1 The characteristics of living things
Answers to
Cambridge Checkpoint Science
Workbook I
You may award one mark for each answer or part of an answer.
1 The characteristics of living things
Living and never lived
1 a)
b)
c)
d)
Never lived; it has come out of the Earth.
Once alive; it is the skin of an animal.
Living; it shows all the characteristics of life.
Once alive; it is formed from wood that is produced by trees.
Signs of life
2 a) 3
b) Feeding – rabbit is eating grass; sensitivity – ears face a sound and the rabbit stops eating;
movement – the rabbit hops away.
Animal life
3 a)
b)
c)
d)
e)
Examples could include a crab or lobster.
Shed it (moult).
It is softer.
It takes in water to stretch it.
Gills.
Plant life
4 a) Reproduction.
b) Movement and growth.
c) Light, carbon dioxide, water, small amounts of chemicals in the soil.
Eating and feeding
5 a) Use the same mass of clay for each tooth; drop them from the same height.
b) Examples could include a cat or dog.
c) Examples could include a rabbit or sheep.
Respiration
6 glucose + oxygen ➔ carbon dioxide + water
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2 Major organ systems
Movement
7 a)
b)
c)
d)
Muscles.
To find food, avoid enemies, find shelter.
Pump blood around the body.
Churn up food to help it digest.
Irritability
8 Skin – touch; eyes – sight; ears – hearing; nose – smell; tongue – taste.
Growth and reproduction
9 a)
b)
c)
d)
e)
f)
Abena.
Chipo.
85 cm.
Abena 48 cm, Bisa 45 cm, Chipo 50 cm, Doli 45 cm.
Abena 5 cm, Bisa 5 cm, Chipo 3 cm, Doli 5 cm.
The elephants grow most in their early years and their growth slows down as they get older and
almost stops by 20 years of age.
g) About 207 cm.
Excretion
10 a) Urine, sweat, air we breathe out.
b) inhaled air
breathe
passes through
this tube
in and out
gently here
exhaled air
passes through
this tube
limewater
c) Limewater.
d) Limewater changes from clear to cloudy or milky.
e) Respiration.
2 Major organ systems
Organs of a flowering plant
1 a) Take up water and minerals; hold the plant in the ground.
b) Transport food and water to all parts of the plant; support other parts of the plant.
2
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2 Major organ systems
c)
d)
e)
f)
Make food.
The flower.
The stem.
Help grip other supports to hold up a weak stem.
Organ systems of a human
2 In any order.
a) heart – circulatory system.
b) lungs – respiratory system.
Skeleton and movement
3 ligament – fibres – hold bones together; cartilage – hard slippery surface – lets bones move easily and
reduces wear; synovial fluid – liquid – lubricant reduces friction.
4 The action of one muscle produces an opposite effect to the other muscle and causes movement in the
opposite direction.
Circulatory system
5 a) 3, 1, 4, 2
b) A throbbing sensation or artery.
Respiratory system
6 a)
b)
Age in years
Breaths per minute
0
3
6
18
24
30
25
20
15
15
30
Breaths per minute
25
20
15
10
5
0
0
3
6
9
12
Age/years
15
18
21
24
c) 17.7 breaths per minute.
d) 15 breaths per minute, when he was 18.
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3 Cells
Digestive system
7 a) Salivary gland, oesophagus, stomach, small intestine, large intestine.
b) Abdomen.
c) Stomach.
Nervous system
8 a) Brain.
b) Spinal cord.
c) Electrical.
Excretory system
9 a)
kidney
ureter
bladder
b) Either or both kidneys.
c) Urea.
Sensory system
10 a) Nose, ear, skin, eyes.
b) To provide information about your surroundings.
Endocrine system
11 a)
b)
c)
d)
Glands.
Insulin.
Diabetes.
By taking extra insulin into the body.
3 Cells
The microscope
1 a) A sunless part of the sky.
b) Directly from the Sun.
c) The lowest power objective lens.
4
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3 Cells
d) Stage clips.
e) Is in the centre of the hole on the stage.
f) Moves away from the specimen on the slide.
