CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Workbook answers
Unit 1 Living Things
1.1 Bones and skeletons
Challenge
Focus
3
1
Animal
skull
jaw
rib cage
arm bones
4
Skeleton
Bird
C
Rabbit
D
Frog
B
Crocodile
A
W is the skull
X is the ribcage
spine
Y is the spine
Z is the hip
1.2 Why we need a skeleton
Focus
1
leg bones
Practice
2
Practice
2
1
a
Skull
b
Rib cage
c
Spine
d
Jaw bone
e
Different bones have different jobs, so
they need to be different sizes and shapes
(or similar answer).
Skull – Protection; Ribs – Protection;
Arm Bone – Movement; Spine – Support and
Protection (the spine protects the spinal cord).
a
A skeleton is important because it makes
a frame that supports the body; it allows
us to move; it protects organs inside the
body and holds them in place.
b
The baby would stay small and not grow
into a child.
c
A broken bone
d
They can take an X-ray picture.
e
The ends of the bone grow back together.
f
The skeleton can grow big to support a
large animal. A worm cannot grow very
big because it does not have a skeleton to
support it.
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Challenge
3
a
Meshack
b
14 cm
c
Ali is the oldest. His upper arm bone
is longer than Ahmed’s. Our bones get
longer as we get older.
d
Ali, Nasreen, Ahmed. Ali has the longest
upper arm bone, Ahmed has the shortest.
e
Fatima and Meshack
f
They have the longest upper arm bones.
g
That skeletons grow and allow us to grow.
h
Learners should add a bar that is shorter/
lower than the bar for Ahmed’s arm bone
length, e.g. 8 cm.
b
Part C lifts
c
Part B relaxes/contracts and gets shorter/
longer. Part B pulls/pushes on part C and
makes it drop/lift.
1.3 Skeletons and movement
1.4 Different kinds of skeletons
Focus
Focus
1
1
Tick boxes below fish, cat and rabbit.
2
a
Vertebrates
b
Invertebrates
c
Exoskeleton
d
Cross in box below beetle and snail
2
When I lift a weight, the muscle at the front of
my arm contracts and gets shorter. The muscle
at the back of my arm relaxes and gets longer.
This shows that muscles work in pairs.
Add labels to drawing: top label – the muscle
relaxes; lower label – the muscle contracts.
Practice
Practice
3
3
4
Muscles work by pulling on the bones they are
joined to. Muscles work in pairs. When one
muscle contracts/relaxes, the other
muscle relaxes/contracts. The muscle that
contracts gets shorter. The muscle that relaxes
gets longer.
a
b is an ant
c is a spider
d is a centipede
e is a snail
The muscle that is working contracts/relaxes.
The muscle that is resting contracts/relaxes.
f is a worm
g is a slug
Challenge
5
a
a is a bee
A upper arm bone; B biceps muscle;
C lower arm bone; D triceps muscle.
b
They do not have a backbone.
c
Bird or bat
Fish, seal, dolphin, whale, or snake
2
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Challenge
4
Row two left-to-right: Does it have fur? Does it
have legs?
Row three left-to-right: Does it have a short
tail? Does it have feathers? Does it have four
legs? Does it have fins?
Unit 2 Energy
2.1 Energy around us
Focus
1
1.5 Medicines and infectious
diseases
Focus
1
Movement
c
Heat and light
d
Sound and movement
2
Sentence
True False
Check with an adult before you take any
medicines. ✓
a Things that do not move
do not have energy.
C
Medicines cannot stop us from getting
illnesses. ✘
b Our bodies contain
energy.
D
Plants and animals can have infectious
diseases. ✓
c There is light energy in
wind.
a
c
d A stove gives off heat
energy.
i
n
j
e
c
t
i
o
n
n
w
e
r
t
a
n
i
o
h
a
s
d
f
b
h
n
l
a
c
b
r
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l
l
t
h
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e
d
i
n
e
m
m
d
e
v
f
p
q
t
d
e
f
r
u
r
k
l
g
o
n
u
m
i
x
t
u
r
e
t
p
Injection; some learners may also say
tablets as we take tablets to prevent
diseases like malaria.
Inhaler
Challenge
3
b
B
b
3
Movement
Practice
A
Medicines make us better when we
are sick. ✓
Practice
2
a
✘
✓
✘
✓
e A television set gives off
movement energy and
sound energy.
f There is energy in running
water.
