Sci Focus 2 HB Answers

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 which results results can be compared. 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. accuracy. Once a collection of different different measurements is taken, an average can be obtained. 11 a Carl's experiments 18 2C 16

1A

14

) m12 m ( t h10 g i e h e 8 g a r e v 6 A

2D

Key 1A 1B 1B

2C 2D

4 2

0

0

1

2

3

4

5

6

Days

b 1A 1B 2C 2D

16 or 17 mm 6 or 7 mm 16 or 17 mm 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 T

2 H

3 E

4 M

5 A

Extreme units

6 R

7 I

8 A

9 N

10 A

11 12 T R

13 E

14 N

15 C

16 H


1.3

A N S W E R S

1


1.2

A N S W E R S

Graphing skills

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2

Predicted energy consumption in Australia in 2009–10 solar 1.0%

other 3.3%

electricity 45.2%

oil 0.4% wood 15.3%

natural gas 34.9%

3

Blood glucose levels 8 7 l e v e l e s o c u l g d o o l B

6 5 4 3 2 1 0 0

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10 10

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Reading number 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 T

2 H

3 E

4 M

5 A

Extreme units

6 R

7 I

8 A

9 N

10 A

11 12 T R

13 E

14 N

15 C

16 H


1.3

A N S W E R S

1


1.2

A N S W E R S

Graphing skills

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2

Predicted energy consumption in Australia in 2009–10 solar 1.0%

other 3.3%

electricity 45.2%

oil 0.4% wood 15.3%

natural gas 34.9%

3

Blood glucose levels 8 7 l e v e l e s o c u l g d o o l B

6 5 4 3 2 1 0 0

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Reading number 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

Mass (kg (kg) 50 60 70 80 90 100 110 120


1.4

A N S W E R S

Body mass index

BMI (1.6 m tall people) 19.5 23.4 27.3 31.3 35.2 39.1 43.0 46.9

2, 3 The greater the height, the lower the graph.

BMI (1.8 m tall people) 15.4 18.5 21.6 24.7 27.8 30.9 34.0 37.0

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45

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40 35 30

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0

20

40

60

4 a 16 b 40 5

Height (m) 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9

80

100

120

140

Mass (kg)

BMI (50 kg people) 34.7 29.6 25.5 22.2 19.5 17.3 15.4 13.9

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

BMI (60 kg people) 41.7 35.5 30.6 26.7 23.4 20.8 18.5 16.6        

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10 Various answers, eg: a 1.4 m, 39.2 kg b 1.6 m, 64 kg c 1.8 m, 129.6 kg

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1.5

A N S W E R S

Sci-skills crossword

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A N S W E R S

1.6

Unit 1.1: What, why and how? 1 experiment 2 micrometer

Unit 1.2: Scientific research 1 2 3 4 5 6 7 8 9

research observations quantitative qualitative inference variable hypothesis aim conclusion

Unit 1.3: Better measurements 1 estimate 2 mistake 3 error


Sci-words 4 parallax error 5 reading error 6 instrument errors 7 average 8 metric 9 period

Unit 1.4: Scientific conventions 1 2 3 4 5 6 7 8 9 10 11

conventions apparatus procedure discussion conclusion bibliography data tabulated independent variable dependent variable line of best fit


A N S W E R S

2.1

1 Tungsten Sodium Zinc Einsteinium Tin Boron Cerium Radon

W Na Zn Es Sn B Ce Rn

2 Am Uub Ne Ar Cd O H Si S

Americium Ununbium Neon Argon Cadmium Oxygen Hydrogen Silicon Sulfur

A N S W E R S


The elements 3 a b c d 4 a b c

2.2

d e

f

5 a b

Radium e Sulfur Potassium f Helium Iodine g Silver Mercury 12 Any atoms before carbon on the list, eg oxygen, helium Any atoms after carbon on the list, eg zinc, silver Atomic weight generally increases AW of Mg = 24 AW of C = 12 24/12 = 2 times heavier AW of He = 4 AW of C = 12 12/4 = 3 times lighter Hydrogen, H Caesium, Cs


