preliminary senior science · 4.7 technologies to purify and treat water 31 4.8 a technology to...
TRANSCRIPT
Marilyn SchellMargaret Hogan
PRELIMINARY SENIOR SCIENCE
© Science Press 2007First published 2007 Reprinted 2011
Science PressPrivate Bag 7023 Marrickville NSW 1475 AustraliaTel: (02) 9516 1122 Fax: (02) 9550 [email protected]
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Science Press. ABN 98 000 073
Contents
Introduction vVerbs to Watch vi
Dot Points
Water for Living viiPlants ixHumans at Work xiLocal Environment xiii
Questions
Water for Living 1Plants 43Humans at Work 81Local Environment 123
Answers
Water for Living 175Plants 189Humans at Work 201Local Environment 217
Dot Point Preliminary Senior Science iii Contents
Science Press
Notes
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Contents iv Dot Point Preliminary Senior Science
Science Press
Introduction
What the book includes
syllabus for the following topics in the Year 11 Senior Science course:
Also included are typical experimental results for students to analyse if the third column of the syllabus indicates
Format of the book
The book has been formatted in the following way:
1. Main topic statement (column 1 of syllabus)
1.1etc Syllabus requirement from columns 2 and 3.
1.1.1
1.1.2
worth in an examination. As a rough rule, every two lines of answer might be worth one mark. Note that in
science involved is worth only one mark.
How to use the book
You may have done work in addition to this with your teacher as extension work. Obviously this is not covered, but you may need to know this additional work for your school exams.
spend more time revising later, and allow you to spend your study time more productively.
Dot Point Preliminary Senior Science v Introduction
Science Press
account, account for State reasons for, report on, give an account of, narrate a series of events or transactions.
analyseIdentify components and the relationships among them, draw out and relate implications.
applyUse, utilise, employ in a particular situation.
appreciate Make a judgement about the value of something.
assess
results or size.
calculate
clarifyMake clear or plain.
classifyArrange into classes, groups or categories.
compare Show how things are similar or different.
constructMake, build, put together items or arguments.
contrastShow how things are different or opposite.
critically (analyse/evaluate) Add a degree or level of accuracy, depth, knowledge
deduceDraw conclusions.
demonstrateShow by example.
describeProvide characteristics and features.
discussIdentify issues and provide points for and against.
distinguishRecognise or note/indicate as being distinct or different from, note difference between things.
evaluateMake a judgement based on criteria.
examine
explainRelate cause and effect, make the relationship between things evident, provide why and/or how.
extractChoose relevant and/or appropriate details.
extrapolateInfer from what is known.
identifyRecognise and name.
interpret Draw meaning from.
investigate
justifySupport an argument or conclusion.
outlineSketch in general terms; indicate the main features.
predict Suggest what may happen based on available information.
propose Put forward (a point of view, idea, argument, suggestion etc) for consideration or action.
recall Present remembered ideas, facts or experiences.
recommend Provide reasons in favour.
recount Retell a series of events.
summariseExpress concisely the relevant details.
synthesisePut together various elements to make a whole.
Verbs to Watch
Verbs to Watch vi Dot Point Preliminary Senior Science
Science Press
Dot Point Page
1. Water for living 21.1 Water as a solvent 21.2 Water in food 41.3 Water in living things 51.4 Water in blood and cells 61.5 Water uptake by plants 71.6 Investigating water loss in plants 81.7 Plant adaptations to reduce water loss 81.8 Investigating water loss in animals 101.9 Animal adaptations to reduce water
loss 112. Water for health and life 122.1 The hydrological cycle 122.2 Water in the local area 152.3 Australian ecosystems and rainfall 172.4 Water pollution and salinity in Australia 182.5 Human impacts on water 192.6 Groundwater solutions 20
issues 203. Water maintaining Australian
environments 213.1 Fertilisers, herbicides and pesticides 213.2 Carrying fertilisers and pesticides into
water 213.3 Investigating effects of fertiliser on
plant growth 223.4 Impact of pollution on water systems 24
3.5 Impact of metals, phosphates and nitrates on water 25
Dot Point Page
3.6 Bioassays for water purity 263.7 Impact of sediment, leaching and
bioaccumulation 274. Chemicals impact on water 284.1 Causes and impacts of algal blooms 284.2 Conditions for algal blooms 284.3 Impacts of algal blooms in rivers 284.4 Reducing chemicals in agriculture 294.5 Reducing water pollution by
households 294.6 Investigating household use of water 294.7 Technologies to purify and treat water 314.8 A technology to reduce water pollution 325. Reducing water pollution 335.1 Indicator organisms in water 33
5.3 The local catchment area 345.4 Investigating the local catchment area 345.5 Investigating the purity of water in the
catchment area 355.6 Sources of water contamination in
catchments 37
5.9 Use and treatment of local water 385.10 Disasters involving water pollution 40
Answers to Water for Living 175
Water for Living
Dot Point Preliminary Senior Science vii Water for Living
Science Press
Water for Living viii Dot Point Preliminary Senior Science
Science Press
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Plants
Dot Point Preliminary Senior Science ix Plants
Science Press
Dot Point Page
1. Functioning of plants 441.1 How plants function 441.2 Plants as autotrophic organisms 45
2. Germination of seeds 472.1 Investigating germination of seeds 472.2 Effects of temperature, moisture and
oxygen concentrations 50
seeds 542.4 Effects of cold storage, vacuum
packing and dehydration 562.5 Effects of heat beds, lime pelleting
and misting on seeds 56
3. Growth of seedlings 58
3.2 Researching variables affecting plant growth 59
3.3 A factor affecting seedling growth 643.4 Effect of variables on seedling growth 653.5 Effects of light intensity and wavelength
on growth 654. Water requirements of plants 694.1 Adaptations of xerophytes, mangroves
and epiphytes 69
Dot Point Page
watering systems 714.3 Technological developments in
supplying water 725. Asexual reproduction 735.1 Vegetative propagation and
regeneration 735.2 Cloning plants 755.3 Genetic advantages and disadvantages
of cloning 755.4 Processes and uses of tissue culture 755.5 The Wollemi pine 776. Maintaining diversity 79
6.2 Endangering Australian plants 796.3 Protecting a rare Australian species 796.4 Conservation of a rare Australian 79
species6.5 Reasons for conserving Australian 80
plants6.6 Methods used to maintain 80
biodiversity6.7 Seed and gamete banks 80
Answers to Plants 189
Plants x Dot Point Preliminary Senior Science
Science Press
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Humans at Work
Dot Point Preliminary Senior Science xi Humans at Work
Science Press
Dot Point Page
1. Risks to the human body 821.1 The Occupational Health and Safety
Act 821.2 Hazards in the workplace 831.3 Injury from hazards in the workplace 831.4 Sources of risk 841.5 Health and safety audit 851.6 Impact of understanding on safety 871.7 Understanding the body and safety
awareness 872. Safety and the respiratory system 882.1 The respiratory system 882.2 Mucus in the respiratory system 902.3 The respiratory system and the
environment 902.4 Inhaled solids and the respiratory
system 912.5 Safety in the school and workplace 923. Safety and the eye 943.1 Structure and function of the eye 943.2 Function of tears 953.3 Effect of injuries on vision 953.4 Development of protective eyewear 973.5 Composition of protective eyewear 983.6 Eye protection at work 1003.7 First aid and the eye 1013.8 Light and eye safety 1014. Safety and the ear 1034.1 Structure and function of the ear 103
Dot Point Page
4.2 Investigating learning in a noisy environment 105
4.3 Causes of industrial deafness 1104.4 Sensory fatigue and hearing loss 1104.5 Uses of earmuffs and earplugs 1115. Safety and the brain 1125.1 Thickness and strength of skull bones 1125.2 The skull protects the brain 1135.3 Concussion 1135.4 Bruising brain tissue 1135.5 Uses of hard hats and safety helmets 1135.6 Design and uses of hard hats and
safety helmets 1135.7 Energy transfers and transformations 1145.8 Laws/regulations on the use of hard
hats and safety helmets 1156. Safety and muscles, joints and bones 1176.1 Investigating the relationship between
bones, tendons, ligaments and cartilage 1176.2 The axial skeleton, synovial joints
and muscles 1176.3 Ligaments, tendons and cartilage in
joint movement 1206.4 Repetitive sprain injury 1206.5 Repetitive actions and injury 1216.6 Safe lifting practices 1226.7 Strengthening exercises for sport
and work 122
Answers to Humans at Work 201
Humans at Work xii Dot Point Preliminary Senior Science
Science Press
Notes
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Local Environment
Dot Point Preliminary Senior Science xiii Local Environment
Science Press
Dot Point Page