2 Numbers 4, 5, 2, 1, 3.
Looking at cells
3 a)
cell wall
cell membrane
vacuole
chloroplast
cytoplasm
nucleus
b) Nucleus, cytoplasm, cell membrane.
4 a)
b)
c)
d)
DNA.
In the nucleus.
Genetic material.
It gives an organism its features.
5 a)
Time in hours
Number of cells
0
1
2
3
4
8
16
32
64
128
b) The number of cells doubles every hour.
c) 256
Adaptations in cells
6 a)
nucleus
phagocyte
Red blood cell
b) Red blood cell.
c) Carries oxygen around the body.
d) Eats harmful microorganisms.
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4 Microorganisms
7 a)
b)
c)
d)
Smooth muscle cells.
In the walls of the oesophagus, stomach or intestines.
Nerve cells.
Any one from: nerves, spinal cord, brain.
8 a) In the throat lining.
b) Cilia.
c) Wave to and fro and carry dust trapped in mucus away from the lungs.
9 a) On the surface of a plant root.
b) Takes up water from the soil.
Cells, tissues, organs and organisms
10 A group of the same kind of cells that do a special task.
11 a) An organ system is a group of organs that perform a vital task in the survival of the body.
b) An organism is formed from all the organs and organs systems that make up a body.
4 Microorganisms
The fungi kingdom
1 Heat, cold and dry conditions.
2 D, B, C, A
3 a)
50
45
40
Height of froth/mm
35
30
25
20
15
10
5
0
0
6
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10
20
30
40
Temperature of sample/°C
50
60
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5 Living things in their environment
b)
c)
d)
e)
Used the same amount of yeast, sugar and water to make each sample.
Carbon dioxide.
Respiration.
The sample at 0 °C was still alive at that temperature and started respiring when the temperature
rose. The sample at 50 °C had been killed at that temperature and so could not respire at a lower
temperature.
The Monera kingdom
4 Spherical, spiral or rod-like.
5 a) Any two from: diphtheria, whooping cough, cholera, typhoid, tuberculosis, food poisoning.
b) Examples could include yoghurt or cheese.
The Protoctista kingdom
6 a) They make their own food by photosynthesis like plants.
b) They feed as animals do.
7 Any two from: malaria, sleeping sickness, amoebic dysentery.
Viruses
8 Virus sticks to cell – 1; virus enters cell – 2; protein coat breaks down – 3; DNA released – 4; DNA
reproduces – 5; protein coat forms around DNA – 6; cell wall breaks down – 7.
9 Any two from: the common cold, influenza, chicken pox, measles, rabies, AIDS.
Decomposer
10 a) Bacteria and fungi.
b) Minerals.
c) The plants take up minerals in the soil water and use them to grow.
5 Living things in their environment
Ecology
1
Factor
Abiotic
temperature
animals eating leaves
trees making shade
wind speed
rainfall
birds using leaves for nesting materials
humans walking through the habitat
Biotic
✔
✔
✔
✔
✔
✔
✔
2 A community of living things and the abiotic factors.
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5 Living things in their environment
Food chains
3 a)
b)
c)
d)
e)
Plant ➔ snail ➔ shrew ➔ hawk.
The plant.
An animal that eats only plants.
The snail.
No. An omnivore is an animal that eats both plants and animals. The food chain only shows the
animals to be either herbivores or carnivores.
Biodiversity
4 a) The number of individuals of the species of moth in the habitat.
b) Checking the level of the population by comparing the numbers he has counted at the site.
5 a)
wood cover
pebbles
yoghurt pot
ground
leaves and soil
Number of individuals
b) The cover.
c) The smooth walls of the yoghurt pot do not let them climb out.
d) The beetle and centipede have fallen into the trap and the centipede has eaten the beetle.
e)
30
20
10
ts
an
rs
id
e
sp
les
et
be
s
ail
sn
slu
gs
0
Species
6 a) Rock pool 1.
b) (i) It goes down.
(ii) It goes up.
c) (i) Mussels.