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

A N S W E R S

G Y M P

Elements wordfind T N U M N H

A R U L U E L

U

I

J

G K N D

P U O E N O T O N

U N O E

R

L

D L

U C D T G N U N O

I

P

M R A O S E I

E R N T

N M M I I

I M I

B O

D T R

R I

G O E C M T M N C

P

R

I

I

I

B U O L A A

E O P

A U U N

U G

R

I

T

A U A U

I

S

L

U E

D U N C

S

I

A

N S

C M N T

A

I

M N M T

D Y M I

L

E O

O H D E U R U R O R N

E

S

R N

I

A

I

H C

H L O R

I

I

I

V L

I

T Q D M U M E

D U C

I

E M U

Q M S

K R Y P

I

I

C

I

I

P O U

N E M P

U M

R A B A E

L X

T O N D P

R

F

B


Element

Combination reactions

Mass of oxide (g) 190.1 139.7 124.5 142.9 103.1 166.7 141.8 175.3 124.5

Aluminium Calcium Copper Iron Lead Magnesium Potassium Sodium Zinc

1


2.4

A N S W E R S

Increase in mass (g) 90.1 39.7 24.5 42.9 3.1 66.7 41.8 75.3 24.5

Percentage increase (%) 90.1 39.7 24.5 42.9 3.1 66.7 41.8 75.3 24.5

Atomic number 13 20 29 26 82 12 19 11 30

Reactivity order 5 3 9 7 8 4 1 2 6

Plot of mass increase v reactivity order 100 90

) 80 % ( s 70 s a 60 m n 50 i e s 40 a e r 30 c n I 20 10 0 0

1

2

3

4

5

6

7

8

9

10

Reactivity order

2 The points are scattered all over the graph. This shows no relationship between reactivity and mass increase on reaction. 3

Plot of mass increase v atomic number 100 90

) 80 % ( s 70 s a 60 m n 50 i e s 40 a e r 30 c n I 20 10 0 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. 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


2.5

A N S W E R S

Atomic graphs (extension)

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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. 3

250

200

) m p ( s 150 u i d a r c i m100 o t A 50

0 0

10

20

30

40

50

60

70

80

Atomic number

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


90

A N S W E R S

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 Gold Oxygen Potassium Sulfur Carbon Silver Iron Sodium

82 79 8 19 16 6 47 26 11

Pb Au O K S C Ag Fe Na

5 9 4 40 13 94 80 22 27 15 14

Fluorine Beryllium Zirconium Aluminium Plutonium Mercury Titanium Cobalt Phosphorus Silicon

F Be Zr Al Pu Hg Ti 27 P 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


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A N S W E R S

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2.8

Unit 2.1: Elements, compounds and mixtures element symbol atom molecule lattice compound formula mixture

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1 2 3 4 5 6 7 8

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Atoms crossword

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2.7

A N S W E R S

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Sci-words 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

A N S W E R S

1

2

Microbe size


The size of microbes

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

Microbe name

Length or diameter as shown

Length or diameter in nanometres

5 µm

5 000

E. coli (bacteria)

3.5 µm

3 500

Cholera bacteria

2.5 µm

2 500

1 400 nm

1 400

Yeast (fungi)

Filovirus 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. 6

flagellum

cytoplasm

cell membrane cell wall

protein coat

chemical with instructions for making new viruses


A N S W E R S

3.2

1


Bacterial growth

Growth of bacteria 55 50

) s d n a s u o h t ( a i r e t c a b f o r e b m u N

45

40 35

30 25

20 15

10 5

0 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.


A N S W E R S

1

3.3


Preserving foods

Kills most microbes

Stops or slows growth of microbes

Pickling

Refrigeration

Pasteurisation

Freezing

Heating in cans

Drying foods

Salting

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. 7

Food

Preservation method

Cream

refrigeration, pasteurisation

Apricots

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

Fish

refrigeration or freezing, pickling, salting

Pasta sauce

refrigeration or freezing, heating and sealing in a jar

Potato chips

salting, airtight

Pizza base

refrigeration

Grapes

dried (sultanas), refrigeration

Orange juice

refrigeration

Peanuts

salting, airtight

Salad

refrigeration

Onions

refrigeration, pickling

Jam

heating and sealing in a jar



3.4

A N S W E R S

Disease

Disease

Symptoms

How do you catch it?

