CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Learner’s Book answers
Unit 1 Living Things
1.1 Bones and skeletons
Getting started
1.2 Why we need a skeleton
Getting started
1
A skeleton is a strong frame that supports our
body from the inside.
1
Learners’ own description, for example the
bones inside our body. The skeleton is a frame
inside the body that gives the body shape and
support.
2
Learners’ own answers, depending on their
existing knowledge, e.g. to give the body shape
and support, to protect organs/parts inside the
body
2
Bones.
3
3
Learners’ own answers. It is a frog skeleton.
Learners’ own answers, depending on their
existing knowledge, e.g. brain, heart,
lungs, stomach.
4
Answers will depend on learners’ existing
knowledge about skeletons. The picture shows
the skull, ribs, backbone, hip bones, leg and
feet bones (also the shoulder blades, but
learners are not required to know this).
Activity: Finding your bones
Questions
1
The skull protects the brain by shielding it.
2
The rib cage protects the heart and lungs.
3
To hold together and support the rest of
our body.
4
Muscles are parts of the body that help us to
move. We can move because there are muscles
joined to the bones of the skeleton.
1
Bones
2
To support our bodies.
3
Because they are in different part of the body
that do different things, e.g. legs for walking
and supporting the upper body, skull for
protecting the brain.
Think like a scientist: Measuring
bone lengths
1
Answers will depend on measurements taken.
Light bones make it easier for the animal to
move its body.
2
Learners should be able to predict that a
teenager’s bones will be longer that their own
bones because teenagers are older and have
grown more, which means that their bones
have also grown.
3
No, because it is not accurate. A person with
a different hand length would get a different
measurement. They also cannot use their
measurements to compare their bone lengths
with those of other people who are using
standard units of length.
4
Think like a scientist: Make a model
skeleton
1
1
The model is the same as the real skeleton
because it shows the position and shapes of
some of the bones in the body. The model
is not the same size as a real skeleton. It is
not made of bone; it does not have the same
number of bones as a real skeleton; it is not
living like a real skeleton is.
2
Learners should compare their models with
those of other pairs. They may observe that
other models are neater, more correctly
labelled, or that other learners have chosen
more suitable pasta shapes for their model,
for example.
1.3 Skeletons and movement
Getting started
1
Learners’ own answers, depending on their
existing knowledge and experience, e.g.
running, jumping, walking, dancing, twisting,
climbing, stretching.
2
Learners’ own answers, depending on their
existing knowledge, e.g. we have muscles
joined to our bones to let us move different
parts of the body.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
b
Activity: Find out how muscles work
in pairs
1
2
The muscle in the front of the upper arm
(biceps) contracts. The muscle in the back or
underside of the arm (triceps) relaxes. Learners
should use their observations to explain that
the muscle that contracts gets shorter, fatter
and feels harder. The muscle that relaxes gets
longer, thinner and feels softer.
To test the strength of arm muscles learners
can use different weights, such as bags
containing different numbers of books of
the same size, and a measuring tape. They
can measure how high they can lift the
weight off the ground.
Questions
1
Learners’ own answers. For example, getting
out of bed, getting dressed, making the bed,
walking downstairs, cycling to school, running
at break time.
2
a
earners’ own answers. For example,
L
sleeping, watching TV, sitting in class,
reading, playing computer games, texting
on a mobile phone.
b
Learners’ own answers.
Results can be recorded in table, for example:
Number of books Height the weight
was lifted
3
They could also draw a bar chart of the results.
To be a fair test, the same person must lift the
different weights in the same way. The only
variable that changes is the number of books
or size of weight lifted.
Any relevant suggestions, such as making
your bed, dancing to your favourite song,
playing games in the playground, playing on
playground equipment, e.g. climbing frame or
slide, taking the dog for a walk, washing the
car.
1.4 Different kinds of skeletons
Getting started
3
Doing exercise makes muscles get bigger.
1
4
The heart is not involved in moving the
body, so it does not need to be joined to the
skeleton.
Learners’ own answers, depending on their
existing knowledge, e.g. bird, fish, cat, goat.
2
Learners’ own answers, e.g. insects and crabs.
3
Learners’ own answers, e.g: No; it has no
bones or Yes; it has a hard covering on the
outside of its body.
Think like a scientist: Make a model of
arm muscles
1
The lower card arm lifts.
Questions
2
The lower card arm drops.
1
3
The elastic bands get shorter when you pull on
them, like muscles contracting. When you pull
on the long elastic band on the inside of the
card arm, it gets shorter and pulls the lower
part of the arm up.
4
2
Answers could include the following
ideas: the muscles are not real, they are
made of elastic bands; the bones in the
model are made of card; we have to pull
on the elastic bands to make the arm
move, but in real life this action is done by
the muscles themselves.
Vertebrates are animals that have a backbone
or spine. Also accept the definition that
vertebrates have a skeleton or have bones
inside their bodies.
Invertebrates are animals that do not have a
backbone or spine. Also accept the definition
that invertebrates do not have a skeleton or
bones inside their bodies.
When you pull on the short elastic band on
the outside of the card arm, it gets shorter and
pulls the lower part of the arm down.
2
Crocodile, goat, eagle, frog.
a
3
Crab, earthworm, spider, beetle.
nswers could include the following ideas:
A
the muscles have to work as a pair to make
the arm move; when one muscle contracts
and gets shorter, the other muscle relaxes
and gets longer; the muscles are joined to
the arm bones.