(ii) The numbers are greatly reduced where starfish are found. The numbers of the other animals do
not change.
d) (i) They cannot survive the drier conditions.
(ii) They have eaten all the mussels.
e) Quadrat.
8
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6 People and the planet
Adaptations
7 a) (i) A and B
(ii) A and D
(iii) B and C
b) B
c) D
d) C
8 Darkness.
9 Aestivation is when animals rest (sleep) for a time in a hot dry season. Hibernation is when animals rest
(sleep) for a time in cold winter conditions.
10 a) Eggs ➔ larva ➔ pupa ➔ adult ➔ in a circle.
b) X marked at egg and pupa.
11 a) Any two from: storing water, thick waxy covering to prevent water loss, spikes to prevent animals
biting in for a drink, long roots to find water.
b) Any three from: can drink large amounts of water, thick foot pads for heat insulation, webbed feet to
stop sinking in sand, holds body on long legs above hot desert surface, can shut nostrils to keep out
sand, long eyelashes keep sand from eye, third eyelid for wiping away sand, strong teeth for grinding
tough desert plants, fat in hump is an energy store.
12 It traps a bubble of air under its wings.
13 a) (i) Strong for grinding up plants.
(ii) On the side of the head to see all around.
(iii) Large to catch sounds and movable to detect sounds from all directions.
b) (i) Conical shape for stabbing.
(ii) Facing forwards so they overlap and allow distances to be judged.
6 People and the planet
Early times to People today
1 Hunter gathering – 1; farming – 2; invention of water mill – 3; invention of windmill – 4; invention of
steam engine – 5; invention of electrical generator – 6.
2 a) Any two from: coal, oil, gas, nuclear fuel.
b) Any two from: wind, water, geothermal, solar energy, biofuels.
3 a) Petrol, diesel, kerosene.
b) Carbon dioxide.
Changes in the environment
4 a) The ground surface is ripped up.
b) Coal, metal ores.
5 Examples could include break in an oil pipe, oil spillage from a tanker that has run aground.
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7 Classification and variation
6 a) It absorbs heat radiated from the Earth.
b) Carbon dioxide is a greenhouse gas produced when fuels are burnt in transport, in factory work and
in many power stations.
7 a)
b)
c)
d)
e)
Oxygen.
It screens out harmful rays from the Sun.
Over the North and South Poles.
CFCs in fridges, air conditioning and aerosol sprays.
The governments in 196 countries have agreed to reduce their use.
Time to save the planet?
8 a) (i) Glass.
(ii) Plastic.
(iii) Metal.
(iv) Cardboard.
(v) Paper.
b) (i) 4900 kg.
(ii) 2400 kg.
c) The campaign has reduced the demand for landfill sites.
d) Paper.
e) Putting out more waste paper bins or a similar solution.
7 Classification and variation
Classifying living things
1
Feature
Plant
Cannot make own food
Has cellulose for support
Has chlorophyll
Can move about
Animal
✔
✔
✔
✔
Dividing up the animal kingdom
2 a) Any three from: A has a shell, B doesn’t; A has a head, B doesn’t; B has five limbs, A doesn’t have any
limbs; A has tentacles, B doesn’t.
b)
Group
A
Jellyfish
Annelid worms
Molluscs
Echinoderms
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B
✔
✔
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8 The states of matter
Vertebrates
3 a) Order, family, genus, species.
b) Species.
The plant kingdom
4 a) Mosses.
b) Ferns.
Variation
5
Continuous variation
Discontinuous variation
A, B, D, E
C, F
6 a)
11
Mass/g
10
9
8
7
6
Jan
Feb
Mar
Apr
May
Jun
Jul
Months
Aug
Sep
Oct
Nov
Dec
b) The mass decreases early in the year then builds up in the latter part of autumn then decreases again
through the winter.
c) Small.
d) A bat. It builds up a food store in its body, which it uses up during hibernation.
e) Continuous.
f) The environment.
8 The states of matter
Comparing the states of matter and the particle theory of matter
1 Easy to compress.
2 a) box a should be packed with circles touching or almost touching each other.
box B should contain very few particles with plenty of space between them.
b) They slide over each other.
