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Chapters start with ‘understand’ or ‘good’
and progress to the more difficult material
in ‘master’ or ‘expert’.
Challenging questions
have hints to help you –
see next page.
The number in brackets tells you how
difficult the question is. It is the Level
in the English National Curriculum.
The pictures are
as important
as the words in
helping to explain
the Big Idea.
Early questions
get you to
summarise and
practise using
the idea.
The top part of
a page connects
to what you
already know
about the topic.
Bold words are
key scientific
terms. To avoid
cluttering the
page, they are
described in the
glossary at the
back.
Later questions
test your
understanding
more.
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Get Science Contents
The Big Ideas
Page Page
1 Explanations
Adaptation 6 Forces 53
Behaviour 9 Geological time 58
Cells 11 Magnetism 60
Changing atmosphere 18 Microbes 63
Chemical patterns 22 Models 67
Chemical reactions 26 New life 70
Classification 30 Particles 73
Drugs 32 Solar system 81
Dynamic Earth 34 Theories 85
Electric current 37 Universe 87
Energy resources 41 Voltage 90
Energy transfer 44 Wave energy 93
Food webs 49 Weathering 98
2 Applications
Decision making 101 Technology 103
3 Communication
Collaboration 105 Interrogator 110
Communicator 107
4 Investigation
Safe experimenter 113 Planner 118
Hypothesiser 115
5 Evidence
Analyser 120 Reasoner 125
Evidence checker 123
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Y7
Y8
Get Science Contents
upd8 units
Unit Sequence Page Unit Sequence Page
A&E Blood 11 Electromancer Watcher 37
Birth 70 Seeker 60
Machines 103 Weaver 118
Therapy 85 Knower 90
Alien Far-side 53 Extinction Mammoths 18
Contact 120, 125 Apprentice 107
Probe 81 Polar Bears 6
Spore 87 Turtles 30, 9
Cook Hot stuff 44 Forensics CSI files 113
Ice-cream 73 Fake 73
Pancakes 26 Cold case 123
Inside story 67 Abduction 22
Unit Sequence Page Unit Sequence Page
Catastrophe Evacuate 105 Pyrotechnics Skycolour 73
Etna 34 Burn 26
Damburst 98 Human torch 113.115
Hobbit 58 Reveal 22
Live & kicking Academy 11 Species at war Disease 63
Mucus 118 Pandemic 67
Wasted 32 Paradise island 49
Expo 123 Big science 103
nViz 2050 18, 85 Studio magic Drummer 93
Music 44 Venue 125
SimEnergy 41 Plug-it 110,107
Leaders 101 Festival 93
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Extras at Getscience.org.uk11
Cells 1 ...understand
upd8 Link A&E > Blood
What keeps you alive?
Mary (58) pale, no pulse A lungs F skeleto-muscular K glucose drip
Dylan (19) back pain, can’t move B intestines G nervous L restart heart
Kasia (10) blue, hardly breathing C bone H respiratory N pin bone together
Jack (2) weak, keeps being sick D heart I digestive N keep patient still
Sam (32) arm broken E nerves J circulatory O clear airways
Symptoms System affected Treatment
Tissue/organ
damaged
If your heart stopped, your circulatory
system couldn’t move blood through other
organs. Delivery of oxygen and glucose
would cease and you’d die.
With no brain to control
your nervous system, you’d
be paralysed and unconscious.
Without lungs, your respiratory
system couldn’t get oxygen into your
blood, or remove poisonous carbon dioxide.
If your intestines
stopped working, your
digestive system
couldn’t bring nutrients
like glucose into your
blood, so you’d starve.
If the muscles and bones in your
skeleto-muscular system seized up,
you couldn’t move; and a fractured skull or
ribs wouldn’t protect your most vital organs.
1 Summarise:
Our bodies are made of many different ___. If any get ___ we could die.
2 Exemplify:
Think of an organ system not shown on this page. Why is it important? (L4)
3 Use the idea:
Match each casualty’s symptoms to the correct letters from the other columns.
Describe how serious each patient’s condition is, and explain why. (L4)
Got it?
Preview

Extras at Getscience.org.uk
12upd8 Link AE Blood
Inside organs
Got it?
1 Summarise:
Your organs are made of ___ and your tissues are
made of ___. These cells do the jobs that make your
___ work. To stay warm and ___, they need
to transfer energy from ___ and ___.
2 Use the idea:
Which two students don’t understand the
Big Idea of cells? Correct their sentences. (L4)
Maria: We have cells in some organs.
David: Cells get energy by taking in glucose.
Kasia: Each sort of tissue is made of different
cells with different jobs.
3 Explain:
a When you run, your circulatory system needs
to send more blood through your leg muscles.
Explain why. (L4) Hint?
b How does the composition of
your blood change as it flows past
your brain cells. (L4) Hint?
c Mr Evans had a stroke, which means
a clot blocked a blood vessel in his brain.
One side of his body is now paralysed.
Yes! Unlike their pictures, real cells are warm and active.
1000s of chemical reactions take place inside them. They
convert nutrients from your blood into spare parts for
growth and repair. All this takes energy and cells get it
by reacting glucose with oxygen.
Are cells actually alive?
To make this happen, millions of these
tiny compartments must make themselves
shorter. They are your heart muscle cells.
...you’d see its muscle
tissue squeezing.
Imagine zooming into
your beating heart...
In your brain, millions of
nerve cells like this pass
messages to each other.
Cells make your
brain tissue active.
So you can sense things,
think, and decide which
muscles to move.
glucose
and oxygen
from blood
skin cell
carbon
dioxide
and
water
Preview

