CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Topic worksheet answers
Unit 1 The human body
Worksheet 1.1
1
a Hummingbird
b Blue whale
2
a Blue whale
b Hummingbird
3
a Blue whale
Cat
Elephant
Mouse
Human
Hummingbird
b The smaller the animal, the faster its heart beats OR The larger the animal, the slower
its heart beats.
4
Large animals have slower heartbeats than small animals, or similar conclusion.
Stretch questions
5
a Horse: 40 to 60 beats per minute; shrew 600 beats per minute
b Answer depends on evidence and learners’ predictions.
6
During hibernation, all the bat’s body processes slow down a lot. It needs very little energy
and oxygen during hibernation as it is inactive, so its heart does not need to beat fast.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 1.2
1
Refer to the drawing of the respiratory system in the Learner’s Book or the answer to question 3.
2
a
What happens to . . .
Breathing in
Breathing out
the diaphragm?
contracts, moves
downwards
relaxes, moves upwards
the ribs?
move upwards and
outwards
move inwards and
downwards
size of the chest?
gets bigger
gets smaller
the lungs?
the lungs fill with air
air is pushed out of the
lungs
b We need to breathe in order to bring air that contains oxygen into the body and to remove
air that contains carbon dioxide.
Stretch questions
3
a Bronchi should also be labelled leading into lungs on the drawing in question 1:
b Alveoli – look like little bunches of grapes inside the lungs:
4
The blood carries oxygen in the body in the red blood cells. People who live in very high
places have more red blood cells in their blood so that they can carry enough oxygen.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 1.4
Answers for the data table will vary according to the class size and number of learners
who are ‘infected’.
1
a More people are ‘infected’ in Round 2 because there are more ‘spreaders’ than
in Round 1.
b Fewer people are ’infected’ than in Round 2 because there are fewer ‘spreaders’.
2
a By a virus
b In body fluids when people with flu cough, sneeze or talk.
c People with flu who cough or sneeze into a tissue or wear face masks to stop
the virus spreading.
Stretch questions
3
Vaccination
4
Repeat the game, but give some people a coloured sticker to represent being
vaccinated against flu.
In the new Round 1, if a ‘vaccinated’ learner gets an infection sticker, it doesn’t count
as an infection. Compare the number of ‘infected’ learners with the original Round 1 results.
There should be fewer ‘infected’ learners.
The ‘vaccinated’ learners should then sit out. Then go on to a new Round 2.
Compare the number of ‘infected’ with the original Round 2 results.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Unit 2 Materials: properties and changes
Worksheet 2.1.1
1
a A line graph
b
2
a 0 °C
b No. Melting point is a property of a substance and each substance has its own
melting point.
c Heat energy from the surroundings is transferred to the particles of ice.
The heat makes the particles move faster and further apart as they gain energy.
When the particles have enough energy, they change state to become liquid water.
Stretch questions
3
a For four minutes.
b This is the time it takes for all the ice to melt.
4
a Learners should use their graphs to predict a temperature of about 10 °C after 20 minutes
by extending the right side of their line graph.
b See graph.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 2.1.2A
1
2
a 100 °C.
b Do the investigation several more times under exactly the same conditions
as the original experiment.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 2.1.2B
1
2
a 100 °C
b Yes. In both graphs the temperature increases up to 100 °C and stays at that temperature,
showing the water has reached boiling point.
c Do the investigation again several more times under exactly the same conditions
as the original experiment.
3
Bubbles form in the boiling liquid, steam forms and condenses in a cloud above
the boiling water.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 2.1.2C
1
2-3 See Worksheet 2.1.2B answers
4
a No.
b The graph of Mr Moola’s class’s results is steeper and the temperature reaches
boiling point quicker than the graph of Mrs Kaur’s class’s results.
c Mr Moola gave the water more heat/used a hotter burner or hotplate. The starting
temperature of Mr Moola’s water may have been higher than Mrs Kaur’s.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 2.3
1
a Water
b Sugar
2
a 100 °C
b 60 seconds
c About 74 seconds
d 5 °C
3
a The quantity of sugar; the quantity of water.
b The time taken for the sugar to dissolve.
c The temperature of the water.
4
Sugar dissolves more quickly as the temperature of the water increases.
