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A N S W E R S

1.1

Answers to worksheets

Carl’s new experiments

1 Qualitative. They were qualitative because all observations were recorded using only words.

2 Carl thought that he should also do a quantitative analysis; that is, record the observations using

numbers to measure how much the grass actually grows under different situations.

3 a Controls.

b Every experiment needs a control against which results can be compared.

4 Types of grass, amount of grass.

5 The amount of water was kept the same.

6 The amount of sunlight.

7 The amount of water.

8 The soil would have had some water in it on Day 1 and would take a few days to dry out.

9 Measurements to be taken at the same time of day. Same ruler to be used and measured from the same

place. Others as appropriate.

10 Repeating measurements is a good way to improve accuracy. Once a collection of different

measurements is taken, an average can be obtained.

11 a

18

16

Carl's experiments

2C

1A

14

Average height (mm)

12

10

8

6

2D

1B

Key

4

2

0

0 1 2 3 4 5 6

Days

b 1A 16 or 17 mm

1B 6 or 7 mm

2C 16 or 17 mm

2D 12 or 13 mm

Science Focus 2 Homework Book Answers © Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.

This page may be photocopied for classroom use.

1.2

Extreme units

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

T H E M A R I A N A T R E N C H

1.3

Graphing skills

1

Predicted energy consumption in Australia in 2009–10

oil

0.4%

solar

1.0%

other

3.3%

electricity

45.2%

wood

15.3%

natural gas

34.9%

3

7

Blood glucose levels

Blood glucose level

5

0 1 2 3 4 5 6 7 8 9 10 11

Reading number

1.4

Body mass index

Mass (kg) BMI (1.6 m tall people) BMI (1.8 m tall people)

50 19.5 15.4

60 23.4 18.5

70 27.3 21.6

80 31.3 24.7

90 35.2 27.8

100 39.1 30.9

110 43.0 34.0

120 46.9 37.0

2, 3 The greater the height,

the lower the graph.

50

1.6 m

45

1.8 m

40

35

BMI

30

25

20

15

4 a 16

b 40

Height (m) BMI (50 kg people) BMI (60 kg people)

1.2 34.7 41.7

1.3 29.6 35.5

1.4 25.5 30.6

1.5 22.2 26.7

1.6 19.5 23.4

1.7 17.3 20.8

1.8 15.4 18.5

1.9 13.9 16.6

20 40 60 80 100 120 140

Mass (kg)

6, 7 The greater the mass,

the higher the graph.

8 a 13

b 28.5

9 a high BMI

b medium BMI

c low BMI

d medium BMI

10 Various answers, eg:

a 1.4 m, 39.2 kg

b 1.6 m, 64 kg

c 1.8 m, 129.6 kg

1.5

Sci-skills crossword

1.6

Sci-words

Unit 1.1: What, why and how

1 experiment

2 micrometer

Unit 1.2: Scientific research

1 research

2 observations

3 quantitative

4 qualitative

5 inference

6 variable

7 hypothesis

8 aim

9 conclusion

Unit 1.3: Better measurements

1 estimate

2 mistake

3 error

4 parallax error

5 reading error

6 instrument errors

7 average

8 metric

9 period

Unit 1.4: Scientific conventions

1 conventions

2 apparatus

3 procedure

4 discussion

5 conclusion

6 bibliography

7 data

8 tabulated

9 independent variable

10 dependent variable

11 line of best fit

2.1

The elements

1 Tungsten W

Sodium Na

Zinc Zn

Einsteinium Es

Tin

Sn

Boron B

Cerium Ce

Radon Rn

2 Am Americium

Uub Ununbium

Ne

Neon

Ar

Argon

Cd

Cadmium

O

Oxygen

H

Hydrogen

Si

Silicon

S

Sulfur

3 a Radium e Sulfur

b Potassium f Helium

c Iodine g Silver

d Mercury

4 a 12

b Any atoms before carbon on the list, eg

oxygen, helium

c Any atoms after carbon on the list, eg zinc,

silver

d Atomic weight generally increases

e AW of Mg = 24

AW of C = 12

24/12 = 2 times heavier

f AW of He = 4

12/4 = 3 times lighter

5 a Hydrogen, H

b Caesium, Cs

2.2

Body elements

1 a 99.99 per cent

b They are averages based on experimental data and are not 100 per cent accurate.

2 Students to colour in diagram.

3 Iron is needed to carry oxygen in our blood from the lungs to all parts of our body.

4 Breathe in, eat them in food, drink them.

2.3

Elements wordfind

G Y M P T N U M N H J G K N D

A R U L U E P U O E N O T O N

L U I U N O E I R L D L I B O

U C D T G N U N O I P D T R R

M R A O S E R I B U O L A A I

I E R N T G O E C M T M N C P

N M M I E O P T A U A U I V L

I A U U N R I S L I S I U E A

U G I M I D U N C N S C M N T

M N M T D Y M I I A I I C I I

L E O I O H D E U R U R O R N

E S R N I T Q D M U M E P O U

A I H C H L O R I N E M P U M

D U C I E M U I R A B A E L X

Q M S K R Y P T O N D P R F B

2.4

Combination reactions

Element Mass of oxide

(g)

Increase in

mass (g)

Percentage

increase (%)

Atomic

number

Reactivity

order

Aluminium 190.1 90.1 90.1 13 5

Calcium 139.7 39.7 39.7 20 3

Copper 124.5 24.5 24.5 29 9

Iron 142.9 42.9 42.9 26 7

Lead 103.1 3.1 3.1 82 8

Magnesium 166.7 66.7 66.7 12 4

Potassium 141.8 41.8 41.8 19 1

Sodium 175.3 75.3 75.3 11 2

Zinc 124.5 24.5 24.5 30 6

Increase in mass (%)

100

90

80

70

60

Plot of mass increase v reactivity order

2 The points are scattered all over the graph. This shows no relationship between reactivity and mass

increase on reaction.

