science DNA strands carry information. Inheritance

DNA Your genes are a set of chemical
molecules are instructions for building someone just
made of two long like you.You inherit them from your
strands twisted parents, which is why you are like
around each other. them in many ways. But unless you
are a twin, your genes are unique.

Chromosome Tiny cells

Cells are the building blocks that make up all
living things. Each cell in your body contains

a complete set of genes – the information to
make you as you are.

Nucleus

Amazing DNA Membrane

DNA is made of long Chromosomes
molecules. Each molecule is
made up of two parts joined Your genes are organised into
together like a twisted rope ladder.
DNA carries instructions on how to 46 chromosomes, arranged in 23
make cells work, and how different types
of cells develop and join together to build pairs. Genes and chromosomes are
a living thing, such as a plant or animal.
made from the chemical called DNA.

What is a gene? of genes.You’ve got two of each
gene, one from your mother and
Every cell in your body contains one from your father. Sometimes
a set of about 20,000 genes. the gene from your mother comes
All living things pass on their into action, and other times your
genes to their offspring. Sexual father’s gene wins out.
reproduction combines two sets

You can only roll your tongue
if the right genes are active.

32

What does DNA stand for?

Inheritance

Colour blindness

Some people have a gene which causes
them to be colour blind. Look at the
circle below. If you can see the number
inside then you aren’t colour blind.

Test your Seeing double
family and
friends to Identical twins share most of their genes.
see if anyone A quarter of these are mirror twins, which
you know is means that they are a mirror image of
colour blind. each other. For example, they might have
an identical mole, but on the opposite
arm to each other.

Who do you look like? The chromosomes of Turn
your father determine and learn
Children have a mixture of genes whether you will be
from their parents. This is why a boy or a girl. Animal
you might have your mum’s reproduction:
eyes but your dad’s smile!
pp. 30-31
Health:

pp. 40-41

This child has
inherited her hair

and skin colour
from her mother.

Deoxyribonucleic acid. 33

Life science Skull

Bones and muscles

You would be like a lump of jelly without Ribcage
your skeleton – a frame of bones
that holds you up and protects
your internal organs.

The vertebrae Bending Backbone
in your back backbone
allow you to The wrist is
twist and bend. Your backbone made up of
contains 24 small eight small
bones called bones.
vertebrae. They
Cranium
move almost
every time
you do.

Head case The hip is a
ball and socket
The bones that make up joint, allowing the
your skull join after you legs to move around.
are born. The skull has
two parts – the lower jaw Lower jaw
and cranium. Only your
The honeycomb
jaw can move. structure of
some bones
Bone marrow makes them
supplies your weigh less
body with red than if they
blood cells. were solid.

Both the knee and elbow are hinged
joints that only move in one direction.

Brilliant bone Ribcage

Bones have a clever A ribcage has
long, curved bones
structure that makes them Snake ribcages that protect vital
organs such as the
light but strong. They can can run almost heart and lungs.
the entire
heal themselves if broken.
length of

their bodies.

34 How many bones does an adult human have?

Bending bits Muscle magic The pectoralis Bones and muscles
Different kinds of joints muscle moves
all over your body keep Muscles are rubbery, Biceps and
you moving. stretchy straps.You your arm at triceps bend
can control some of the shoulder. and straighten
Fingers and thumbs your muscles, like the your arm.
have joints that allow muscles in your arms
them to move in and legs. Others,
many ways. such as your heart
and bladder, operate
Ankles contain different without you having
joints for up-and-down and to think about it.
side-to-side movement.

Wrists have a joint that
allows them to turn but
not go all the way round.

Neck bones feature a
pivot joint that allows
your head to turn.

Making faces The tibialis
muscle bends
Muscles in your face are
attached to skin as well as your foot.
bone. They allow you to
make all kinds of expressions Pulling pairs
to show how you are feeling.
Muscles can pull
but they can’t push.
They work in pairs
that pull in opposite
directions.

The biceps
contract to pull
the forearm up.

The triceps relax
and stretch when
the biceps contract.

There are 206 bones in an adult skeleton. 35

Life science

Blood and breathing

Every few seconds you breathe in air.
Inside your lungs, oxygen from the air
passes into your blood, which then
carries the oxygen all round your body.