Stretch questions
5
a To make sure that the results obtained are reliable.
b The sugar dissolves faster as the temperature of the water increases.
c Yes. In one test at 40 °C the sugar dissolved much faster (19 seconds) than in the
other tests at 40 °C (26 seconds and 27 seconds).
d
Temperature
in °C
Time for sugar
to dissolve in
seconds
Time for sugar
to dissolve in
seconds
Time for sugar
to dissolve in
seconds
Average time
for sugar to
dissolve in
seconds
10
77
73
75
75
20
52
48
50
50
30
34
36
32
34
40
26
27
19
24
50
19
18
17
18
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
e&h
f Fastest: 50 °C; slowest: 10 °C
g When a solid dissolves in a liquid, the solute particles move and spread out between
the solvent particles until they are evenly spread. The particles of both the solute
and the solvent have less energy at a lower temperature so the solute particles
spread more slowly between the solvent particles. When the temperature increases,
the particles gain energy and move more quickly and further apart. This allows the
solute particles to spread faster through the solvent particles.
h About 10 seconds
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 2.4
1
a Dependent variable – temperature of the mixture; independent variable – quantity
of water used; control variables – quantity of plaster of Paris used, how often the
temperature was measured, water temperature at the start of the experiment.
b Yes, only one variable was changed.
2
a Change in temperature.
b Formation of gas; change in colour.
3
The temperature increases as more water is added, up to when two parts of water are
mixed with one part of plaster of Paris (2:1 ratio). This gives the highest temperature
reached. As the quantity of water added increases further, the highest temperature
reached drops/decreases.
4
No. Dissolving is not chemical reaction. No new substances are formed when salts dissolve.
Stretch questions
5
It takes time for all the particles of plaster of Paris to react completely with the
water particles, or similar answer.
6
Heat is given off during the chemical reaction. As more and more particles of plaster of
Paris and water react, more heat is given off and the temperature rises. When all the
particles of plaster of Paris have reacted with the water particles, no more heat is
released and the product starts cooling down (to room temperature).
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Unit 3 Rocks, the rock cycle and soil
Worksheet 3.2
1
a Foundations are the underground base of a building. They are made of concrete.
b The slab is the floor of the building. It is made of concrete.
c Cement is made from crushed limestone and shells.
d To set means to become solid.
2
Cement + crushed stone + sand + water + air (can be in any order).
3
The sedimentary rock limestone is crushed to make cement. Igneous rock is crushed
to make the crushed stone.
4
The substances used to make concrete are all extremely hard – crushed igneous rocks,
crushed limestone and sand which is made of the hard mineral quartz.
When water is added the mixture sets very hard.
5
Stretch questions
6
Mortar is a mixture of cement, sand and water. Builders use mortar to stick layers
of bricks together.
7
Learners’ own responses.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Topic 3.4 Soil
Worksheet 3.4A
1
The family grows vegetables in the soil.
2
Each vegetable uses different things from the soil.
So Mrs Mbatha plants different vegetables in different soil each year.
3
They use chicken manure to put organic matter into the soil.
4
They dig the soil to put air into the soil.
5
In dry weather they water the soil.
6
They move their cows every week so that they don’t eat all the grass.
7
If there is no grass, there are no roots to hold the soil and it blows away in the wind.
Worksheet 3.4B
1
Vegetables
2
They plant different vegetables in the soil every year.
3
Chicken manure
4
They dig it and turn it.
5
To keep it moist in dry weather.
6
They move their cows every week so they don’t eat all the grass.
If there is no grass there are no roots to stop the soil blowing away in the wind.
Worksheet 3.4C
Action taken by the Mbatha family
How this action helps the soil
Plant different vegetables in different soil
each year
The soil has time to re-build itself since
different vegetables use different nutrients in
the soil
Spread chicken manure on soil around the
vegetables
Adds organic matter to the soil
Waters soil in dry weather
Keeps the soil moist
Move cows every week to different pasture
The grass roots keep the soil in place, so
making sure that the grass is not all eaten
saves the soil from blowing away in the wind
Dig the soil regularly
Puts air in soil and mixes in manure.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Unit 4 Food chains and food webs
Worksheet 4.2: Make a food web
1
The person who was the Sun.
The energy for all food chains and food webs comes from the Sun.
2
a Many food chains.
b Answers will depend on the food chains that each learner was part of.
For example, if the learner was a locust:
grass → locust → thrush→ cat→ eagle
grass → locust → frog→ cat → eagle
grass → locust → rat→ cat→ eagle
grass → locust → rat→ fox
grass → locust → rat→ snake
3
a The Sun’s energy
b It represents the transfer of energy in the food chains.
4
The game shows that:
• energy for food webs comes from the Sun
• energy is transferred from one living thing to another in the food chains that
make up a food web
• food webs are made of many linked food chains
• when one type of living thing in a food web is harmed or killed, it affects many
other living things and food chains in a food web (or similar answer).
