Science Focus 2 - Coursebook Answers - Pearson Australia Media ...

Answers to coursebook questions Chapter 1Unit 1.1 What, why and how?Checkpoint1 Answers will be wide and varied. All can be accepted.2 Answers follow on from question 1.3 Scientists normally gather information from their own experiments and research andfrom sources such as the Internet, journals, encyclopaedias and textbooks.4 Scientists and other workers find the answers to questions by researching theliterature, but scientists also conduct experiments.Think5 The cartoon could include pictures showing the following:Frame 1: Placing micrometer on object, screwing down the shaft.Frame 2: Reading off the shaft reading.Frame 3: Reading off the barrel reading.6 a True.b False: A micrometer is used to measure thin objects.c True.d False: The measurements that you control in an experiment should always go onthe horizontal axis of a graph.e False: Points on a graph should have a line or curve of best fit drawn through themiddle.Skills7 Draw a 2-D diagram of the micrometer used for the experiment, making sure theshaft and barrel are labelled and showing one of the measurements made in theexperiment.8 a 11.49 mm.b 19.74 mm.c 36.20 mm.9 Diagram needs to show shaft set between 12 and 13, and barrel 87.Unit 1.2 Scientific researchCheckpoint1 a Observation: a fact, made by one of the five senses.b Qualitative: descriptive only, not involving any numbers.c Inference: logical explanation.d Hypothesis: prediction, or educated guess.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 1e Variable: factor that may affect an experiment.f Controlled variable: factor not changed in an experiment.2 a True.b False: Observations never involve guesswork.c True.d False: A variable is not the same as an inference.e True.f False: ‘The grass grew 5 mm in a day’ is a quantitative observation.g True.3 The three questions scientists ask when they are planning an experiment are:• What do I want to test?• What am I going to change?• What am I going to keep the same?4 Only one variable should be changed at the one time, otherwise the cause of anychange observed would never be known.Think5 a The observations made were: the TV wasn’t working; there was water on thetop; there was water underneath.b The inferences made were: the roof leaked; water got into the TV; the watershorted out the TV.c Predictions about the TV and room in the future were: the roof needs to berepaired; then the TV needs repair or replacement.6 a Variables in the race: footwear, spoon size, handbag, distance run, egg size,shopping bag.b This was not a fair race since there are too many different variables changing atonce.c It would be a fair race if variables were controlled by ensuring that both runnerswore the same footwear, used the same type of spoon and did not carry bags, bymaking the tracks the same lengths and by having the same-size egg.Analyse7 a The two variables that Carl tested were the amount of sunlight and the amount ofwater.b Other variables that may have affected the growth of the grass under the tentfloor were: the lack of carbon dioxide; trampling.c The previous knowledge Carl used in designing his experiments was thatphotosynthesis requires carbon dioxide and sunlight.8 a A suitable heading for Carl’s research project would be: ‘Why grass dies’.b Introductory sentences might be: Grass was found to die after a week of beingcovered by a tent floor. Lack of sunlight, water or carbon dioxide and tramplingcould have been factors.c The aim for the whole research topic is to find what variable was the mostimportant in killing the grass under a tent floor. Experiment 1 aim: To find if© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 1lack of sunlight kills grass in a week. Experiment 2 aim: To find if lack of waterkills grass in a week.d Conclusion for Experiment 1: A lack of sunlight kills grass in the way seenunder the tent floor.Conclusion for Experiment 2: A lack of water kills grass but not in the way thathappened under the tent.The conclusion for the whole research project is that a lack of sunlight causedthe death of the grass under the tent floor.Investigate9 Carl could make an educated guess (hypothesis) about the outcome of the grass andthen design an experiment to test the hypothesis. For example, he could decide thatthe grass could grow again if not deprived of sunlight for too long. The variable hewould then be testing would be number of days of sunlight or deprivation. Hisdependent variable would then be a range of days from perhaps 1 to 30. Hisindependent variable would require measurement of time needed for the grass to begreen again. The experiment might result in a cut-off point beyond which the grasscannot recover.Unit 1.3 Better measurementsCheckpoint1 An error is small and unavoidable; a mistake is avoidable with care.2 Errors occur due to human reflexes, human reading ability, accuracy of theinstrument itself and the temperature of the day. These errors vary with individualcapability and cannot be entirely avoided.3 Four types of errors: parallax, reading, instrument, human reflex.4 Scientists take multiple measurements to improve accuracy.Think5 a False: Errors make all measurements slightly inaccurate.b True.c False: A mistake is not an error.d False: A measurement of 56 ± 2°C is between 54°C and 58°C.e False: Human reflexes are not always fast and accurate.6 a The number of kangaroos in Australia: estimate.b The number of kangaroos in the zoo: accurate.c The duration of a science class at school: accurate.d The number of hours of cloudy days in the next month: estimate .e The number of students who buy chips at the school canteen: estimate.7 a Error.b Mistake.c Mistake.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 1d Error.e Mistake.Skills8 Averages:a 39.6 mm.b 26.533 ≅ 26.5°C.c 46 mL; ignore the ‘bad’ measurement 58 mL.9 Type of error shown:a Parallax error (and reading error).b Human reflex or reaction time.c Reading error.10 a ± means ‘give or take’ or ‘plus or minus’.b Measurements with ± error:a 3.3 ± 0.1.b 170 ± 1.c 80 ± 5.Unit 1.4 Scientific conventionsCheckpoint1 a Convention: rule that scientists use.b Hypothesis: ‘educated’ guess about what you think you will find out in anexperiment.c Line of best fit: line drawn through the middle of points on a graph, not dot-todot.d Relationship: pattern or rule that exists between two variables.e Bibliography: list of resources used.2 The discussion of an experiment needs to include a description of what you thinkyour results show. It can also contain researched information. It can include graphsand ideas for further experiments, as well as a description of any problemsencountered and solutions to overcome them.3 A graph must have a heading, ruled vertical and horizontal axes, logical and regularmarkings along the axes, labels and units on the axes, and all points marked on thegraph with a fine pencil cross.4 The independent variable is placed on the horizontal axis. The number ofmeasurements and their intervals are chosen by the experimenter and are placed onthe graph before measurements of the dependent variable are made.5 The metric system allows all scientists to use a common language when reportingresults. This helps scientists to understand results more clearly and to be able toduplicate them.6 A line of best fit is obtained by drawing a straight line or a curved line which is notdot-to-dot. The line needs to go through as many points as possible. It is sometimes© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 1necessary to consider several possibilities and then choose that which goes throughthe most points.7 Two places where a diagram can be useful in an experimental report are in themethod and discussion or results.8 Pie charts and bar graphs are useful for showing data but cannot be used to predictmissing results. Line graphs can be extended to extrapolate further data.Think9 a 5 ML = 5 000 000 L.b 375 mL = 0.375 L.c 500 000 mm = 0.5 m.d 6 000 000 000 nm = 6 m.10 a 1 kilosecond or 1 ks = 1 000 s = 16.67 minutes.b 1 centiminute or 1 cmin = 0.01 min = 0.6 seconds.c 1 kiloday or 1 kd = 1000 days = 86 400 000 seconds.d 1 megasecond or 1 Ms = 1 000 000 seconds = 16 666.7 min = 277.8 hours =11.6 days.Analyse11 a An aim for Sam’s experiment: To compare the time taken for a feather and astone to fall the same distance.bcHeight(m)Stone droptime (s)0.5 0.32 0.601.0 0.45 0.952.0 0.63 1.353.0 0.77 1.704.0 0.89 2.00Predicted times:i 1.5 m Feather: 1.18 s Stone: 0.54 sii 2.5 m Feather: 1.53 s Stone: 0.70 sFeather droptime (s)iii 3500 mm Feather: 1.85 s Stone: 0.83 sd Height dropped from:i 0.5 s Feather: 0.3 m Stone: 1.3 mii 1.2 s Feather: 1.5 m Stone: Beyond limitiii 1.9 s Feather: 3.6 m Stone: Beyond limite i 5.0 m Extrapolate curve Feather: 2.35 sii 5.0 m Extrapolate curve Stone: 0.98 siii 2.5 s Extrapolate curve Feather position: 6 mfThe stone fell much faster than the feather. The fall of the feather was moreunpredictable than the fall of the stone.