Learners to add examples of their own to
each list.
4
The crab, spider and beetle have exoskeletons.
5
An invertebrate with an exoskeleton grows
by shedding or moulting its exoskeleton and
growing a new exoskeleton.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Think like a scientist: Identify
vertebrates and invertebrates
2
Animals in key: a) eagle; b) cat; c) fish; d) snake;
e) crab; f) snail; g) worm
You would not get better or not get better
as quickly.
3
No. Creams treat skin problems, not illnesses
inside the body such as a sore throat.
4
Because the blood carries medicines very
quickly around the body and because people
in hospital may be too ill to swallow tablets
or mixtures.
illness or disease.
1
Eagle, cat, fish, snake.
2
Crab, worm, snail.
3
a
Vertebrate groups are fish, amphibians,
reptiles, birds, mammals.
b
Fish – fish; amphibians – crab; reptiles –
snake; birds – eagle; mammals – cat.
Think like a scientist 2: Research
information about vaccinations
1.5 Medicines and infectious
diseases
Answers will depend on learners’ findings.
Getting started
1
Learners should explain in their own words
that an infectious disease is one that is caused
by germs that get into plants and the bodies of
animals and people and make them ill.
2
To prevent the bird flu spreading from the bird
to her.
3
She can vaccinate the chicken.
1
Learners’ own answers, depending on their
experience, e.g. I took cough mixture when
I had a cough; I took a tablet when I had
a headache.
2
Learners’ own answers, depending on their
existing knowledge and experience, e.g. tablets
or pills, creams, injections, inhalers, powders.
3
Learners’ own answers, e.g. the adult knows
how much medicine the girl must have; or
the adult will make sure the girl has the right
medicine or the right amount of medicine.
Questions
Check your progress
1
Think like a scientist 1: How to take
medicines safely
3
The information sheet should include at least
four of the following points:
•
Only take medicines meant for you.
•
Only take medicines meant for the illness
you have.
•
Always take the amount of medicines the
instructions tell you to take.
•
Take the medicine for as long as the
doctor tells you to.
•
Remember to take the medicine at the
correct time. Don’t take more the next
time if you have forgotten.
•
Follow the instructions about how to take
the medicine, for example with food.
•
Never take old medicines that have passed
their expiry (best before) date.
•
2
3
a
Skeleton
b
Skull
c
Model
d
Organs
e
Invertebrates
f
Muscles
g
Exoskeleton
h
Vaccination
a
1
b
The muscle contracts/relaxes. The muscles
gets longer/shorter and pushes/pulls on
the arm bone.
c
Muscle 2 relaxes
a
A – spine; B – jaw; C – skull
b
The skull/part C
c
To protect the heart and lungs
d
Part F
e
Part E
f
Supports or provides a frame for the animal.
Ask an adult to help you take medicines.
Questions
1
3
We take medicines to make us better when we
are ill or to prevent/stop us from getting an
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
4
Sleeping
b
Riding a bike and eating
c
2½ hours (1.5 hours playing football,
1 hour riding bike)
d
Watching TV and playing computer
games – they involve very little movement.
e
f
5
2
a
Any suitable suggestions, e.g. walking to
school, playing on playground equipment,
gardening, carrying his mother’s shopping
from the shops.
Flag – movement; kettle – heat (also sound);
Sun – heat and light; drum – movement and
sound; bird – food energy
Think like a scientist: Demonstrate
what energy does
•
The ball moves
•
The ball will move faster and go further.
•
Answer depends on the prediction.
•
The ball had more energy when it was
flicked harder. This made it move faster and
further
Any three from the following:
•
it makes your heart and lungs
work better
Questions for Think like a scientist
•
it makes muscles and bones stronger
1
•
it lets you stretch your body easily
The flicking finger, the ping pong ball.
They were both moving.
•
it helps to stop you from getting
some illnesses
2
a
nergy made the ping pong ball move;
E
it also made the finger move.
•
it helps you think better
b
Energy changed how fast and far the ball
moved.
•
it puts you in a good mood.
a
Germs cause infectious diseases. [¸]
b
If you take more medicine you will get
better faster. [˚]
c
Always follow the instructions on the
medicine label. [¸]
d
It is OK to take medicine that a friend
gives you. [˚]
e
Plants do not have any infectious
diseases. [˚]
Unit 2 Energy
2.1 Energy around us
3
Blow on the ping pong ball to make it move,
or similar suggestion.
2.2 Energy transfers
Getting started
1
Movement energy
2
From another object that contained energy
that made the ball move, e.g. a person kicking
the ball. (The idea is for them to start to think
about energy being transferred from one
object to another.)
3
Yes. Any suitable example, such as a hot stove
which has heat energy but is not moving.
Think like a scientist 1: Observe an
energy transfer
Getting started
1
Learners’ own answers – idea is to identify
any existing ideas about energy, especially
with regards to the everyday use of the
term.
The bead falls off the spoon. Heat energy moves
from the hot water to the spoon. The heat energy
moves from the spoon to the petroleum jelly and
melts it, which makes the bead fall off.
2
From the food he eats. Probe other answers to
explore learners’ ideas.
Suggested question: Is energy transferred from one
object to another object?
3
Learners’ own answers, e.g. from the Sun or
electricity – to identify any existing ideas and
knowledge about energy.
Suggested conclusion: Energy is transferred from
one object to another object.