1. Biotic and abiotic factors 1241.1 Difference between biotic and abiotic
factors 124
terrestrial environments 1261.3 Distribution and abundance of species 127
populations 130
resources 1382. Energy and matter in ecosystems 1402.1 Investigating food chains and webs 1402.2 Cycling of materials in ecosystems 1442.3 Water, carbon, oxygen and nitrogen
cycles 1452.4 Uses of energy in organisms 1472.5 Flow of energy through a natural
ecosystem 1473. Aquatic and terrestrial ecosystems 1493.1 Population sizes in ecosystems 1493.2 Factors affecting predator and prey
populations 1513.3 Decomposers in the local ecosystem 1543.4 Trophic interactions between
organisms in the local ecosystem 154
Dot Point Page
3.5 Risks in investigating a local environment 156
ecosystem 157
in a local ecosystem 1603.9 Adaptations of organisms in the local
ecosystem 1644. Impact of humans on the
environment 1664.1 Uses of the local environment in
the past 166
about the local environment 1674.3 Human impacts on the local
environment 1684.4 Importance of features of the local
environment for groups 1694.5 Views of different groups on the
human impact on the local environment 1704.6 Criteria for local government
regulations 171
Answers to Local Environment 217
Local Environment xiv Dot Point Preliminary Senior Science
Science Press
Notes
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Dot Point Preliminary Senior Science 1 Water for Living
Science Press
Water for Living
Water for Living 2 Dot Point Preliminary Senior Science
Science Press
1. Water is essential for the health of humans and other living things.
the solute and solvent in each case.
1.1.1 Distinguish between the terms solute, solvent and solution.
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1.1.2 Some students decided to test the solubility of a number of substances. For each of the following mixtures, identify which substance is the solute and which is the solvent.
Mixture Solute Solvent
Salt and water
Paint and turps
Grease and alcohol
Copper sulfate and water
1.1.3
(a) Identify three substances you tested that dissolved in water.
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(b) Identify three substances you tested that were insoluble.
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(c) Outline one safety precaution you took for this experiment and explain why this is necessary.
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(d) Comment on the reliability of your experimental results.
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Dot Point Preliminary Senior Science 3 Water for Living
Science Press
(e) Suggest a possible improvement in the method you used for your investigation.
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1.1.4 Some students decided to compare the solubilities of sodium chloride and sodium carbonate. They wrote up their method as:
Pour some water into two beakers.
Add sodium chloride to one beaker.
Add sodium carbonate to the other beaker.
See if they are soluble.
how the students could improve their method.
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1.1.5 The following diagrams show a solution before heating and after heating. Deduce which substance is the solvent and justify your deduction.
After heatingBefore heating
Particles of substance B
Particles of substance A
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Water for Living 4 Dot Point Preliminary Senior Science
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amount of water present in a variety of fruits, vegetables and meat.
1.2.1variety of fruits, vegetables and meat.
(a) Describe the method you used for this investigation.
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(b) Describe how you could calculate the percentage of moisture present in each food.
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1.2.2in a variety of fruits, vegetables and meat. The method they used was:
Collect a variety of samples of meat, fruit and vegetables.
Weigh about 10 grams of each sample.
Place each sample on a Petri dish.
Place the dishes of food into an incubator.
Observe the samples each day for one week.
Weigh the samples.
Discuss one problem with this method and describe how you could improve it.
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1.2.3 A group of students decides to compare the water content of green beans and potatoes.
State an hypothesis for this experiment.
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Dot Point Preliminary Senior Science 5 Water for Living
Science Press
1.2.4and chicken. The hypothesis tested is that chicken contains more water than the same mass of beef. After testing, the following results are found:
Food Moisture content (%)
Chicken – sample 1 76
– sample 2 73
– sample 3 75
Beef – sample 1 73
– sample 2 74
– sample 3 77
(a) Draw a conclusion based on these results.
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(b) Suggest reasons to account for the variability of measured water content of the samples of chicken.
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1.3 Identify the relative amount of water in a variety of living things.
1.3.1 Fresh samples of a number of plant products were tested for moisture content. The results obtained were:
Type of plant Moisture content Percentage moisture content (%)
Peas 35 g water in 50 g peas
Tomatoes 9.5 g water in 10 g tomatoes
Potatoes 77 g water in 100 g potatoes
Apples 63 g in 75 g apples
(a) Complete the table by converting the water content of each plant tested to a percentage.
(b) Compare the relative amounts of water in these substances.
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1.3.2 Water is often referred to as a universal solvent. Discuss this statement.
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Water for Living 6 Dot Point Preliminary Senior Science
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1.4 Describe the importance of water as a solvent in the:
1.4.1 Water makes up more than two thirds of the human body and is essential for the proper functioning of the body. Identify some functions of water in the body.
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1.4.2 Describe the importance of water as a solvent in the bloodstream.
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1.4.3
(a) Water is present in cells of living things. Use diagrams to show the structure of a typical plant and animal cell.
(b) Explain what is meant by a turgid cell and why the turgidity of cells is important in plants.
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Dot Point Preliminary Senior Science 7 Water for Living
Science Press
(c) Describe the effect of hot, dry weather on plants.
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1.4.4 Identify functions of water in the cytoplasm of cells.
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1.4.5 The average person needs to drink about 2 litres of water daily to replace water lost from the body. Identify how we get this water.
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1.5 Discuss ways in which plants optimise water uptake.
1.5.1(a) Describe how plants obtain water.
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reaction.
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1.5.2 Plant cells depend on water to maintain their shape and allow for transport of substances. Discuss ways in which plants optimise water uptake.
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1.5.3of water through plants.
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Water for Living 8 Dot Point Preliminary Senior Science
Science Press
water loss.
1.6.1 Describe how you investigated adaptations of plants that assist in reducing water loss.
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1.6.2 A group of students decided to see if removing the leaves from a branch of a plant would reduce the loss of water from the plant. They decided to use celery for their experiment.
They chose two identical sticks of celery and removed the leaves from one. Both sticks of celery were placed in identical containers of water. A plastic bag was placed over each stick.
The next day the students observed the celery and noticed that water had collected inside the plastic bags.
(a) Which bag would you predict to have more water inside.
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(b) Justify your prediction.
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1.6.3 Identify adaptations you observed that could help plants reduce water loss.
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1.7 Discuss ways, using examples, that plants reduce water loss such as:
1.7.1
(a) Identify the part of the plant that controls the loss of water from a plant.
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Dot Point Preliminary Senior Science 9 Water for Living
Science Press
(b) The following diagram shows the structure of a stomate on the underside of a leaf. Describe how it controls the loss of water from plants.
Stomate
Pore (opening)
Guard cells
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(c) Explain why the guard cells of stomates cannot be closed all the time.