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 1Skills12 a The measurement at 6 minutes does not fall into the same pattern as the othermeasurements and is best not included in the line of best fit as it is probably anerror.b Copy the graph in Figure 1.4.5, choosing a line of best fit.c Many examples are possible. An example might be ‘Time take for masses to fall10 metres’.13 a Five things that are wrong about the graph are: no units on vertical axis; no labelon the horizontal axis; uneven markings on the vertical axis (the first few areprobably the measurements taken); the points are joined dot-to-dot and not witha line or curve of best fit; a probable mistake is included at 8 seconds.b The independent variable is on the correct axis as the experimenter has chosenhow often the measurements will be made (at 1-second intervals).c Copy the graph in Figure 1.4.6 and correct the errors in a.Chapter 1 review questionsSummary questions1 Scientists and other workers have perform many tasks in common, but scientistsfind solutions to problems by conducting experiments.2 Examples of observations that are:a Qualitative: colour, shape, sound, texture.b Quantitative: any measurement.c Visual: colour, measurements.d Made with the sense of touch only: texture, shape.e Made with the sense of hearing only: description of sound, its relative loudnessand direction.f Made with the sense of taste or smell only: food quality, identification ofsubstances.3 a An experiment is an individual test. Research is a set of experiments on the sametopic.b A qualitative observation is one that is descriptive only. A quantitativeobservation involves numbers.c An aim is a description of what is to be found out in an experiment. Ahypothesis is what you think will happen.d An error is unavoidable. A mistake is something that can be avoided with care.4 Diagrammatic answer required.5 The independent variable is determined by the experimenter, who determines arange of measurements before the experiment is conducted. The results obtained aredependent variables as they are not known before the experiment and depend uponthe conditions of the experiment. For example, the measurements taken in Figure1.4.4 could have been extended beyond 5 metres, if practical.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 16 Human reflexes are not exact. Any measurement that depends on reflex will thus beslightly inaccurate. For example, an elderly person will have slower reflexes than ayoung person, resulting in a slight variation if taking measurements, say, using astopwatch.7 The order in which the parts of an experimental report should be written: Name,Heading, Partners, Date; Introduction; Aim; Equipment; Method; Results;Discussion; Conclusion; Resource list (optional).Thinking questions8 The length of an insect could have been anywhere from 2.0 cm (smallest) to 2.2 cm(biggest) long.9 a 2.5 ± 0.5 s.b 105 ± 3°C.10 a 89 mL.b 121 g.11 Scientists use the same units for their measurements to avoid confusion and to allowcomparison between results.12 285 kW = 285 000 W.13 Recommended 10.9 MJ = 10 900 000 J. Australians eat 13 500 kJ = 13 500 000 J.This calculation demonstrates that Australians eat more than the recommendedallowance.14 a The length of a sugar ant: mm.b The amount of water in Botany Bay: GL or ML.c The distance from here to the next galaxy: Gm (light years used in practice).15 In designing the experiment, choices need to be made about the amount of salt,amount of water, speed of heating, and measurement time intervals. All of thesevariables need to be measured and recorded accurately to increase reliability of theexperiment. The independent variable, the temperatures recorded over the chosentime period, will enable the boiling point of the salt water to be determined. Theexperiment is then repeated, keeping all variables identical to determine the boilingpoint of water, so that a fair comparison can be made with that of the salt water.Interpreting questions16 a Distance is the independent variable as it is on the horizontal axis.b Sound intensity is the dependent variable, which changed naturally with distancein metres.c The units are missing from the vertical axis.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 1dDistance (m)Sound intensitye0.5 521 402 253 184 145 12fgi 1.5 m 34ii 2.8 m 18iii 350 cm 15iv 6000 mm 11v 0 m About 75i 45 0.8 mii 32 1.7 miii 20 2.7 miv 55 0.4 m© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 2Unit 2.1 Elements, compounds and mixturesCheckpoint1 A pure substance containing only one type of atom.2 By heat or the action of other chemicals.3 92.4 Oxygen and silicon.5 Shiny solid (except mercury), high melting point, high density, malleable, ductile,good electrical conductors.6 Many answers, eg gold—jewellery, copper—pipes, and wires.7 Solid liquids or gases, low melting point, low density, brittle, not ductile, poorelectrical conductors.Many answers: sulfur—sulfuric acid. carbon—graphite for fishing rods, bicycleframes.8 An atom is the smallest part of a substance capable of separate existence.9 An element is made up of identical atoms.10 A compound is a group of atoms bonded together.11 Molecular (eg water) and lattice (eg sodium chloride).12 A mixture contains combinations of elements and/or compounds that are not bondedtogether and with no new substance formed.13 Elements contain only one type of atom; compounds are made of elementschemically combined; mixtures can contain elements and/or compounds that are notchemically combined.Think14 Carbon (C), calcium (Ca), copper (Cu), chlorine (Cl), chromium (Cr).15 Hydrogen (H), boron (B), carbon (C), nitrogen (N), oxygen (O), fluorine (F),iodine (I), potassium (K), sulfur (S), uranium (U), tungsten (W).16 Sodium (Na), potassium (K), iron (Fe), tungsten (W), tin (Sn), gold (Au), lead (Pb),mercury (Hg), silver (Ag).17 a Plutonium.b Mercury.c Iron.d Potassium.18 a H.b He.c S.d Na.19 a Americium.b Einsteinium.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 2c Mercury.20 a Mixture.b Compound.c Mixture.d Compound.e Compound.21 Sodium chloride, silicon dioxide.22 a Ship’s hull: metal, strong, malleable.b Fishing rod: non-metal, non-conductor of electricity.c Electrical wires: malleable, ductile, conduct electricity.d Barbecue hot plate: metal, conducts heat, malleable.Analyse23 Diagrammatic answer required.24 a Metal: aluminium.b Non-metal: oxygen.c Non-metal: sulfur.d Metal: copper.e Metal: mercury.25 Diagrammatic answer required.Unit 2.2 Physical and chemical changeCheckpoint1 A physical change occurs when a substance changes, but no new substance isformed.2 Ice melting; salt dissolving.3 A chemical change occurs when a new substance is formed; for example oxygenand hydrogen combining to form water.4 Heat, light, colour change, gas forming, new substance.5 Fruit ripening, cake cooking.6 Combination, breaking down, precipitation, combustion.7 Reactants.8 A solid that forms from two liquids.9 (s) solid, (l) liquid, (g) gas, (aq) aqueous (in solution), → produces.10 Fast—fireworks exploding; slow—iron rusting.11 More concentrated reactants, higher temperature, greater surface area, usingcatalysts.12 A catalyst is something that speeds up a reaction without reacting itself.13 So the energy from food may be obtained more quickly.