0 1 2 3 4 5 6 7 8 9 10

Reactivity order

Plot of mass increase v atomic number

0 20 40 60 80 100

Atomic number

4 As atomic number increases there is a decrease in percentage increase in mass.

5 The higher the atomic number of the metal, the lower the mass gain on reaction with oxygen

6 a Approximately 17 per cent increase in mass.

b Approximately 10 per cent increase in mass.

7 a Iron.

b The result was well above the line of best fit and may have been incorrectly weighed.

8 a The purity of the reacting metals.

b The surface area of the metal sample.

There may be others.

2.5

Atomic graphs (extension)

2 The graph is very close to a straight line, sloping upwards as you move right. You can predict the atomic

weight by multiplying the atomic number by 2.5, or you could read the atomic weight from the graph.

250

200

Atomic radius (pm)

150

10 20 30 40 50 60 70 80 90

4 The graph is cyclical, with several peaks and troughs.

2.6

The periodic table

1 112

2 The number of protons in the nucleus of the elements.

3 Nobelium, Einsteinium, Mendelevium, Lawrencium, Seaborgium, Bohrium, Rutherfordium, Curium,

Fermium. There may be others.

4 Lead 82 Pb

Gold 79 Au

Oxygen 8 O

Potassium 19 K

Sulfur 16 S

Carbon 6 C

Silver 47 Ag

Iron 26 Fe

Sodium 11 Na

5 9 Fluorine F

4 Beryllium Be

40 Zirconium Zr

13 Aluminium Al

94 Plutonium Pu

80 Mercury Hg

22 Titanium Ti

27 Cobalt 27

15 Phosphorus P

14 Silicon Si

6 a Sodium, Sulfur, Silicon, Selenium, Seaborgium, Scandium, Strontium, Silver, Samarium.

b In order as above: Na, S, Si, Se, Sg, Sc, Sr, Sm.

c As many elements start with the same letter, a second letter is needed to tell them apart.

7 a Alkaline metals, Alkaline earth metals, Noble gases

b Helium He, Neon Ne, Argon Ar

c Helium Balloons, blimps

Neon Neon lights

Argon Fluorescent light tubes

2.7

Atoms crossword

2.8

Unit 2.1: Elements,

compounds and mixtures

1 element

2 symbol

3 atom

4 molecule

5 lattice

6 compound

7 formula

8 mixture

Unit 2.2: Physical and

chemical change

1 physical

2 chemical

3 combination

4 reactant

5 product

6 decomposition

7 precipitate

8 arrow

9 solid

10 concentration

11 area

12 catalysis

13 enzymes

Unit 2.3: Inside atoms

1 Dalton

2 Thomson

3 Rutherford

4 Bohr

5 alpha

6 nucleus

7 protons

8 neutrons

9 electrons

10 charge

11 atomic

12 mass

3.1

The size of microbes

1 Microbe size Convert to micrometres (mm X 1000) Convert to nanometres (µm X 1000)

3 millimetres 3000 3 000 000

5 millimetres 5000 5 000 000

7 millimetres 7000 7 000 000

5 micrometres 5 000

8 micrometres 8 000

10 micrometres 10 000

2 Microbe name Length or diameter as shown Length or diameter in nanometres

Yeast (fungi) 5 µm 5 000

E. coli (bacteria) 3.5 µm 3 500

Cholera bacteria 2.5 µm 2 500

Filovirus 1 400 nm 1 400

Thiomargarita (fungi) 200 nm 200

Retrovirus 100 nm 100

Cold virus 1.1 nm 1.1

Water molecule 0.3 nm 0.3

3 Thiomargarita (fungi).

4 Thiomargarita (fungi), E. coli (bacteria), yeast (fungi), cholera bacteria.

5 Filovirus, retrovirus, cold virus, water molecule.

cytoplasm

flagellum

cell membrane

cell wall

protein coat

chemical with

instructions for

making new

viruses

3.2

Bacterial growth

55

Growth of bacteria

Number of bacteria (thousands)

0 5 10 15

Time (hours)

2 Identify the time periods that correspond to each of the four phases:

• lag phase = 0 to 2 hours

• log phase = 3 to 8 hours

• stationary phase = 9 to 12 hours

• death stage = 13 to 15 hours.

3 a The antibiotic was taken at about the 13th hour of infection.

b The number of microbes fell very quickly between hours 13 and 14.

4 If you extended the graph to the 16th hour the number of bacteria would be about 4000.

5 The body’s immune system starts killing the bacteria.

3.3

Preserving foods

1 Kills most microbes Stops or slows growth of microbes

Pickling

Pasteurisation

Heating in cans

Salting

Refrigeration

Freezing

Drying foods

2 To keep microbes out; to stop microbes infecting the food, making it go off.

3 The frozen peas contain frozen microbes that will reproduce once the peas are defrosted.

4 a The milk ‘goes off’ because microbes start to reproduce.

b This implies that the pasteurisation process does not kill all of the microbes present in milk.