Liquid of life Transport system Arteries
Blood is made up of
three types of cells Blood travels around our Heart
floating in plasma. body in tubes called blood
vessels. The vessels called
Red blood cells, the arteries (red) carry blood
most common type of away from your heart.
blood cell, carry oxygen. Vessels called veins
(blue) carry blood
White blood cells, which back to your heart.
are part of the immune
system, fight disease.

Platelets help to Veins
repair broken skin
and blood vessels. Blood to all
parts of body
Your beating heart
Blood to
Every time your heart left lung
beats, it pumps
blood around your The left-hand
body. Half of the pump squirts
heart sends blood blood to the
through your organs and
lungs. The other muscles.
half sends blood
around the rest
of your body.

Blood from
right lung

The right-hand
pump sends blood

to the lungs to
receive oxygen.

Blood from legs and feet Blood to legs and feet

36 How many times does a child’s heart beat every day?

Blood and breathing

Lungs

Your lungs fill most of the space inside
your ribcage. They take in oxygen
from the air and send out waste
carbon dioxide.

No lungs

Not every animal has lungs.
There are other ways
animals breathe.

Nostril

You breathe
through your nose

or your mouth.

Mouth

Tooth

Frogs can absorb oxygen
through their skin – even
underwater.

Insects such as caterpillars Your lungs are like The muscle under
breathe through body sponges. They are your lungs is called
openings called spiracles. full of tiny channels the diaphragm. This
and chambers. moves up and down
Many sea creatures such as to make you breathe.
sharks breathe through gills.

A child’s heart beats between 130,000 and 170,000 times a day. 37

Life science

The digestion ride

Take a ride down your digestive
system as it breaks down your
food to take out the nutrients
and get rid of waste.

Mouth Oesophagus

First stop is the mouth. Saliva
moistens the food to make it easier
to chew and swallow. Food then heads
down the oesophagus to your stomach.

Stomach

In your stomach, muscles
churn the food around.
Stomach acids help
turn it a semi-liquid
before it is squirted
into the intestines.

Liver

Your liver stores some
vitamins and a sugar
called glucose, which
gives you energy.

Intestines

Your intestines are
a long, tangled tube.
The small intestine
absorbs food into
your bloodstream.
The large intestine
deals with
undigested
leftovers.

38

Which is longer, your small intestine or your large intestine?

Super system The digestion ride

Cows have an amazing Food for health
digestive system. You need to eat a variety
There are four parts of foods to keep your
to a cow’s stomach. body working efficiently.
Each one performs A good diet includes
a different function a balance of food
to make sure food is from each of the
digested and used in five food groups.
the most efficient way.
Cows need this system Carbohydrates, found in
to help them digest food such as bread, cereal,
tough grass. and potatoes.

Stone eaters Fats, which can be found
in food such as oils. Fats
Some birds eat grit. give you energy.
The tiny stones help
digestion by breaking Proteins, which can be
found in eggs, fish, meat,
down food in the dairy products, and nuts.
bird’s stomach.
Minerals such as iron and
Kidneys calcium. Iron is found in
some green vegetables.
Your kidneys filter and
clean your blood, taking Vitamins such as vitamin
out the chemicals that C are found in fresh fruit
your body doesn’t need. and vegetables.
Kidneys also control
the amount of water weird or what?
in your blood.
Humans taste with
Waste disposal their tongues – but other

Solid waste from the large animals have different
intestine is stored in the methods. Butterflies
rectum, and urine is stored
in the bladder, until you are use their feet!
ready to go to the toilet.
39
Your small intestine.

Life science

Health 5-a-day

Our way of life affects our health. You need to
Eating properly, exercising regularly, eat at least five
and getting enough sleep are all portions of fruits and
vegetables each day.

important for staying happy and fit.A balanced diet Fruit and vegetablesThese foods proTvhideey yhoeulpwtoithprveivtaenmtinysouanbdecmoimneinrgalsilla. s well as fibre.