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 2Think14 aPhysical changesA prisoner breaks up rocks.A puddle of water evaporates.Juice is squeezed from a lemon.Rain turns the surface of a sportsground to mud.Sawdust is produced when a circularsaw cuts timber.Margarine melts in a frypan.Chemical changesLeaves turn red in autumn.Food is digested and waste expelledfrom your body.Sugar and water are heated in asaucepan to produce caramel.A match is struck and burns.Bread goes mouldy.Butter burns in a frypan.Water freezes to make ice cubes. After being stored in a cellar for 10years, a bottle of red wine tastes likevinegar.15 a Various answers.b Wax melts (physical); smoke, gas and carbon produced (chemical).16 The finely ground headache tablet will be more effective as it has a greater surfacearea for contact compared with the solid tablet.17 a More rapid burning.b Less rapid burning.18 There is less reactant left.Analyse19 C.Skills20 hydrogen + chlorine → hydrogen chloride (or hydrochloric acid).(reactants)(product)21 a sodium chloride + silver nitrate → sodium nitrate + silver chloride.b copper oxide + hydrogen → water (or hydrogen oxide) + copper.c zinc + sulfur → zinc sulfide.d calcium + oxygen → calcium oxide.22 a magnesium (s) + oxygen (g) → magnesium oxide (s) .b hydrogen (g) + oxygen (g) → water (l) .c sodium (s) + water → sodium hydroxide (aq) + hydrogen (g) .d mercury oxide (s) → mercury (l) + oxygen (g) .23 Diagrammatic answer required.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 2Unit 2.3 Inside atomsCheckpoint1 Greek word atomos meaning ‘indivisible’.2 Dalton, Thomson, Rutherford, Bohr.3 Thompson, Rutherford, Bohr.4 Solid mass of positive protons.5 Electrons.6 Deflection of positively charged alpha particles.7 a 1914.b 1932.c 1897.8 Protons and neutrons.9 a True.b True in a neutral atom. False in a charged atom or ion.c False.d True.10 a Negative.b No charge.c Positive.Think11AtomicnumberMassnumberElementNumberof protonsper atomNumberofelectronsper atom1 1 Hydrogen 1 1 02 4 Helium 2 2 23 7 Lithium 3 3 44 9 Beryllium 4 4 55 11 Boron 5 5 66 12 Carbon 6 6 67 14 Nitrogen 7 7 78 16 Oxygen 8 8 89 19 Fluorine 9 9 1010 20 Neon 10 10 10Numberofneutronsper atom© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 211 23 Sodium 11 11 1212 24 Magnesium 12 12 1213 27 Aluminium 13 13 1414 28 Silicon 14 14 1415 31 Phosphorus 15 15 1616 32 Sulfur 16 16 1617 35 Chlorine 17 17 1818 40 Argon 18 18 2219 39 Potassium 19 19 2020 40 Calcium 20 20 2012 a 17 protons.b 18 neutrons.c 17 electrons.13 Atoms are mainly empty space because the electrons are in shells which areenormous distances from the nucleus and from each other.Skill14 a Diagrammatic answer required.b Diagrammatic answer required.Chapter 2 review questionsSummary questions1 D.2 A.3 a C.b Al.c Au.d Sn.4 a Silver.b Iron.c Copper.d Boron.5 Protons (positive), electrons (negative), neutrons (no charge).© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 26 The different properties of metals and non-metals.Metals Properties Non-metalssolid (except mercury) Physical statesolid liquid or gasshiny Appearance dullhigh Melting point lowhigh Density lowmalleableductileMalleability (ability to be shaped) brittle (easily broken)Ductility (ability to be stretchedinto wires)good Electrical conductivity poor7 Many answers—copper for pipes, aluminium for drink cans, iron for buildings.8 a True.b False.c False.d True.Thinking questions9 Copper: Conducts electricity, can be stretched into wires without breaking.Silver: Attractive, shiny, and able to be shaped (malleable).Aluminium: Light, strong.Diamond: Very hard.Liquid nitrogen: Very cold, liquid.Sulfur: Kills bacteria (antibacterial).10 Beating of egg (physical), cooking of egg (chemical), chewing of egg (physical),other stages of digestion (chemical).11 A combination reaction involves substances joining together and a breaking downreaction involves a substance being separated into two or more different substances.12 Various answers, eg carbon + oxygen → carbon dioxide.13 a Speed up.b Slow down.c Slow down.d Speed up.Interpreting questions14 Atom B, element C, compound E, molecule A, mixture D.15 See Figure 2.3.5 in your coursebook.16 a 26 protons, 26 electrons, 30 neutrons.b 29 protons, 29 electrons, 35 neutrons.c 53 protons, 53 electrons, 74 neutrons.d 92 protons, 92 electrons, 146 neutrons.no© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 3Unit 3.1 MicrobesCheckpoint1 Microbes are minute living things that are not visible to the naked eye.2 a False.b True.c False.3 Light microscope and electron microscope.4 Fungi are visible with the naked eye. Viruses, bacteria, protists are not visible withthe naked eye.5 A eye piece (ocular lens)B objective lensC stageD diaphragmE lightF baseG armH coarse focusing knobI fine focusing knob6 10 000 to 100 000 times.7 a Bacteria consist of a cell wall and cell membrane, and do not have nucleus.b Some bacteria cause disease.c Bacteria have three basic shapes.8 Spherical coccus, rod-shaped bacillus, and spiral.9 Mushrooms, moulds such as on orange peel, and yeast used in bread making.10 They feed on dead and decaying material.11 A one-cell living organism.12 Diagrammatic answer required.13 Giardia, cryptosporidium.14 a True.b False.cTrue.15 Smallest microbes; protein coat; DNA within protein coat; reproduce within hostcell.Think16 Bacteria do not have a nuclear membrane or cell organelles as do protozoa.17 They behave like living things because they are able to reproduce and grow.18 A.19 a Light microscope or stereomicroscope.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the may be photocopied for classroom use.

Answers to coursebook questions Chapter 3b Electron microscope.c Light microscope.20 We often clean the toilet bowl at home, but we hardly ever clean the telephone, orcomputer, so allowing them to have more bacteria than the toilet.21 To remove bacteria from your hands so as not to allow bacteria to enter your bodyand cause infection.Skills22 a All plates have bacterial colonies that are similar in size and appearance.b Bacterial colonies similar in appearance have grown on each of the plates, soeach of the non-living surfaces may have been covered in the same bacteria. Butthe difference in colony numbers indicates that each surface was notcontaminated to the same extent.23 a 0.001 m.b nm.c 1000 nm.Unit 3.2 Reproduction in microbesCheckpoint1 Parent cell, the original cell before reproduction; daughter cell, one of two cells afterreproduction that are identical to the parent cell; antibiotic, a chemical or drug thatkills bacteria, usually by destroying the cell wall.2 See Figure 3.2.1a, page 64 of Science Focus 2.3 Two individual cells are formed, each identical to the parents. Numbers are able toincrease rapidly.4 Moisture and warmth and food.5 See Figure 3.2.3, page 65 of Science Focus 2.6 Hyphae grow into the food source and digest nutrients.7 Spores are produced that are like eggs—these are released and grow into new fungi;or pieces can break off and grow into new fungi.8 The parent forms a bud which elongates, the parent’s nucleus divides, and onenucleus migrates to the bud which separates as a new cell.9 a Protozoa reproduce by binary fission.b Protozoa can produce cysts which is a form of sexual reproduction.c Water which contains giardia is not safe to drink.10 Binary fission—see Figure 3.2.6, page 66 of Science Focus 2.11 A host cell is one in which a virus reproduces. The virus uses the resources of thehost cell to reproduce.12 a False.b True.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 3c True.d False.13 a After getting chicken pox for the first time your body creates antibodies thatattack the chicken pox virus if you come into contact with it again. The chickenpox virus is killed before it can make you sick again.b Vaccination involves injecting your body with a disabled or modified version ofthe virus. Your body responds to this by making antibodies to kill the real virusif you come into contact with it.Think14 They have a variety of reproduction options and doubling leads to large numbersrapidly.15 Once there are too many in one place their food runs out, their wastes pile up, andthey crowd each other out. They also have natural predators.16 a False.b False.c True.17 Bacteria contain the genetic blueprint and all the tools needed to reproducethemselves. However, viruses contain their own genetic blueprint but need toreproduce inside a host cell.18 a Bacteria reproduce very fast, so after only a few hours out of the fridge theremay be enough bacteria on chicken to make you sick.b The cold temperature slows the growth and bacteria.19 Most of the mushroom exists as hyphae growing into the food source. The part wesee is only the small part called the sporangium.Analyse20 a To compare the effectiveness of three mouthwashes in reducing oral bacteria.b Mouthwash 2 was not effective, as there was no reduction in the number ofcolonies counted after using this mouthwash.cThe mouthwash was contaminated with bacteria. Perhaps someone had beendrinking it directly out of the bottle.d Mouthwash 1 was the most effective as it reduced the level of bacteria the most.21 a Six doublings would occur in two hours, which is 2 multiplied by itself 6 times= 128.b Diagrammatic answer required.c Bacteria reproduce very fast so there are easily enough produced in one day tomake you sick.d Extrapolate from graph.