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9 Properties of matter and materials
3 a)
b)
c)
d)
e)
Raise its temperature to its melting point.
It loses its fixed shape and starts to flow.
They receive more energy.
The solid particles vibrate to and fro but when melting occurs they slide over each other.
Freezing.
4 a) Identical containers were used; the same amount of liquid was put in each one; they were left for the
same length of time.
b) B
c) Warm and windy.
d) C
e) At the surface.
f) High energy.
g) A gas.
5 a) Gas bubbles form inside it and rise to the surface.
b) Boiling point.
c) It boils faster.
6 a) By cooling down a gas.
b) On dust particles in the air.
7 a) Liquid.
b) The solid sulfur inside the volcano sublimes in the heat and becomes a gas. It rises out of the
volcano, cools, sublimes and forms a solid on the side of the volcano.
8 a) A solute is a solid that dissolves in a solvent. A solvent is a liquid that dissolves the solute.
b) In the gaps between the liquid particles.
9 Properties of matter and materials
Introducing elements
1 a) A substance made from just one kind of atom.
b) A group of atoms of one or more elements.
Metals and non-metals
2 a)
Substance
Metal
A
B
✔
Non-metal
✔
b) oxygen, nitrogen.
c) Metals usually have shiny surfaces.
3 Carbon – barbecue charcoal; chlorine – keeping swimming pools water clean; iodine – portable water
purifying kits; phosphorus – matches; sulfur – car tyres.
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9 Properties of matter and materials
Metal alloys
4 Bronze – copper and tin – bells; brass – copper and zinc – ornaments; steel – iron and carbon – car bodies.
The properties of materials
5 a) A – rigid, brittle, transparent. B – opaque, absorbent, flexible. C – translucent, rigid, heat insulator.
D – opaque, flexible, electrical conductor.
b) D
c) A
6 a) A ruler.
b) Drop the ball bearing from the same height above each material and measure the width or depth of
the impression it leaves in the material.
% increase in mass
7 a) 12%, 10%, 20%, 8%.
20
b)
15
10
5
0
A
B
Cloths
C
D
c) C, A, B, D.
d) He could have used samples of cloth that all had a mass of 100 g.
Comparing the properties of materials
8 a) It is malleable – can be pressed into a shape; it is a good conductor of heat; it is waterproof.
b) It is a heat insulator; it is soft enough to be carved into shape; it is rigid.
9 a) B
b) C
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10 Acids and alkalis
c)
40
Temperature/°C
30
20
10
0
0
1
2
3
4
Time/min
5
6
7
8
d) 7.4 minutes.
10 Acids and alkalis
Early acids and alkalis
1 Acid – sour; alkali – the ashes.
Acids
2 methanoic – nettles; citric – lemon; lactic – exercising muscles; tartaric – grape; hydrochloric – mammal
stomach.
Alkalis
3 a) Because they can burn the skin.
b) Alkalis.
Detecting acids and alkalis
4 Boyle.
The pH scale
5 Litmus – red – blue; Methyl orange – pink – yellow; phenolphthalein – colourless – pink.
6 a) X is on 7.
b) The circle is around 0–2.
c) The circle is around 8–11.
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11 Rocks and soil
Neutralisation
7 acid + akali ➔ salt + water
8 a) nitric acid + sodium hydroxide ➔ sodium nitrate + water
b) sulfuric acid + potassium hydroxide ➔ potassium sulfate + water
c) hydrochloric acid + sodium hydroxide ➔ sodium chloride + water
9 sodium hydrogen carbonate + hydrochloric acid ➔ sodium chloride + carbon dioxide + water
10 a) Soap, because the sting is acidic and soap is alkaline.
b) Vinegar, because the sting is alkaline and vinegar is a weak acid.
11 a) The stomach makes too much acid as it digests food.
b) It dissolves to make an alkaline solution, which neutralises the acid.
12 a) It contains two solids, which will only react together when they dissolve in water.
b) Carbon dioxide, which makes the texture light.