3
✘
✓
a
Energy makes the stroller move.
b
Energy makes wet washing dry.
c
Energy changes the raw egg into a cooked
egg.
d
Energy makes the rattle make a sound.
Challenge
4
Mixed-up
word
Form of
energy
Something
that has this
form of energy
ghitl
light
Marcus took medicine meant for someone
else. He did not check to see whether he
should take it or how much he should take.
Sun/lamp/bulb/
candle/torch
veomtnem
movement
He did not check that the tablets were meant
for headaches.
ball rolling/
person/cycling/
running water
ehte
heat
He did not ask an adult to help him take
the medicine.
stove/fire/Sun/
heater/toaster
nosdu
sound
radio/TV/
phone/musical
instrument
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5
a
The ball had energy.
b
The ball did not have enough energy to
move that far.
c
Sofia can throw the ball harder. This will
give it more energy and it will move a bigger
distance.
2.2 Energy transfers
Focus
1
a
Food → donkey
b
Air → balloons
c
Fire → meat
d
TV set → person
Practice
2
3
4
The heat energy from your hand is transferred
to, or moves to, the ice which makes the ice
melt.
a
Movement energy
b
There is a transfer of movement energy
from your hand to the toy to make the
toy move.
a
Heat moves from the hot water to the
spoon. The heat moves from the spoons
to the petroleum jelly and melts it, which
makes the bead fall off.
b
40 °C
c
100 °C
d
The bead falls off faster when the
temperature is higher.
e
The hotter the water, the more energy it
has that can be transferred/move to the
spoon.
f
Any from 13 to 15 minutes is acceptable.
Data point and line segment added to
graph.
2.3 Energy changes
Focus
1
a
Electrical energy →
light energy + heat energy
b
Electrical energy → heat energy + sound
energy
c
Movement energy →
heat energy + sound energy
d
Movement energy → sound energy
Sun → solar panels → water
Challenge
Practice
16
5
2
15
Time for bead to fall off in minutes
14
13
Picture
What form
Where
of energy is does the
transferred? energy go
to?
A
heat
the food/
no change
water in the
pot
B
movement
the block of sound
wood, surrounding
air
C
electricity
heater
12
11
10
9
8
7
6
5
4
3
2
1
0
4
10 20 30 40 50 60 70 80 90 100
Water temperature in °C
Does the
form of
energy
change?
If so, how?
heat,
movement
D
movement
trampoline heat
E
light
plant
food
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e
Challenge
3
a
To make them warm
b
Movement energy → heat energy
c
Electrical energy is changed in the light
bulb into light energy.
d
Electrical energy → light energy + heat
energy + sound energy
e
The banana
f
Energy in food → movement energy in legs
g
Sound energy
h
The sound energy moves/is transferred
from the bell through the air to Vikal’s
ears.
4
Cabbage → snail → duck
b
Leaf → caterpillar → bird
c
Corn → locust → lizard → cat
d
Melon → mouse → snake → eagle
Practice
2
a
The plant
b
Herbivores
c
Rat, rabbit
d
Eagle, rat
e
Rat and rabbit are prey for eagle; rabbit is
prey for rat.
f
Rat – it eats plants and animals
g
Plant → rat; or plant → rabbit
h
Plant → rat → eagle; plant → rabbit
→ eagle or plant → rabbit → rat
3.1 Materials, substances and
particles
Focus
1
a
Liquid
b
Solid
c
Solid
d
Liquid
e
Liquid
f
Solid
Practice
2
a
5
a
he grass plant produces food for the
T
deer/herbivore.
b
The grass uses energy from the Sun to
makes its own food.
c
The direction in which the energy in the
food is passed along the food chain.
d
The energy in the grass passes to the deer
when it eats the grass. The energy in the
deer passes to the tiger when it eats the
deer.
b
Solid
Liquid
a
All substances are made of particles.
b
Solids have a fixed shape due to their tightly
packed particles which move in a fixed
position.
c
Liquids can spread and take on the shape
of their container.
Challenge
3
Grass → deer → bear → tiger
Unit 3 Materials
Focus
a
a
An animal that eats plants and other
animals.
b
2.4 Energy and living things
1
Yes. The herbivore will always eat the
producer/plant, and the carnivore will
always eat the herbivore.