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 3Unit 3.3 Friend or foe?Checkpoint1 a False.b True.c True.d False.2 Examples: Producing food and medicine, modifying organisms by geneticengineering, increasing soil fertility and decomposing waste.3 a Yeast, penicillium notatum, and truffles or mushrooms.b Yeast is used for making bread and alcohol, penicillium notatum for makingantibiotics.Truffles or mushrooms are used for food.4 a Penicillin is an antibiotic that is produced by a fungus.b Alcohol is produced by anaerobic respiration of yeast on grapes.c Thrush, tinea and ringworms are caused by different fungi.5 a Glucose + oxygen → carbon dioxide + water + energyb Glucose → alcohol + carbon dioxide + energyc Anaerobic respiration is also called fermentation.6 Viruses can be used in genetic engineering to modify plant or animal genes. Theycan also be used to help cure cancers in the brain.7 Anaerobic respiration uses no oxygen and produces alcohol, water, carbon dioxideand energy. Aerobic respiration uses oxygen and produces water and carbon dioxideand energy. Both require glucose to make energy.8 Grapes are left to ferment in the absence of oxygen at 37 o C. Yeast on the grapesfeeds on the sugar in the grapes and produces alcohol as a waste product.9 a Yeast causes bread to rise by producing carbon dioxide gas.b Yogurt is made by bacteria that sour the milk.c Yeast causes fermentation, creating flavours and ethanol (and carbon dioxide inchampagne).d Bacteria break down waste and make it safe. They recycle the waste andnutrients are released for other organisms.e Bacteria and fungi break down food scraps and release nutrients for otherorganisms to use.10 Yeast is feeding on sugar in the bread dough and carbon dioxide is produced as awaste product. The bubbles of carbon dioxide are trapped in the dough and cause itto rise and look frothy.11 Bacteria could consume the oil as food, turning it into a safe product.12 The virus enters the cancer cell; it uses it as a host cell to reproduce. The cell iskilled in the process and the new viruses go on to kill other cancer cells.13 The bubbles in wine are allowed to escape. Champagne is fermented in the bottle sothe bubbles are trapped.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 3Analyse14 Different bacteria produce different types of cheeses. Also, the length of time thebacteria are allowed to grow can affect the style and flavour of the cheese.15 a Disease-causing microbes affect society in many ways, such as: making peoplesick, causing loss of work time and productivity; causing the deaths of manypeople each year; creating business for drug companies; requiring us to practisegood daily hygiene to stop the spread of disease.b Many answers possible, such as: the flu (Influenza) causes many people to misswork, bacteria and fungi cause many infections that require drugs.16 Either case could be justified as long as sufficient examples are chosen to supportthe argument.Chapter 3 review questionsSummary questions1 Microorganism: A minute living thing that cannot be seen by the naked eye.Budding: A process of cell division used by yeast to reproduce.Binary fission: The process of cell division used by protists and bacteria toreproduce.Fermentation: The process used by yeast to make energy. In the process, yeast alsoproduces alcohol and carbon dioxide.Antibiotic: A drug that kills bacteria.Mould: A type of fungus.Flagella: A whip-like tail found on some bacteria and protists.Fomite: A non-living object that has bacteria on it.Decomposition: The breakdown of living material by microbes.2 a Protozoa are single-celled animals found in water.b Electron microscopes are used to view viruses.c Yeast reproduces by means of asexual reproduction.3 Anaerobic respiration is used by some microbes for making energy. It producesalcohol, carbon dioxide and energy using glucose.glucose → alcohol + carbon dioxide + energy4 Diagrammatic answer required.5 Seal petri dishes and label with name, date, contents; autoclave and do not openPetri dishes; clean benches with disinfectant after experiment is done.6 Many answers possible, eg penicillin made from mould.7 Light microscope; stereomicroscope.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 38MicrobeExample Method of reproductionTypeBacteria E.coli Binary fissionFungi Yeast BuddingProtist Amoeba Binary fissionVirus Influenza Inside host cellThinking questions9 Any protists, such as amoeba, paramecium, giardia or euglena.10 Bacteria reproduce faster on hot days, so food will go off more quickly.11 a True.b False.c True.12 Many examples: for example, bacteria can be used to make food such as cheese andyogurt, but also cause many diseases such food poisoning.13 Spa temperatures are usually around 35 o C, which means that bacteria can reproducevery quickly in a spa. Chlorine levels therefore need to be checked regularly toensure bacteria are controlled.14 Binary fission is a very effective reproduction strategy as it is fast, resulting in largenumbers of individuals very quickly.15 Viruses cause the common cold. After catching a cold virus, your body makesantibodies to stop you getting it again. When a virus mutates, your antibodies nolonger recognise it, as the virus is slightly different. Your antibodies to the previouscold do not fight off the new mutated version of the virus, so you catch the coldagain, and make new antibodies.16 Diagrammatic answer required.17 Diagrammatic answer includes cocci, bacilli and spirilli.18 The yeast is placed in the bread mix, which contains sugar that the yeast uses forenergy. When the yeast starts to grow it produces carbon dioxide, which makes thebread rise by causing bubbles in the dough.19 Bacteria are important in cleaning up the environment as they break down deadmaterial and release it back into the environment. This is called decomposition.20 Diagrammatic answer required. Keys will differ depending on information used bystudents.21 Parmecium = 100 µm, 100 × 1000 =100 000 nm.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 322 Various answers possible. Some examples are given below.Microbe type Benefits Problems and cost to societyBacteria Making foods such as yogurtand cheese.Decomposition of deadmaterial.Cause many diseases costingmillions of dollars each year andkilling people.Medical research is aimed atdeveloping new antibiotics all thetime.FungiSupply food.Decomposition of deadmaterial.Cause many diseases, costingmillions of dollars each year andkilling people.Protists Part of natural ecosystem. Cause many diseases, costingmillions of dollars each year andkilling people.VirusesMay be used in geneticengineering and for treatingsome cancers.Cause many diseases, costingmillions of dollars each year andkilling people.Medical research is aimed atdeveloping cures.