What causes it?

Malaria

Fever, shivering, headaches

Insect—mosquito

Protozoa

Common cold

Runny nose, sore and dry throat, headache

Air, coughing and sneezing

Virus

Mumps

Painful swelling of the neck. High fever, headache


Virus

Chickenpox

Itchy, small red blister all over the body

Contact with infected person

Virus

Cholera

Diarrhoea, vomiting, dehydration

Contaminated drinking water

Bacteria

Ring worm

Ring-shaped itchy patches


Fungi

Scarlet fever

Fine red rash, sore throat, high temperature, vomiting, tongue looks white with red spots

Air

Bacteria

Whooping cough

Extended period of coughs ending with a ‘whoop’ sound


Bacteria

Tinea

Itchy red patches between toes


Fungi


3.5

A N S W E R S

Microbes crossword 1

P O 2

B

I

N A

R Y

F

I

S

S

I

O N

S 3

4

5

H Y P

H A

E

6

O

B

M

N S

U L

I

D

C

S

D

R

P

I

O

I

O N

B

R

G

E

I

7

O

I

N

8

9

F

L

A

G

E

L

L

A

10

C

H 11

E

12

U

A

R M E

N T A

T

T

C

I

T

13

B

H

14

N

F

E

T

T

I V

15

I

P

L

16

M U

17

S

H R O O M

B

E

E 18

E

O

I

T

T

O

19

R

Y

T

I

E

H

L

20

C

I

L

I

A

E

21

R

I

T

A

N A

E

R O B

I

C

22

E

S

V

I

S

U

T

T

I

C

T

S

R

O R E

S

H

O

23

S

P

U

N

24

C Y S

T


A N S W E R S

3.6


Sci-words

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


A N S W E R S

4.1


Analyse this!—page 1

1 100 grams contains Cereal

2

Energy (kJ)

Protein (g)

Fat (g)

Carbohydrate (g)

Sugar (g)

Fibre (g)

Sodium (mg)

Potassium (mg)

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

80 60 40 20 s t i r B a t i V

x i b t e e W

�

s e i t e e W

0       �     

         

        

25

15 10 5

�

x i b t e e W

s e i t e e W

      �     

         

        

� � �

s t i r B a t i V

x i b t e e W

s e i t e e W

      �     

         

        

s e i t e e W

      �     

         

        

x i b t e e W

s e i t e e W

      �     

         

        

         

        

Fibre (g) 14 12 10 8 6 4 2 0

�

0

s t i r B a t i V

�

Fat (g)

�

x i b t e e W

Sugar (g) 40 35 30 25 20 15 10 5 0

20

s t i r B a t i V

s t i r B a t i V

�

Protein (g)

0

Carbohydrate (g) 100

s t i r B a t i V

x i b t e e W

s e i t e e W

      �     


A N S W E R S

�

4.1


Analyse this!—page 2 �

Sodium (mg) 900 800 700 600 500 400 300 200 100 0

s t i r B a t i V

x i b t e e W

s e i t e e W

Potassium (mg) 400 350 300 250 200 150 100 50 0

      �     

         

        

s t i r B a t i V

x i b t e e W

s e i t e e W

      �     

         

        

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.


A N S W E R S

4.2


The human digestive system

1 See Figure 4.2.5 in Science Focus 2. 2 a b c d e f g h i j

Produces enzymes that aid in digestion. Digests food through chemical and mechanical processes. Cut and grind food. Absorbs minerals and water from food. Stores glucose, detoxifies blood. Helps manipulate and push food back for swallowing. Produces saliva. Stores bile, which helps digestion of fats. Absorbs protein, carbohydrates and lipids from food. Most digestion occurs here. Pushes food from mouth to stomach.