Acid rain
13 a) East and south east.
b) South west and west.
c) The south west, since all the recordings were 6, which is slightly acid. No other direction had as
many readings of 6.
d) Recording event 4, north east contaminated with acid and recording event 8, north west
contaminated with alkali.
11 Rocks and soil
From Big Bang to the Sun
1 Big Bang – hydrogen and helium; Nebula making stars – carbon, nitrogen, oxygen; supernovas – gold
lead, platinum.
The formation of the Solar System
2 Mercury, Venus, Earth, Mars.
3 Jupiter, Saturn, Uranus, Neptune.
The structure of the Earth
4 a)
b)
c)
d)
e)
f)
A – mantle, B – inner core, C – crust, D – outer core.
A – mantle.
B – inner core.
C – crust.
D – outer core.
Radioactive materials such as uranium.
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11 Rocks and soil
The rock cycle
5 a) Molten rock made from some of the rocks in the lower crust and upper mantle.
b) Basalt and granite.
Types of rock
6 a)
Rock
sandstone
granite
limestone
basalt
chalk
Igneous
Sedimentary
Small crystals
Large crystals
✔
Rock fragments
Shells
✔
✔
✔
✔
✔
✔
✔
✔
✔
b) Metamorphic.
c) Limestone.
d) It is heated and squashed in the Earth’s crust.
7 D, C, A, B, E
8 Crystal shape, colour, luster, hardness and colour of streak.
9 A rock rich in metal compounds.
Soil
10 Weathering.
11
litter layer
topsoil
subsoil
lumps of
bedrock
12 a)
b)
c)
d)
bedrock
Humus, clay particles, sand, stones.
Clay particles and sand.
Loam.
The rotting remains of plants and animals.
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12 Finding the age of the Earth
13 a)
water
soil
glass wool
measuring cylinder
water that has drained
through the soil
b) Same amount of soil; allowed to drain for the same amount of time; same amount of glass wool in funnel.
c) A – clay, B – rocky, C – sandy.
14 a)
8.0
7.5
L
L
7.0
W
pH
6.5
C
6.0
5.5
5.0
4.5
b)
c)
d)
e)
f)
P
P
H
1
2
3
4
5
H
6
Stations
7
8
9
10
It increased.
It decreased.
See graph in answer a.
Each plant type grows in a soil of a certain pH.
Station 9 wild onion; station 10 lilac.
12 Finding the age of the Earth
How rock layers formed
1 Sedimentary.
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12 Finding the age of the Earth
Naming the rock layers
2 Cambrian – Wales – 542; Permian – region in Russia – 300; Devonian – county in England – 416;
Cretaceous – chalk rock in Europe – 145; Jurassic – mountains in Switzerland – 200.
3 Sedimentary.
How fossils form in rocks
4 a) It prevents scavengers ripping up the body.
b) It reduces oxygen so decomposers cannot thrive and rot the body.
5 Minerals.
6 a)
b)
c)
d)
e)
Cambrian.
Quaternary.
Carboniferous.
Jurassic.
Cretaceous.
Fossils and rocks
7 Trilobite.
The fossil record
8 a) Molluscs.
b) Examples could include snail, slug, octopus.
9 a)
Number of groups
20
15
10
5
0
Pc
C
O
S
D
Ca
Time period
P
T
J
b) Silurian and Devonian.
c) No, it remained the same in the Ordovician and Silurian periods and in the Carboniferous and
Devonian periods.
d) (i) Permian.
(ii) The number of groups was one lower in the following period, the Triassic.
e) As time passes the number of groups increases.
The fossil record and the age of the Earth
10 An element whose atoms break down to smaller atoms of other elements and release large amounts
of energy.
18
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13 Measurements
11 a) 250 g.
b) 125 g.
c) 16 million years old.
12 4.6 billion years
13 Measurements
Fooling our senses
1 Dots appear in the gaps between the squares and seem to move as you move your eyes.
Length, mass and time
2 a)
b)
c)
d)
e)
mm
km
nm
µm
cm
3 a) milligram – mg – 0. 000 001; tonne – t – 1000; gram – g – 0.001; kilogram – kg – 1.
b) Megatonne, Mt.