Questions
1
4
Flag, wind (moving air); hot water, kettle,
stove; Sun and tree; drumsticks, the drum
and the sound of the drum; the worm and
the bird
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Think like a scientist 2: Plan a fair test
on energy transfers
Suggested question: Do some materials transfer
more heat than other materials?
Examples of materials needed: cup or beaker, hot
water, spoons or stirrers made of plastic, different
kinds of metal, glass, bamboo; beads or dried
peas, petroleum jelly.
Methods: as for Think like a scientist 1, but
learners will place a bead on each of the spoons or
stirrers. They will observe the order in which the
beads fall off the spoons or stirrers.
Learners could also suggest timing how long it
takes for each bead to fall off. In this case they
need to add a timer to their list of materials and
equipment.
Activity: Identify energy transfers
Type of
energy
transferred
A Movement
B Heat
C Sound
D Movement
Where the
energy comes
from
Boy
Iron
Radio
Air
Where the
energy is
transferred to
Football
Clothes
Girl’s ears
Kite
2.3 Energy changes
Getting started
1
Learners’ own answers – probably tired and
hot. Reason – they feel tired because their
bodies used up a lot of energy; the pedalling
movement made them feel hot (no scientific
explanation expected).
To make it a fair test:
•
the spoons or stirrers should all be the same
size
2
Movement energy in legs is transferred to the
bicycle to make it move.
•
the beads should be the same size
3
Heat energy
•
the same amount of petroleum jelly should be
used on each bead
Think like a scientist: Observe energy
changes
•
the water temperature must be the same for all
the spoons or stirrers
•
the spoons or stirrers should all be placed in
the cup of hot water at the same time.
Learners could suggest that no one touches the
lamp to make sure they don’t burn themselves; or
no one knocks over the lamp as it could cause a
fire in the classroom.
Reason for fair test: so that we know that the
results we get are due only to the factor we change
and are not affected by the other factors, or similar
answer.
Dangers: hot water can cause burns, or other
reasonable suggestion.
Work safely: wear protective gloves when working
with hot water, ask an adult to pour the hot water,
or other reasonable suggestion.
Test results: repeat the experiment a few times to
see if they get the same results.
Present results: learners could rank the materials
according to how long it takes for the beads to fall
off, and then draw a table of their results. They
could then display the results in a bar chart.
Learners should observe that the paper spiral starts
to turn when they hold it above the lamp.
Questions for Think like a scientist
1
Heat energy
2
Movement energy
3
a
Energy moved from the lamp to the
paper spiral.
b
4
Some of the heat energy changed form
into movement energy.
Any two suitable examples, such as:
TV set – electrical energy changes into sound,
light and heat energy.
Stove – electrical energy changes into
heat energy.
Kettle – electrical energy changes into heat
and sound energy.
5
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Questions
Check your progress
1
1
2
Because we cannot always see signs that an
object has energy. Any suitable example,
such as when a fire goes out and does not
give off any more heat and light, or a ball
stops rolling along the ground.
Transfer – when something moves from one
thing or place to another
Food chain – a drawing that shows how
energy moves from one living thing to another
The energy changes form or it moves into the
surrounding environment.
2.4 Energy and living things
Producer – a living thing that gets its energy
from the food it makes itself
Getting started
Consumer – a living thing that gets its energy
from eating other living things
1
To carry out body processes or activities, such
as running, playing and growing.
2
Yes
3
From their food
Questions for Animals need plants for
energy
1
Plants are called producers because they make
or produce their own food.
2
Animals are called consumers because they eat
or consume other living things as food.
3
a
Predators kill and eat other animals. The
prey are the animals that predators kill
and eat.
b
They are both consumers.
c
No, herbivores eat plants and do not eat
other animals.
Questions for Food chains
1
2
3
a
Palm tree, rice plant
b
Tiger, snail, crocodile, person
a
Snail, cow
b
Tiger, crocodile
2
3
1
a
Movement energy changes to sound energy
b
Electrical energy changes to sound, light
and heat energy
c
Heat energy changes to movement energy
a
Leaf ‡ caterpillar ‡ bird
Grass ‡ rabbit ‡ eagle
Seeds ‡ beetle ‡ lizard ‡ snake
b
4
The direction which energy moves from
one living thing to another living thing.
Any three predators from bird, eagle,
lizard, snake.
Bird’s prey is caterpillar; eagle’s prey is rabbit;
lizard’s prey is beetle; snake’s prey is lizard.
Unit 3 Materials
3.1 Materials, substances
and particles
Getting started
The person – most people eat plants and
animals.
1
Materials that are solids could include wood,
metal, glass, brick, paper, plastic.
2
Materials that are liquids could include
water, fruit juice or liquid soap, depending
on what you have in the classroom. Gases
include air (oxygen).
3
Expect the following kinds of answers:
‘I know it’s a solid if it’s hard’ or ‘I know
it’s a liquid if it’s wet’ or ‘I know it’s a gas
if I can’t see it’.
Think like a scientist: Draw food chains
6
Energy – anything that can cause movement
or carry out an action
a
Tomato ‡ bird ‡ cat
b
Rice plant ‡ grasshopper ‡ frog ‡ snake
2
ny suitable food chain, e.g.
A
grass ‡ sheep ‡ person
3
Energy moves from the plant to the herbivore,
which eats the plant. The energy from the
herbivore moves to the person who eats
the herbivore.