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4Unit 4.1 FoodCheckpoint1 For energy, growth and good health.2 Water and fibre.3 Dietary fibre comes from the cell wall of plants and is not digested, which helpskeep water in the large intestine and reduces constipation.4 Cereals, vegetables.5 Carbohydrates are required for energy; bread, potato. Lipids are also a source ofenergy; margarine, vegetable oil. Proteins are needed for growth and repair of cells;meat, eggs. Vitamins speed up chemical reactions in the body and are required forgood health; fruit and vegetables. Minerals are required for good health; milk,cereals.6 a A, B1, B2, B3, B6, B12, D, E, H (biotin), B6.b Vitamins H and B6.c potassium, calcium.7 Trace elements are needed in smaller amounts than major elements.8 Calcium and copper.9 Vitamin A, vitamin B1 (thiamine), cobalt, copper.10 Beriberi may be caused by lack of vitamin B1 (thiamine). Scurvy may be caused bylack of vitamin C.11 A balanced diet contains the correct number of foods from each food group.12 A standard amount eaten at one time, eg a bowl of cereal or a piece of fruit.13 Low blood sugar creates hunger to replace glucose in blood.14 Sample menus allow a comparison of nutrients in various foods so that a balancedmeal may be selected.15 The energy used for different types of human activity.16 Energy expenditure, even when compared for the same activity, can varyindividually.17 Anorexia nervosa is a disease where people starve themselves.18 Obesity is being more than 25 per cent overweight, while compulsive eating iseating huge amounts despite not being hungry.Think19 Teenagers are growing at a more rapid rate and require higher levels of nutrientsthan adults.20 Males are generally bigger than females and require higher levels of nutrients andcalories.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 421 Pregnancy would be likely to increase a woman’s energy requirements, as additionalgrowth is required.22 Sleeping, writing, cleaning jogging, dancing.23 a 690 kJ.b 1500 kJ.24 Energy is still needed for your body to breathe, heart to beat, cells to be grown orrepaired, and so on.25 Energy expenditure may be different for different-sized people, and people mayundertake activities at different speeds.26 You may lose weight as fat reserves are used.Analyse27 Diagrammatic answer required.28 Various answers.Skills29 Diagrammatic answer required.30 Energy requirements increase as a person ages from 10 to 17 years.31 Diagrammatic answer required.32 Various answers.Unit 4.2 DigestionCheckpoint1 Incisors—cutting, canines—biting, molars—grinding.2 Enamel, dentine, pulp cavity, blood vessels.3 Plaque is a film of food, saliva and bacteria that builds up on the teeth and can leadto decay—holes in the teeth caused by acid produced by the bacteria in plaque.4 By regular brushing after meals, check-ups at the dentist and avoiding too manysugary foods.5 Mouth, oesophagus, stomach, (pancreas), (liver), (gall bladder), duodenum, smallintestine, large intestine.6 a Small intestine.b Large intestine.c Stomach.d Large intestine.e Small intestine.7 a Liver.b Large intestine.c Mouth.d Stomach.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4e Liver.f Oesophagus.g Pancreas.h Small intestine.8 The large intestine is wider than the small intestine.9 The top of the trachea extends and combines with the epiglottis to block the entranceto the trachea.10 Sphincters stop food from moving the wrong way through the alimentary canal.11 Enzymes break down food.12 By stomach acid (hydrochloric acid).13 Semi-liquid, partly digested food produced in the stomach.14 Heat production, detoxification of poisons, conversion of glucose to glycogen.15 Sulfur dioxide, methane, hydrogen.16 Bacteria produce useful vitamins.17 Carbohydrates are broken down to glucose and stored as glycogen in the liver;proteins are broken down to amino acids; lipids are broken down to fatty acids.18 They may require a reserve for times when food is not plentiful.19 They eliminate harmful germs from the body.20 The liver.21 a More water is absorbed.b Moves more slowly.Think22 There may be bile present, which is green.23 No; heartburn is the sensation caused by stomach acid flowing back up to irritate theoesophagus (in the vicinity of the heart).24 More food is broken down by the enzyme in saliva.25 Most bile passes into the duodenum to assist with the breakdown of food.26 Vomiting.27 So that the food can pass into the blood stream and then enter cells.28 There would be less area for digested food to pass through, so digestion would takelonger, and nutrients may not reach cells quickly enough.29 Gases lower than the stomach cannot move back up through the alimentary canaldue to sphincters controlling the flow of materials.Create30 Diagrammatic answer required.31 Various answers, eg Dear, I Am Really Really Happy Over Eric’s Appointment.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4Unit 4.3 Blood and circulationCheckpoint1 Water, oxygen, red cells, white cells, platelets, nutrients and carbon dioxide.2 Diagrammatic answer required.3 Destroys bacteria and viruses.4 Platelets.5 A clear yellow fluid making up 55 per cent of blood and containing red and whitecells, dissolved food, waste products and hormones.6 Oxygen.7 White blood cells have a nucleus.8 a False (there are two antigens with letter names—A and B. O represents theabsence of A and B antigens).b True.c True.d True.9 It is easy to see if an injury results in bleeding, allowing the injured person to takecorrective action.10 a Blood travels away from the heart to the body. The aorta walls expand andcontract as blood is pumped to help move it along.b The pulmonary vein carries blood from the lungs back to the heart.c A ventricle fills with blood that comes from the atrium, then contracts to pumpblood out of the heart.d An atrium is where blood enters the heart from the veins. Blood passes from theatrium through valves to the ventricle.11 An atrium receives blood at low pressure, while a ventricle pumps blood out to thelungs or the rest of the body at high pressure.12 Cardiac muscle.13 Arteries, capillaries and veins.14 Veins carries blood at the lowest pressure.15 Nutrients are carried from the capillaries in the intestine to the larger veins and backto the heart. Blood is pumped from the heart to the lungs. Blood returns from thelungs to the heart. Blood is pumped out of the heart through the aorta (main artery)to the body. It passes through smaller and smaller arteries and vessels until itreaches the capillaries in the toe. The nutrients pass out of the capillaries into thecells of the toe.16 The death of a region of heart tissue caused by a blocked artery.17 Pacemaker, artificial valve.Think18 In case they suffer an injury or have an operation requiring a blood transfusion—they know the blood is safe for them.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 419 Arteries carry blood away from the heart at high pressure, while veins allow bloodto drain back to the heart under low pressure.20 A systolic pressure reading is taken when the heart contracts, and a diastolic readingis taken when the heart relaxes.21 a Artery.b Artery.c Vein.d Vein.e Vein.f Lungs.g Liver.h Gut.i Kidneys.22 To supply our muscle cells with extra energy for faster movement or in readiness for‘fight or flight’.23 Reduce the amount of cholesterol in your diet.24 Using an electrical stimulus.25 To test for the presence of banned performance-enhancing drugs.26 To supply muscles with extra oxygen should additional exertion be required to copewith a threat.27 The right ventricle must pump blood to the lungs only, while the left ventricle mustpump blood to the rest of the body, and so requires stronger walls.28 a 6480 L.b 45 360 L.c 2 365 200 L.d 160–190 million L.Analyse29Donor’s bloodPatient’s A B AB ObloodA Yes No No YesB No Yes No YesAB Yes Yes Yes YesO No No No Yes© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4Unit 4.4 Excretion: getting rid of wastesCheckpoint1 Removal of waste from the body.2 a By chemical reactions in cells.b Filtered from blood by the kidneys.c Filtered from blood by the kidneys.3 Via the bloodstream.4 78 L.5 Over 1 million.Think6 Diagrammatic answer required. See Figure 4.4.1 in Science Focus 2 as an example.7Body partsCirculatorysystemKidneysUretersBladderUrethraFunctionsTransports wastes and nutrients.Filter blood.Allow urine to reach storage area.Urine storage.Tube which allows urine to leave the body.8 Less water is lost due to sweating, so more is lost through urination.9 Urine contains many chemicals that have been processed (or not) by the body.10 Average sized-bladder can hold 1 L. At 300 mL you feel the urge to urinate. Thisallows some ‘breathing space’ or margin for error (ie time to find a toilet!).11 A kidney stone may irritate the lining of the ureter which is not designed for themovement of solids.12 Solids are less likely to crystallise out of solution if there is more water present inthe urinary system. Also, more water ‘flushing through’ the system will move tinyparticles out before they have time to become larger.13 It is possible to live normally with one kidney (which both donor and recipientwould have).Skills14 Diagrammatic answer required.