upd8 Link AE Blood
Long, thin nerve cells like
this carry messages from
your spine to muscle cells
up to a metre away.
Why do cells look different?
Giant fat cells store
nutrients, and add them to
your blood when you
need them.
Tiny, flexible red blood
cells squeeze through narrow
blood vessels to bring oxygen
to every cell.
1 Summarise:
Cells have different
shapes and ___ so
they are suitable for
different ___.
2 Deduce:
Use the structures of each
of these cells to match
them to jobs D-F. (L4)
3 Explain:
Each of these cells has
100s of tiny hairs on top
of it so it looks like a brush.
This brush of hairs keeps
bending, and sweeping from
left to right. What job could
these cells be specialised
to do? Explain why. (L5) Hint?
4 Solve:
Read the description below and
decide what job the cells do. (L5) Hint?
‘These cells keep dividing. New cells
push older ones upwards and cut off
their blood supply. Before each cell
dies it turns everything left inside it
into a hard protein. As the dead cells
pile up, they make a solid plate.’
B This cell produces a jelly
which slowly turns hard.A When this cell’s
hairs vibrate, it
sends a signal to
the nerve below it.
Specialist jobs
D Build bones.
E Take nutrients out of your intestines.
F Detect sound.
C The fringes on
these cells let
them absorb
chemicals quickly.
Got it?
Preview

Extras at Getscience.org.ukupd8 Link AE Blood
Inside cells
skin
leaf
What if cells get damaged?
Every cell takes in supplies, carries out reactions
and releases energy. Whatever its shape or size,
it uses the same structures to do these jobs.
Your brain and heart cells can last a
lifetime, but skin cells wear out and
need replacing. Cells make more cells
by splitting into two. Some cells can’t
divide, but stem cells keep dividing
to replace the damaged ones.
1 Summarise:
All cells are ___ from the same components,
but plant cells have extra structures to
provide ___ and let them make ___. Some
cells can copy their contents and split into
two ___ cells. Those that can’t, are replaced
by ___ cells.
2 Recall:
Name the cell parts that do each
of these jobs. (L3)
a Let in glucose and oxygen.
b Make food.
c Release energy.
d Support a plant cell. (2)
e Build new cell parts. (2)
3 Explain:
a Jen cut her finger last week, but it looks fine now.
How did she get more cells to repair it? (L3)
b In diagrams, animal and plant cells are
easy to tell apart. With photographs, like
the one on the right, it’s more difficult. (L4)
i What makes it look like an animal cell?
ii What makes it look like a plant cell?
iii Suggest why plants might not have
chloroplasts in every cell.
c Red blood cells have no nucleus and their
cytoplasm is full of red protein, which they use
to carry oxygen. Suggest why they cannot divide.
(L5) Hint?
Got it?
14
cytoplasm
where chemical reactions
make new cell parts
chloroplasts
which absorb
sunlight and let
plants make
their own food
a vacuole
for support
a cell wall
for support
a membrane
to control what goes
in and out
a nucleus
to store genes, which are
instructions for building cells
mitochondria
where energy is released
from glucose and oxygen
Preview

Changing atmosphere 1 ...understand
upd8 Link Extinction Mammoths
Got it?
Why worry about climate?
1. Summarise:
The climate is the usual pattern of ___ and rainfall.
When the climate changes, living things can find it
harder to ___.
2. Exemplify:
a Name an animal that has been made extinct by
climate change recently. (L3)
b Why did the climate change make it harder for the
animal to survive? (L3)
3. Recall:
The temperature is different everywhere, so
scientists work out an average. How has Earth’s
temperature changed in the past? (L3)
4. Explain:
a Some people think mammoths went extinct
because their woolly coats made them too hot.
Explain another reason why a warm, wet
climate could have made them die out. (L4)

b Sabre-toothed tigers were fierce predators. They
also became extinct at the end of an Ice Age.
Use the ideas about climate change to
suggest why they did not survive. (L5) Hint?