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1.7.2 Plants which live in dry conditions have adaptations in their structure, their physiology (how they work) and their behaviour that allow them to conserve water. Explain how each of the following adaptations helps the plant reduce its water loss:
(a) a thick outer coating (cuticle) on leaves
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(b) reduced leaves
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(c) dropping leaves in times of drought
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Water for Living 10 Dot Point Preliminary Senior Science
Science Press
1.7.3 Identify the method used to reduce water loss by the plants in each of the following photographs.
(a) (b)
(c) (d)
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1.8 Gather, process and analyse information to identify the different ways in which a range of terrestrial animals reduce water loss.
1.8.1 Identify three ways in which terrestrial animals reduce water loss.
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Dot Point Preliminary Senior Science 11 Water for Living
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1.9 Discuss ways, using examples, that animals reduce water loss such as:
1.9.1(a) Distinguish between urea, uric acid and urine.
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(b) The excretion of urine involves loss of water from the body. For animals living in hot, dry climates this water loss may lead to dehydration. Identify two ways in which animals living in such environments reduce water loss in the excretion of wastes and give an example of each.
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1.9.2 Nocturnal behaviour is one way for animals to help conserve water in a dry environment.
(a) Identify the meaning of the term nocturnal.
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(b) Explain how nocturnal behaviour helps animals conserve water in a dry environment.
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1.9.3 Describe how reduced activity and lying in the shade during the hot part of the day can help animals survive in hot, dry climates.
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1.9.4 Describe how living in burrows during the hot part of the day can help animals survive in hot, dry climates.
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Water for Living 12 Dot Point Preliminary Senior Science
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2. Water is an important factor in the maintenance of Australian environments.
2.1 Outline types of surface and ground waters in the hydrological cycle such as:
.
2.1.1 The following diagram provides a model for the hydrological cycle.
Transpiration
Sea
CondensationPrecipitation
Streams Evaporation
InfiltrationUnderground water flow
PrPrececipipititatatioiooonn
Evaporation
(a) Explain what is meant by the hydrological cycle.
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(b) Identify and describe two processes that occur during the hydrological cycle.
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chemical processes.
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Dot Point Preliminary Senior Science 13 Water for Living
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2.1.2 A teacher carried out a survey of the ideas about the water cycle held by 100 Year 11 Science students and found that some of them expressed the incorrect ideas listed below. Replace each
(a) The water cycle involves mainly freezing and melting of water.
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(b) Water only gets evaporated from the oceans and the lakes in the water cycle.
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(c) Rain falls out of the sky when the clouds evaporate.
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(d) Clouds are made of water vapour.
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(e) Humid air is oppressive and heavy. It is more dense than dry air.
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2.1.3
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(b) Identify the state in which most water occurs on Earth.
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2.1.4
(a) Describe the relationship between ground water and the water table.
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Water for Living 14 Dot Point Preliminary Senior Science
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(b) Describe the use of ground water in Australia.
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2.1.5
Distribution of the world’s water
Oceans 97%
All water
Easily accessible
surface fresh water
Fresh water
Fresh water 3%
Icecaps and glaciers 79%
Easilyaccessiblesurfacefresh water 1%
Lakes 52%
Soil moisture 38%
Water within livingorganisms 1%
Atmospheric water vapour 8%Rivers 1%
Ground water20%
(a) Identify the following percentages:
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(b) State whether each of the following statements is true or false:
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(iv) There is more water underground than in all the rivers and lakes of the world combined.
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Dot Point Preliminary Senior Science 15 Water for Living
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2.2 Process information from secondary sources to map the location and type of surface and ground water in the local area.
2.2.1 The following diagram shows the Great Artesian Basin which is the largest and deepest known basin in the world. It occupies an area of 1 800 000 km2 and has been estimated to contain between 9 and 65 cubic kilometres of ground water. Most of the water enters along
of a few metres per year.
Australia
N
GreatArtesian
Basin
1000 km0
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(b) Account for the importance of the Great Artesian Basin in Australia.
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Water for Living 16 Dot Point Preliminary Senior Science
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2.2.2 Identify your local area and describe the surface and ground water in your local area. Include a map in your answer.
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2.2.3your local area.
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Dot Point Preliminary Senior Science 17 Water for Living
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2.3 Analyse information from secondary sources to outline the relationships between rainfall and types of Australian ecosystems
2.3.1 The maps below show the rainfall and some types of ecosystems that occur in Australia.
Analyse the information in these maps and use this to outline the relationship between rainfall and types of ecosystems in Australia.
1500 12501000
750
500
250
250
200
250
500750
10001500
Western Australia
Northern Territory
South Australia
Queensland
Victoria
Tasmania
1000
1500
3500
100
200
1250
750500
250
1000
200
500750
1000
25003500
2500
1500
Rainfall (mm)
New South Wales
Rainforest
Forest
Woodland and shrubland
Grassland
Desert
Ecosystems
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2.4 Discuss the effects of water pollution and ground salinity on the continued supply of fresh water to living things and provide examples of these occurring in Australian environments.
2.4.1
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2.4.2 Complete the following table to show sources of fresh water pollution and their effects on the environment.
Pollutant Source Effects
Sediment
Nutrients – ammonia, nitrates and phosphates
Faecal bacteria
Heavy metals, e.g. lead, mercury, cadmium and other chemicals
Pesticides, herbicides, fungicides
2.4.3
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Dot Point Preliminary Senior Science 19 Water for Living
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(b) Salt occurs naturally in the Australian landscape. Salinity of rivers and soil can develop naturally, however when ecosystems become disturbed by humans the movement of salt into rivers and soil may accelerate. Identify some actions of humans which have led to an increase in salinity of rivers and soil in Australia.
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(c) Identify some effects of salinity on buildings.
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(d) Identify one area in Australia where salinity is a problem.
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2.5 Process, analyse and present information from secondary sources to assess human impact on one aquatic ecosystem or water source in Australia and identify some consequences of this impact and one possible rehabilitation technique.
2.5.1
by salinity.
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(b) Account for the increase in salt content, explain the impact of this on society, and suggest
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Water for Living 20 Dot Point Preliminary Senior Science
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2.6 Identify possible solutions to environmental problems associated with the use of ground water.
2.6.1 Salinity problems along Australian rivers have been largely caused by rises in the water table. A number of solutions have been suggested to deal with such ground water problems in Australia. Discuss three of these.
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increasing problems with water supplies across NSW.
2.7.1relation to increasing problems with water supplies across NSW. Outline a problem addressed by one of these bodies and a policy introduced to deal with this problem.
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Dot Point Preliminary Senior Science 21 Water for Living
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3. A wide range of chemicals used in human activity may impact on water systems.
in the Australian context.
3.1.1
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3.1.2 Name a fertiliser and explain why fertilisers are used in Australia.
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3.1.3 Identify examples of chemicals used as a herbicide and as a pesticide and discuss problems associated with their use in Australia.
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3.2 Identify the conditions under which fertiliser and pesticides may be carried into water systems.
3.2.1 Identify the conditions under which fertiliser and pesticides may be carried into water systems.
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Water for Living 22 Dot Point Preliminary Senior Science
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the effect of various concentrations of fertiliser on plant growth.
3.3.1(a) State the hypothesis you tested.
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(b) Describe the method you used to investigate the effect of various concentrations of fertiliser on plant growth.
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(c) Identify the dependent and independent variables in this experiment.
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(d) Identify variables that needed to be controlled to make this a valid experiment.
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(e) Tabulate the results you obtained from your investigation.
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(f) Comment on the reliability of your experimental results.
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Dot Point Preliminary Senior Science 23 Water for Living
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3.3.2concentrations of fertiliser on the growth of 5 groups of identical seedlings.
Group A B C D E
Concentration of fertiliser (%) 0 0.1 0.5 1.0 1.5
Average growth of seedlings (mm/week) 5 mm 7 mm 8 mm 8 mm 8 mm
(a) Graph these results on the grid below.