5 Microbes like warm conditions in which to reproduce and grow. At lower temperatures they grow more

slowly, as chemical reactions are slower at colder temperatures.

6 Salted meat would last longer as the salt actually kills the microbes. Dried meat would be more easily

spoilt, as the bacteria are already there waiting to grow, but the salted meat would need to be reinfected.

Food

Cream

Apricots

Fish

Pasta sauce

Potato chips

Pizza base

Grapes

Orange juice

Peanuts

Salad

Onions

Jam

Preservation method

refrigeration, pasteurisation

dried, refrigeration, heating and sealing in a can or jar

refrigeration or freezing, pickling, salting

refrigeration or freezing, heating and sealing in a jar

salting, airtight

refrigeration

dried (sultanas), refrigeration

refrigeration, pickling

heating and sealing in a jar

3.4

Disease

Disease Symptoms How do you catch it What causes it

Malaria Fever, shivering, headaches Insect—mosquito Protozoa

Common

cold

Mumps

Chickenpox

Runny nose, sore and dry throat,

headache

Painful swelling of the neck. High

fever, headache

Itchy, small red blister all over the

body

Air, coughing and sneezing

Contact with infected person

Virus

Cholera Diarrhoea, vomiting, dehydration Contaminated drinking water Bacteria

Ring worm Ring-shaped itchy patches Contact with infected person Fungi

Scarlet fever

Whooping

cough

Fine red rash, sore throat, high

temperature, vomiting, tongue looks

white with red spots

Extended period of coughs ending

with a ‘whoop’ sound

Air

Bacteria

Tinea Itchy red patches between toes Contact with infected person Fungi

3.5

Microbes crossword

C

E

N

T

I

3 4 5 6

This page may be photocopied for classroom use.

8 9

11 12 13

16 17

M

R

U

B

F

23

L

P

24

A

Y

G

22

V

21

18 19 20

D

3.6

Unit 3.1: What is a microbe

1 microorganisms

2 formite

3 microscope

4 electron

5 bacteria

6 cocci

7 flagella

8 fungi

9 yeast

10 mould

11 protists

12 cilia

13 amoeba

14 virus

Unit 3.3: Friend or foe

1 decomposition

2 toxins

3 yoghurt

4 cheese

5 rennin

6 truffles

7 penicillin

8 aerobic

9 fermentation

10 carbon dioxide

11 yeast

12 athlete’s foot

13 flu

Unit 3.2: Reproduction in microbes

1 binary

2 daughter

3 antibiotics

4 hyphae

5 spore

6 sporangium

7 budding

8 fission

9 host

10 antibodies

4.1

Analyse this!—page 1

1 100 grams contains

Cereal

Energy

(kJ)

Protein

Fat

Carbohydrate

Sugar

Fibre

Sodium

(mg)

Potassium

Vita Brits 1510 10.9 2.2 67.6 1.1 11.9 400 n.a.

Weetbix 1390 12 1.3 67 2.8 11 280 340

Weeties 1520 10.9 2.2 68.0 1.1 12.0 405 n.a.

Nutri-Grain® 1596 21.9 0.6 69.4 32 2.7 600 147

Corn Flakes® 1582 7.8 0.2 83.6 7.9 2.6 800 93

Coco Pops 1603 5.4 0.3 87.7 36.5 1.2 564 243

1650

1600

1550

1500

1450

1400

1350

1300

1250

Carbohydrate (g)

Vita Brits

Weetbix

Weeties

Protein (g)

Fat (g)

Sugar (g)

Fibre (g)

Analyse this!—page 2

900

800

700

600

500

400

300

Sodium (mg)

350

Potassium (mg)

3 a All contained similar amounts of energy, though Nutri-Grain®, Corn Flakes and Coco Pops®

contained the most (about 1600 kJ).

b Nutri-Grain® stands out as containing the most protein (21.9 g per 100 g—about double all the

others).

c All contained low amounts of fat, but Vita Brits and Weeties contained most (2.2 g per 100 g—about

triple that of the others).

d Corn Flakes and Coco Pops® contained the most carbohydrate (about 85 g per 100 g).

e Vita Brits and Weeties contained almost no sugar compared with the others, while Nutri-Grain®

and Coco Pops® were made up of about one-third sugar.

f Vita Brits, Weetbix and Weeties contained most fibre (about 12 g per 100 g).

g Corn Flakes stand out as containing most sodium (800 mg per 100 g).

h Weetbix contained most potassium (340 mg per 100 g).

4 a Vita Brits and Weeties are low in sugar and high in fibre.

b Coco Pops® and Nutri-Grain® are high in sugar and low in fibre.

5 Various answers depending on student response.

6 Various answers depending on student response.

4.2

The human digestive system

1 See Figure 4.2.5 in Science Focus 2.

2 a Produces enzymes that aid in digestion.

b Digests food through chemical and mechanical processes.

c Cut and grind food.

d Absorbs minerals and water from food.

e Stores glucose, detoxifies blood.

f Helps manipulate and push food back for swallowing.

g Produces saliva.

h Stores bile, which helps digestion of fats.

i Absorbs protein, carbohydrates and lipids from food. Most digestion occurs here.

j Pushes food from mouth to stomach.