c Earth has been hotter in the past than it is
today. Explain why scientists worry about rising
temperatures. (L5) Hint?
Around 10,000BC,
an ice age ended and
the climate got warmer
and wetter. That was
bad news for this
animal.
Earth’s temperature is
always going up and down.
But most extinctions have
happened after the climate
warmed.
Mammoths ate
grass, but climate
change let trees take
over the grasslands.
Lack of food pushed
mammoths towards
extinction.
In 2004, golden toads were declared extinct.
They had all died. Why?
Their forest home became warmer and drier. Ponds dried up
and their tadpoles couldn’t hatch. So climate change made
them extinct. That’s happened many times before in Earth’s
history.
Mass extinctions
Millions of years ago
500 250 today
Temperature
Preview

upd8 Link Extinction Mammoths
Got it?
Past, present, future
1. Summarise:
Carbon dioxide is a ___ gas. It helps keep the Earth
at a suitable ___ so that life can exist. By studying
past changes, we can ___ what might happen in the
future.
2. Recall:
The amount of water vapour in the atmosphere
varies. List the other gases in the atmosphere with
the one there is most of first. (L3)
3. Deduce:
a How have temperature and carbon dioxide
levels varied in the past? (L5) Hint?
b How similar are the changes in temperature
and carbon dioxide levels? (L5) Hint?
c Explain why James Hanson is worried about
present carbon dioxide levels. (L5) Hint?
d Explain how scientists measure past levels of
carbon dioxide. (L5) Hint?
Scientist James Hansen believes that his
grandchildren face climate chaos if we keep putting
more carbon dioxide in the atmosphere. His argument
is based on past climates.
Scientists discover past carbon dioxide levels by
digging out ice buried for thousands of years. Trapped
air bubbles show what the climate and atmosphere
were like when the ice formed.
Carbon dioxide is a very small part of the
atmosphere, but very important. It’s one
of the ‘greenhouse gases’. Without them,
Earth would be too cold to live on.
Argon 1%
Carbon
Dioxide
0.04%
Oxygen
21%
Nitrogen
78%
400 200 0
Thousands of years before now
carbon dioxide
temperature
Present carbon
dioxide levels
The graph shows that carbon
dioxide levels are higher
now than they have
been for the past
400,000 years.
Preview

upd8 Link nViz 2050
Got it?
Out of balance?
1. Summarise:
Carbon dioxide is added to the ___ by both
natural and ___ activities.
2. Exemplify:
Describe how natural and human activities
affect atmospheric carbon dioxide. (L4) Hint?
3. Explain:
a Calculate the total carbon dioxide
human activities release each year. (L4)
b How much do natural sources release? (L4)
c Why do scientists worry more about
CO2
from human activities? (L5)
d What consequences could there be if CO2
levels continue to rise? (L5)
In this toy, many things work together to keep the balance.
It’s the same with the carbon dioxide in the atmosphere. But it
only takes one change to cause problems.
Animals breathe out CO2
and volcanoes add more.
Plants absorb CO2
and
use it for photosynthesis.
Human activities like
deforestation and burning
fossil fuels release extra
carbon dioxide.
Until recently, the
CO2
going in and out
of the atmosphere was
balanced.
Now we
have upset
the balance.
Earth’s oceans can absorb part
of the excess, but not forever.
Temperaturerise
(°C)carbon
dioxide
CO2
To predict future climates, scientists use computer models.
They show that extra greenhouse gases, like carbon
dioxide, methane and water vapour, will cause global warming.
Preview

Changing atmosphere 2 ...master
upd8 Link nViz 2050
Got it?
The greenhouse effect
1. Summarise:
To stay at the same temperature, Earth must emit as
much energy as it ___. Solar ___ can
get through the ___, but some of the ___ Earth
emits is absorbed by ___ gases.
2. Deduce:
Sam beamed infra-red radiation into a jar of air and
a jar of carbon dioxide. An hour later the carbon
dioxide jar was much warmer.
3. Explain:
a Explain why Earth’s temperature doesn’t usually
change much. (L5) Hint?
b Use a model to explain how CO2
can
make Earth’s temperature rise. (L6) Hint?
c The amount of CO2
we release is rising faster
than ever. Explain why. (L6) Hint?
d Roger doesn’t understand how a little bit
of extra CO2
could warm the Earth. Write a
step by step explanation that he can’t fail to
understand. (L7) Hint?
If you’re warm, you take your jacket off and cool down.
Earth has a jacket too – the greenhouse gases in the atmosphere.
That jacket is getting thicker every year - and we can’t take it off.
Earth could soon get very uncomfortable to live on.
Greenhouse gases are
spread all through the Earth’s
atmosphere. The more we add,
the more energy they trap...
...so Earth absorbs more than
it emits, and its temperature
rises.
Deforestation means less
carbon dioxide is absorbed.
So levels are rising faster
than ever.
As Earth’s population increases we use more energy, burn
more fossil fuels and release more carbon dioxide.
greenhouse
gases
solar
energy
in
energy
absorbed and emitted
energy
trapped
infra-red
radiation
out
atmosphere
warms
Preview