Questions
1
Matter is everything around us.
2
A material is a certain type of matter.
A substance is a pure type of solid, liquid
or gas: it is not a mixture.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
3
Glass is a material. It is made of different
substances.
4
a
They are both made of particles of matter.
b
Pure water is a substance. Sand is not a
substance: it is a mixture or material.
Think like a scientist: Demonstrate that
particles of liquids move
Question: Can water change its shape?
Learners should plan to pour the same amount of
water into different containers to find out if water
can change shape.
Learner’s sentence: The colour spread through the
water without being stirred. This shows that particles
can move on their own (or something similar).
Learners should choose different shaped
containers, a jug or cup and water.
The type of scientific enquiry used is observing
over time.
Conclusion: water can change shape/take on the
shape of the container it is in.
Activity: Play the particle game
Explanation: the particles of a liquid can slide past
one another and change places. This lets water
(and other liquids) change shape easily.
1
2
We could shake our bodies as ‘solids’ but not
our arms because they were linked tightly with
people next to us. We could shake more easily
as ‘liquids’.
We could not move closer together or further
apart as ‘solids’. We could as ‘liquids’ but our
arms remained linked so we were still held
together in the group.
3
We could not change the shape of our group
as ‘solids’. As ‘liquids’ we could change shape
in some ways but we were still held together in
the group.
4
Learners should be able to say that when they
were a ‘solid’ their movement was very restricted.
They could shake a little but not change places.
This represents the particles in a solid that are
held tightly together and cannot move very
much so the solid cannot change shape.
When they were a ‘liquid’ they could move
around a bit more, but were still linked
together. This shows that the particles in
liquids are held less tightly together than
solids. The particles can move more than in
solids which allows the liquid to change its
shape in some ways.
7
Think like a scientist 1: Plan an
investigation about changing the shape
of water
Learners draw pictures of their observations.
Think like a scientist 2: Investigate
solids that can flow
1
Sugar (or other larger grained solid – flow rate
will depend on size and shape of grains)
2
Flour
3
The solid with the smoothest, smallest grains
flowed slowest (because there are smaller air
spaces between the grains, so the grains are
more tightly packed together). The larger,
rough grains of sugar flowed fastest (because
there a bigger spaces between the grains, so
the grains are more loosely packed together).
4
Small grains flow slower, big grains flow faster.
5
Look at size of the grains, if they are big, the
solid will flow faster. If the grains are small,
the solid will flow slower.
6
Learners can suggest comparing their group’s
results with those of other groups, or repeating
the tests.
7
Seconds. They are a standard unit for
measuring time so we would expect to get
similar results to other groups when we
measure the same thing.
3.2 How do solids and liquids
behave?
3.3 Melting and solidifying
Getting started
Getting started
•
All substances are made from particles – true
1
•
Materials are not made from particles – false
•
Particles in solids cannot move – false
Solids have a fixed shape and they are
often hard; liquids can flow/be poured
and change shape.
•
Particles in liquids can slide past one
another – true
2
Yes. Candle wax melting, for examle.
3
Yes. Melted candle wax hardening, for example.
•
There are always space between particles – true
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Think like a scientist 1: What happens
to ice when it is heated?
1
Adding heat to the ice made it change
to a liquid.
2
No. The ice was made from frozen or solid water.
When the ice melted, the liquid formed was water.
3
a
Cool it down or put it in a freezer.
b
Solidifying
Think like a scientist 2: Compare
melting in different solids
1
Solids melt when they are heated/heat is added.
2
The ice. Yes or no depending on learners’
predictions.
3
The chocolate melted last/did not melt.
4
Melting – heating a solid makes its particles
move faster. When the particles have enough
energy, they can move away from each other.
When this happens the solid melts and
becomes a liquid.
5
Conclusion: Air and water react with the
metal to make the wire wool rust. Reason:
the metal rusted in the jars which had air and
water in them.
4
The type of scientific enquiry used is observing
over time.
Activity: How can we prevent rusting?
Learners should mention some of these methods
to prevent rusting:
•
paint the metal to prevent it coming into
contact with air and water in the atmosphere
•
coat the metal with a layer of less reactive
metal to keep air and water out - this is what
happens with tin cans that are coated with a
thin layer of tin
•
coat the metal with a more reactive metal such
as zinc, so that the air and water react with
the zinc instead of the iron – this is called
galvanising
•
coat the metal with a plastic coating to keep
out air and water.
It was not a fair test because the quantities of
the solids heated were not all the same as they
were not measured.
6
Some solids melt faster than others, or similar
conclusion.
7
It will get hot and boil.
Learners should be able to explain that if
objects did not rust, people would be less
likely to throw them away, which would cause
less waste in the environment (or similar
answer).
3.4 Chemical reactions
Check your progress
Getting started
1
1
The chocolate melts and becomes liquid.
2
No. The chocolate still tastes the same and
does not become another substance, it just
changes state to a liquid.
a
Both
b
Solid
c
Liquid
d
Solid
e
Both
3
Yes, cool it down/put it in the fridge.
f
Solid
4
a
o. The nuts do not change the chocolate:
N
they become covered in the chocolate.
g
Liquid
b
Yes, melt the chocolate and pick out
the nuts.
a
Liquid
b
The particles are not very close together.
The particles are not packed in a regular
pattern.
a
Solid
b
Flour is made of lots of very tiny grains.