(b) Draw a conclusion based on these results.
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(c) Explain the purpose of group A plants.
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(d) The instructions for this particular fertiliser were to mix 10 mL fertiliser with 2 litres of water and apply to the plants. Comment on these results in light of these instructions.
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Water for Living 24 Dot Point Preliminary Senior Science
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(e) Some farmers add fertiliser at greater concentrations than recommended by the manufacturer.
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3.4 Assess the impact on water systems of the release of substances produced or used by households, such as:
3.4.1 Identify substances produced or released by households that pollute our water systems.
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3.4.2its release on water systems.
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Dot Point Preliminary Senior Science 25 Water for Living
Science Press
3.5 Identify the use of and impact on water systems of substances such as:
3.5.1(a) Identify what is meant by heavy metals.
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(b) Explain why heavy metals are considered a problem in the environment.
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(c) Complete the following table to show the sources of the heavy metals lead and mercury in water systems and their possible effects on the body.
Heavy metal Source Effects
Lead
Mercury
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3.5.2 The release of phosphates and nitrates into waterways can result in eutrophication.
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(b) Identify the conditions under which eutrophication is likely to occur.
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Water for Living 26 Dot Point Preliminary Senior Science
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3.6 Process information from secondary sources on methods of bioassay for water purity.
3.6.1
(a) Describe what is meant by a bioassay.
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(b) Identify uses of bioassays.
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Dot Point Preliminary Senior Science 27 Water for Living
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(c) Describe the use of bioassays to test water samples.
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3.6.2During 1998, water contamination hit the headlines when it was found that two protozoans, cryptosporidian and giardia were present in some samples present.
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(b) Oultine how such organisms are usually removed from the water supply.
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3.7 Identify the impact on aquatic ecosystems of factors such as:
3.7.1
Factor Impact
Accumulated sediment
Leaching from tips
Bioaccumulation
Water for Living 28 Dot Point Preliminary Senior Science
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4. Strategies to reduce water pollution can be a result of personal initiative or government legislation.
4.1 Gather information from secondary sources to identify causes and impacts of algal blooms in waterways in NSW.
4.1.1 Describe how you gathered information about algal blooms in NSW waterways.
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4.1.2 Comment on the reliability of the information you gathered about algal blooms.
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4.2 Identify conditions under which algal blooms may occur in the rivers of New South Wales.
4.2.1 Describe conditions under which algal blooms may occur in the rivers of New South Wales.
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4.3 Describe impacts of algal blooms in rivers.
4.3.1 Describe impacts of algal blooms in rivers.
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Dot Point Preliminary Senior Science 29 Water for Living
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4.4 Discuss alternative strategies to the use of chemicals in agriculture to reduce water pollution.
4.4.1 Discuss possible alternative farming practices that do not involve the use of chemicals in agriculture, and the need for these alternative strategies.
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4.5 Describe some of the strategies that households can use to reduce water pollution.
4.5.1 Describe some of the strategies that households can use to reduce water pollution.
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4.5.2 Explain the need to use recycled water or treated sewage or desalinate sea water in Australia.
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activity such as:
and identify ways in which it can be reduced.
4.6.1household for one activity.
(a) Identify the activity you investigated.
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Water for Living 30 Dot Point Preliminary Senior Science
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(b) Describe the method you used.
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4.6.2 Identify ways to reduce water use in the home.
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4.6.3 The following information shows the volumes of water used by a household for various activities. Use a bar graph to represent this information.
Activity Water used for each use (litres)
Toilet flush 6
Bath 80
Shower (15 minutes) 150
Dishwasher 70
Washing up (by hand) 8
Washing machine 150
Washing car 300
Watering garden (20 minutes) 500
Dot Point Preliminary Senior Science 31 Water for Living
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4.6.4 The following illustration shows activities around a home.
EXTRASTRONG
FERTILISER
(a) Put a cross on any activities which are wasting water and state how these could be changed.
(c) Identify any examples of pollution.
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4.7 Gather, process and present information from secondary sources on the latest technologies being used to purify and treat water.
4.7.1(a) Identify secondary sources you used to research technologies used to purify and treat water.
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(b) Comment on the validity of the information in the sources you accessed.
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Water for Living 32 Dot Point Preliminary Senior Science
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4.8 Identify an example of technology being used and developed to reduce water pollution and
4.8.1
(a) Outline an example of technology being developed and used to reduce water pollution.
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Dot Point Preliminary Senior Science 33 Water for Living
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5. Water pollution at the local level impacts on global water quality.
5.1 Discuss types of indicator organisms that are found in safe water supplies and those found in polluted water.
5.1.1 Discuss types of indicator organisms that are found in safe water supplies.
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5.1.2 Discuss types of indicator organisms that are found in polluted water.
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5.1.3 The following table lists the numbers of colonies of faecal coliform bacteria considered safe in water used for different purposes. Use a suitable graph to represent this information.
Water use Safe faecal coliform colony count per 100 mL
Drinking water 0
Swimming 200
Fishing 1000
Sewerage effluent 2000
Water for Living 34 Dot Point Preliminary Senior Science
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5.2.1
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5.2.2 Use the following key to solve the puzzle below.
Key:
a b c d e f g h i j k l m
Κ
n o p q r s t u v w x y z
# $ & ! € & Y †
Puzzle:
€ € € # Κ $ Κ
Solution:
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5.3 Identify a local catchment area and the sources of water feeding into this catchment.
5.3.1 Identify a local catchment area and the sources of water feeding into this catchment.
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5.3.2 Identify some activities that are permitted in a catchment area and some that are not permitted.
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5.4 Gather information on the source of water feeding into the local catchment area using maps or
5.4.1 Describe how you gathered information on the source of water feeding into the local catchment area.
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Dot Point Preliminary Senior Science 35 Water for Living
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5.4.2 Sketch the catchment that you studied.
the indicator organisms present in a local catchment area and from these deduce the chemical purity of water.
5.5.1
present in your local catchment area.
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(b) Describe the results of your investigation of your local catchment area.
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Water for Living 36 Dot Point Preliminary Senior Science
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5.5.2 Explain safety precautions necessary when investigating water in a local area.
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5.5.3 A class of Year 11 Senior Science students investigated two local creeks which were part of the local catchment area. One group collected organisms, another carried out chemical tests and a third group tested turbidity. Their results are shown below.
Use these test results to compare the chemical purity of the creeks and justify your deductions.
Organisms foundNumbers found
Creek A Creek B
Frogs 2 10
Mayfly nymph 1 6
Yabbies 2 8
Mosquito larvae 20 0
Chemical and other testsResults
Creek A Creek B
pH 4 6.5
Turbidity Visibility to 50 cm Visibility to 1.0 metre
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5.5.4 Describe two chemical tests you carried out on water from a local catchment area.
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Dot Point Preliminary Senior Science 37 Water for Living
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5.6 Describe possible sources of contamination that may enter catchments.
5.6.1 Contamination of water catchments may be caused by land clearing, industry, agriculture and urbanisation. Describe examples of contamination from each of these sources.
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5.7 Describe the types of tests that are used to monitor and assess local water quality.
5.7.1 Complete the following table to show the available tests for monitoring water contaminants and the contaminants each test will detect.
Test for contaminants Contaminants detected by this test
Flame tests
Turbidity
Acidity – indicators, pH meters, pH probes and data loggers
Dissolved oxygen/ BOD
Tests for nitrogen and phosphorus content
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5.8 Explain how water quality in one area can impact on the water quality in other areas.
5.8.1
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5.9 Gather information from secondary sources concerning the use and treatment of local water.
5.9.1
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5.9.2 Match the water treatment processes listed below to the correct process outline.