3 a Large intestine.

b Pancreas.

c Small intestine.

d Rectum.

e Mouth.

4.3

The heart

1 See Figure 4.3.7 in Science Focus 2.

2 See Figure 4.3.7 in Science Focus 2.

3 The left side pumps blood to the entire body and must work harder than the right, which just pumps to

the lungs.

4.4

The human circulatory system

1 See Figure 4.3.14 in Science Focus 2.

2 See Figure 4.3.14 in Science Focus 2.

4.5

Blood flow rates

2000

Blood flow

12 500

At rest

During strenuous exercise

Blood flow rate (mL/minute)

1000

Abdomen Brain Heart Kidney Muscles Skin Other

Part of the body

2 The brain.

3 The muscles.

4 a 5800 mL/min

b 17 500 mL/min

4.6

The urinary system

1 See Figure 4.4.3 in Science Focus 2.

2 a The blood.

b Body wastes, including excess water and salts, and urea.

3 Kidneys, ureters, bladder, urethra.

4 The urinary system acts like a filter. Blood flows through the kidneys and is ‘cleaned’, so that useful

substances are kept in the blood and the wastes are removed into the urine. It also ensures that the

amount and composition of body fluids are kept at levels that are safe.

4.7

Asthma

1 See Figure 4.5.1 in Science Focus 2.

2 Triggers include dust, smoke, irritants, chemicals and exercise.

3 The airways become narrower. This is caused by the contraction of the airway muscles with swelling

and inflammation of the airway lining. This then leads to the production of excess mucus, which further

restricts airflow. The result is a reduced amount of air going in and out of the lungs.

4 Wheezing, chest tightness, breathlessness and sometimes coughing.

5 Reliever and preventer medication.

6 A reliever relaxes the muscles of the airway, allowing them to open and produce normal breathing.

A preventer reduces swelling and inflammation of the airways, which helps reduce excess mucus

production.

7 The normal airways are open, not inflamed or irritated, and produce a little bit of mucus.

The asthma sufferer would have a swollen, inflamed lining that may be producing excess mucus, even

between attacks.

4.8

Other respiratory systems

1 These organisms are too large to allow gases to move directly from the atmosphere to all body cells.

2 The movement of gases across the lining requires a moist surface.

3 a Large surface area and moist surface.

b Insect—oxygen moves directly from the air to the tissues; fish—oxygen moves from water into the

bloodstream.

c Large surface area and moist surface.

4.9

Body systems crossword

1 2

P A C E M A K E R

3 4

P F L A C C I D

5 6

S T O O L M

O E S O P H A G U S

P T A B

P T

H A T I

L O

I S U

8 9 10

U R E A T R A N S F U S I O N

11 12

N S S M N C S Y

C I

13

A L I M E N T A R Y A

T U

O M P A T

E M

E X C R E T I O N H

E Y L L

D E H Y D R A T I O N

V N G

E E

19 20

E S A D E F I C I E N C Y Y

F I B R I N Y R

N G

22 23

A N U S Y

Y T T

D I A R R H O E A

E O

D I A L Y S I S

27

D E C A Y

26

P E R I S T A L S I S

Unit 4.1: Food

1 dehydration

2 water

3 lipids

4 proteins

5 vitamins

6 minerals

7 carbohydrate

8 deficiency

9 thiamine

10 potassium

11 energy

12 nervosa

13 bulimia

14 obese

Unit 4.2: Digestion

1 molars

2 incisors

3 enamel

4 decay

5 fluoride

4.10

6 alimentary

7 bolus

8 oesophagus

9 peristalsis

10 villi

11 caecum

12 anus

13 rectum

14 liver

15 sphincter

16 chyme

17 poisons

18 stool

19 flatus

20 glycogen

21 diarrhoea

22 vomit

Unit 4.3: Blood

and circulation

1 plasma

2 fibrin

3 transfusion

4 artery

5 aorta

6 capillary

7 oxygenated

8 atrium

9 ventricle

10 valves

11 systolic

12 pacemaker

13 vein

Unit 4.4:

Excretion: getting

rid of wastes

1 excretion

2 urea

3 water

4 kidney

5 nephron

6 urine

7 ureter

8 urethra

9 bladder

10 dialysis

Unit 4.5:

Respiratory systems

1 respiration

2 glucose

3 carbon dioxide

4 enzymes

5 metabolism

6 anaerobic

7 lactic acid

8 ethanol

10 windpipe

11 alveoli

12 epiglottis

13 haemoglobin

14 diaphragm

15 exhaled air

16 capillaries

5.1

Zapping car doors

2 Hot, dry windy weather.

3 The contact between your clothes and the seat’s surface causes the build-up of static electricity through

‘frictional’ or ‘contact’ charging.

4 One surface ends up with more negative charges (your body) and the other surface has more positives

(the car).

5 Normally 10 000 V but up to 20 000 V.

6 Any one of the following:

• changing the surface materials of the car seat

• changing the type of material in your clothing; some materials, however, such as woollen jumpers

and pants, certain human-made fabrics and plastic raincoats, make the effect worse

• always going barefooted, so the charge will leak away when you step outside the car—not good in

winter!