Got it?
Dynamic Earth ...understand
Journey to the centre
of the Earth
In a famous story, a scientist falls down a volcanic pipe, and finds
prehistoric life. In reality, the Earth is solid. But if you could fall
through the planet, you would travel
through three different layers.
A volcanologist predicts
eruptions and whether they will
send out lava, gas or ash.
Summarise:
Earth has 3 layers: the ___ , ___ and ___ .
The core is hot. Convection carries ___ up
through the ___ towards the crust.
In places, the mantle melts to form ___.
If this breaks through the crust, it becomes ___.
Compare:
Which is hottest, the core or mantle? (L4)
How do magma and lava differ? (L4)
How do ash, gas and lava differ? (L4)
Deduce:
Why does magma solidify faster if it flows
into a lake? (L5) Hint?
No-one can stop a volcano erupting. How do
volcanologists reduce the number of deaths
volcanoes cause? (L5) Hint?
A volcanic eruption often affects more than one
country. Suggest why. (L5) Hint?
Food crops grow well in soil that contains volcanic
ash. Suggest a possible problem that could cause.
(L5) Hint?
upd8 Link Catastrophe Etna 34
1.
2.
a
b
c
3.
a
b
c
d
High temperatures and
huge pressures make the
solid rocks flow like liquids.
They carry heat upwards
by convection and
make volcanoes
possible.
Crust
1) The crust passes by quickly.
It’s just a thin skin of rocks.
2) Most of your journey is through
the mantle. The temperature is
unbearable - over 3000o
C.
Some rocks have melted,
to form magma. This
lies just below the
crust, ready to
shoot out of
the Earth
as lava.
Mantle
3) Finally, you reach the
source of Earth’s heat, a
core made of molten iron.
Its temperature is over 5000o
C
Core
Preview

Dynamic Earth ...understand
35upd8 Link Catastrophe Etna
Rock detective
Got it?
Summarise:
Volcanoes bring magma to the surface to
form ___ rocks. The size of their ___ tells
us how fast they cooled. ___ rock forms
when heat and ___ change existing ___.
Compare:
Describe the differences between:
The crystals in granite and basalt. (L4)
The crystals in granite and slate. (L4)
Igneous and metamorphic rocks. (L4)
This is where rocks are born, out of the fire of a volcano.
By examining a rock carefully, you can deduce how it formed.
This is basalt. It has tiny crystals.
This means it turned to solid quickly.
It must have formed on the surface,
where it could lose
heat quickly.
Deduce:
What sorts of rocks are these?
Gneiss – dense and hard, with layers. (L5)
Obsidian - non-porous with microscopic crystals. (L5)
Gabbro – has large, attractive crystals. (L5)
Explain:
Why does granite cool slowly? (L5) Hint?
What makes a rock metamorphic? (L5) Hint?
Why are metamorphic rocks non-porous? (L5) Hint?
1.
2.
a
b
c
3.
a
b
c
4.
a
b
c
Igneous rocks, like basalt and
granite, have interlocked crystals,
which makes them hard. Water can’t
get through, so they are non-porous.
Deep underground, limestone and mudstone were heated by ris-
ing magma and squeezed, which changed their structure.
Marble and slate are dense and hard,
and slate has layers. They were not
made by cooling lava. They are
changed or metamorphic rocks.
slatemarble
limestone mudstone
HEAT
PRESSURE
This is granite.
It has large crystals.
They form slowly, so
it must have taken
longer to cool. It solidified
inside the crust, insulated by rock.
Preview

Low
Density
High
Density
Gas bubbles break up
erupting magma,
to form huge
ash clouds.
upd8 Link Catastrophe Etna 36
Dynamic Earth ...master
Countdown to disaster
Got it?
Summarise:
Volcanoes erupt when molten _____ rises up
through the ____ and breaks through to
the surface. Ash, ____ and ___ escape
and can change the appearance of the ____ .
Explain:
What makes magma rise? (L5) Hint?
Why do gases escape? (L5) Hint?
How is volcanic ash made? (L5) Hint?
Deduce:
What can you tell about
the lava that produced
this volcano? (L6) Hint?
Explain:
In the past, a giant volcanic eruption killed most
plants and animals on Earth. How could it affect
every continent? (L6) Hint?
Why is the rock on the sides of a volcano in layers?
(L6) Hint?
Why do volcanologists need to know how viscous
new lava is? (L6) Hint?
Predict:
When magma cools suddenly it shatters like glass.
When water boils it produces clouds of steam.
Imagine a volcano erupting under a glacier. Suggest
what damage the volcano could do. (L7) Hint?
What signs might indicate that a volcano was about
to erupt? (L7) Hint?
It looks innocent from above,
but this volcano is about to erupt.
1.
2.
a
b
c
3.
4.
a
b
c
5.
a
b
Dissolved
gases explode
out of the
pipe, like fizz
from a bottle.
Magma is
less dense
than solid
rock, so
it rises.
Lava flows
Runny lava flows
fast and travels a long
way before it solidifies.
It forms gently
sloping cones.
Thick, viscous,
lava flows slowly.
It forms a
steep cone.
The pipe feeds magma to the surface
through a weak spot in the crust.
Preview