Water treatment processes Process outline
(a) Screening ...................................(i) Sand filters are used to remove solids. A 2 m deep bed of sand is
used. The solids are collected when the sand filters are cleaned and are used as compost.
(b) Flocculation ................................ (ii) Fluoride is added to harden teeth.
(c) Sedimentation ...........................(iii) Chemicals, e.g. aluminium hydroxide are added to coagulate fine
particles and thus help to remove them.
(d) Filtration ......................................(iv) Chemicals are then added as needed, e.g. sulfuric acid may be
needed to break down organic matter, then limewater (calcium hydroxide) is added to neutralise any excess acid.
(e) Water testing ............................. (v) Sludge collected from settling tanks is dried and disposed of.
(f) Chemical treatment ................. (vi) Chlorine is added to kill micro-organisms.
(g) Disinfection ................................(vii) Water testing is carried out for ions, colour, pH, hardness, turbidity,
conductivity, micro-organisms.
(h) Fluoridation ................................ (viii) Solid objects (e.g. organisms, twigs) are screened out.
(i) Sludge processing ................... (ix) Slow water flow allows particles to settle to the bottom.
5.9.3 Complete the following table to explain the addition of the listed chemicals during the water
Chemical additive Reason for adding chemical
Aluminium hydroxide or iron(III) chloride
Sulfuric acid
Limewater or other alkali
Fluoride
Chlorine
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5.10 Gather, process and present information from secondary sources to identify some major disasters involving water pollution.
5.10.1 Identify two major disasters involving water pollution.
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5.10.2
Water is our most precious resource. Without water, life would not exist on our planet and
to become one of the most pressing resource issues of the 21st century. In some areas, such as India and Africa, surface water supplies are shrinking and groundwater supplies are being depleted faster than they can be replenished.
and polluted water sickens more than 1 billion people each year. Population growth will cause a rapid increase in agricultural demand for water. Water pollution adds enormously to existing problems of water scarcity by contaminating large volumes of available water, thus making it unsuitable for use. If we continue at the present increasing rate of use it is estimated that by the year 2030 the global water demand for fresh water will exceed the supply.
Approximately one out of every three people in the world experiences moderate to high water stress. Moderate water stress levels are said to occur when water consumption exceeds renewable freshwater supply by 10 per cent. The UN expects the global water situation to get considerably worse over the next 20 years. It estimates that by 2025 the proportion of the
three people.
Globally, water supplies are unevenly distributed. Some countries experience an abundant water supply. Other countries experience severe water shortages. In rich countries, people use between 850 and 1000 litres of water each day. In wealthy urban communities, an abundance of irrigated gardens and household appliances is responsible for an increase in household water consumption. In poor areas where people rely on public taps for their water, consumption drops to between 20 and 70 litres each per day. Where there are no taps at all and people (usually women) have to travel to collect water, daily consumption often drops to between 2 and 5 litres. This is close to the absolute biological minimum people need to stay alive.
(a) Explain why obtaining supplies of fresh water is likely to become one of the most pressing resource issues of the 21st century.
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(b) Identify household appliances that account for some of the increase in consumption of water in wealthy urban communities.
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Dot Point Preliminary Senior Science 41 Water for Living
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(d) Identify the increase in water stress predicted by this article.
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(e) Tabulate the maximum and minimum daily water usage mentioned in this article for people living in different areas.
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Notes
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Dot Point Preliminary Senior Science 173 Answers
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Answers
Answers 174 Dot Point Preliminary Senior Science
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Notes
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Water for Living
1.1.1 Solute – substance which gets dissolved, e.g. sugar. Solvent – substance which does the dissolving, e.g. water. Solution – the mixture obtained when one substance dissolves in another, e.g. sugar solution.
1.1.2Mixture Solute Solvent
Salt and water salt water
Paint and turps paint turps
Grease and alcohol grease alcohol
Copper sulfate and water copper sulfate water
1.1.3 (a) Various, e.g. sucrose, sodium chloride, copper sulfate, sodium hydrogen carbonate (carb. soda), fertiliser.
(b) Various, e.g. copper carbonate, chalk, sand.
(c) Wash hands thoroughly after the experiment as some of the chemicals tested may be toxic, e.g. copper sulfate.
(d) Reliability is determined by repeating an experiment to see if you always get the same results. You may have repeated the experiment or you may have compared your results with those of other students in your class. If the results were consistent then they are reliable.
(e) Various, e.g. Test solubility in hot water as well as cold water, test a wider range of substances.
1.1.4 The teacher was correct as this method would not provide a fair test of the relative solubility of each substance. For a validexperiment, the only variable that should change is the independent variable – in this case the identity of the chemical to be tested. All other variables must stay the same. The students must:
or estimate the amount of chemical left after a stated time interval.
1.1.5 Substance A is the solvent – there are fewer particles of A in the second beaker, so it has evaporated on heating. Substance B is the solute, the same number of particles is present before and after heating.
1.2.1 (a) Various, e.g.
Collect a variety of samples of meat, fruit and vegetables.
Weigh about 10 grams of each sample.
Record the exact weight.
Place each sample on a Petri dish.
Place the dishes of food into an incubator.
Observe the samples each day for one week.
Weigh the samples each day until the weight is constant.
(b) Percentage of moisture in food = decrease in weight/initial weight × 100
1.2.2 Weighing once is not enough as all of the water may not have evaporated yet. They should weigh every day until they are getting the same weight all the time. Then they will know that all the water has evaporated from the samples.
1.2.3
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1.2.4 (a) These results do not support the hypothesis that chicken contains more water than beef. The average water content is
(b) Food samples can vary in water content based on how they have been treated, e.g. if they have been washed in water, some water may have been absorbed; some may have been exposed to the air or different air temperatures prior to testing; some chicken samples may have been frozen.
1.3.1
(b) Tomatoes contained the most water, followed by apples and potatoes with peas containing the least water.
1.3.2 This statement is based on the fact that water dissolves so many things. It does not dissolve everything, e.g. fats and oils arenot soluble in water.
1.4.1 Various, e.g.
For transport of substances dissolved in blood; most chemical reactions occur in solution in cells; a reactant in photosynthesisin plants; to help excrete wastes; to lubricate joints.
1.4.2 Water dissolves many substances that can be present in blood, e.g. food, hormones and waste products such as urea and carbon dioxide. It acts as a solvent for these substances.
This is very important as these substances must be able to be transported around the body and they do so dissolved in blood. For example, food is absorbed into blood vessels in the villi of the small intestine and from there must travel to all cells forrespiration; waste products must be carried away from all the body cells, urea travels to the kidneys and carbon dioxide to thelungs, for excretion. Hormones are produced by glands, such as the ovaries and testes. They go directly into the bloodstream and travel dissolved in blood to wherever they are needed in the body.
1.4.3 (a)Animal cellPlant cell
Largevacuole
Nucleus
Cytoplasm
Cell membraneCell wall
Chloroplast
(b) If a plant cell contains lots of water the contents will press against the cell wall and the cell is described as turgid.Turgid cells help to maintain the structure of the plant – they give it rigidity so it can stand up and expose its leaves to the Sun.
1.4.4 Thousands of chemical reactions occur in the cytoplasm of cells. Most of these reactions occur in solution. Water is the solvent in cells.
1.4.5
1.5.1 (a) Water is absorbed from the soil by the root hairs of plants. It travels from the roots to all parts of the plant through special tissue called xylem.
(b) Photosynthesis:
1.5.2
area under the ground, or grow deep into the ground, to maximise the water absorbed. A process called the transpiration stream draws the water up the stem and helps pull more water from the soil into the plant.
1.5.3 Transpiration is the movement of water from the roots, up through the stem, into the leaves and out through the stomates. As the water evaporates from stomates, more water is drawn up to replace the water lost. This is called the transpiration stream.