Challenge
3
a
Drawing A – liquid; drawing B – solid
b
The particles in liquids (A) are not as
close together as the particles in solids.
They have larger spaces between them and
can move more freely than in solids.
c
he particles in solids (B) are held tightly
T
together. They have small spaces between
them and cannot move freely.
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a
Solids have a fixed shape because their
particles do not move very much.
b
Liquids can change shape in some ways
because their particles can move around
each other.
3.2 How do solids and liquids
behave?
Focus
1
a
Challenge
6
Time taken for sand to flow in minutes
4
a
10
8
6
4
2
0
b
2
3
0
Volume of sand in ml
To make it a fair test.
Particles in a liquid are close together, but they
can slide past each other and change places.
Because of this, a liquid can change shape
easily.
a
No
b
Particles in a solid are packed close
together in fixed positions. They cannot
change shape easily.
b
The time taken for the sand to flow
increases as the volume of sand increases.
c
he size of the sand grains, the size of the
T
hole in the funnel, how dry the sand is, or any
other suitable idea.
d
Bigger grains flow faster; the bigger the
hole in the funnel, the quicker the sand
flows through it; dry sand will flow faster
than wet sand because there is more
airspace in the dry sand.
Practice
4
5
In solids, the particles are packed close
together in a fixed position. They cannot move
freely. This explains why solids have a fixed
shape.
6
3.3 Melting and solidifying
Focus
In liquids, the particles are closely packed
but further apart than in solids. This allows
the particles to move past one another. This
explains why liquids, such as water, can flow
and take the shape of the container they are
in.
1
a
Sand can flow or be poured.
2
b
Sand is made up of lots of tiny grains.
There is air between the grains which
means that the grains have space to move
into. This lets the grains flow past one
another like the particles in a liquid.
c
50 100 150 200 250 300 350 400 450 500
a
Liquid
b
Solid
c
You must cool it.
d
Water (liquid state)
(solid state)
a
Solid
b
Liquid
c
Melting
d
Butter (solid state)
(liquid state)
cool
heat
ice
butter
Any two, such as flour, salt, sugar or
uncooked rice.
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Practice
Practice
3
2
a
B
a
True
b
C
b
False
c
A
c
True
d
A
d
True
e
D
e
False
f
False
a
Yes
b
A new substance formed.
Challenge
4
a
80 °C
b
10 °C
c
14 minutes
Challenge
d
He should put the same amount of water
in each beaker; ice cubes must be the same
size.
4
e
f
g
h
a
A Water
B Air
b
There was water and air in tube A.
Ice melts faster in hot water than in cold
water (or similar conclusion).
There was no water in tube C.
When we heat the ice, the heat energy
makes the particles move faster and move
away from each other. This makes the
solid ice melt and become liquid water.
When we increase the water temperature
we add more heat energy. This makes the
particles move even faster so they move
away from each other quicker, which
makes the ice melt faster.
To rust, the iron must be in contact with
water and air.
It would take less time for the crushed ice
to melt. The heat energy in the water only
has to be transferred to small pieces of
ice. This transfer will happen quicker than
a heat transfer to bigger ice cubes.
He can ask an adult to heat the water
for him. He should wear protective
gloves and clothing when he works
with the hot water.
3.4 Chemical reactions
Focus
1
3
There was no air in tube D.
c
Steel does not rust like iron.
Do all metals rust in the same way? (Or
similar question.)
Do all metals rust? (or similar question)
d
Factors can include the shape and size of
the test tubes and the amount of water in
each test tube.
e
The type of metal the nails or other
objects are made from.
Unit 4 Earth and its
habitats
4.1 The structure of the Earth
Focus
1
The internal structure of the Earth describes
what is below the surface.
a
Chemical reaction
b
No chemical reaction
c
Chemical reaction
The Earth’s crust is thinner below the oceans
than below the land.
d
Chemical reaction
The outer core of the Earth is liquid.
e
No chemical reaction
The core consists of metals.
The mantle consists of magma.
The Earth’s crust is the thinnest layer of
the Earth.
The temperature increases as you get closer
to the centre of the Earth.
7
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The core is the thickest layer of the Earth.
Practice
The inner core of the Earth is solid.
2
a
Magma is a liquid material.
Practice
2
a
The world map in the Workbook is
centred on Africa and Europe. So, the
Pacific Ocean is half on the left-hand side
and half on the right-hand side.