3 a b c d e

Large intestine. Pancreas. Small intestine. Rectum. Mouth.

A N S W E R S

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.

A N S W E R S

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.


A N S W E R S

1

4.5


Blood flow rates 12 500

Blood flow 2000 At rest During strenuous exercise

) 1500 e t u n i m / L m ( 1000 e t a r w o l f d o 500 o l B

0 Abdomen

Brain

Heart

Kidney

Muscles

Skin

Other

Part of the body

4 a 5800 mL/min b 17 500 mL/min

2 The brain. 3 The muscles.

A N S W E R S

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.


A N S W E R S

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.

A N S W E R S

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

A N S W E R S

Body systems crossword

1

2

C

3

P

F

L

5

S P

T

A

H

A

T

S

R

I

D

H O E

S O P H A G U S

7

I 8

9

U R

S

E

A

T

T

L

O

R A N S

11

C

F

U S

I

O N 12

C

S

Y

M E

N

A

T

R

H

B

13

A

A

M

O

P 10

N

M 14

U

T

E M A K E

6

I

C

C

B

U

S

N

A C M

T O O L

I

P A C

4

L

I

P

T

A

R

A

Y

15

M

E

E

X

C

R

E

T

I

O N

16

R

17

E

Y

N

G

L

L

18

V

L 19

E

E

D

E

S

A

N

Y

R

E

H

Y D

R

A

T

I

S

O N H

20

D E

F

I

C

I

E N C

Y

Y

21

F

I

B

R

I

22

N

G

A N U

S

Y

S

D 23

R

V 24

Y

T

T

E

O

D

I

A

R

R

H O E

A

L

T

L

E

25

D

I

A

L

Y

S

I

S 26

I

P

E

R

I

S

T A L

S

I

S

27

D E

A N S W E R S

Unit 4.1: Food

4.10

C A Y


Sci-words

6 alimentary 7 bolus 1 dehydration 8 oesophagus 2 water 9 peristalsis 3 lipids 10 villi 4 proteins 11 caecum 5 vitamins 12 anus 6 minerals 13 rectum 7 carbohydrate 14 liver 8 deficiency 15 sphincter 9 thiamine 16 chyme 10 potassium 17 poisons 11 energy 18 stool 12 nervosa 19 flatus 13 bulimia 20 glycogen 14 obese 21 diarrhoea Unit 4.2: Digestion 22 vomit 1 molars Unit 4.3: Blood 2 incisors and circulation 3 enamel 1 plasma 4 decay 2 fibrin 5 fluoride

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 9 fermentation 10 windpipe 11 alveoli 12 epiglottis 13 haemoglobin 14 diaphragm 15 exhaled air 16 capillaries


5.1

A N S W E R S


Zapping car doors

1

�

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.


A N S W E R S

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.

6

2 See Figure 5.2.1 in Science Focus 2. 3 See Figure 5.2.2 in Science Focus 2. 7

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.

A N S W E R S

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

B


Appliance

Power rating (W) 75

Standard globe


5.4

A N S W E R S

Fluorescent light

Electricity costs

Power rating (kW)

40

0.075

Time used for 36 hours

0.04

24 hours 10 minutes

Hair dryer

1500

1.5

Fan heater

2000

2

Time used for (hours)

2 hours

Energy used (kWh)

Cost ($)