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1.6.1 Various, e.g.
Your teacher may have provided plants or you may have visited a national park, botanic gardens, the school grounds or a nursery to examine a range of plants and identify adaptations that would help them reduce water loss.
1.6.2 (a) The one over the celery stem with leaves.
(b) Reducing the leaves of a plant would reduce the loss of water from the plant as you would reduce the number of stomates.
1.6.3 Various, e.g. thick cuticles, sunken stomates, reduced leaf size, a hairy surface.
1.7.1 (a) The stomates, which are mainly found on the lower surface of the leaves.
(b) When plenty of water is available the guard cells may allow the pore of the stomate to open so water can evaporate. When water is scarce, the guard cells close the pore so water cannot be lost.
(c) Stomates also allow for the diffusion of gases, e.g. carbon dioxide and oxygen into and out of the plant for photosynthesis and respiration.
1.7.2 (a) The cuticle is the waxy layer that covers the outside of leaves. It is made of cutin which is impermeable: it will not allow water to pass through. Some plants, e.g. eucalypt trees have a thick cuticle to help reduce evaporation.
(b) The bigger the leaf, the greater the area exposed to the drying effects of sunlight and also the greater the number of stomates likely to be present and so the greater the loss of water. Some plants have small leaves so they have a smaller area over which they lose water by evaporation, e.g. wattle, cactus.
(c) Dropping leaves reduces the area over which water can be lost by evaporation from stomates and also reduces the area of plant exposed to the sunlight so during drought some plants drop their leaves to reduce water loss, e.g. eucalypts.
1.7.3
(b) Leaves reduced to scales/needles (hakea).
(c) Thick outer cuticle and leaves hang down (eucalypt).
(d) Reduced leaf area (wattle).
1.8.1 Impervious skin coverings, excretion of concentrated or solid wastes, nocturnal behaviour.
1.9.1 (a) Urea is the soluble waste product formed by the metabolism of proteins. It is toxic if it accumulates in the body so must be excreted.
Uric acid is a solid form of nitrogenous waste produced by some animals living in dry environments to conserve water.
(b) Various, e.g.
Camels and kangaroos conserve water by excreting very concentrated urine. Reptiles and birds in desert regions excrete wastes as solid uric acid.
1.9.2 (a) Active at night and sleep during the day.
(b) In hot, dry climates water is lost as sweat especially during the heat of the day. To reduce this water loss, many desertanimals sleep during the hot daylight hours and are active at night when it is cool. This reduces the production of sweat and thus reduces water loss.
1.9.3 In hot, dry climates water is lost as sweat especially during the heat of the day. To reduce this water loss, many animals reducetheir activity and shelter in shady places during the hot daylight hours. For example, kangaroos and wallabies are active at dawn and dusk and rest during the heat of the day.
1.9.4 In underground burrows, the air is relatively cool and has high humidity so animals living in burrows lose less water via sweatthan those living at the surface in hot, dry areas.
2.1.1
Precipitation – water falling as rain, snow or hail.
(c) Physical because there is no new substance formed, water is simply changing from one state to another. In chemical processes a new substance is formed.
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2.1.2which falls to Earth.
(b) Water can evaporate from plants (transpiration), animals (perspiration), puddles and the ground as well as from large bodies of water.
(c) Rain begins to fall when drops of water in the cloud are too heavy to remain airborne.
(e) Humid air is less dense than dry air. It has more water vapour in it and water molecules are lighter than the other molecules in air.
2.1.3 (a) The oceans, dams, lakes, rivers and wetlands.
2.1.4 (a) Ground water is water found under the ground. This includes water in artesian basins and in caves. The water table is
water.
(b) More than half of Australia relies on ground water for all except drinking water. The high mineral content makes it unsuitable for drinking. It is used extensively for irrigation and in some areas is being used faster than the water can be replaced.
(c) Wells are drilled down to the water table and water pumped out. This is called bore water.
2.1.5
(b) (i) True
(iv) True
2.2.1 (a) An underground reservoir of fresh water surrounded by impermeable rock that will not let the water escape.
(b) It provides the only reliable source of water through a large part of the arid inland areas of Australia. The water is used for irrigation, stock and domestic use (when treated). Thousands of bores take water from the basin and there is concern that it is being used too fast and some areas may go dry.
2.2.2 Various. Your map could be based on a road map, a tourist map or an aerial photograph, e.g. from the Internet. It should include any rivers, lakes, dams and known ground water. There may also be wetlands or caves in your area.
2.2.3 Various. You may have found information at your local library or council or on the Internet. Australian Government State of Environment reports are useful for information about different areas.
2.3.1 Various, e.g.
Rainforests occur in areas with high rainfall.
Forest occurs along the southern coast in areas of high rainfall.
Grassland occurs in areas with rainfall less than 500 mm.
Desert areas have a rainfall below 250 mm.
2.4.1 Various, e.g.
sediment from erosion of soils.
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2.4.2 Various, e.g.
Pollutant Source Effects
Sediment Wind and water erosion of land Fertile topsoil removed.Light cannot penetrate water.Water temperature rises.Aquatic organisms die.
Nutrients – ammonia, nitrates and phosphates
Sewage spills Water becomes cloudy.Stimulate plant growth so excess growth of algae can occur (algal blooms).Toxic blue-green algal blooms may occur.Algal blooms die off and oxygen is used for their decay. Water becomes stagnant and aquatic organisms die.
Faecal bacteria Faeces in run-off or seepage from urban areas, grazing paddocks, septic tanks, stormwater
Cause disease, e.g. diarrhoea, dysentery, salmonella and typhoid fever.
Heavy metals, e.g. lead, mercury, cadmium and other chemicals
Chemical use in home and industry and disposal of excess and waste
Toxic to aquatic organisms and people. Accumulate in sediments and in tissues of organisms.Accumulate in food chain.
Pesticides, herbicides, fungicides
Run-off from agricultural use Toxic, can kill not only targeted organisms but also others.Toxic to humans.
2.4.3 (a) The presence of salt in surface soils or rocks or dissolved in rivers or ground water.
(b) Various, e.g.
Clearing land, irrigation of extensive areas.
(c) Increased rate of corrosion of metals, bricks become spotted with precipitated salt and then crumble.
2.5.1
(b) Increased salinity has been caused by clearing surrounding land of the natural vegetation and irrigation of large areas which have led to rising water tables.
This area supplies domestic, industrial and agricultural water to a large area of eastern Australia, so this river system is vital to the economy and food production. Its increasing saltiness is leading to the establishment of salt deserts in some areas. If this increase in salinity is not halted and reversed the whole area could eventually become a wasteland and there would not be enough food to support the population.
(c) Various, e.g.
cause minimal damage.
2.6.1 Various, e.g.
out through their leaves (transpiration). Even in areas of crops we can maintain native vegetation in strips along waterways and between crop areas.
tolerant native pastures. In urban areas, councils need to consider zoning, reduce land clearing for developments, and
further along the river system. People in urban areas can do a lot to reduce wastage of water, in homes, on gardens and in industry. Also, water use for irrigation can be reduced to a minimum. For some crops, standing water can be used
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2.7.1 Various, e.g.
Problem – Increasing population and the need to supply larger volumes of unpolluted water.
NSW Government – Catchment Management Authorities Act 2003. This established 13 catchment management authorities in NSW. Each authority is responsible for managing natural resources
3.1.1 Fertiliser – substance added to soil or water to increase the growth rate of plants by providing essential nutrients.
Herbicide – substance used to kill unwanted plants, e.g. those competing with crops.
Pesticide – substance used to kill unwanted animals, e.g. rats and insects such as locusts.
