Checkpoint Science Workbook 1 answers.pdf

1 THE CHARACTERISTICS OF LIVING THINGS

A NS WE R S TO CAMBRIDGE CHECKPOINT SCIENCE WO RK B O OK 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 eating grass; sensitivity – ears face a sound and the rabbit stops eating; movement – the israbbit 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 Cambridge Checkpoint Science Workbook 1 © Hodder & Stoughton Ltd 2012

1

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 Abena. Chipo. 85 cm. Abena 48 cm, Bisa 45 cm, Chipo 50 cm, Doli 45 cm. Abena 5 cm, Bisa 5 cm, Chipo 3cm, 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.

9 a) b) c) d) e) f)

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 tocloudy 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) Make food. d) The flower. e) The stem. f) 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

30

3

25

6

20

18

15

24

15

30

25

te 20 u n i m r e p 15 s th a re B 10

5

0 0

3

6

9

12

15 Age/years

18

21

24

c) 17.7 breaths per minute. d) 15 breaths per minute, whenhe was 18.

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3

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

8 16

2

32

3

64

4

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. Cambridge Checkpoint Science Workbook 1 © Hodder & Stoughton Ltd 2012

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4 MICROORGANISMS

7 a) Smooth muscle cells. b) In the walls of the oesophagus, stomach or intestines. c) Nerve cells. d) 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 awayfrom 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

35

m 30 /m h t o fr 25 f o t h ig e H 20

15

10

5

0 0

6

10

20 30 40 50 Temperature of sample/°C

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

Biotic

✔

animals eating leaves

✔

trees making shade

✔

wind speed

✔

rainfall

✔

birds using leaves for nesting materials

✔

humans walking through the habitat

✔

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

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 s l a u id iv 20 d in f o r e b 10 m u N

0

slu

gs

s ail sn

les et be Species

i sp

rs de

ts an

a) Rock pool 1.

6

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 waterloss, 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

Animal

Cannot make own food

✔

Has cellulose for support

✔

Has chlorophyll

✔

Can move about

✔

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’thave any limbs; A has tentacles, B doesn’t. b) Group

A

B

Jellyfish Annelid worms Molluscs Echinoderms

10

✔ ✔

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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

6 a)

Continuous v ariation

Discontinuous v ariation

A, B, D, E

C, F

11

10

/g s s a M

9

8

7

6 J an

F eb

Mar

Apr

May

Ju n Ju l Months

Au g

Se p

O ct

Nov

De c

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

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.

3

a) b) c) d) e)

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

12

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. 7 a) 12%, 10%, 20%, 8%. 20 b) s15 s a m in e s10 a e r c in %5

0 A

B

C

D

Cloths

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

30

C ° / e r u t ra 20 e p m e T

10

0 0

12345678 Time/min

d) 7.4 minutes.

10

Acids and alkalis

Early acids and alkalis Acid – sour; alkali – the ashes.

1

Acids methanoic – nettles; citric – lemon; lactic – exercising muscles; tartaric – grape; hydrochloric – mammal stomach.

2

Alkalis a) Because they can burn the skin. b) Alkalis.

3

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, whichwill only react together when theydissolve 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

Igneous

sandstone granite

chalk

Small crystals

Large crystals

✔

Rock fragments

Shells

✔

✔

limestone basalt

Sedimentary

✔ ✔

✔

✔ ✔

✔

✔

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

bedrock

12 a) Humus, clay particles, sand, stones. b) Clay particles and sand. c) Loam. d) 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 oftime; same amount of glass wool infunnel. c) A – clay, B – rocky, C – sandy. 14 a)

8.0

7.5 L L 7.0 W 6.5 H p

C

6.0

5.5

P

P 5.0

H

H

4.5 123456

7

8

9

10

Stations

b) c) d) e)

It increased. It decreased. See graph in answer a. Each plant type grows in a soil of a certain pH.

f) 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 thebody. b) It reduces oxygen so decomposers cannot thrive and rot the body. 5 Minerals. 6 a) Cambrian. b) Quaternary. c) Carboniferous. d) Jurassic. e) Cretaceous.

Fossils and rocks 7 Trilobite.

The fossil record 8 a) Molluscs. b) Examples could include snail, slug, octopus. 9 a)

20 s p u ro 15 g f o r e b 10 m u N

5

0 Pc

C

O

S

D

Ca

P

T

J

Time period

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.

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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 7 s d6 n o c e /s ll 5 fa o t e im4 T

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)

The hotness or coldness of a substance. Celsius. –273 Alcohol, mercury. The bulb.

f) It expands. g) It contracts.

14

Forces and motion

Forces and their effects 1 Action of a force

Action in the game

Changingdirectionofamovingobject

C

Stoppingamovingobject

D

Changinganobject’sspeed

B

Changing an object’s shape Startinganobjectmoving

A

E

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

Pulling force in N 40

Roughlysanded

30

Smoothlysanded waxed

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

20

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) Air resistance. b) It is pulled out of the backpack. c) The skydiver slows down. d) 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

30 m /c n io 20 s n e t x E

10

0 0

200

40 0

600

80 0 1000 Mass/kg

12 0 0

14 0 0

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.

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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)

30

m25 /c ll a b y b 20 d e ll e v a tr 15 e c n ta s i D 10

5

0 0123456 Distance band pulled back/cm

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 bevery accurate as they do not show thepattern 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) D, C, E, B, A b) Coal. c) Oil and methane gas. d) 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

b)

100

100

90

90

80

80

70

70

C °/ 60 re tu a re p 50 m e rt te a 40 W

C /°e 60 r tu a re p 50 m e rt e ta 40 W

30

30

Charcoal

20

20

10

10

0

Briquettes

0 0

5

10

15 20 Time/min

25

30

0

5

10

15 20 Time/min

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.

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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 4 a) Stored chemical energy Stored chemical energy b) Stored chemical energy.

Miguel Miguel

kinetic energy. thermal energy.

c) Kinetic energy and thermal energy. d) Miguel. 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. 24

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.

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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)

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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.

Cambridge Checkpoint Science Workbook 1 © Hodder & Stoughton Ltd 2012

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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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Cambridge Checkpoint Science Workbook 1 © Hodder & Stoughton Ltd 2012