There is air between the grains so the grains
have space to move into. This lets the grains
flow past each other like in a liquid.
Think like a scientist: Which substances
react to form rust?
1
2
8
3
a
ost rust will be in jar 1, less in jar 2 and
M
no rust in jar 3.
b
Answers depend on predictions made.
a
o allow time for any changes to the wire
T
wool to take place, or similar answer.
b
There will be more rust in jar 1 and
possibly in jar 2, but still no rust in jar 3.
2
3
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
4
a
Activity: Summarise the structure of
the Earth
iii and v
b
5
a
Rust
b
Metal, water, oxygen
c
It can damage buildings, bridges and
other metal things and make them weak.
d
Chemical reaction
Name of layer
Crust
Mantle
Core
Thickness
5–70 km
3000 km
3400 km
Material
Rocks
Magma
Iron and
nickel
Temperature
20 –400 oC
1000 oC
5000–
6000 oC
Solid, molten
or liquid
Solid
Molten
Outer
core
liquid;
Inner
core
solid
Unit 4 Earth and its
habitats
Think like a scientist: Use a model to
explain the structure of the Earth
1
The peach is not very much like the shape of the
Earth. The peach has a skin like the Earth’s crust.
4.1 The structure of the Earth
2
Getting started
The skin of the peach is the crust. The flesh is
the mantle. The stone is the inner core.
3
A peach is a good model because:
1
The Earth is ball-shaped. It is actually
slightly flattened at the North and South
Poles, and it is called a geoid, which means
Earth-shaped.
•
it has a thin skin, just as the Earth has a crust
which is much thinner than the other layers
•
2
Land and sea
it has a solid core (the stone) just as the
Earth has a solid inner core
•
3
The correct answer is molten rock and metals,
but learners will most likely say there is
more rock.
the flesh is not solid, which is similar to
the mantle.
A peach is a bad model because:
4
Ice
Heating
water
We call this melting.
5
Heat from the Sun
Questions
1
The peach has a thin, pink skin covering
the flesh.
2
The internal structure
3
The flesh and the stone.
•
it is not exactly the same shape as Earth
•
the inner core is the stone but there is no
outer core
•
the flesh is not liquid like magma.
4
In 2014 scientists used new equipment in a
laboratory to measure the temperature when
iron melted under pressure and found it was
6000 °C. This meant that the inner core was
hotter than they had thought.
5
Temperature increases the deeper you go into
the Earth’s crust, so it will be much hotter in
a deep mine than at the surface.
4.2 Volcanoes
Getting started
9
1
The mantle
2
Magma
3
It is molten rock that is very hot and flows like
a liquid.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Questions
Activity 3: What have I learnt about
volcanoes?
1
The lava that is still flowing is red.
2
The lava that has cooled down and hardened
into rocks is black.
1
A, because it is a mountain built up of layers
of ash and lava.
3
Both the photograph and the diagram show
a cone-shaped mountain, a crater, an ash
cloud and lava flowing down the side of
the mountain. Also, the diagram shows a
secondary cone and internal features such as
the vent and layers of lava and ash.
2
B, because lava spread out in a huge flat plateau.
3
Buildings and power lines were destroyed;
poisonous gasses polluted the lake and killed
45 people.
4
Sicily is in an area where rocks of the Earth’s
crust are moving past each other. This causes
magma from the mantle to come up cracks to
the surface.
Activity 1: Describe the features of
a volcano
1
a
Vent/pipe
b
Crater
c
Secondary cone
Getting started
d
Lava
1
Rubbing (causing friction)
My hands get warm/I feel it as heat
4.3 Earthquakes
2
The crater and the lava
2
3
You can follow the path of the magma coming
through the Earth’s crust up the vent and
erupting at the surface. You can see the layers
of ash and lava forming a cone-shaped hill.
Activity 1: Find information about
earthquakes
1
Multi-storey buildings collapsed.
The diagram shows both the external and the
internal structure of the volcano.
2
The epicentre. Because the epicentre is on the
surface of the Earth immediately above the
focus, which is in the Earth’s crust where the
earthquake started
3
Many people were crushed underneath fallen
buildings.
4
The railway lines have bent.
5
Mexico
6
The rocks are rubbing together. This creates
huge amounts of energy. The energy transfers
into waves which travel to the Earth’s surface.
Think like a scientist: Draw a diagram
of a volcano
Learners’ drawings should follow the outline of
the cone-shaped mountain in the photograph. The
features should be the same as the diagram above
the photograph, but without the secondary cone,
because there is none visible on the photograph.
Activity 2: Describe where volcanoes
erupt
1
The Pacific Ocean
Questions
2
New Zealand, Indonesia, the Philippines,
Japan, Alaska, west coast of Canada and
USA, Central America, west coast of South
America (Peru, Ecuador, Bolivia and Chile)
1
A tsunami is a huge sea wave.
2
A tsunami happens when there is an
earthquake or a volcanic eruption under the
sea. The energy from the earthquake transfers
to the sea to make huge waves.
3
The sea close to the coast is shallow, which
causes the waves to get bigger.
4
The boat was carried on top of a huge wave
(tsunami) and dropped further inland.
3
10
It is called the Pacific Ring of Fire because the
Pacific Ocean is surrounded by a line of active
volcanoes.
4
Examples: North and South America except
for the west coasts, Australia, India, Middle
East, Northern Europe. In these regions there
are no breaks in the Earth’s crust for magma
to come through.