Label from top to bottom:
Crust
Atlantic Ocean
Mantle
Outer core
Inner core
b
Crust – rocks
Mantle – magma
b
It is called the Pacific Ring of Fire
because there are many active volcanoes
along it.
c
Parts of the world where there are lots of
breaks in the Earth’s crust have lots of
volcanoes. Parts of the world where there
no breaks in the Earth’s crust have no
volcanoes.
Outer core – metals
Inner core – metals
c
Crust – solid
Mantle – liquid
Outer core – liquid
Inner core – solid
Challenge
Challenge
3
3
a
12 km
b
It is too hot.
c
The speed of earthquake waves passing
through the Earth.
A-6; B-1; C-4; D-3; E-2; F-5.
4.3 Earthquakes
Focus
1
a
An earthquake happens when there is a
sudden movement of rocks in the Earth’s
crust. This creates huge amounts of
energy. The energy transfers into waves.
The waves travel through the Earth’s crust
to the surface.
b
Any three from:
4.2 Volcanoes
Focus
1
When a volcano erupts, magma from the
mantle reaches the surface through a crack in
the crust. When magma reaches the surface it
is called lava.
•
buildings collapse
Sometimes lava and ash come out of the
volcano. These materials build up to form
a cone shaped mountain called a composite
volcano.
•
landslides and mudslides
•
flooding
•
railway lines bent
When the lava is very hot it runs quickly
over the surface. The islands of Hawaii were
formed like this. The lava cools to form black
rocks.
•
bridges and roads destroyed
•
electricity lines broken
•
fires caused by broken gas pipes.
c
8
The Pacific Ring of Fire
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c
Practice
2
a
A tsunami
b
When an earthquake begins under the
sea a huge wave develops. When the huge
wave reaches a low-lying coastal area it
floods the land.
c
The village will be flooded and there will
be a lot of damage. The people could be
seriously injured or drown.
Unit 5 Light
5.1 How we see things
Focus
3
1
b
Buildings must be built with deeper,
stronger foundations to reduce the effects
of shaking.
They notice animals behaving strangely.
For example, snakes come out of their
winter sleep.
4.4 Animals in different habitats
a
The Sun
b
Light travels from the Sun to the palm
tree. The light reflects off the palm tree
into Arun’s eyes. This is how Arun sees the
palm tree.
Practice
a
A lamp
Focus
b
The needle and the thread
1
c
Light travels from the Sun to her sewing.
The light reflects off her sewing into Mrs
Liong’s eyes. This is how she sees her
sewing.
2
b
Polar bear
c
Polar bears have very thick fur to help
keep them warm.
a
Water
b
A fish
c
A fish has gills to allow it to take in oxygen
under water. Its fins and shape allow it to
swim well.
Practice
3
Challenge
3
a
A box of books.
b
It is too dark.
c
She must shine a flashlight into the
cupboard.
d
The light from the flashlight travels to the
box of books. The light reflects off the
box of books into Zara’s eyes. This is how
she sees the box.
a
Bird C (and B)
5.2 Light travels in straight lines
b
Bird D
Focus
c
Bird A
1
d
A duck, swan, goose or other water bird
e
Bird B
f
An eagle, falcon, owl, hawk or other bird
of prey
Challenge
4
2
a
Very cold with snow and ice (North Pole/
Arctic)
Polar bears have a thick layer of fat to
help keep them warm.
9
Its mouth is covered with very thick skin
to protect it from the thorns.
Challenge
a
A giraffe has a long, thick tongue to curl
round branches and bring the leaves to his
mouth.
a
Tropical grasslands with thorn trees. It is
hot and dry most of the time.
b
By using/extending its long neck.
Sofia shines the flashlight down the tube. Zara
can see the light when she looks up the tube
from the other end.
Sofia makes a bend in the tube. She shines the
flashlight again down the tube. This time Zara
cannot see the light.
This demonstrates that light travels in
straight lines.
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2
a
5.3 Light reflects off different
surfaces
The Sun
b
Focus
ray
arriving
1
refle
cted
ray
a
Smooth and shiny surface
b
Image or mirror image
c
Light shines from the lamp on to Zara’s
face. Light from Zara’s face travels to the
mirror. The mirror reflects Zara ‘s image
into her eyes.
d
Wood absorbs/does not reflect light.