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4Unit 4.5 Respiratory systemsCheckpoint1StructuresTracheaEpiglottisNoseCiliaAlveolusFunctionsCarries air to and from the lungs.Prevents food from entering the trachea.To filter, warm and humidify air.To remove foreign particles from the lungs.The site of gas exchange.2 a Larynx and epiglottis.b Coughing occurs.3 Alveoli.4 a In red blood cells.b To carry oxygen from the lungs to body cells.5 Gases cannot diffuse efficiently to all body cells in the required amounts.6StructuresSkin and lungs/bloodstreamGills/bloodstreamMoist body surface/bloodstreamLungs/bloodstreamBody surface/no circulatory systemAir-filled tubes/no bloodstreamOrganismsFrogFishEarthwormLizardSingle-celled amoebaInsectThink7 a Contracts.b Enlarges.c Raised.d Contract.e Decreases.8 Allows maximum rate of gas diffusion.9 High surface area, a thin, moist surface and a means of transporting gases to andfrom cells.10 a About the same.b Less.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4c Greater.d Greater.11 The nose filters, warms and humidifies the incoming air. The mouth does not dothis.12 a Nasal cavity.b Epiglottis.c Trachea.d Bronchus.e Larynx.f Alveoli.g Diaphragm.h Intercostals.13 a Trachea.b Carries air to and from the lungs.c Alveoli.d The site of gas exchange between air and blood.14 aApparatus Body partsPlastic tube TracheaBalloonsLungsBell jarChestRubber floor Diaphragmb The space enlarges, causing pressure to drop, so air flows in.c Bell jar walls are fixed. Our ribs move upwards and outwards.Analyse15 a Oxygen.b Haemoglobin.c Haemoglobin allows more oxygen to be carried than would be possible if itsimply dissolved in the blood.Chapter 4 review questionsSummary questions1NutrientsCarbohydrateWaterDescriptionsOur main source of energy. Converted to glucose duringdigestion.Not a nutrient, but required for chemical reactions in the body.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 4ProteinLipidsFibreVitaminsMineralsRequired for growth.High in energy.Provides bulk to move waste through intestines.Required in small amounts for good health.Chemically simple, required for good health, not for energy.2 a B1 (thiamine).b D.c C.d B3.3 a Boron, cobalt, copper, fluorine, iodine, iron or zinc.b Calcium, sodium, phosphorus, sulfur, potassium, or magnesium.4 Bulimia.5 32.6 Dentine is a bone-like substance that lies under the enamel.7 A normal filling is where a small cavity in the enamel is filled. Root canal treatmentinvolves the sterilisation and filling of the pulp cavity.8 See Figure 4.2.5 in Science Focus 2.9Parts of digestive systemMouthOesophagusStomachPancreasLiverGall bladderDuodenumSmall intestineLarge intestineDescriptionsDigestion begins here.Connects mouth to stomach.Like a cement-mixer for food and gastricjuices.Produces enzymes including insulin.The body’s chemical factory.Stores bile.Start of small intestine.Where most absorption of nutrientsoccurs.Where water is absorbed.10 See Figure 4.3.7 in Science Focus 2.11 Amylase (found in saliva in the mouth), pepsin (found in the stomach).12 B (a little under 50 per cent).13 Platelets trigger production of fibrin, which causes clotting.14 Angina involves pain caused by a severe reduction of oxygen and glucose reachingthe heart (eg due to a narrowed artery), while a heart attack is the death of hearttissue due to a blocked artery.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 415 Cholesterol.16 Electrocardiogram.17 Plastic or animal tissue (eg pig).Thinking questions18 a We excrete when we breathe out.b Water and carbon dioxide are waste products of cells.c Our kidneys are about the size of our fists.d Kidneys filter about a quarter of the blood pumped by the heart in the same time.e Urine travels down tubes called urethras to the bladder, which has a capacity ofabout 1 litre.f Drinking at least a litre of water each day decreases the risk of kidney stones.g It is possible to live normally with only one kidney.19 Fats contain about twice the energy of carbohydrates. Various answers for menu.20 A sphincter opens or closes a section of the digestive tract, while peristalsis movesmatter through it.21 a Ulcer.b Appendicitis.c Cirrhosis.22 They both consist of glucose molecules. Glycogen can be stored in muscle tissue.23 Vein—return blood to heart, artery—high pressure, capillary—fine tubes near cells.24 a ib vc ivd iiie ii and vif viInterpreting questions25 Contracts, contract, upwards, outwards, increase, decrease, flows in.26 a • Thin moist surface.• Large surface area.• Lie close to the circulatory system.b • For efficient diffusion of gases.• For maximum rate of diffusion.• To transport gases to cells.27 Calcium 1100 mg, sodium 2000 mg, protein 60 g, iron 14 mg.28 12.8 kJ (male), 9.4 kJ (female). Answers vary with age.29 a No.b Yes.c No.d No.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 5Unit 5.1 Static electricityCheckpoint1 a Negative.b Positive.2 a They are equal.b There are more protons than electrons.c There are more electrons than protons.3 Attraction of unlike charges and repulsion of like charges.4 Since opposite charges attract, a charge can induce the opposite charge in aneighbouring surface.5 Diagramatic answer required. See Figure 5.1.6 in Science Focus 2.6 A collection of charges that remain stationary for some time.7 Stationary charge is built up in the Van de Graaff generator by a belt that transfersnegative charge to its metal dome.8 Photocopiers, painting cars.9 Shock from carpet, shock when aircraft touchdown, closing car doors, trampoline.10 An area where a force can act is called a field.11 The direction of an electric field is the direction a small positive charge would moveif free to do so.Think12Positive charge Negative charge Neutral chargeRepel Attract AttractPositive chargeAttract Repel AttractNegative chargeAttract Attract No forceNeutral charge13 a Because the like charges on paint particles repel each other.b So the paint is attracted to the panel.14 Clothes rubbing on plastic slide, fuel rubbing on hose.15 The rubbing of the mirror can cause a static charge that attracts more dust, makingthe mirror dirty.16 Charge concentrates on the head and hair. Like charges repel each other, so hairattempts to move as far away from the head and other hair as possible. Standing on arubber mat prevents charge escaping through the floor and so aids charge build-up.17 Charge concentrates on sharp objects. A pointed finger is sharper than a forehead.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 518 Pieces may become charged during ripping, and are attracted to neutral objects suchas your fingers and hands.19 Moisture in the air conducts charges away by other routes.20 a A positively charged object contains a majority of positive charges.b A neutral object contains equal numbers of positive and negative charges.c Induction is the ‘coaxing’ of charges in a neutral object to move to differentpositions within the object.d An object may become charged by rubbing electrons off or onto it.e Lightning is caused when build up of charge within a cloud jumps from thecloud to the Earth or elsewhere.21 Both have a direction, are invisible and may move objects. Also, opposite chargesattract and like charges repel.Analyse22 Diagrammatic answer required.23 Friction between the roller and the band produces static electricity which is carriedto the dome.Skills24 Diagrammatic answer required.25 Diagrammatic answer required.Unit 5.2 Moving electricityCheckpoint1 An energy source; a conductor; a device, eg globe; a switch.2 Various answers, eg clock, dishwasher, television, computer, toaster.3 a Current is the flow of electric charge.b Voltage is a measure of the energy given to charges.4 a Ammeter.b Voltmeter.5 Various answers, eg clock, train set, torch, smoke alarm, laptop computer, iPod.6 A chemical reaction between the paste or liquid contents and the electrodes.7 Lithium.8 Because of the lead plates and acid they contain.9 It is not frequently recharged (as the car is driven).10 A conductor is a material that can conduct electricity, eg copper, or other metals. Aninsulator is a material that does not allow the flow of electricity, eg plastic, rubber,wood.11 The gas helps conduct heat away from the filament, protecting it from melting.