• covering your car seats with a conductor such as aluminium foil—this stops the contact-charging

effect

• before you get out of the car, touching something metal or glass, which may be enough to take the

charges away without the zap.

7 Your shoes insulate you. Removing them allows the charge to leak out.

8 Trampoline.

Carpet in a house.

Taking a hat on and off.

Taking clothing on and off.

Others as suggested by students.

9 Various answers as suggested by students.

5.2

Electrical symbols and circuits

1 An energy source, such as a battery, a conductor

(wires) for the electricity to flow through,

something to use up the electrical energy such

as a globe or motor, a switch to turn the current

on and off.

2 See Figure 5.2.1 in Science Focus 2.

3 See Figure 5.2.2 in Science Focus 2.

4 Circuit with symbols, as it is faster and requires

fewer details in diagrams; also it is 2D not 3D.

5 See Figure 5.2.4 in Science Focus 2.

5.3

Electrical current at the footy

1 Circuit A.

2 More people could enter the ground.

3 Total number = 2 × 5 = 10 people every minute.

4 Circuit B.

5 There are two ways for the current to go, so more current flows.

6 The gate is twice as wide so will admit 10 people every minute.

7 Resistance is lower (half).

8 All the people (current) would enter at the truck entrance gate.

9

5.4

Electricity costs

Appliance

Power rating

(W)

(kW)

Time used

for

for (hours)

Energy used

(kWh)

Cost ($)

Standard globe 75 0.075 36 hours 36 2.7 0.324

Fluorescent light 40 0.04 24 hours 24 0.96 0.1152

Hair dryer 1500 1.5 10 minutes 0.167 0.25 0.03

Fan heater 2000 2 2 hours 2 4 0.48

Iron 750 0.75 30 minutes 0.5 0.375 0.045

Computer 350 0.35 5 hours 5 1.75 0.21

Microwave oven 1200 1.2 15 minutes 0.25 0.3 0.036

Stove 8000 8 30 minutes 0.5 4 0.48

Frypan 1500 1.5 15 minutes 0.25 0.375 0.045

Refrigerator 600 0.6 1 week 168 100.8 12.096

Washing machine 1000 1 1.5 hours 1.5 1.5 0.18

Television 250 0.25 2 hours 2 0.5 0.06

Kettle 1800 1.8 5 minutes 0.0833 0.15 0.018

Cassette player 10 0.01 20 minutes 0.333 0.003 33 0.0004

$14.1196

5.6

Electricity crossword

1 2 3

4 5 6

D I R E C T

L A T T R A C T

D M I

M C B

I E

7 8 9

13 14

C U R R E N T

17 18 19 20 21

N E U T R A L

K E T T L E

T U N G S T E N

T I

E C

S E R I E S

M E T A L S

P O S I T I V E

F U S E

A R G O N

O P A R A L L E L

L H

T O

A L T E R N A T I N G

I O

C C

V O L T A G E O

L M

L P

N E G A T I V E

28

R E S I S T A N C E

E T

N E

I N S U L A T O R

5.7

Unit 5.1: Static electricity

1 positive

2 negative

3 neutral

4 attract

5 repel

6 static

7 induced

8 photocopier

9 field

Unit 5.2: Moving

1 voltage

2 currrent

3 ammeter

4 voltmeter

5 nichrome

6 insulator

7 metals

8 cell

9 battery

10 lithium

11 photovoltaic

12 resistance

13 argon

14 tungsten

15 component

Unit 5.3: Using electricity

1 parallel

2 series

3 transformer

4 direct

5 alternating

6.1

Bushfire intensity

1 A measure of the ferocity, size and impact of the

fire.

2 Fuel consumed, rate of spread and heat energy

available in the fuel.

3 I = H × W × R

4 I = kilowatt per metre, H = kilojoule per

kilogram, W = kilogram per square metre,

R = metres per hour

5 a I = H × W × R

= 4 × 10 × 50

= 2000 kW/m

Ecological impact—medium impact, trees

killed, slow recovery of ecosystem.

b I = 4 × 50 × 200

= 40 000 kW/m

Ecological impact—extremely high,

ecosystem completely destroyed.

6 Lower limit

I = H × W × R

20 = 4 × W × 5

20 = 20 W

W = 1 kilogram per square metre

Upper limit

500 = 4 × W × 5

500 = 20 W

W = 25 kilograms per square metre

A sample of the area would need to have

between 1 and 25 kilograms per square metre.

7 a More moisture, lower intensity; less

moisture, higher intensity.

b Higher wind, higher intensity, as the wind

supplies more oxygen and keeps fire moving

faster.

c Fires burn faster and hotter when travelling

uphill than down. Sheltered areas may burn

at lower intensity than open, exposed areas.

6.2

Whodunnit

1 Huntsman spider and mermithid worm.

2 An organism that lives in or on another.

3 Either directly or via food.

4 Body fluids, digestive glands, gonads, muscles.

5 By bursting out of its body.

6 Weakened.

7 a To water.

b Possibly thirst.

c The worm is aquatic, so its chances of survival are increased.

6.3

A load of garbage

2 a 71.76 kg

b 66.04 kg

c 53.56 kg

3 a Steady decrease.

b Initial increase, then steady.