36

2.7

0.324

24

0.96

0.1152

0.167

0.25

0.03

2

4

0.48

0.5

0.375

0.045

5

1.75

0.21

Iron

750

0.75

30 minutes

Computer

350

0.35

5 hours

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

600

0.6

1 week

Refrigerator Washing machine

1000

Television Kettle

168

1.5 hours

1

100.8

12.096

1.5

1.5

0.18

2

0.5

0.06

250

0.25

2 hours

1800

1.8

5 minutes

0.0833

0.15

0.018

0.01

20 minutes

0.333

0.003 33

0.0004

Cassette player

10

$14.1196

1


5.6

A N S W E R S

2

F

Electricity crossword 3

S

P

O

S

I

T

I

V

E

4

5

D

I

R E

C

E L D

7

I

N D

H

A

O

A T

T

M

I

R A C

T

A

E T U N G S

T E N

E

T

15

C U R R E N T C 17

I

N E U T R A L D

T

R

I

O

H

I

O

Y

R

C

C

A

L

A R A

P

T

L

L

E

L

L

T

E

R N A

T 19

22

V O L

M

E

T

I

N G 20

N

C

A G E

O

O

L

M

L

L

P

T

O

M

P

E G A

E

T

I

V

V

26

U

R

E

27

M E

E

E

S

21

C

24

H E

T

O L

R

16

25

S

H

R

I T

L

C

23

K E

P

E

18

E 12

O 14

E

A R G O N

V

13

S H

T

B

U

9

O

C

6

F 8

10

M 11

T

T

A L

S

S

I

S

T

A N C E E

T

N

E

28

I

N S U L A T O R


A N S W E R S

5.7

Unit 5.1: Static electricity 1 2 3 4 5 6 7 8 9

positive negative neutral attract repel static induced photocopier field


Sci-words Unit 5.2: Moving electricity 1 voltage 2 currrent 3 ammeter 4 voltmeter 5 nichrome 6 insulator 7 metals 8 cell 9 battery 10 lithium

11 12 13 14 15

photovoltaic resistance argon tungsten component

Unit 5.3: Using electricity 1 parallel 2 series 3 transformer 4 direct 5 alternating


A N S W E R S

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.

A N S W E R S

6.2

6 Lower limit I = H × W × R 20 = 4 × W × 5 20 = 20 W W = 1 kilogram per square metre Upper limit I = H × W × R 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.


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.


A N S W E R S

6.3


A load of garbage

�

1 � �     �   �   



�



�



�

 

� � � � 

2 a b c 3 a b



��

71.76 kg 66.04 kg 53.56 kg Steady decrease. Initial increase, then steady.

4 Possibly plastic being used to replace glass containers. 5

� 250 200

Other Garden Food Paper

n o s r 150 e p r e p 100 g k 50 0 �

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

A N S W E R S

Rabbit advance

y

16

15

14

13

1 98 0 12

11

0 0 1 9

10

9

0 9 1 8

8

7

1880

6

5

1870

4

3

2

1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

x


1


6.5

A N S W E R S

Threatened plants

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

1–50 51–100 101–200 250

201–400 401 +

78

774 34

30

27

7

13

45 162 29 44

62 18

63

31

78 86

85

99 57

14 17

40

82

28 24

125

128

209

464 32 197

15

28

30

150

35

35

47

435

237

76

419 452

480

308

51

71

128

41

27

46

48

152

16 19 34

154

73 27

9 45

5

37 15

3

16

73

133

23

13

48 42 63 74 27 56 66

2 Various answers, eg cattle grazing, land clearing, food for rabbits and other introduced species. 3 Various answers depending on student research.



6.6

A N S W E R S

Ecology crossword

1

2

G

4

5

6

G L O B A L U I 9 E C O

10

12

I

W E B

16

C A R N I

19

21

22

D E C H

T

23

A

H

O T R

24

A B I N B

O

I P H O T H A

26

28

M U T

6.7

ecosystem community terrestrial aquatic biosphere biomes habitat microhabitat

environment adaptations abiotic photic zone pH biotic competition

T Y 13

I D C

M

R

C O N S E R V A T

I O N

N

H

14

25

Unit 6.2: Physical attributes of an ecosystem 1 2 3 4 5 6 7

A C

15

B I O D I V E R S I T Y R A E R 17 18 A V O R E L F C 20 X N I N A O O Q S S O M P O S E R S M M T U E E P P N A I S I E T O T I C T R T