Forces ...understand
upd8 Link Alien Farside
Got it?
What can forces do?
1. Summarise:
Forces can make an object change its shape, ___
or ___. We use ___ to show their ___.
2. Use:
A skateboard is sliding downhill. You try to
stop it. Sketch the skateboard and add an
arrow to show the force you applied. (L4)
3. Predict:
Suppose Venus hit the ball even harder.
What difference would that make to the
racket and the ball? (L4) Hint?
4. Deduce:
When this carriage
got to the bend it
changed direction.
A force from the track made it turn.
Which arrow shows the force correctly? (L4)
5. Compare:
How does the
distance from
Earth affect
a satellite’s
speed? (L5)
Forces can slow things
down too. The arms of
the tackler pull backwards
to stop the player in his
tracks.
Instead of changing speed, a force
from the side makes the female skater
change direction and move in a circle.
Venus Williams is one of the
fastest servers in history. The
strings of her racket push the ball
with great force. It speeds up to an
amazing128mph (206km/hr).
Not all forces rely on contact.
The invisible pull of gravity is what
makes the Moon circle the Earth.
Gravity keeps any satellite in a circular
orbit, if its speed and distance are right.
fast
slow
medium
gravity
a force towards
centre of Earth
pull
Preview

Got it?
Combining forces
1. Summarise:
If the forces on an object are balanced it will stay at
the same ___. If they are ___ its speed will change.
It gets faster if the forward force is ___and slower if
the ___ force is bigger.
2. Exemplify:
a Draw this airship and add
arrows to show the forces
that make it move at a steady speed. (L3)
b Add another pair of arrows to show that
it is also rising at a steady speed. (L4)
c On a second airship, draw forces that would make it
go faster and faster. (L4)
3. Use:
A boat is crossing a lake. The wind pushes with
a 500 N force, but there is 300 N of friction.
a Sketch the boat and forces. (L4)
b What is the resultant force? (L5)
c If you want to go faster you need a bigger
resultant force. Describe 2 ways you could
make the resultant force bigger. (L5) Hint?
4. Explain:
You ride a bike. There is 150 N of friction, and
your driving force is 200 N. What is the
resultant force, and what effect will it have?
(L5) Hint?
In a clash between a car and motorbike, the bike usually loses.
It’s best for the rider to avoid a collision. But how do bikes speed
up or slow down, and what decides their maximum speed?
It all depends on the resultant force when all the others combine.
The rider twists the throttle. He
makes the forward force bigger
than the backwards force, so his
speed increases.
The bike’s speed makes
friction increase. The forces are
now equal, so the speed stays the
same.
The rider eases back on
the throttle. The forward
force is smaller, so the
speed decreases.
Unbalanced forces
friction 1000 N driving force 2000 N
resultant force 1000 N speed increases
Balanced forces
driving force 2000 Nfriction 2000 N
resultant force 0 N speed unchanged
Unbalanced forces.
resultant force 1000 Nspeed decreases
friction 2000 N driving force 1000 N
Unbalanced forces
Preview

Got it?
Lose weight in space
1. Summarise:
Mass is the amount of ___ an object is made from.
Weight depends on mass and on the strength of ___.
An object’s weight changes when ___ changes, but
its mass always stays the ___ unless you ___ some of
its atoms away.
2. Recall:
a How does weight change as you get further
from the surface of the Earth? (L3)
b How would your weight change if you went
to a planet with a bigger mass like Jupiter? (L3)
c Astronauts can jump much higher on the moon
than on Earth. Suggest why? (L5)
3. Use:
At the Earth’s surface, an astronaut weighs
500N. Show how she can calculate her mass.
(L4) Hint?

4. Explain:
An astronaut eats a meal on the Moon. Her
mass and weight both change. Explain why.
(L5) Hint?

5. Predict:
You are returning to Earth in a space
elevator. Explain how your weight changes
as you get closer to the surface. (L5) Hint?
In the future, tourism could be
very different. The space elevator
could take you 40,000 km up, and
then it’s off to the Moon. Going
into space would be an easy way
to lose weight.
Weight is the
force of gravity,
pulling towards the
centre of the Earth.
On the surface it is
strong and he
weighs a lot.
As the elevator rises
further from the Earth,
gravity decreases and
he weighs less.
Celebration on
the Moon. Gravity
is much less than on
Earth because the Moon
has less mass.
A force
meter works
in a similar
way to scales.
The bigger
the weight,
the more the
length of the
spring inside it
changes.
Bigger
weights make
the spring
longer.
Mass
Unfortunately, his mass
stayed exactly the same for the
whole trip. Mass is the amount
of stuff (atoms) he’s made of.
The scales actually measure
weight in Newtons and then
convert it to kilograms.
The gravity at the Earth’s
surface is 10 N/kg. The weaker the
gravity the smaller the number you
divide by.
mass in
kilograms
=
weight in Newtons
10
Preview