4 Possibly plastic being used to replace glass containers.

kg per person

Other

Garden

Paper

1999 2004

6 a 133.64 kg

b 127.92 kg

c 190.84 kg

7 Various answers, eg paper used in non-packaging steadily increases.

8 1994: 205.40 kg, 1999: 193.96 kg, 2004: 244.40 kg

9 Packaging and non-packaging totals show different trends. The vertical scale for non-packaging involves

values around three times larger than those for packaging.

6.4

Rabbit advance

y

1980

11

1900

1890

1880

1870

0 1

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

x

6.5

Threatened plants

Total numbers of rare or threatened Australian plants in all conservation categories

1–50

51–100

101–200

201–400

401 +

78

774

34

162

62

29

44

99

125

464

435

419

452

308

197

480

63

32

76

48

47

17

71

41

46

73

5 3

31

133

19

51

37

16 23

42 63 48

74

56

66

154

128

86 85

57

150 237

152

82

209

2 Various answers, eg cattle grazing, land clearing, food for rabbits and other introduced species.

3 Various answers depending on student research.

6.6

Ecology crossword

2 3

7 8

G L O B A L A D A P T A T I O N S A C I D

U I

C O E

10 11

C O M M U N I T Y C O N S

E R V A T I

O N

S E V

12 13 14 15

W E B I B I O D I V E R S I T Y A

A R

16 17 18

C A R N I V O R E F C L A

N X O O I N A T

21 22

U D E C O M P O S E R S M S S Q A

H E T E P M P U T

O H A N I S E

I A

T A B I O T I C T T

R T

R B N

M A G N I F I C A T I O N

O I

T T

T C

P H O T O S Y N T H E S I S I

H A

O O P R O D U C E R

M U T U A L I S M N N N

6.7

Unit 6.1: Ecosystems

1 ecosystem

2 community

3 terrestrial

4 aquatic

5 biosphere

6 biomes

7 habitat

8 microhabitat

Unit 6.2: Physical

attributes of an ecosystem

1 environment

2 adaptations

3 abiotic

4 photic zone

5 pH

6 biotic

7 competition

8 dispersal

9 predation

Unit 6.3: Food chains and

food webs: interactions

of life

1 glucose

2 photosynthesis

3 producer

4 autotroph

5 consumer

6 heterotroph

7 carnivore

8 omnivore

9 herbivore

10 food chain

11 food web

12 biodiversity

13 organic matter

14 decomposers

15 mutualism

16 commensalism

17 parasitism

Unit 6.4: Effects of

human civilisation on the

ecosystem

1 pollutant

2 global warming

3 acid rain

4 transpiration

5 overgrazing

6 deforestation

7 exotic species

8 conservation

7.1

Water movement in trees

1 A push and a pull force.

2 a Evaporation: Change of

state of water from liquid

to gas.

b Transpiration: Evaporation

of water from a plant.

c Stomata: Hole in the leaf

that allows a water and

gases in and out.

3 See Figures 7.1.2 and 7.1.4 in

Science Focus 2.

4 See Figure 7.1.5 in Science

Focus 2.

5 Strong attractions between

water molecules that make

them stick together.

6 The Sun.

7 The water in the straw should

be higher than the water in

the glass.

8 Fill a glass above the rim

and observe the curved

surface. This is due to the

cohesion forces between water

molecules.

9 There is a push and pull force

involved. Pressure in the

roots pushes water upwards.

The force of this push can

take water about two to three

metres. Evaporation of water

from the leaves—called

transpiration—pulls the water

molecules up the tree. As

molecules evaporate they

attract the molecules around

them, as there are strong

attractions between water

molecules that make them

stick together. This creates a

small suction force and pulls

water upwards. The attraction

chain continues to the ground

and causes the water to move

from the roots to the tree top.

Capillary action also helps.

As the xylem is a tube, water

molecules are attracted to and

rise up the walls of the tube a

little.

7.2

The effect of temperature on

photosynthesis

1 a Carbon dioxide, water.

b Glucose (sugar), oxygen.

c Light, chlorophyll.

2 a 6CO 2

+ 6H 2

chlorophyll

light

C 6

H 12

O 6

+ 6O 2

b

A lighted splint will flare when placed

in the oxygen gas.

3 a The rate of most chemical reactions

increases as the temperature

increases.

b At these higher temperatures the

enzymes involved in photosynthesis

are altered (denatured). Without

effective enzymes, the rate of reaction

slows.

Bubbles per minute

4 Carbon dioxide level and light intensity. 20 30 40

Temperature (°C)

7.3

Photosynthesis and respiration

All organisms require energy to carry out their life

functions. The Sun is the ultimate source of energy

for all life on Earth.

During photosynthesis plants use the energy

from the Sun to make food. Photosynthesis is a

chemical reaction in which water and carbon

dioxide react to form oxygen and glucose. Glucose

is the chemical in which the energy is stored.

Chlorophyll is a pigment in plants that absorbs the

sunlight. The chlorophyll is contained in structures

called chloroplasts inside the leaf cells.

This stored energy is available to be used later.

The energy in glucose is released in a process called

respiration. Both plants and animals release energy

in this way.

In respiration, glucose reacts with oxygen to

form the products carbon dioxide and water.

Respiration and photosynthesis would occur very

slowly without enzymes to act as catalysts and speed

up the reactions.