Unit 6.1: Ecosystems 1 2 3 4 5 6 7 8

8

11

M A G N I F T T I O S Y N T H E S I S O O N N U A L I S M

A N S W E R S

M

7

A D A P T A T I O N S H M

C O M M U N I E V S

A U

3

C

A B I T A T

I C A T I O N C T I 27

P R O D U C E R N


Sci-words 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 2 3 4 5 6 7 8

pollutant global warming acid rain transpiration overgrazing deforestation exotic species conservation


A N S W E R S

7.1


Water movement in trees

1 A push and a pull force. 7 The water in the straw should 2 a Evaporation: Change of be higher than the water in state of water from liquid the glass. to gas. 8 Fill a glass above the rim b Transpiration: Evaporation and observe the curved of water from a plant. surface. This is due to the c Stomata: Hole in the leaf cohesion forces between water that allows a water and molecules. gases in and out. 9 There is a push and pull force 3 See Figures 7.1.2 and 7.1.4 in involved. Pressure in the roots pushes water upwards. Science Focus 2. 4 See Figure 7.1.5 in Science The force of this push can Focus 2. take water about two to three 5 Strong attractions between metres. Evaporation of water water molecules that make from the leaves—called them stick together. transpiration—pulls the water 6 The Sun. molecules up the tree. As

A N S W E R S

7.2

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.


The effect of temperature on photosynthesis

1 a Carbon dioxide, water. b Glucose (sugar), oxygen. c Light, chlorophyll. 2 a

6CO2 + 6H2O

chlorophyll light

C6H12O6 + 6O 2 50

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.

4 Carbon dioxide level and light intensity.

e t u n i m r e p s e l b b u B

40

30

20

20

30

40

Temperature ( C) °


A N S W E R S

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.

A N S W E R S

7.4

2 a Photosynthesis: Light

b

3 a 4 a b

c 5 a b c d

water + carbon dioxide → oxygen + glucose Respiration: oxygen + glucose → water + carbon dioxide (+ energy) B b A Oxygen. The rate of gas production would increase, as more light increases the rate of photosynthesis. Insert a glowing splint and it should burst into flames. Carbon dioxide. Insert alighted splint and it should go out (or limewater test). Yes. Oxygen from photosynthesis, as the set-up is now in the light. And carbon dioxide, as respiration goes on all the time.


Leaves

1 See Figure 7.3.1 in Science Focus 2. 2 mesophyll 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

phloem cells

carries food and glucose away from the leaf

air space

spaces in the leaf where gases move around cells

lower epidermal cells

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

upper epidermal cells

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

cuticle

waxy waterproof layer that reduces loss of water from the leaf

stomata

small openings on the leaf surface

xylem cells

supplies water to the leaf

palisade cells

this layer is tightly packed and contains large numbers of chloroplasts; a large amount of photosynthesis occurs here

chloroplast

structure in plant cells that contains the green chlorophyll

guard cells

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


7.5

A N S W E R S


Plants crossword 1

G 2

3

4

A

R E

S

P

I

R A

T

I

O N

5

C

E

L

L

U L

O S

E

O 6

R

E

O

M E

S

N

O P

H Y L

T

7

B

C

I

H

H 8

C

L

S

A

9

O

P

R

H

H O T

O

I

10

W A

T

E

A

R

11

12

O

L

R O O T

P

O

C

S 13

U

G

14

L

E

C

15

H L

O R O P

H Y L

L

16

D

I

A

T

O M

G

A

U

17

S

C

U T

I

C

L

E

C

18

C A

T A

L

Y S

T

D

I

O

S

S

A

E

D 19

X Y L

A N S W E R S

7.6

Unit 7.1: Plant transport systems 1 glucose 2 starch 3 photosynthesis 4 xylem 5 phloem 6 vascular 7 minerals 8 flaccid 9 turgid 10 cambiam

E

M


Sci-words 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 2 3 4 5 6 7 8 9

cuticle stomata xylem cells phloem cells palisade cells mesophyll cells epidermis guard cells green


A N S W E R S

1

Planet


8.1

Discovering the asteroid belt 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

–

2.8

Jupiter

5.2

5.2

Saturn

9.6

10.0

Unknown planet?