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 512 In the resistance (eg a globe).Think13 Copper is cheaper and lighter, and is a better conductor (so little energy is lost in it)than tungsten.14Current electricityChargeCurrentCellConnecting wireGlobeSwitchWaterWater particlesWaterPumpPipesWater wheelTap15 To prevent current flowing through the tools to their bodies if they accidentallytouch a ‘live’ circuit.16 A cell is a single power unit. A battery is a group of cells.17 a 1.5 V.b 240 V.c 12 V.Skills18 Various answers, eg good conductors—metal, coin, paperclip; bad conductors—plastic, rubber, glass.19 Diagrammatic answer required.20 See Figure 5.2.2 in Science Focus 2.Analyse21 A, C and D.22 Many, many cells combine to produce a much higher voltage than an individual cell.Unit 5.3 Using electricityCheckpoint1 A series circuit contains several components in the one ‘line’ or branch, while aparallel circuit contains components in more than one branch between the samepoints.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 52 In a series circuit, the voltage is shared between the components, but the current isthe same. In a parallel circuit, the current is shared between the branches, but thevoltage is the same for each branch.3 a Just that globe stops glowing.b All globes stop glowing.4 a True.b False.c False.5 Various answers, eg never handle faulty electrical equipment that is connected to ahigh voltage, such as in household circuits.Analyse6 a A, C.b B.7 a B.b A.c D.d C.e A, B, C and D.8 Diagrammatic answers required.9Switch 1 atpositionSwitch 2 atpositionLightA X ONB X OFFA Y OFFB Y ON10 B.11 Half.12 Globe 4 would glow more brightly (or burn out). The others would cease glowing.Both globes would go out, as all current would travel along the short circuit.13 C.Skills14 Diagrammatic answer required.15 Diagrammatic answer required.16 Diagrammatic answer required.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 5Chapter 5 review questionsSummary questions1 a False.b True.c True.d True.e False.2 a Current is the flow of electric charges.b Current is measured in amperes.c An insulator does not allow charge to flow through it.d Most metals are good conductors.e Voltage provided by a cell is a measure of the energy available to push chargesaround a circuit.f A dry cell contains a chemical paste and electrodes to produce free electrons.g It is usually negative charges that flow in a circuit.3 a True.b True.c False.d False.e False.f True.4 A cell refers to a single unit and a battery to a group of cells.5 By comparing current in and out of a house. If there is a difference (eg caused by anelectrical fault), it shuts off the main power.6 Electric circuit from power point to jug and back to power point is compete whenthe switch is turned on, but a nichrome wire acts as a resistor, building up currentwhich is converted to heat.7 A fuse is a short section of wire made from a metal with a lower melting point thanthe copper wire in the circuit. When a larger current flows the wire melts, breaksthe circuit, and prevents an electrical fire or damage to the circuit.Thinking questions8 Rubber-soled shoes prevent current flowing through the wearer’s feet and so reducethe risk of electric shock (though it is still possible through other paths in the body).9 a Hair/comb.b Car body/air.c Seal/container.d Clothes/chair.10 To allow charges produced by friction between air and the car to escape gradually toEarth without sparking.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 511 Household power supplies alternating current (AC) which flows back and forth(oscillates) whereas the current in batteries flows in one direction only and is calleddirect current (DC). AC current is easier to generate than DC current.12 Static electricity is stationary, or unable to move, whereas current, by definition, ismoving charge.Interpreting questions13 Diagrammatic answer required.14 See Figure 5.2.11 in Science Focus 2.15 a D and E.b A and B.c C and F.16 Diagrammatic answer required.17 Diagrammatic answer required.18 Diagrammatic answer required.19 Diagrammatic answer required.20 C.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 6Unit 6.1 EcosystemsCheckpoint1 a Living organisms.b Non-living environment.c Community.2 a Ecology is the study of an organism’s home.b The broadest details about where an organism lives is called its biosphere.c The secondary level of an organisms biosphere is its biographical region.3 Australia.4 The first level is a biosphere; the second level is a biographical region; and the thirdlevel is the biome.5 Examples to choose from: grassland; tundra; desert; coniferous forest; temperateforest; tropical forest; marine; coral reef.6 The habitat is the fourth level of an organism’s address. In a desert biome, a habitatcould be a sand dune.7 Sand dunes; clay pans between sand dunes; tussocks of grass; scraggly tree.8 Some examples—tree canopy; moist ferns; lichen-covered rocks; streams.9 In a desert sand dune, a microhabitat in a clump of Spinifex will be different from aburrow under the sand.10 The microhabitat is a subsection of the biome and defines the address morespecifically.11 Drought; flood; and fire.12 Lack of water degrades the land; living organisms die; famine; disease.13 Floods can be destructive to ecosystems, but can replenish ground and soil water.14 Release of nutrients to replenish soil.15 Diagrammatic answer required.Think16 a L.b NL.c NL.d NL.e NL.17 a The term ‘biosphere’ refers to that part of the earth (including its atmosphere) inwhich living organisms can be found.b The term ‘biome’ refers to areas that have similar climatic conditions.c The term ‘habitat’ is used to describe a more specific area than the term ‘biome’.d An example of a desert microhabitat would be a claypan.18 Various answers.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 619 a Ecosystem refers to the living organisms that inhabit a specific area, how theyinteract with each other and the effects of the non-living environment aroundthem.b The plants and animals in each biogeographical area are unique.cThe plants and animals that live in a grassland biome in differentbiogeographical regions are likely to show similarities.d The island of Tasmania is considered a biogeographical region.20 Microhabitat; habitat; biome; biogeographical region; biosphere.21 Similar biomes have similar climatic conditions. This means that the organismsliving there exemplify similar behavioural and physical adaptive features. Forexample, animals living in alpine regions are likely to have thick, woolly coats as ameans of conserving body heat. They are also more likely to hibernate during thecolder months.22 The kowari, and animals living in similar conditions, often burrow underground inorder to avoid dust storms.23Carnarvon Gorge, QueenslandThe upstream side of a river rockEarthAnalyseCarnarvon RiverTemperate biomeMicrohabitatBiosphereHabitat24 There will be a difference in the vegetation found in Broken Hill and Newcastle.This is because different plants have different water requirements. Broken Hill has alower rainfall and will favour plants adapted to dry conditions such as Spinifex.Newcastle with a higher rainfall will be able to support more leafy plants.25 Salinity is a factor that varies from one water source to another. The saltwater oceanhas higher salt levels than the freshwater rivers, lakes and dams. Water is deeper inthe the saltwater ocean. The availability of light and the temperature of the waterwill vary as a consequence of its depth.26 In the cold waters of the upstream rivers, there is little food at the time of year thatthe salmon spawn. The dead bodies of the parent salmon provide the food necessaryfor the fingerlings to survive.27 Fish kept in a tank get acclimatised to the environment of the fish tank. When theenvironment is changed, the fish have to adjust to changes in pH, temperature,oxygen content and so on. It is helpful to the fish if the change is kept to aminimum, so that they have time to adjust and acclimatise to the new conditions.The tank must be cleaned and the water exchanged because the fish release wastesinto the water which make the water toxic.