3.1.2 Plants need nutrients to grow, especially minerals, e.g. calcium, iron and magnesium, and nitrogen and phosphorus in the form
of nitrates and phosphates. The amount of these chemicals present in soil can vary with the type of rock that formed the soil. Australian soils are generally not very fertile soils. Sandstone, which is the main rock in the Sydney Basin, produces a soil
3.1.3 Various, e.g.
Herbicide – Dalapon – used to control plants that compete with orchards, lawn and crops such as beans.
Pesticide – Methoxychlor – used to kill insects on fruit, vegetables and alfalfa.
The use of such chemicals needs to be carefully controlled and monitored as they can potentially cause harm to people and other animals, e.g. Dalapon can cause liver and kidney damage and Methoxychlor affects the nervous system, causes liver and kidney damage and affects growth.
3.2.1 In agricultural areas fertiliser, pesticides and also herbicides are often administered to crops by aerial spraying. This causesconsiderable concern as, despite precautions, such as spraying only on relatively calm days, the spray may drift across water supplies, e.g. dams and rivers causing contamination.
eventually makes its way into rivers and dams, causing contamination.
3.3.1 (a) Various, e.g. The greater the concentration of fertiliser, the taller the bean seedlings will grow.
(b) Various. You should:
to the same height)
Note that you are not testing germination (seed growth) so if you are growing your plants from seeds your experiment will not start until all the seeds have sprouted.
you administered it to the plants
light and use the same soil
(c) The independent variable will be the various concentrations of fertiliser that you used.
The dependent variable will be how you measured the growth, e.g. did you measure each plant and calculate average increase in height over each week or some other method.
(d) The type and age of plants should be the same throughout, they should all receive the same amount of sunlight and water (at the same time of day), they should be in the same pots and soil/potting mix, temperature and wind (if outside) conditions should be the same.
(e) Various – you should rule up a table, remember to put headings and include units (e.g. mm) in the heading.
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(f) State whether you repeated the experiment or compared your results with those of other groups doing the same experiment. If the results were always the same then your results are reliable.
3.3.2 (a)
E
21.5
D
1.0
C
10
5
Growth ofseedlings(mm/week)
0.50.10
A
B
Concentration of fertiliser (%)
Seedling growth with fertiliser
there was no further increase in the growth of the seedlings.
(c) These plants act as the control. They allow the tester to ensure that the results really were due to the addition of fertiliser. Having a control improves the validity of the experimental method.
(e) It is easy to understand why the farmer thinks that way. However, the manufacturer makes recommendations about
most suitable concentration to use. If the farmer uses more than the recommended concentration, it will not be able
3.4.1 Various, e.g. Oils, detergents, bleaches and toilet cleaners, insoluble materials, sewage.
3.4.2 Various. For each substance you should describe how it is used in the home, how it gets into waterways and the damage it can potentially do there.
Follow this with an assessment statement.
For example, Oil – Oil from cooking food, from cars and from dirty clothes is washed down drains and enters waterways or
it clings to animals such as birds causing damage to their feathers and it can cause turbidity which can lead to the death of
3.5.1 (a) Metals with high atomic masses, e.g. mercury, lead, copper, barium, silver, arsenic and cadmium.
(b) They inferfere with enzyme systems and body metabolism, cannot be easily eliminated from the body, bioaccumulate (build up to high levels in tissues) and biomagnify (increase along the food chain), persist in the environment for long periods of time and over recent years their concentrations in the environment have increased.
(c) Heavy metal
Source Effects
Lead Lead water pipes, lead-based solder and other alloys containing lead, mining and extracting lead from ores, old paint, lead glazing on pottery, stained glass lead linings, batteries
Damage to kidneys and nervous system, causes anaemia, learning disabilities
Mercury Batteries (no longer manufactured), mercury waste released by industrial production, electric switches
Damage to kidneys and nervous system, loss of hair, insomnia, birth defects
(b) Bioaccumulation – the accumulation of substances in the tissues of the body. This happens with heavy metal
3.5.2 (a) An increase in the nutrient content of water leading to excessive algal growth (an algal bloom) which is followed by decay of the organisms and depletion of oxygen in the water. This results in the water becoming stagnant.
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(c)
The decomposition of the algae (by
bacteria and other micro-organisms)
uses up the oxygen in the water
Algae die as all nutrients used up.
Algae grow rapidly, some producing
toxins
Water becomes stagnant
Shortage of dissolved oxygen
leads to the death of aquatic organisms
Excess nutrients, particularly nitrogen
and phosphorus wash into the water
as pollution
water. They produce toxic products and can cause diarrhoea and skin rashes.
In 1991 toxic blooms formed on many Australian rivers due to drought, warm weather and pollution. It occurred
3.6.1 (a) A bioassay involves using an organism to test for chemical toxicity (e.g. using a canary to detect methane in a coal mine).
(b) Drugs and skin products are tested on laboratory animals before they are released for use of humans. Organisms are
seeds) are all used for bioassays of water samples. Each type of organism reacts in predictable ways to various environmental contaminants.
3.6.2 (a) Cryptosporidium and giardia cause abdominal cramps, diarrhoea, nausea and vomiting. They indicate that the water
contaminated water.
(b) By disinfecting with chlorine and sometimes also ammonia.
3.7.1Factor Impact
Accumulated sediment Increases turbidity (cloudiness) of water; fills in wetlands; reduces water flow; covers vegetation; blocks drains and watercourses; damages aquatic organisms, e.g. fish gills.
Leaching from tips Substances leached from tips can include nutrients and toxic chemicals. The nutrients can contribute to algal blooms when they reach waterways or ground waters. Toxic chemicals get into the food chain.
Bioaccumulation Substances such as heavy metals accumulate in the tissues of the body of organisms (bioaccumulation). These then pass on through the food chain, so organisms high in the food chain can have very high levels of toxic substances in their bodies.
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4.1.1the Internet.
You should be able to describe references that you used. For Internet sites, give complete URL; for books give title, author,publisher and date of publication; for personal contacts, give name of person, title and occupation.
4.1.2 Various. Comment on the agreement you found between information provided in different sources (this is one reason for using a range of resources). Also comment on the likely reliability of the sites you chose to access. Reliable websites would be those
4.2.1cause an increase in the concentration of phosphorus and nitrogen compounds in the waterways, especially nitrates and phosphates.
accumulate and promote the growth of large numbers of algae in the waterway, algal blooms form.
4.3.1 Algal blooms cause increased cloudiness (turbidity) of the water. The algal bloom consists of such large numbers of algae that they use up all of the nutrients in the water. They then die and the decomposition of their bodies uses up the oxygen in
(cyanobacteria) are present, then they may also cause illness in people and other animals due to toxins.
4.4.1 Various, e.g.
Alternatives include: Using physical barriers, e.g. mulching around plants to prevent slugs and snails reaching the plants.
Biological control – releasing an organism that will kill the pest and not damage the crop.
Chemicals such as fertilisers, herbicides and pesticides are used on agricultural crops to maximise yield. Some of these are toxic
off into water courses and contribute to water pollution. Some accumulate within living things and along the food chain.
4.5.1 Various, e.g.
Do not put food scraps, oil and grease, unused paint or other chemicals down the sink, compost all possible food scraps, use minimal detergent, pick up pet faeces, disconnect any downpipes and stormwater from the sewer.
4.5.2 Australia is a very dry continent, suffering regular droughts and hence an unreliable water supply. Also, increasing salinityof natural waterways and increased pollution are reducing our available water supplies. At the same time, an increasing population has led to greater demand for water, for drinking, growing more food and increased industry. In the future, as population increases, it will be necessary to recycle water, desalinate sea water or even to treat sewage to meet water demands.
4.6.1
(b) Various, e.g.
Alternatively, you might have used your water meter, reading it before and after an activity such as a washing machine cycle. Of course, you would have to ensure that no other water was being used in the house at the time.