5
Indonesia, the Philippines and Japan have a high
risk of volcanoes because they have cracks in the
Earth’s crust that allow magma to erupt.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Activity 2: Case study: an earthquake
in Chile
1
a
b
n epicentre is the point on the Earth’s
A
surface where the most earthquake
damage occurs.
The epicentre was off the coast of Chile.
2
The focus is the point inside the Earth’s crust
where the earthquake begins.
3
Chile is in the Pacific Ring of Fire. In this
area there are many breaks in the Earth’s
crust. When sections rub together they cause
earthquakes.
4
Buildings destroyed, huge cracks in roads
5
You must feed the fish the same nutrients it
gets in its natural habitat.
Put plants and stones in the tank to make it
more like the fish’s natural habitat.
4
Activity 1: How birds are suited to
different habitats
1
Bird
Shape of
beak
How can the
bird 's beak help
it to catch and
eat food?
Pigeon
Many people died because they were crushed
by falling buildings. Others died because they
were on roads when roads were destroyed.
Small and
pointed
It cracks open
seeds
Kingfisher
6
Powerlines were destroyed by the earthquake.
Large with It catches fish
a sharp
point
7
The earthquake was very strong so waves
reached as far as Peru.
Starling
Long and
pointed
It uses the point
to dig for worms
8
The focus of the earthquake was under the sea
just off the coast of Chile. This started a huge
sea wave or tsunami.
Flamingo
Long and
flat
It strains plants
and animals from
water
9
The wave travelled across the Pacific Ocean
and reached the coasts of Japan and
California.
2
Getting started
Parks and gardens have a variety of plants. So
some birds can eat seeds, some can eat nectar
and others can eat insects or worms. There
may be a pond or a lake in the park where
water birds can find food. Also people come
and feed the birds in parks and gardens.
3
Seagulls eat any left-over food and dead animals.
1
Think like a scientist: Bird watching
4.4 Different habitats
Picture A is a hot, wet habitat with lots of tall
trees and plants.
Picture B is a hot, dry habitat with very few
plants.
2
Habitat A has more plants and probably has
more animals because there will be a lot more
food available for them to eat. But the hot, dry
habitat will have lots of different insects, small
animals and birds.
Answers will vary according to which birds learners
observed. Learners must show their recordings
made at different times to show that they have
repeated observations. For dot plots, refer to the
New science skills section.
Questions
1
The orchid must be kept in a warm but shady
place because in its natural habitat it grows in
a tropical forest which is warm, but the orchids
are shaded by the trees. It must be given the
correct amount of water. In their natural
habitat orchids grow on branches of trees and
rely on drops of rainwater falling on them.
2
It can survive if it is protected from frost and
given plenty of water.
3
Learners’ own responses. Hopefully they will
say that you must remember to water it, give it
light, cut off dead parts and change the soil or
add nutrients to the soil from time to time.
Questions
11
The fish can only use its gills to breathe in water.
1
They use their gills.
2
They have to move away from predators
(bigger fish that will eat them). They use their
fins to move fast.
3
Discussion points: the water must be the
same temperature the fish are used to in their
natural habitat.
You must replace the water in the tank
regularly.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Activity 2: How are tigers suited to
their habitat?
Think like a scientist: Investigate how
we see an object
1
Dense, dark forests in parts of Asia.
1
No
2
The stripes help the tiger to blend in with the
sunlight filtering through from the tops of the
trees. The stripes break up the tiger’s body shape.
2
Yes
3
Light travels from the light source (the
flashlight) to the object (the coin). The light
bounces or reflects off the coin into our eyes.
This is how we can see the object.
3
The tiger has very good hearing so it can hear
other animals moving around.
4
It is difficult for a tiger to live in a zoo because
it does not have much space. But zookeepers
make sure their space has trees and they feed
the tigers animals they are used to eating.
Check your progress
1
1 – D; 2 – C; 3 – H; 4 – A; 5 – B; 6 – G;
7 – E; 8 – F
2
a
A composite volcano
b
1 – magma; 2 – Earth’s crust; 3 – secondary
cone; 4 – lava; 5 – vent/pipe; 6 – crater
3
a
The epicentre is the point on the surface
of the Earth immediately above the focus
of the earthquake deep in the crust.
b
4
Movements in the crust create energy that
transfers into waves, which ripple through
the Earth and across the surface as an
earthquake.
1
The Sun
2
The car
3
Light from the Sun travels to the car. Light
reflects off the car into the person’s eyes.
4
At night street lamps will be on. Light from
the street lamp travels to the car. Light reflects
off the car into the person’s eyes.
5.2 Light travels in straight lines
Getting started
1
The Sun and a film projector
2
In a straight line
3
No. Some learners may say Yes – this is a
misconception that they will realise when you
do the first activity.
a
Long, thin, curved and pointed.
b
The sunbird can push its beak deep down
into the flowers to reach the nectar.
Think like a scientist: Prove that light
travels in straight lines
c
It could survive if there were other flowers
that it could get nectar from.
Prediction: learners should predict that they will
be able to see the light at the end of the tube.
d
I think proteas survive if they have sandy,
well-drained soil, plenty of sun during the
summer, very little water.
Can your partner see the light when they look
down the other end of the tube? Yes.
Unit 5 Light
Prediction with bent tube: learners should predict
that they will not be able to see the light at the end
of the tube.