4
Time taken for four parachutes to fall three metres
10
9
8
Time to fall/seconds
7
6
5
4
3
2
1
0
A
B
C
D
Parachute
This gives the students a chance to produce their own graph, which should be of a size that fills most of the
paper available. Make sure they have labelled the axes and given the chart a title.
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14 Forces and motion
Accuracy of measurements
5 From directly in front.
Heat and temperature
6 a)
b)
c)
d)
e)
f)
g)
The hotness or coldness of a substance.
Celsius.
–273
Alcohol, mercury.
The bulb.
It expands.
It contracts.
14 Forces and motion
Forces and their effects
1
Action of a force
Action in the game
Changing direction of a moving object
Stopping a moving object
Changing an object’s speed
Changing an object’s shape
Starting an object moving
C
D
B
E
A
Different types of forces – Contact forces
2 An impact force.
3 Tension.
4 a) Static friction is stronger than sliding friction.
b) Sliding friction.
5 a)
Condition of runners
Rusty
Roughly sanded
Smoothly sanded
waxed
Pulling force in N
40
30
25
20
b) The rusty runners had rough surfaces but sanding and waxing the surface has made them smooth.
c) The frictional force has been reduced.
6 a) Su Lin.
b) Less water will be moved out of the way and the water between the tyre and road will reduce
friction.
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15 Energy
Different types of forces – Non-contact forces
7 a)
b)
c)
d)
Air resistance.
It is pulled out of the backpack.
The skydiver slows down.
Gravity.
8 a) Making the objects out of the same mass of material and timing them over the same distance.
b) B – It was the most streamlined or had the least water resistance acting on it.
c) C – It was least streamlined or had the most water resistance acting upon it.
9 The weight is due to the gravitational field strength (pull) of the Earth or the Moon and the gravitational
pull of the Moon is only a sixth of the gravitational pull of the Earth.
How springs stretch
10 a)
40
Extension/cm
30
20
10
0
0
200
400
600
800
1000
Mass/kg
1200
1400
b) The extension increases in proportion to the increase in mass.
c) 1000–1200 kg.
d) He could increase the mass to 1000 kg, then increase the mass 50 g at time until the spring no longer
extends in proportion.
15 Energy
What is energy?
1 Energy is a property of something, that can exist in different forms and can make something exert a
force or do work.
Forms of energy
2 a) Chemical energy.
b) Gravitational potential energy.
c) Strain energy.
3 a)
b)
c)
d)
Chemical energy.
Gravitational potential energy.
Strain energy.
At the top of the dive when she is highest in the air.
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15 Energy
4 a)
Distance travelled by ball/cm
30
25
20
15
10
5
0
0
1
2
3
4
5
Distance band pulled back/cm
6
b) The further the band is pulled back, the further the ball travels.
c) The greater the stored energy in the band, the further the ball travelled. Pulling the band back further
increases its stored energy.
d) They do not seem to be very accurate as they do not show the pattern clearly. The line is wobbly
instead of straight.
e) She could repeat them, taking more care over her measurements.
f) The elastic band broke.
5 It moves.
6 Solids, liquids and gases.
7 Electrical energy is the movement of electrical charges through a conductor. Electromagnetic energy is
electrical energy that travels in the form of electromagnetic waves.
8 Internal energy or thermal energy.
Energy changes
9 It changes from electromagnetic energy in light into stored, chemical energy in the food in the leaf.
10 Heat and sound.
Fuel
11 a)
b)
c)
d)
D, C, E, B, A
Coal.
Oil and methane gas.
Tiny plants and animals that lived and died in the upper waters of ancient seas; dead plankton.
12 a) Use the same mass of each fuel, the same mass of water; have the pans the same distance above the
fuels; make sure the air is still around both barbecues; hold the thermometer in the same position in
both pans when taking the temperature.