Forces ...master
Got it?
Air resistance
1. Summarise:
As an object’s speed increases, its air___
goes up too. When the resultant ___on the object
is cut to ___, its speed can’t increase. ___ is a force
that also ____ motion.
2. Explain:
As you walk, friction stops one foot sliding while you
push the other forward. Skaters vary this friction by
angling their blades. Explain when they need low
friction and when they need high friction. (L6) Hint?
3. Use:
Before his parachute
opened, Mark was falling
at a constant speed.

a Sketch him and his
parachute and show the
forces on them. (L5)
b Mark’s parachute opens. Sketch the forces now
and describe their effect. (L7) Hint?
c How will the air resistance change as he
continues to fall? (L6) Hint?
Friction
As the jumper falls he’ll get faster. But if he drops far
enough his speed will eventually stop increasing. Why?
He takes off. The only
force acting is gravity, so
he quickly gains speed.
Friction is a
nuisance for Kasia.
Her pushing force
isn’t big enough
to move the sledge.
As he falls, air pushes back on him. This air
resistance opposes gravity. It cuts the resultant
force, so his speed increases more slowly.
The faster he falls, the
bigger the air resistance.
When it balances gravity, he
stays at the same speed.
Friction always tries to stop one surface moving over another.
Eva makes use
of friction. It stops
her sliding on
tight turns.
gravity gravity gravity
air
resistanceair
resistance
pushing force friction
no movement
pushing force friction
pushfriction
Preview

Forces ...master
Got it?
Speed
1. Summarise:
The average speed is the total ___ divided by
the total ___. The more steep a distance-time graph
is, the greater the ___.
2. Exemplify:
a A runner took 10 seconds to run the 1st
50 metres of a race and 20 seconds to run the last
200 metres. Did his speed change? (L5) Hint?
b During which part of the race would his
distance-time graph be steeper? (L5) Hint?
c A driver travels 100 km in 2 hours, stops for an
hour and then travels 200 km in 2 hours. Draw the
distance-time graph. (L6)
3. Explain:
A sprinter and cyclist set off at the same time.
Describe what happened during the 1st 10 s
and explain why. (L7) Hint?
Why was Bolt slower? A distance-time graph can solve the puzzle.
The relay team ran 400 metres (m)
in a time of 37.10 seconds (s)
average = 400 m = 10.78 m/s
speed 37.10 s
The Jamaican crowd had plenty to
cheer about. Bolt took the 100 metre
world record in 9.58 seconds.
Then the relay team took gold with
a speed that was even faster. Don’t
believe it?
You calculate average speed
with this formula:
average = distance
speed time
in metres per second
Bolt’s average speed
= 100 metres (m)
9.58 seconds (s)
= only 10.44 m/s
In the relay, only the
first runner had to
speed up.
The others were
running before they
took the baton, so their
average speed was
faster.
Distancerun(m)
Time (s)
distance(m)
0 10
0
5
40
80
100 cyclist
sprinter
The arrows show the times Bolt
took to run each 10m. As the times
get shorter, his speed increases
and the graph gets
steeper.
Time after start (s)
The 4th and 5th
arrows are the same
length and the graph is a
straight line. His speed has stopped
increasing, so he now has a constant speed.
Preview

Models ...understand
upd8 Link Cook Inside story
How can we
explain the
invisible?
Ice-cream becomes a runny liquid
when it warms up. Why?
Replacing something difficult
to think about (particles) with
something easy and familiar (an
audience) is called using a model.
It’s not easy to answer. You can’t see
what’s happening inside. Ice-cream
particles are far too small.
Imagine ice-cream
particles are like an
audience. In the solid
form, the people stay
in their places.
Heating gives the
audience (ice cream)
energy. The people
(particles) start moving
around and they
spread out. So that’s
why the ice-cream
becomes runny.
Got it?
1. Summarise:
Models help scientists explain scientific ideas. They
use something ___ to represent ___ we cannot see,
like particles.
Physical models use ___. Thinking models use ___
and computer models show how things ___ or
change with time.
2. Exemplify:
Use a model to explain why chocolate goes runny
when you heat it. You could draw the model (L3) or
describe it. (L4)
3. Recognise:
Three students wrote about models. Which one
doesn’t understand what they are? (L4)
Jay: they are not completely realistic but they
explain how real things behave.
Kuba: they can be objects, animations or analogies
that help explain things.
Karen: they are exact 3D copies of things.
4. Use:
Emma uses models to explain why her cake tastes so
good:
i Gas bubbles in the cake mix
blow up like balloons as it bakes.
ii The sponge shows what her
cake is like inside.
a Which is a thinking model? (L3)
b Which properties of Emma’s cake could her second
model explain? (L4) Hint?
c Emma’s dad smelt the cake as soon as he opened the
front door. Draw a particle picture to explain how
the smell got from the cake to his nose. (L4) Hint?
d In part c you used a model. How does it make the
job of explaining easier? (L5) Hint?
Thinking models
use analogies e.g. solid
particles are like people
in an audience.
Physical models
use objects e.g.
Lego bricks, to
represent particles.
Computer models
show how things move
or change with time.
Preview