Stretch questions
5
The food web unravelled. This is because some of the links in the different food chains were
removed when all the insects were killed by the pesticide. This could be because they
had no food or were poisoned by eating animals that contained the pesticide.
6
Learners’ own ideas. For example, the insects must pull hard on the string to show that
they have been affected by the substance. Each person that felt the pull must also pull
hard on the string and say the name of the plant or animal they represent.
This will show that the toxic substance moves through the food web and affects many
other living things.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Unit 5 Forces and electricity
Worksheet 5.1A
1
Servant
A force that pulls objects towards the Earth.
Scholarship
Used evidence to make a decision.
Downwards
The path taken by a body in space around a bigger body.
Attracted
Somebody who looks after another person for payment.
Gravity
An instrument which allows you to see things much
bigger than with the naked eye.
Concluded
A direction towards the centre of the Earth.
Orbit
Caused objects to move in a certain way.
Telescope
Payment of fees for attending university.
2
Cambridge University
3
Any three from the force of gravity, the laws of motion, calculus, reflecting telescope.
4
The force of gravity
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 5.1B
1
An apple falling off a tree.
2
a Newton thought there must be a force that is pulling everything towards the Earth.
He called the force gravity.
b Newtons
3
Newton thought that because the Moon is so far away, the Earth’s force of gravity is
not strong enough to pull it down to Earth.
4
He used a telescope.
5
84 years (1643–1727).
Worksheet 5.1C
1
Newton invented a type of mathematics called calculus, he discovered the force of gravity
and the laws of motion in physics, and he invented a reflective telescope which allowed him
to study astronomy.
2
Newton was sitting under an apple tree and an apple fell to the ground. He tried to think why
the apple fell to the Earth and realised that there must be a force attracting it downwards.
He named this the force of gravity.
3
There was an outbreak of Bubonic Plague (also called the Great Plague) in England between
1665 and 1666. The disease was carried by fleas that lived on black rats although at the time
people did not realise this was the cause. People got swollen glands, headaches and fever
and died within a few days. Today, antibiotics would cure it.
About half of Europe’s population died of this disease, especially in crowded cities like
London. In 1669 a huge fire destroyed most of London and also destroyed many of the
fleas and rats.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Worksheet 5.4
1
A 12 V battery (or four 3V batteries or two 6V batteries or eight 1.5V cells joined together)
four lamps, four switches and connecting wires.
2
A parallel circuit. Each lamp and switch has the full strength of electricity and can be
used independently.
3
So that you can turn on one lamp and leave the others switched off.
4
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Stretch question
The first diagram shows the possible positions of the lamps and switches.
The second, complete diagram adds in the wiring and power supply.
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CAMBRIDGE PRIMARY SCIENCE 6: TOPIC WORKSHEET ANSWERS
Unit 6 Light and the solar system
Worksheet 6.1A
1
An optical fibre is a very thin thread or strand of pure glass.
2
Inside the optical fibre, total internal reflection takes place as light reflects over and
over again as it travels.
3
Optical fibres are used to make endoscopes to help surgeons see inside people’s bodies.
4
Optical fibres are used to send or transmit telephone signals, internet communication
and cable television signals.
Worksheet 6.1B
1
Optical fibres are very thin strands of pure glass. A cable carrying up to several hundred
optical fibres is called a fibre optic cable.
2
The light inside the glass fibre reflects off the wall of the glass over and over again at an angle
of less than 42 ° as it travels along the fibre.
3
Surgeons use endoscopes to see inside people’s bodies without the need for major cutting. An
endoscope has a camera which sends images transmitted through the optical fibre to a screen.
4
Telecommunications companies use fibre optic cables to transmit telephone calls,
internet communication and cable TV signals.
Worksheet 6.1C
1
A surgeon only has to make a very small cut to insert the endoscope which will send
back pictures of the patient’s organ. The patient will recover far more quickly.
2
Optical fibre technology is much faster for telecommunications. It is also not weather
dependent – overhead cables can be damaged during storms. It is also less likely to be
damaged or stolen since it is underground.
3
For total internal reflection to occur the light has to reflect at an angle of less than 42 °,
so the cable must not be bent too much.
4
John Tyndall
5
Narinder Kapany
6
A gastroscope (an endoscope for looking into a person’s stomach)
7
Nobel Prize in Physics
Worksheet 6.3
1
The Moon’s orbit around the Earth
2
29.5 or 29½ days
3
Point E
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