Now can your partner see the light when they look
down the other end? No.
5.1 How we see things
Conclusion: light travels in straight lines.
Getting started
12
Activity: How can the person see
the car?
1
Electric lights and fireworks
2
The Sun or electric light
3
Some learners will say the light shines out of our
eyes and lights up the teacher – this is a common
misconception. Some learners might say that
light from the teacher shines into their eyes. (The
full answer is that light shines from the source
of light in the classroom onto the teacher and
reflects off the teacher into their eyes.)
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Activity: Practise drawing ray diagrams
2
The Sun is a star and Earth is a planet.
1
B
3
2
1 is the arriving ray and 2 is the reflected ray.
A star sends out/emits its own light. A planet
reflects light from a star.
3
Activity: Planets in our solar system
1
The Sun. It gives us light and heat.
2
Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, Neptune.
3
a
B. Saturn takes 29.5 ‘Earth years’. It is
much further from the Sun than Earth so
its orbit is much bigger.
A
Learner
B
person next to learner
a
A = Arriving ray
B = Reflected ray
5.3 Light reflects off different
surfaces
Getting started
1
There is no light.
2
Light shines on the person. Light reflects off
the person into my eyes.
Activity: Describe how people use
mirrors to see things
1
2
3
Light travels from the bike behind me to my
rear view mirror. Light reflects off the mirror
into my eyes.
The shop manager can see what people are
doing at the back of the shop. Light travels
from the people to the mirror. Light reflects
off the mirror into the shop manager’s eyes.
Light from the underside of the patient’s teeth
travels to the mirror. The light reflects off the
mirror into the dentist’s eyes.
Think like a scientist: Investigate how
well different surfaces reflect light
Questions
1
This will depend on the materials used and
what learners predicted.
2
Flat, smooth, shiny surfaces reflect light best.
3
Smooth, shiny surfaces reflect light well. Rough
surfaces absorb more light than they reflect.
4
Pattern seeking
5.4 Light in the solar system
Getting started
1
13
A is the Sun, B is Earth and C is the Moon
A. Mercury takes 88 ‘Earth days’. It is
closer to the Sun than Earth, so its orbit
is smaller.
Questions
1
An asteroid is a rocky mass that orbits the
Sun.
2
Most of the asteroids are between the planets
Mars and Jupiter.
3
A moon is a body in space that orbits a planet
or an asteroid.
4
Half of Titania is in darkness because it is facing
away from the Sun.
5
Titania
Uranus
t
Orbi
6
Jupiter has 79 moons!
Think like a scientist: Find out what is in
our solar system
1
Moons, asteroids and comets
2
Any two from a planet, an asteroid and a star.
3
Sun
4
5
a
Saturn has 62 moons.
b
Saturn’s largest moon is Titan.
Earth
The biggest asteroid in the solar system
is Ceres.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
5.5 Day and night
Getting started
1
Learners can say where the Sun is in the
morning, e.g. the Sun rises on this side of our
school.
2
Learners can say where the Sun is in the
evening, e.g. the Sun sets on the other side of
our school.
3
Think like a scientist: Investigate the
changing length and position of a
shadow
1
The learner’s picture should be similar to the
one in the Learner’s Book. Make sure that
learners have labelled the time at the end of each
shadow line.
2
a
The Sun was low in the sky in the early
morning and the shadow was long. The
Sun was high in the sky at midday and
early afternoon and the shadow was
short. The Sun was low in the sky in the
late afternoon and the shadow was long.
No. It is the Earth that moves, not the Sun.
Think like a scientist: Use a model to
show day and night
b
The Earth spins on its axis once every 24
hours. This movement causes day and night.
2
Left semi-circle of Earth in diagram shaded
black, right semi-circle of Earth in diagram
shaded yellow.
3
The shadow started long in the early morning,
became shorter up to about 13.00 and then
became longer again.
3
When Malaysia is having daylight, Spain is
having darkness because it is on the other
side of the Earth. So if Ali phones Farouk at
lunchtime it will be the middle of the night
before in Spain.
4
The shadow falls on one side of the stick in
the morning and on the other side of the stick
in the afternoon.
5
On some days there were clouds so we were
not able to see shadows. On sunny days we
were able to see and record the shadows.
6
The Sun appears to move from one side of the
sky to the other and start low in the sky, go up
higher and then come down low again. This
apparent movement is caused by the Earth
spinning on its axis. The Sun does not move.
4
We would only have five hours of day and five
hours of night.
5.6 Investigating shadow lengths
Getting started
1
The Sun
2
The children
Check your progress
3
Shadows
1
A-5, B-1, C-7, D-3, E-4, F-2, G-6.
Questions
2
Reflecting surfaces: mirror, clear water.
Absorbing surfaces: muddy water, wood.
3
a
1 – Sun, 2 – Earth, 3 – Moon, 4 – axis,
5 – orbit
1
The golf flag and the stick block the light from
the Sun.
2
They are different lengths and different
directions.
3
The short shadow is the midday one and the
long shadow is formed in the late afternoon.
4
Wrong answer: The Sun moves across the sky
throughout the day.
Correct answer: The Earth spins on its axis
once every 24 hours.
14
The Sun appears to be in the east in the
morning, overhead in the middle of the
day and in the west in the afternoon.