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16 Energy transfers
100
90
90
80
80
70
70
60
60
Water temperature/°C
100
Water temperature/°C
b)
50
40
30
50
40
30
Charcoal
20
20
10
10
0
0
5
10
15
Time/min
20
25
30
0
Briquettes
0
5
10
15
Time/min
20
25
30
c) (i) The temperature rises quickly, stays high for a short time then falls quickly.
(ii) The temperature rises slowly and remains high for longer and starts to cool down more slowly.
d) The charcoal releases its energy as heat faster than the briquettes but releases less energy than the
briquettes later in the investigation.
16 Energy transfers
Energy transfers and transformations
1 Examples might include beating heart, movement of intestines, blinking of eye, movement of ribs in
breathing.
2 a) (i) 20 joules.
(ii) 60 joules.
b) (i) 3200 joules.
(ii) 9600 joules.
(iii) 12 800 joules.
(iv) 2 250 000 joules.
(v) 2250 kJ.
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16 Energy transfers
How energy use has increased
3 a) Cars, buses, trains, aeroplanes.
b) Oil, candles, wood fires.
c) Electricity.
Energy transfer diagrams
Miguel
4 a) Stored chemical energy
Miguel
Stored chemical energy
b) Stored chemical energy.
c) Kinetic energy and thermal energy.
d) Miguel.
kinetic energy.
thermal energy.
5 a) C, A, G, B, E, D, F
b) The more strain energy in the balloon the greater the distance the balloon will travel.
c) They match the prediction because the balloon with the greater circumference has the greater strain
energy and it travels the greater distance.
6 a) and b)
a) Car A
Energy in
fuel 200 kJ
Kinetic energy 50 kJ
Waste
heat
energy
150 kJ
b) Car B
Energy in
fuel 200 kJ
Kinetic energy 100 kJ
Waste heat
energy
100 kJ
c) B
7 23% – makes water circulate in the water cycle; 47 % – absorbed by the atmosphere; 0.02 % used by
plants in photosynthesis; 30 % reflected back into space; less than 1 % – produces winds and currents.
Plants and energy
8 The seed at depth 4 cm used up all its energy trying to grow into the light and did not make it. The other
seeds had enough energy to bring them into the light, then they began to photosynthesise and grow.
Energy and ourselves
9 The table should have two columns headed ‘food’ and ‘energy in 100 g of food in kJ’.
Generating electricity
10 a) Kinetic energy of wheel
b) Kinetic energy in steam.
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dynamo
electrical energy.
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17 The Earth and beyond
Conservation of energy
11 In any energy change some energy is lost as heat. Energy is always conserved.
17 The Earth and beyond
Movements in the sky
1 a) An imaginary line running through the Earth between the North and South Poles.
b) 24 hours.
c) East.
2 a) The path of the Earth around the Sun.
b) 1 year.
c) Yes. We have 365 days in a year and each day and night is the result of a rotation.
3 Summer – towards the Sun – winter; Spring – neither towards or away from Sun – autumn; winter –
away from the Sun – summer.
4 a)
154
153
Distance from Sun/millions of km
152
151
150
149
148
147
146
Ja
M
Ju
Jy
Month
S
D
b) It would be a straight horizontal line.
Lights in the sky
5 Light sources – Sun, Arcturus, Milky Way Galaxy, Spica, Andromeda Galaxy. Light reflectors – Moon,
Mars, Jupiter, Neptune, Halley’s comet.
Measuring with light
6 a) 40.85 million million kilometres.
b) 20.9 million million million kilometres.
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17 The Earth and beyond
Bright stars
7 a) 3 000 – red; 4000 – orange; 6000 – yellow; 11 000 – white; 25 000 – blue
b) 6000 °C.
The Moon
8 E, C, B, D, A
The parts of the Solar System
9 F, D, A, G, C, B, E
10 a) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
b) Mercury. It is nearer the Sun where the Sun’s gravity pulls more strongly on it.
Asteroids
11 a) Asteroid belt, Kuiper Belt, Ort Cloud.
b) Kuiper belt.
c) Ort Cloud.
Planets around other stars
12 Take photographs at regular intervals and look at them. Look for stars that wobble and dim.
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