It is vital to eat a balance of the

right foods. There are five major

food groups and they all help

your body in different ways.

sdhaioluylddiemt.akepulses

ocfellyso.uIrtand
damagedish,

per cent
Proutpeianbroeuptair1s5Meat, f
Drink up!
shiotrnsantshpeorotrsgsaonsmienviytoaurmibnso.dyats and sugarsFaantdcuF
We can last
quite a long time mwiutshclcesa.lcium,Dairy productsaynodu
without food, but fporrodbuocntess,prteoevitdh,e and dairy
not without water. You need to drink water necessary Milk
Water helps to frequently each day or
digest food and you will dehydrate.
flush out waste.
Low water levels Which vitamin do we get from sunlight?
(dehydration) can
cause headaches,
dry skin, and
tiredness.

40

Health

Ideally, children Keeping clean
should be getting Dirt contains harmful
about 60 minutes bacteria. Keeping clean
of exercise a day. helps you stay healthy.

Swimming is a good way of Brush your teeth in the
exercising all your muscles. morning and again before
you go to bed.

Wash off the dirt with
regular baths or showers.

Exercise Wear clean clothes,
especially clean pants
Exercise strengthens the and socks, each day.
muscles and heart, and
encourages the production
of special chemicals called
endorphins. These make
us feel good and act to
reduce pain.

Many childrenCaFooydosuirnbtohdisygernoeurpgyin. cTluhdeyeRead a book!
relax more easilybread,
into sleep with a Health is not just about your
special, cuddly toy.rboshould body; it helps to have an
hydpmaasktae, active mind. Reading is
ratesuapndjusptootavteoreas. Sleep a good activity because
it stimulates your brain.
es purrovdiiedte.tChiardrboofhyydorat When you sleep, your body rests
and your mind refreshes itself. Turn
When you are young, you need and learn
a lot of sleep, but you need less
as you get older. Muscles:
pp. 34–35
A child needs Digestion:
between 10 and pp. 38–39
12 hours sleep
a night. 41

Vitamin D, which is important for strong bones.

Life science 5 Decomposers

Food chains At the start and end of every food
chain there are decomposers, such
Everything in the living world as earthworms, fungi, and dung
needs food to survive. And beetles. They help break down dead
everything must feed animals and plants, releasing the
on something else.
This is called a nutrients back into the soil.
food chain. Each
species is part of
several different
food chains.

1 Producers

Plants, such as acacia
trees and grasses, get
their energy from the
Sun. They are known
as producers.

2 Herbivores

Herbivores, such as
impala or zebra, eat
the plants. They do
not eat meat.

42

What carnivorous plant catches and eats flies and spiders?

4 Scavengers Food chains

Dead meat is known as Sea food
carrion and is eaten by
scavengers such as hyenas, The further you go up the
vultures, and bald eagles. chain, the fewer animals there
These creatures rarely are. So, in the sea, there are
kill for food – they find countless plankton, fewer fish,
animals that have died just a few seals, and fewer
of natural causes and eat polar bears.
other animals’ leftovers.
Polar bear
3 Carnivores
Seals
Carnivores only
eat meat. On the
African plains,
carnivores include
lions, leopards,
and cheetahs.

Fish

Zooplankton

Phytoplankton

A Venus flytrap. 43

Life science

Ecosystems

All over the world, living things
exist in distinct kinds of places
called ecosystems. Each has its own
climate, soil, and complex community
of plants and animals. Oceans and
deserts have their own ecosystems.

Natural variety

There are different ecosystems all over the world, and the
animals and plants in each one are adapted to its conditions.

Forests

Wherever there is enough rain,
forests grow, and they provide
homes for a huge range of
plants and animals.

Homes, sweet homes Oceans

One ecosystem contains a More than 70 per cent of the
number of habitats. A habitat Earth’s surface is covered by
is the natural home of a oceans, which contain many
particular plant or animal. different habitats.
A tree, or even a leaf, can
be a habitat. Rivers and lakes

Freshwater ecosystems exist in
pools, lakes, rivers, and streams.
They are found over most of the
world’s land surface.

Turn Polar and tundra
and learn
The freezing polar lands are

Animal survival: at the far north and south of the

pp. 46-47 Earth, in the Arctic and Antarctic.
The carbon cycle: At the edges farthest away from
the poles, they merge into
pp. 50-51

warmer tundra areas.

44

What are the different types of forest ecosystem?