1
4
b
The Earth spins on its axis.
c
Mercury, Venus, Mars, Jupiter, Saturn,
Uranus, Neptune
a
Flashlight
b
Cat
c
Diagram:
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
a
Shorter
b
Longer
Think like a scientist: Investigate
whether water conducts electricity
c
Longest
1
Learners’ own response.
d
Shortest
2
e
The Earth spins on its axis.
Pure water did not allow electricity to pass
through it. Salty water did allow electricity to
pass through it.
3
Pure water is not a conductor but salty water
is a conductor of electricity.
4
Unit 6 Electricity
Yes, my body would be a good conductor
of electricity because the water in my body
contains salts.
5
6.1 Which materials conduct
electricity?
My body is a good conductor so if I touch
bare wires the electricity will pass into my
body and I could get an electric shock.
6
Seawater is salty so it conducts electricity.
5
6
There was a bend in the tunnel. Light travels
in straight lines so they could only see the light
at the end of the tunnel when they had gone
round the bend.
Getting started
1
(1) Connecting wires, (2) Lamp, (3) Lamp
holder, (4) Cell
2
Terminals
3
The cell stores energy and pushes electricity
around the circuit.
Getting started
1
1. television; 2. microwave oven; 3. drill;
4. iron.
Think like a scientist: Test which
materials conduct electricity
2
Learners’ own responses; kitchen is the
most likely.
1
To avoid cutting yourself.
3
2
You could get an electric shock.
It is the same except for the strength. The
electricity we use for appliances is much
stronger.
3
Learners’ own responses.
4
We used the same testing apparatus for each
material. We tested each material for the same
length of time.
5
Conductors are metals. Insulators are nonmetals such as plastic, glass, cork and paper.
6
Learners’ own responses.
7
Learners’ own conclusions.
8
Pattern seeking and fair testing.
9
Because copper is a good conductor
of electricity.
6.2 Does water conduct
electricity?
Getting started
15
6.3 Using conductors and
insulators in electrical appliances
1
The salt disappears into the water – it
dissolves.
2
Make a circuit with a lamp and put the object
you want to test in the circuit and see if the
lamp lights up or not.
Activity 1: Classify materials used
in electrical appliances as electrical
conductors or insulators
1
Plastic is an electrical insulator so it is safe to
handle it.
2
Copper is a good electrical conductor.
3
Learners’ own responses
4
110 V or 220 V depending on which country
you live in.
5
Drawing should label plastic casing, which is
an insulator, and point inside to wiring, which
is a conductor.
6
The x-axis should name different rooms.
Learners draw a dot for each electrical
appliance in each room. They should find their
dot plot shows most appliances in the kitchen
and lounge.
For full instructions on how to draw a dot
plot refer to the Skills section at the end of
the Learner’s Book.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Activity 2: Predict safe or unsafe use
of appliances
2
In the wire
3
The cell
1
He could get an electric shock.
4
The switch
2
He is pushing a metal screwdriver into the
holes of the socket when the power is on. The
electricity could flow from the wires in the
wall to the screwdriver in his hand. The wires
and screwdriver are made of metal which is a
conductor of electricity.
Think like a scientist: What happens
when we change the number of
components in a circuit?
1
Cutting the plastic off the ends of the wire.
Touching bare wire when the circuit is closed.
Tap water conducts electricity. If she touches
the bare wire inside the toaster with wet hands
she could get an electric shock.
2
Always cut away from you and cut on a hard,
non-slip surface. Do not touch bare wires
when the circuit is closed. Open the circuit
first if you have to touch wires.
3
More brightly. The same strength of current
had to light up one less lamp. This made the
remaining lamps shine more brightly.
4
The lamp will ‘pop’ or burn out. This is
because the current passing through is too
strong.
5
More dimly. There was a smaller strength of
current to light up the same number of lamps.
6
The lamps shine less brightly when you add
more lamps to the circuit.
3
6.4 Switches
Getting started
1
The lamp comes on.
2
The lamp goes out.
Think like a scientist 1: Make a switch
1
The metal paper clip will conduct electricity.
2
The metal drawing pins will conduct electricity.
3
The wooden base is an insulator of electricity.
4
Learners should suggest other materials
made of metal to replace the drawing pins
and paper clip, such as nails and coins. They
could suggest using a plastic base instead of a
wooden base since plastic is also an insulator.
The lamps shine more brightly when you add
more cells to the circuit.
7
Think like a scientist 2: Make a circuit
with a switch
Conclusion: Changing the number of lamps
or cells in a circuit can make a lamp brighter
or dimmer.
8
Pattern seeking
1
The lamp lights up because the circuit is
complete.
Check your progress
2
Turn the switch off.
1
3
Learners’ drawings should contain a cell,
a switch, a lamp and connecting wires.
4
The circuit could be broken because wires are
not connected properly. If the circuit is broken
the lamp will not light up.
5
We were careful cutting the plastic off the
ends of the wires (if they had to do this). We
did not touch any bare wires when the circuit
was closed. (An insulator, such as a chopstick,
could be used to open and close the switch.)
6.5 Changing the number of
components in a circuit
a
Switch
b
Lamp holder
c
Cell
2
Cork and plastic
3
a
It closes or opens the circuit.
b
Open the switch.
c
More dimly.
d
More brightly.
4
He has not turned the switch off and pulled
the plug out of the wall socket.
5
The correct order is C, B, A, D.
Getting started
1
16
A cell, a lamp in a lamp holder, a switch and
connecting wires.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021