2 a Photosynthesis:

Light

water + carbon dioxide → oxygen + glucose

b Respiration:

oxygen + glucose → water + carbon dioxide

(+ energy)

3 a B b A

4 a Oxygen.

b The rate of gas production would increase,

as more light increases the rate of

photosynthesis.

c Insert a glowing splint and it should burst

into flames.

5 a Carbon dioxide.

b Insert alighted splint and it should go out (or

limewater test).

c Yes.

d Oxygen from photosynthesis, as the set-up

is now in the light. And carbon dioxide, as

respiration goes on all the time.

7.4

Leaves

1 See Figure 7.3.1 in Science Focus 2.

mesophyll cells

phloem cells

air space

lower epidermal cells

upper epidermal cells

cuticle

stomata

xylem cells

palisade cells

chloroplast

guard cells

loosely packed cells that give this part of the leaf a spongy appearance;

loose packing allows large spaces for gases to move between the cells

carries food and glucose away from the leaf

spaces in the leaf where gases move around cells

transparent layer of cells on the bottom of the leaf that act like a skin

transparent layer of cells on the top of the leaf that act like a skin

waxy waterproof layer that reduces loss of water from the leaf

small openings on the leaf surface

supplies water to the leaf

this layer is tightly packed and contains large numbers of chloroplasts; a large

amount of photosynthesis occurs here

structure in plant cells that contains the green chlorophyll

cells that change the size of the stomatal openings, allowing stomata to open

and close

7.5

Plants crossword

W

2 3 4

E L

T E

L U L O S E

Y S

H O

14 15

T O I

D I

E S O P

X

G A

U T I C L

Y L E

7.6

Unit 7.1: Plant transport

systems

2 starch

3 photosynthesis

4 xylem

5 phloem

6 vascular

7 minerals

8 flaccid

9 turgid

10 cambiam

Unit 7.2: Photosynthesis

and respiration

1 oxygen

2 carbon dioxide

3 chlorophyll

4 chloroplasts

5 iodine

6 cellulose

7 light reaction

8 respiration

9 enzymes

Unit 7.3: Leaves

1 cuticle

2 stomata

3 xylem cells

4 phloem cells

5 palisade cells

6 mesophyll cells

7 epidermis

8 guard cells

9 green

8.1

Discovering the asteroid belt

Planet Astronomical distance (AU) Bode’s Law

Mercury 0.39 0.4

Venus 0.72 0.7

Earth 1.0 1.0

Mars 1.52 1.6

Unknown planet – 2.8

Jupiter 5.2 5.2

Saturn 9.6 10.0

2 The discovery of Uranus provided proof that Bode’s Law was correct and other scientists would more

strongly believe it.

3 Astronomers thought that the asteroids were fragments of a larger planet that had exploded.

Planet Astronomical distance (AU) Working Bode’s Law

Uranus 19.2 Align equals signs in following lines

192 + 4 = 196

196/10 = 19.6 AU

Neptune 30.1 384 + 4 = 388

388/10 = 38.8

Pluto 39.6 768 + 4 = 772

772/10 = 77.2

19.6

38.8

77.2

5 There is a large inaccuracy in the last two results. Bode’s Law does not seem to work in these cases.

6 Bode’s Law holds for the first seven planets only. A law must hold for all cases; therefore Bode’s Law

is not a true law. The large error in the results for the last two planets showed that the law was a

mathematical coincidence only.