Practice
3
a
The lamps.
b
Light shines on Khalid. Light reflects off
Khalid and travels into Rabah’s eyes.
c
Rabah cannot see Khaild when he goes
around the corner because light cannot
travel round corners. Light travels in
straight lines.
Practice
2
4
arri
vin
Challenge
5
10
g ra
y
reflected ray
a
Aluminium foil
b
Reflects light
c
Water
d
All surfaces reflect some light, otherwise
we could not see them.
Challenge
3
Order of
event
Event
2
The light reflects off the cars
behind Mr Damsong.
6
Mr Damsong sees the cars
behind him.
4
The light reflects off the rear
view mirror.
5
The light travels into
Mr Damsong’s eyes.
3
The light travels to the rear
view mirror.
1
Light from the Sun shines on
the cars behind Mr Damsong.
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5.4 Light in the solar system
g
The atmosphere consists mostly of
carbon dioxide.
Focus
1
a
Letter on
diagram
D
Focus
Sun
C
1
Earth
E
Orbit of the Moon around
the Earth
B
Orbit of the Earth around
the Sun
A
A planet
E
A star
C
A body in space that
gives out light
C
A body in space that
reflects light
E or D
b
Mercury, Venus, Earth, Mars, Jupiter,
Saturn, Uranus, Neptune
c
Asteroids, moons and comets
Sun’s rays
Spin
Earth’s axis
b
24 hours
c
Learners should colour in the part facing
away from the Sun on the diagram. This
is the half of the Earth to the right of the
vertical line.
Practice
2
a
The Earth spins on its axis and makes one
complete turn in 24 hours. Almost every
place on the Earth faces the Sun and has
day for part of the 24 hours. When a place
is facing away from the Sun it has night.
b
All the planets orbit the Sun. When parts
of each planet face the Sun, these parts
have day, and parts facing away from the
Sun have night.
The solar system
b
The Sun
c
2 – Mercury; 3 – Mars; 4 – Neptune
d
365¼ days or 1 year
e
A shorter time
f
Venus is closer than the Earth is to
the Sun.
c
Longer
Neptune
d
Shorter
Neptune is the planet furthest from
the Sun.
Challenge
a
A planet
b
Further from the Sun
c
A telescope magnifies everything (makes
everything look bigger).
d
They looked at the night sky with their
eyes.
e
They knew it was red in colour.
f
They discovered that Mars has
two moons.
They discovered that there was ice on Mars.
11
a
a
g
3
5.5 Day and night
Moon
Practice
2
The rocks contain iron oxide.
Challenge
3
a
Day
b
Venus
c
121½ Earth days
d
Jupiter
e
2½ hours (6 hours on Earth is one quarter
of 24 hours. So on Jupiter one quarter of
10 hours is 2½ hours)
5.6 Investigating shadow lengths
Focus
1
a
12:00
b
Short
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CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
c
09:00 and 15:00
d
Long
e
During the morning the shadow becomes
shorter and is shortest at midday. During
the afternoon the shadow becomes longer.
f
The shadow at 18.00 will be beyond the
shadow at 15:00 and much longer.
2
Practice
2
Material Electrical Electrical
object conductor insulator
is made
from
1 Key
metal
2 Bottle
glass
✓
3 Toy duck
plastic
✓
4 Paper clip metal
S
S
Object
S
S
5 Book
S
✓
✓
paper
✓
6 Shopping plastic
Bag
✓
Practice
3
09:00
a
b
11:00
12:00
13:00
a
Circuit A – Yes; circuits B, C and D – No
b
Material A is an electrical conductor
and materials B, C and D are electrical
insulators.
c
Materials made of metal, such as the key,
are electrical conductors. Materials made
of ceramic, plastic and cork are insulators
of electricity.
15:00
The Sun appears to move across the sky.
No. The Sun only appears to be moving.
It is actually the Earth that is moving as it
spins on its axis.
Challenge
3
a
10:00 – drawing 5
12:00 – drawing 2
Challenge
4
a
Holding the plastic covered wires, allow
the bare metal wires to touch each other.
If the lamp lights up, the circuit works.
b
Coin ✓ chopstick ✘ glass ✘ plastic
spoon ✘
c
Test each object by holding one of the
plastic-coated wires in each hand so that
the bare wires touch two different parts of
the object. Observe the lamp. If the lamp
lights up, the object conducts electricity.