Mountains Ecosystems

Climate conditions change Trees offer shelter for
as you go up a mountain, animals, and food in
so different ecosystems can
exist here. the form of leaves
and berries.
Seashores
Insects feed on
Seashore ecosystems are flowers, and
half land and half sea. pollinate them
They change as the tide at the same time.
comes in and out.

Grasslands

Humans evolved in grassland
habitats. Today, the largest
and fastest land animals
live here.

Deserts

They can be hot or cold, but
deserts are always dry, with
little rain. Only a few animals
and plants survive here.

Living together

A group of living things in a
habitat is called a community.
Each one contains plants,
animals, and other organisms

that all rely on each other.

Frogspawn hatches Rotting leaves and Snails feed on the Ferns grow Frogs, which eat
into tadpoles. Some wood are home to leaves of plants, and absorb insects, live both
of these are eaten fungi and small and provide food nutrients from on land and in
by other water animals, such as for other animals. the soil. the water.
creatures. beetles and slugs.
45
Tropical rainforests, deciduous woodlands, and cold, coniferous forests.

Life science

Staying alive

In order to survive, all animals
and plants need food, water,
shelter, and space. Each type
of animal or plant has its own
particular way of finding them.

Let’s stick together Camouflage

Clownfish and sea anemones On the grasslands
live together and help each of Africa, lions try
other (symbiosis). The sea to creep up on their
anemone’s tentacles can prey. They can hide
sting most fish, but the in the long grass
clownfish don’t get hurt. because they are the
same colour. This is
called camouflage.

Long-eared bat
eating a moth

Night hunter

Some animals hunt for food

at night. The long-eared bat uses

sound to find insects in the dark.

It makes a squeaking noise and

listens to the echo as the noise

A huge worm is bounces back off objects. It can
enough food to keep tell exactly where an insect is.
a shrew going for
only a few hours. All-day hunter

Some animals have to

hunt for food day and

night. Shrews need to

eat 80 to 90 per cent

of their body weight

every day to survive.

These animals are

tiny, but aggressive.

46

A tapeworm is a kind of parasite. Where does it live?

The tiny Arctic tern Staying alive
makes a long migration.
Parasites
It flies between the
North and South Some organisms, called
poles each year. parasites, live on or
inside the bodies of other
organisms, which they
feed on. Caterpillars live
as parasites on plants.

Great travellers A wasp has laid eggs on this caterpillar.
The grubs that hatch out will feed on
When food and water become the caterpillar as parasites.
scarce in one place or the weather
gets too cold, animals may move An elephant eats for about 16 hours each day.
home (migrate). Some animals
migrate once every year.

Pack of wolves

Wolves live and
hunt in groups called
packs. This is safer
than living alone, and
makes it easier to hunt
larger animals.

House builders
Many animals build
homes for themselves
to provide shelter
from predators
and bad weather.

Birds make nests out of
mud or twigs, often hidden
away in trees or bushes.

Rabbits and badgers Big hunger
use burrows dug into
the soil. Elephants have big
appetites. A hungry
Beavers pile up sticks in elephant will push over
rivers to make a nest with a whole tree and eat
an underwater entrance. every leaf and twig
to satisfy its hunger.
Wasps chew up wood to
make soggy paper, which
they then shape into nests.

Inside the human body, feeding on food you’ve swallowed. 47

Life science At night, plants take
in oxygen and give
The Earth’s cycles out carbon dioxide.

Everything in nature is recycled. Living things CARBON DIOXIDE
take in oxygen, nitrogen, carbon, and water OXYGE N
and use them to live. When they die and
decompose, the substances they are
made of are used again.

Nitrogen cycle

All living things need nitrogen. Plants
take in nitrogen from the soil. Animals
get nitrogen from eating plants. When
animals and plants die, they put
nitrogen back into the soil.

Certain bacteria play an important role in Nitrogen is
the nitrogen cycle. They change nitrogen abundant in
into the form plants can use. Without our atmosphere.
bacteria, plants would
die of nitrogen
starvation.

Bacteria Decaying animals
and plants put
Other bacteria nitrogen back
take in nitrates and into the soil.
release nitrogen back
into the atmosphere.

Animals eat plants,
which contain nitrates.

48

Is there more oxygen or nitrogen in our atmosphere?