Models ...understand
upd8 Link Cook Inside story
Using models
Why does a runny egg turn solid
when you cook it?
To explain something using a model, follow these 3 steps:
Explanation:
“Eggs turn solid
as they cook
because their
particles unwind
and tangle.”
What
happens next?
“The particles
tangle up into
a solid lump.”
Characters:
“Let’s use balls
of string to
represent egg
particles.”
Action:
“When they get
hot, the string
unwinds.”
Got it?
1. Summarise:
Models use ___ to represent real things and actions
to ___ what they do.
To use a model, choose the characters and ___.
Play the model in your ___, like a ___, and ___
what happens next. Then match the model to the
real thing and use it to ___ what happens.
2. Use:
Pancackes contain egg, flour and milk.
a Why are egg particles like balls of string? (L4) Hint?
b Eggs go solid when heated. How does the model
make this easier to understand? (L5) Hint?
c If you don’t add the egg, pancakes fall apart. Use the
model to explain how egg particles hold flour and
milk particles together. (L5) Hint?
3. Explain:
Ben’s dentist showed a model to explain how cola
harms teeth. He dropped acid onto a piece of marble.
The solid dissolved.
a One character in the dentist’s model is the acid.
What is the other one? (L4) Hint?
b Suggest why the dentist chose acid to represent
cola. (L4) Hint?
c What makes marble a good model for a tooth?
(L4) Hint?
d How does the model make tooth decay easier to
explain? (L5) Hint?
e Sugar has no effect on marble but it causes severe
tooth decay. Use the model to suggest what happens
to sugar in your mouth. (L5) Hint?
1. Choose characters to
represent the real thing
and actions to show
what they do.
2. Decide what happens
next by playing the
model in your mind,
like a movie.
3. Match the model to the
real thing and use it to
explain what happens.
Preview

Models ...master
upd8 Link Species at war Pandemic
Is your model good enough?
Karen wants a
model to understand
her immune system.
How does it fight off
microbes to keep
her healthy?
To decide if the
model is ‘good
enough’ we need
to see what it
can explain.
A. There are more
macrophages in the
organs that microbes
enter more easily,
like your lungs.
Observations to explain...
B. When scientists
destroyed the
macrophages,
in a tissue, it
filled up with
microbes.
C. Macrophages don’t
have eyes but they
recognise microbes.
D. Macrophages
can destroy microbes.
If it has too many
weaknesses we
can change its
characters or actions
to improve it.
Got it?
1. Summarise:
To decide if a model is ‘good’ ___ , we see
how many observations it can ___.
Every model has it strengths and ___ .
2. Exemplify:
Ben uses a thinking model to
describe what macrophages
do. “My macrophages are
like piranhas. When they
detect any microbes, they
attack them ferociously.”
3. Recognise:
Jen uses a model based on Karen’s.
“This is how macrophages guard
my body. They scan the surfaces of
microbes for chemicals that normal
body cells don’t have.”
Which of observations A to D, does this
model explain? (L5)
4. Explain:
Which of these do you agree with? Explain why. (L6)
a Simple models can be ‘good enough’ to explain ideas.
b Models can be improved by changing their characters
or actions.
c Models aren’t useful unless they are totally realistic.
5. Predict:
Carl uses a different model to explain how macrophages
work. “Macrophages are like blobs of slime. They don’t have
fixed shapes, so their cytoplasm flows around things.”
Extend Ben’s model to explain how
macrophages could trap microbes. (L6)
6. Solve:
Karis used a high-powered microscope to
look at macrophages. She saw tiny bags of fluid in their
cytoplasm. These are lysosomes. They contain enzymes to
break down fats, carbohydrates and proteins.
Use this new information to extend Carl’s model. Explain
how macrophages could destroy microbes. (L7)
Karen’s model
Skin is a tough barrier. It keeps
most microbes out. If any
break through, your immune
system deals with them. Its
security guards are cells called
macrophages which patrol the
tissues beneath your skin.4 4
8
8
Preview

Particles 1 ...understand
upd8 Link Forensics Fake
Why are materials so different?
Everything is made up of particles. Air, water and rock feel different
because their particles have different amounts of energy.
In a solid like rock, the
particles have less energy. A force
of attraction keeps them in place.
They can only vibrate.
In a gas like air, the particles
have most energy. They break
away from their neighbours, and
move around very quickly.
In a liquid like water, the
particles have more energy. They
are still held close together, but
they can move around.
Got it?
1. Summarise:
Everything is made from moving ___. Solids, liquids
and ___ are different because their particles have
different ___ of energy. Solid particles have least
energy, so they can only ___. Gas particles have
most ___ so they ___ around freely.
2. Use:
Say whether each of these is a solid, liquid or gas:
wood, steam, milk (L4), toothpaste, jelly
and a sponge. (L5)
3. Explain:
Use ideas about particles to explain these
observations:
a Rock is hard, strong and heavy. (L4)
b Rock and water cannot be squashed, but air can. (L5)
c Cooking smells can spread to fill the whole house.
(L5) Hint?
d Boats can move through water but not through ice.
(L5) Hint?
e Dry sand contains the same particles as rock, but
flows like a liquid. (L5) Hint?
Hard Rock
Moving Air
Flowing Water
Preview