If the lamp does not light up, the object
does not conduct electricity.
d
Metals are conductors and non-metals are
insulators of electricity.
16:00 – drawing 4
19:00 – drawing 3
b
The position of the Sun and the length of
the shadow.
Unit 6 Electricity
6.1 Which materials conduct
electricity?
Object
Focus
1
12
a
A material that allows electricity to pass
through it is an electrical conductor.
b
A material that does not allow electricity
to pass through it is an electrical insulator.
Material
object
is made
from
Electrical
conductor
Electrical
insulator
Key
Metal
Glass
bottle
Glass
✓
Spoon
Plastic
✓
Cork
Cork
✓
✓
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
6.2 Does water conduct
electricity?
Practice
2
Focus
1
An electric kettle.
b
The plastic insulation on the electric wire
has worn away. This exposes the metal
wire. The metal wire conducts electricity.
If a person touches the wire they will get an
electric shock.
aPure water is water with no salts dissolved
in it.
b
Tap water contains salts dissolved in it.
c
They can conduct electricity because they
contain water with salts dissolved in it.
The kettle is close to the sink. The water has
salts dissolved in it. Salty water conducts
electricity. So a person who touches the bare
wire with wet hands will get an electric shock.
Practice
2
a
Assess poster using this grid:
Does
poster…
Yes, very Yes, fairly
well
well
No
Challenge
3
catch peoples’
attention?
Pylon
contain a
picture that
clearly conveys
the message?
Ceramic separator
contain a short
clear written
warning?
Cable
Challenge
3
The cables are made of metal because
metal is a good conductor of electricity.
The electricity was switched ON.
b
Copper
B
The plastic insulation had worn off
the wire where he held it.
c
The separators are made of ceramic because
ceramic is a good insulator of electricity.
C
He had sweaty hands. Salt water
conducts electricity.
Jawad got an electric shock
b
A
4
Arun and Marcus must not climb the pylon.
They could fall, and if they touch the cables they
will get an electric shock which will kill them.
6.3 Using conductors and
insulators in electrical appliances
6.4 Switches
Focus
Focus
1
13
a
a
a
A is an electric kettle; B is an electric
hairdryer and C is an electric mixer/whisk.
b
110 V or 220 V (or similar, depending on
location).
c
Plastic
d
An electrical insulator.
e
Electrical insulators do not conduct
electricity.
f
The wires are the electrical conductors.
These are inside the appliances.
1
a
A switch open or closes a circuit.
b
The lamp should light up in circuit B.
In circuit B the switch is closed so the
electricity can pass through the circuit.
c
A switch causes a break in a circuit when
it is open, as in circuit A. The electricity
cannot flow all around the circuit.
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021
CAMBRIDGE PRIMARY SCIENCE 4 TEACHER’S RESOURCE
Practice
Practice
2
2
a
No, electricity is not flowing in circuit A.
b
The switch is open.
c
Close the switch.
d
Yes, electricity is flowing in circuit B.
e
The switch at the wall is turned on. (Not
‘heat is coming from the iron’.)
f
Turn off the switch at the wall.
Challenge
3
Three cells, a cell holder, three lamps,
three lamp holders, a switch and five
connecting wires.
b
No. The switch is open.
c
More brightly
d
Less brightly
e
Less brightly
f
More brightly
Challenge
a
Learners should circle everything except
one of the lamps in a lamp holder and
one of the cells.
b
6.5 Changing the number of
components in a circuit
You can stick two cells together using the
sticks and tape. Make sure that the + end
of each cell is next to the – end of the cell
next to it.
c
The lamps will come on if I close the
switch, but not if I leave the switch open.
Focus
d
The remaining lamp will burn more
brightly.
e
The same strength of electricity will only
be used by one lamp instead of two lamps.
f
The lamps will burn less brightly.
g
The same strength of electricity will be
shared between three lamps instead of
two lamps.
4
1
14
aA cell, a switch, a lamp, a lamp holder
and connecting wire.
a
b
The switch is closed.
a
The switch is open so the circuit is broken.
b
They must close the switch so that the
circuit is complete.
a
Cells, lamps, lamp holders, connecting
wire and a switch.
b
Close the switch.
c
Less brightly
d
The same strength of electricity has to be
divided between three lamps instead of
two lamps.
3
Cambridge Primary Science 4 – Baxter & Dilley © Cambridge University Press 2021