8.2

Constellations

Common name

Constellation Scrambled Clue Unscrambled

AQUARIUS RATEW RIRECAR A bucket is also one WATER CARRIER

AQUILA LEGEA Powerful bird EAGLE

ARA RATLA Found in a church ALTAR

BOOTES SAMNERDH Looks after herds HERDSMAN

CANCER ABCR Sea creature with

exoskeleton

CRAB

CANIS GOD Common pet DOG

CAPRICORNUS TOAG Horned animal GOAT

CENTAURUS TENRACU Half-human, half-horse CENTAUR

CETUS AHELW Large aquatic mammal WHALE

COLUMBA VEDO Bird of peace DOVE

CORVUS RWOC Black bird CROW

CRATER UPC Drinking vessel CUP

CRUX SROCS On the Australian flag CROSS

CYGNUS SNAW The ugly duckling was

one

SWAN

DELPHINIUS PINHOLD Intelligent sea mammal DOLPHIN

DORADO WORDSHISF Type of fish SWORDFISH

DRACO ARDNOG Medieval beast DRAGON

FORNAX ACENURF Oven FURNACE

GEMINI NITSW Born together TWINS

GRUS RANEC Lifting device or bird CRANE

HYDRA TARWE SONTREM Type of monster WATER MONSTER

HYDRUS ESA PENTERS Ocean-going snake SEA SERPENT

LEO LINO King of beasts (Africa) LION

LEPUS RAHE Like a rabbit HARE

LIBRA SASECL For measuring mass SCALES

MONOCEROS NINROCU Mythical horned horse UNICORN

MUSCA LYF Annoying insect FLY

ORION RENTUH Seeks animals HUNTER

PAVO PECKACO Bird that displays blue

and green colours

PEACOCK

PEGASUS DINGWE ROSEH Flying thoroughbred WINGED HORSE

PICTOR TINREAP Artist PAINTER

PISCIS AUSTRINUS NERTHOUS HISF Fish from the south SOUTHERN FISH

SAGITTARIUS HERARC Uses bow and arrows ARCHER

SCORPIUS POONIRCS Stinging arthropod SCORPION

TAURUS ULLB Male cow BULL

TRIANGULUM

AUSTRALE

HTOSNREU GIANRELT

Three-sided shape in the

south

TUCANA CANOUT Tropical bird with large

beak

SOUTHERN TRIANGLE

TOUCAN

URSA AERB The grisly is one BEAR

VOLANS NYILGF IFHS Fish that flies FLYING FISH

8.3

Parts of a galaxy

1 See Figure 8.3.1 in Science Focus 2.

2 See Figure 8.3.2 in Science Focus 2.

3 The three main areas are the bulge, the disk and spiral arms, and the halo.

4 Elliptical galaxies have a bulge and a halo, but do not have a disk or spiral arms.

5 The bulge is about 10 000 light years in diameter and contains mostly old stars, gas and dust.

6 The halo contains either individual or clusters of old stars, called globular clusters.

7 Bulge = 1 cm, disk = 10 cm, halo = 13 cm

8.4

Global positioning

1 Celestial navigation is the finding of a position on Earth by observation of the Sun, moon, stars and

planets.

The celestial sphere is an imaginary hollow sphere with an imaginary centre at the centre of the Earth.

2 G = Global, P = Positioning, S = System.

3 A constellation is group of stars. Celestial bodies are objects in the night sky. The ‘human-made celestial

bodies’ are the satellites. This phrase therefore describes the group of satellites orbiting the Earth.

4 NAVSTAR could mean navigation by the stars (these stars being satellites). The actual meaning of

NAVSTAR is NAVigation System by Timing And Ranging.

5 Positional accurately to within metres.

6 The satellites orbit at 20 000 kilometres. The 24 NAVSTAR satellites are in different orbital planes. This

provides global coverage for the GPS.

7 Three satellites will give a latitude/longitude position. This is called a 2D position fix. With four or more

satellites, you get a 3D position which includes latitude, longitude and altitude.

8.5

Astronomy crossword

W I N K L E

O N S T

U B B L E

E L L A T I O N

K

S T E R O

Z

Y W

O D I

8.6

Unit 8.1: Space rocks

1 astronomy

2 asteroid

3 comet

4 meteor

5 meteorite

6 meteoroid

7 Halley

8 tails

9 Ceres

Unit 8.2: The night sky

1 light year

2 sphere

3 ascension

4 declination

5 constellation

6 Crux

7 Centauri

8 Hadar

Unit 8.3: The Milky Way

and other galaxies

1 galaxy

2 spiral

3 Milky Way

4 quasar

5 radio

6 AAT

7 Hubble

8 universe

Unit 8.4: Satellites and

remote sensing

1 satellite

2 asynchronous

3 polar

4 Positioning

5 meteorology

6 false

7 Spirit

1.1 9.3

Solids, Team research liquids and project gases crossword

3 4 5

I R D

O R

C L U S I

V A R I A

Q

I B L I O G R A

N D E P E N D E N T

O N T

U A L I

Y P O T H E

9.4

Unit 9.1: Teamwork and topics

1 scientific research

2 explorer

3 scientist

4 team player

5 researcher

6 open-ended

Unit 9.3: Testing and evaluation

1 quantitative

2 qualitative

3 discussion

4 graph

Unit 9.2: Planning your investigation

2 variables

3 independent

4 dependent

5 controlled

6 aim

8 procedure

9 replicating

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A N S W E R S 1.1 Answers to worksheets Carl’s new experiments 1 Qualitative. They were qualitative because all observations were recorded using only words. 2 Carl thought that he should also do a quantitative analysis; that is, record the observations using numbers to measure how much the grass actually grows under different situations. 3 a Controls. b Every experiment needs a control against which results can be compared. 4 Types of grass, amount of grass. 5 The amount of water was kept the same. 6 The amount of sunlight. 7 The amount of water. 8 The soil would have had some water in it on Day 1 and would take a few days to dry out. 9 Measurements to be taken at the same time of day. Same ruler to be used and measured from the same place. Others as appropriate. 10 Repeating measurements is a good way to improve accuracy. Once a collection of different measurements is taken, an average can be obtained. 11 a 18 16 Carl's experiments 2C 1A 14 Average height (mm) 12 10 8 6 2D 1B Key 1A 1B 2C 2D 4 2 0 0 1 2 3 4 5 6 Days b 1A 16 or 17 mm 1B 6 or 7 mm 2C 16 or 17 mm 2D 12 or 13 mm Science Focus 2 Homework Book Answers © Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005. This page may be photocopied for classroom use.

Page 2 and 3: A N S W E R S 1.2 Answers to worksh
Page 4 and 5: A N S W E R S 1.5 Answers to worksh
Page 6 and 7: A N S W E R S 2.3 Answers to worksh
Page 8 and 9: A N S W E R S 2.5 Answers to worksh
Page 10 and 11: A N S W E R S 2.7 Answers to worksh
Page 12 and 13: A N S W E R S 3.2 Answers to worksh
Page 14 and 15: A N S W E R S 3.4 Answers to worksh
Page 16 and 17: A N S W E R S 4.1 Answers to worksh
Page 18 and 19: A N S W E R S 4.2 Answers to worksh
Page 20 and 21: A N S W E R S 4.7 Answers to worksh
Page 22 and 23: A N S W E R S 5.1 Answers to worksh
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