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. 4

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

19.6

Neptune

30.1

384 + 4 = 388 388/10 = 38.8

38.8

Pluto

39.6

768 + 4 = 772 772/10 = 77.2

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.


A N S W E R S

8.2


Constellations

Common name Constellation AQUARIUS AQUILA ARA BOOTES CANCER

Scrambled RATEW RIRECAR LEGEA RATLA SAMNERDH ABCR

CANIS CAPRICORNUS CENTAURUS CETUS COLUMBA CORVUS CRATER CRUX CYGNUS

GOD TOAG TENRACU AHELW VEDO RWOC UPC SROCS SNAW

DELPHINIUS DORADO DRACO FORNAX GEMINI GRUS HYDRA HYDRUS LEO LEPUS LIBRA MONOCEROS MUSCA ORION PAVO

PINHOLD WORDSHISF ARDNOG ACENURF NITSW RANEC TARWE SONTREM ESA PENTERS LINO RAHE SASECL NINROCU LYF RENTUH PECKACO

PEGASUS PICTOR PISCIS AUSTRINUS SAGITTARIUS SCORPIUS TAURUS TRIANGULUM AUSTRALE TUCANA

DINGWE ROSEH TINREAP NERTHOUS HISF HERARC POONIRCS ULLB HTOSNREU GIANRELT

URSA VOLANS

AERB NYILGF IFHS

CANOUT

Clue A bucket is also one Powerful bird Found in a church Looks after herds Sea creature with exoskeleton Common pet Horned animal Half-human, half-horse Large aquatic mammal Bird of peace Black bird Drinking vessel On the Australian flag The ugly duckling was one Intelligent sea mammal Type of fish Medieval beast Oven Born together Lifting device or bird Type of monster Ocean-going snake King of beasts (Africa) Like a rabbit For measuring mass Mythical horned horse Annoying insect Seeks animals Bird that displays blue and green colours Flying thoroughbred Artist Fish from the south Uses bow and arrows Stinging arthropod Male cow Three-sided shape in the south Tropical bird with large beak The grisly is one Fish that flies

Unscrambled WATER CARRIER EAGLE ALTAR HERDSMAN CRAB DOG GOAT CENTAUR WHALE DOVE CROW CUP CROSS SWAN DOLPHIN SWORDFISH DRAGON FURNACE TWINS CRANE WATER MONSTER SEA SERPENT LION HARE SCALES UNICORN FLY HUNTER PEACOCK WINGED HORSE PAINTER SOUTHERN FISH ARCHER SCORPION BULL SOUTHERN TRIANGLE TOUCAN BEAR FLYING FISH


A N S W E R S

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

A N S W E R S

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 NAV igation System by Timing A nd R anging. 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

A N S W E R S

Astronomy crossword

1

2

C

R U X

C 3

O

A

S

T

E

R O I

M

D

M 4

E

L

M

5

T

W I

N K L

E

U

G

N

H

I 6

T

G

C

7

H U B

B

Y 8

L

E

O

T

9

S

A

T

A 10

E

L

L

I

T

E

B

Z

O D

I

A

C

11

A

W

M

A

O

12

R

C

O N S

T

E

L

L

A

T

I

O N

T 13

H A

14

L

L

E

Y S

S 15

O

S

P

I

R I

T

16

C

E

R E

S

I

O

R

17

M I

L

K Y

W A Y

A

A N S W E R S

1 2 3 4 5 6 7 8 9

astronomy asteroid comet meteor meteorite meteoroid Halley tails Ceres

Unit 8.2: The night sky 1 2 3 4

light year sphere ascension declination


8.6

Unit 8.1: Space rocks

L

Sci-words 5 6 7 8

constellation Crux Centauri Hadar

Unit 8.3: The Milky Way and other galaxies 1 2 3 4 5 6 7 8

galaxy spiral Milky Way quasar radio AAT Hubble universe

Unit 8.4: Satellites and remote sensing 1 2 3 4 5 6 7

satellite asynchronous polar Positioning meteorology false Spirit


Sci Focus 2 HB Answers

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