Particle explanations
Solids turn into liquids if you heat them enough. This is a change of state.
Sugar cubes dissolve in tea.
The smell of perfume reaches your nose.
Moving tea particles hit the
sugar and separate the particles.
Individual sugar particles
are too small to be seen.
Got it?
1. Summarise:
The idea of particles explains many observations.
Changes of state are caused by changes in the
amount of ___ particles have. Dissolving is different.
It happens when particles ___.
2. Use:
Draw a particle picture to show:
a What would happen to the particles in molten gold
if you continued to heat it. (L4)
b What would happen if a small piece of silver was
dropped into the molten gold. (L4)
3. Deduce:
Use the data in the table below to find:
a The temperature at which gold becomes a gas. (L4)
b The temperature at which mercury melts. (L4)
c Whether mercury is a solid, liquid or gas at 0°C. (L5)
d The state gold is in at 900°C. (L5)
metal melting point (°C) boiling point (°C)
gold 1100 2856
mercury -39 357
Some liquid
particles have more
energy than others.
The most energetic
particles escape and
mix with the air – they
evaporate.
Heating adds energy, so the
particles in the gold bar vibrate more.
Eventually, they break free
and form molten gold.
Preview

Separating mixtures
There are only water particles
in distilled water, so it is pure.
We can separate substances if they have different properties:
Got it?
1. Summarise:
You can separate the substances in a mixture if they
have different properties. If their boiling points differ
use ___. If they have different solubilities use ___. If
one substance has large, insoluble particles, use ___.
2. Use:
Name the methods that could be used to separate
each of these mixtures:
a Tea leaves from tea.
b Water from ink.
c The food colourings in a sweet.
d Water from salty water. (L5)
3. Explain:
Salt is often found mixed with sand.
a Explain how you could use water to separate sand
from salt. (L5) Hint?
b What difference between sand and salt makes this
possible? (L5) Hint?
c Draw particle pictures to show the sand and salt at
each step in your method. (L5) Hint?
d Explain how you could separate water from a
mixture of salt and water. (L5)
e What difference between water and salt makes this
possible? (L5) Hint?
Pure water, or is it? Bottled water contains
dissolved substances. It is a mixture.
Distillation works because the
particles with the lowest boiling
point leave the mixture first.
Filtration separates
liquid particles from large
insoluble ones.
Chromatography works
because the most soluble
particles move further.
solvent
X
Filter paper traps
sand but lets water
through.The particles
in red and
yellow ink
separate as the
solvent moves
them upwards.
alcohol
water and
alcohol
Preview

Glossary
127
A
Absorb
Acidic
Actions
Adaptations
Addictive
Air resistance
Alcohol
Alert
Alkaline
Alveoli
Ammeter
Amphibian
Amplitude
Angle of incidence
Angle of reflection
Antibodies
Atoms
Attract
To take something in e.g. lungs absorb oxygen.
A solution with a pH less than 7.
In a model, the actions are what the characters do.
The physical features or behaviours that make an animal or plant better
suited to their environment.
Something that changes your brain in a way that makes it difficult
for you to stop taking it.
The force produced when air pushes against a moving object.
It increases as the object’s speed increases.
A legal drug found in beverages like beer and wine.
Wide awake and ready to react quickly.
A solution with a pH greater than 7.
Tiny air sacs in the lungs. Their large surface area, thin walls and good blood
supply allow blood to absorb oxygen quickly.
A device that measures the size of an electric current in amps.
A group of cold blooded vertebrates that lay their eggs in water and have
smooth, moist skin.
The size of the vibrations that produce a sound or the disturbance a wave
causes. On an oscilloscope trace it is half the height of a wave.
The angle between the incident ray and the normal.
The angle between the reflected ray and the normal.
Molecules made by B-cells which lock onto specific pathogens and make
them easier to destroy.
The smallest particles in an element. They are different in each element and
cannot be broken down into anything simpler.
Pull towards each other like the opposite poles of a magnet.
16
22
68
6
32
56
32
32
22
15
37
31
95
96
96
64
76
60
Preview

GetScience is different to most textbooks in lots of ways - to help you learn better
Don’t get stuck – get science!
The book was written by many teachers and writers:
Main authors: Gemma Young, Ben Rogers, Alison Dennis, Pam Large and Tony Sherborne
With Sophie Boles, Gary Talbot, David Hinchley, Nigel Heslop,
Ed Walsh, Lucy Austin and Joanne Porter
www.getscience.org.uk
Scholio Educational Research Publishing
The Big Idea is clear on every page 4
Pictures help you ‘get it’ so there are fewer words 4
The questions are about science, not writing 4
The pages are easy to read 4
You can understand the science and it’s interesting 4
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