4.6.2 Restrict the time you spend in the shower, turn off the tap when brushing teeth and use a cup of water, check that there are no
ones, follow water restrictions in the garden, use a broom rather than a hose to clean paths, wash your car with a bucket of water and the car parked on a lawn.
Dot Point Preliminary Senior Science 183 Water for Living
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4.6.3
GardenCarWashingmachine
Washingup
Dish-washer
500
450
400
350
300
250
200
150
100
50
Volumeof waterused (L)
ShowerBathToilet
Water use
Activities
4.6.4 (a) Various, e.g.
Car should be washed, on grass, with bucket of water only, no hose.
Child should not be playing with the hose.
Girl is hosing path – this should be swept.
(b) Various, e.g.
(c) Dog droppings on footpath; fertiliser left open in yard; rubbish falling out of bin; leaves being washed down drain; car suds going down drain; weed killer should be out of the reach of children.
4.7.1videos and/or the Internet.
You should be able to describe references that you used. For Internet sites, give complete URL; for books give title, author, publisher and date of publication; for personal contacts, give name of person, title and occupation.
(b) Validity will be high if you have used information from reliable sources, e.g. universities, government departments. Be aware that sites of companies that sell products may give a biased view in favour of products they sell.
4.8.1 (a) Various, e.g.
giardia and cryptosporidium could be kept out of our water supply. They could also be used to purify catchment water and allow water from households and industry to be recycled. This would ensure the water supply in droughts.
of water as well as increasing the volume of water available for use. Increases in population and an uncertain rainfall
As technology improves, and products are mass produced, new technologies often become more affordable and thus their use spreads to more areas and applications. It is often the case that a need in society has resulted in new and improved technology .
5.1.1 Safe water supplies contain a diversity of organisms. Organisms which are sensitive to pollution, and thus only found in safe
5.1.2and faecal coliform, e.g. E. coli.
Water for Living 184 Dot Point Preliminary Senior Science
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5.1.3
SewageFishing
2000
1000
Faecalcoliform count(colonies/100 mL)
Swimmingwater
Drinkingwater
Source of water
Bacteria in water
5.2.1
5.2.2 Water is essential for life.
5.3.1 Various – you should be able to describe and sketch your local catchment area. Include dams, rivers, towns.
Burragorang. This is the lake formed by Warragamba Dam and is fed by the Cox, Wollondilly and Kowmung rivers.
5.3.2 Permitted activities include picnicking, bushwalking and recreational activities.
Not permitted include: swimming or boating on the dams, farming. logging or urban development, industry or the use of chemicals such as insecticides.
5.4.1
5.4.2 Various, e.g. Sydney catchment area.
Warragamba Dam
KATOOMBA
WINDSOR
PARRAMATTA
SYDNEY
WOLLONGONG
KIAMA
Tallowa Dam
Cox's River
Grose River
Nepe
an R
iver
Nepean River
Geor
ge R
iver
Nattai River
Kowm
ung R
iver
Wollondilly Rive
r
Wingecarribee RiverWingecarribee Reservoir
Cordeaux Dam
Cataract Dam
Lake Burragorang
CAMPBELLTOWN
Woronora Dam
MITTAGONG
Nepean Dam
Avon Dam
5.5.1 (a) Various. You should identify the catchment area you investigated, stating exactly where you carried out your
– describe what you did. You may also have examined water specimens under the microscope and cultured a sample on nutrient agar plates to estimate bacteria present.
(b) Describe the plant and animal life you detected in the area you studied and comment on the diversity of organisms in the area. Describe the results of tests you carried out such as water turbidity, pH and salt concentration.
5.5.2 Remember that streams may be polluted so wear gloves when collecting and testing water to protect against possible acidic or other corrosive materials coming in contact with the skin and wear protective glasses to prevent such substances entering the eye. Corrosive/acidic substances could burn the skin.
Dot Point Preliminary Senior Science 185 Water for Living
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these could make you ill.
5.5.3 Creek A was polluted, creek B was not polluted.
can tolerate polluted water with low oxygen concentration.
The turbidity readings indicate that the water in creek A was relatively turbid (50 cm visibility) compared to water in creek B (1.0 m). This could be caused by erosion particles or large numbers of algae.
The pH of creek A (4) showed that it was acidic which could indicate pollution by acidic substances. The pH of creek B was only very slightly acidic (6.5).
5.5.4 Various, e.g.
We tested for the presence of chloride ions by adding a few drops of silver nitrate solution. We rated the cloudiness on a scaleof 1 to 5. The more cloudiness produced the greater the concentration of chloride ions present in the water.
We tested for the presence of carbonate ions by adding dilute hydrochloric acid to a sample. If bubbles are produced then thewater has carbonates such as sodium carbonate present.
5.6.1 Various, e.g.
Land clearing – Removal of plants means soil is not held together by roots and can be eroded. Erosion results in soil particlesand salt grains being washed into waterways.
Industry – Careless or illegal use of chemicals by industries, or dumping of chemicals illegally can contaminate waterways and catchments, e.g. corrosive acids, and alkalis, radioactive wastes, toxic heavy metals. Also leaching of chemicals from an industrial site, including mines, or corrosion from structures in the area can cause the release of corrosion products into theenvironment.
Agriculture – Animal urine and faeces, e.g. from cattle grazing near waterways, can be washed into waterways that enter catchments. Dead and decaying organisms can be present and bacteria can enter the water from such sources. Insecticide, herbicide and fertilisers applied to crops can be carried by rain or irrigation water into waterways and when these chemicals are sprayed the spray may drift across the catchment.
Urbanisation – Nutrients from grass clippings and animal droppings, sewerage seepage from septic tanks and sewerage
5.7.1Test for contaminants Contaminants detected by this test
Flame tests Metal ions especially heavy metals.
Turbidity Insoluble solids such as silt, clays, sludge suspended in the water. An indication of erosion and microbe contamination such as algae and faeces.
Acidity – indicators, pH meters, pH probes and data loggers
Acids or alkalis, acid rain.
Dissolved oxygen/BOD Low DO indicates increased activity of aerobic microbes which use up the oxygen. High BOD can be due to sewerage or industries such as food processing, paper production.
Tests for nitrogen and phosphorus content
Indicates sewage, fertiliser or detergents in water.
5.8.1
into estuaries, lakes and eventually the ocean. Pollutants may also seep into ground water and spread to other areas.
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5.9.1
Filtration
Sedimentation
Flocculation
Screening
Sludgeprocessing
Fluoridation
Disinfection
Addingchemicals
Watertesting
5.9.2 (a) (viii) (b) (iii) (c) (ix) (d) (i) (e) (vii) (f) (iv) (g) (vi) (h) (ii) (i) (v) 5.9.3
Chemical additive Reason for adding chemical
Aluminium hydroxide or iron(III) chloride
Coagulates fine suspended particles so that they will sediment or can be more easily filtered.
Sulfuric acid Breaks down organic wastes and aids coagulation.
Limewater or other alkali Neutralises acid and restores neutral pH.
Fluoride Hardens tooth enamel and helps prevent tooth decay.
Chlorine Bleaches coloured matter in the water and disinfects the water by killing micro-organisms.
5.10.1
The Exxon Valdez disaster in Alaska in 1989.
5.10.2 (a) Many areas are already short of water, the population is increasing at a very rapid rate and much of our drinking water has been polluted.
(b) Dishwasher, washing machine. (c) When water consumption exceeds renewable freshwater supply by 10 per cent. (d) From 1/3 to 2/3 of the population by 2025. (e)
AreaDaily water use per person (L)
Maximum Minimum
Rich countries 1000 850
Poor areas 70 20
Very poor areas (no taps) 5 2
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Water for Living 188 Dot Point Preliminary Senior Science