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 6Unit 6.2 Physical attributes of an ecosystemCheckpoint1 A physical adaptation is passed on to the offspring by the parents. The offspring hasno choice in what DNA it does or does not receive. Behavioural adaptations arethings the organism chooses to do in response to some environmental stimulus, egwhen an echidna is attacked it rolls up into a tight ball.2 Instinctive behaviour is automatic, like seeking shade on hot days. Learnt behaviourneeds to be taught, eg a seal pup watches its mother fish and therefore learns how tohunt for food.3 Abiotic features of the environment are non-living.4 Choose from: temperature, light, humidity, salinity, acidity, water, wind.5 Biotic features of the environment include living things.6 a The non-living factors that influence where an organism can live are calledabiotic factors.b The more saturated with water the air is, the more humid it is.c On land, the percentage of oxygen in the air decreases with altitude.d Water that flows quickly has more oxygen than water that is still.Think7 This is an example of a behavioural adaptation because the animal has control overits behaviour.8 This is an example of a physical adaptation because camels’ nostrils have made achange to adapt to the environment.9 Physical adaptation and the beak has adapted to suit the dietary needs of the animal.See Figure 7.2.2 in Science Focus 2.10 a We would expect them to eat the same type of seed.b They would live in a similar type of habitat, possibly grassland.11 a True.b True.c True.d False.12 a Water temperature, currents.b Shelter.c Temperature, water, nutrients in the soil.d Temperature, weather, rain, water, availability of shelter.13 The large surface area of an elephant’s ears allow for the dissipation of heat, therebyallowing it to cool off more quickly. The abiotic factors involved includetemperature, humidity and air currents.14 Mangroves would have to contend with such abiotic factors as wave action,increased exposure to salt concentration and reduced light at high tide, and windaction, higher levels of light and greater temperature changes during low tide.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 615 They show similar characteristics because they live in the same conditions. Watercurrents and wave action, salinity, temperature and light availability are abioticfactors that affect them both.16 Abiotic factors that influence each of us include temperature, water availability,light availability and the soil type which determines what foods we eat.17 The biotic factors that influence each of us include the types of vegetation available(used for both food and dwelling construction) and the types of animals and plantsthat are available for food.18 Marine fish survive in water of a specific salinity. Fresh water is therefore not ableto support them.19 Legumous crops work in a mutually helpful (symbiotic) relationship with nitrogenfixingbacteria. This keeps the soil more fertile for the farmer’s crops.20 In alpine regions, water is present as snow and in this form it is unavailable to thepine trees. Thus, in effect, both the cacti and the pine experience water shortage.21 As altitude increases, soil is often less plentiful, with more rocky material taking itsplace. In this situation, the extensive root system of a tree is unable to form.Unit 6.3 Food chains and food websCheckpoint1 Photosynthesis.2 They produce food that is then available for others in the food chain to consume.3 a False.b False.c False.d True.4 Six at the most.5 Food chains are interrelated because organisms that make up food chains havevarious food sources. The interrelated food chains form a food web.6 Greater biodiversity ensures survival. For example, a herbivore that eats a variety ofplants has more chance of survival than if it only ate one type of plant.7 Glucose.8 Plants only use about 0.2 per cent of the Sun’s energy. At each level of the foodchain only 5–20 per cent of energy is transferred, so there has to be a larger numberof plants in an ecosystem to ensure sufficient energy transfer to higher levels in thefood chain.9 Contains carbon; came from living things.10 The dead bodies of plants and animals are broken down by decomposers such asbacteria and fungi and returned to the soil as organic matter.11 a Organisms that live together and provide food for each other, eg false clownanemone fish with anemone.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 6b One species benefits from the interaction while the other does not, eg suckersattached to sharks.c One species is harmed while the other is not, eg animals that destroy plants.d Different plants or animals fight for the same resource, eg birds.e One species is benefited and the other is harmed, eg dingo hunting lizard.12 Predation, herbivory and parasitism are all examples of exploitation.Think13 Yes, as it supplies the energy used by plants, which are the basis of the food chain,supplying energy to all other organisms.14AutotrophRose bushHeterotrophOmnivoreKoalaHuman being15 This is an accurate description of a plant as it produces its own food from water,carbon dioxide and sunlight.16 a Parasitism.b Parasitism.c Mutualism.17 The fleas are parasites; the dog is their host (parasitism).18 Cooperative hunting allows the carnivore species to take down more prey, andbigger prey so it could benefit a carnivore species.19 Two organisms of the same species may not need similar amounts of food becauseone may be younger than the other, and males generally tend to require more foodthan females (unless the female is pregnant, in which case she would need more).20 At each level of the chain, only a small percentage of the energy is passed on to theconsumer of the next level. For this reason, food chains rarely have more than sixlinks.Skills21 Grass mouse snake owl.22 The producer is the grass. The primary consumer is the mouse. The secondaryconsumer is the snake. The tertiary consumer is the owl.23 For example: rose aphid spider bird domestic cat.24 Area B will have the greatest biodiversity because there are more organisms livingthere (we know this because there are more food chains in this area).© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 6Unit 6.4 Effects of human civilisation on the ecosystemCheckpoint1 The Industrial Revolution introduced machinery into the workplace. Withmachinery came increased production; more people in cities and, from theecological point of view, mass pollution.2 Pollution is the introduction of substances into the environment that cause the livingorganisms to become unhealthy.3 Three air pollutants are sulfur dioxide, nitrogen dioxide and hydrogen sulfide.4 Three products of air pollution and sunlight are ozone, nitric acid and formaldehyde.5 Burning fossil fuels results in a build-up of greenhouse gases, which trap heat andlead to global warming.6 Sewage, agricultural run-off, sediment pollution, salinisation, inorganic chemicals.7 Overgrazing, deforestation.8 Possible example: Introduction of foxes and cats has led to the extinction of twothirdsof Australia’s native animals.9 Predation by introduced species; competition with introduced species; destruction ofhabitats by humans.10 Conservation involves keeping alive all the plants and animals that live in a specifichabitat. This maintains biodiversity and conserves food webs so that all species in acommunity can survive. Every species in a community interacts in some way withall of the other species living there.11 Humans rely on plants for food and oxygen. Plants also provide food for the animalswe eat, and the materials we make our houses out of. Animals are used for a varietyof things including clothing (eg wool and leather) and food.Think12 The increased pollution of a city environment causes the tree to die more quickly.13 When the animals grazing in an area eat the plants completely away, the bare soil isleft exposed to the erosive forces of wind and rain. This is also the case when treesare removed by deforestation. The root systems of plants hold the soil together andact as a protective agent against erosion.14 Rabbits, cane toads, foxes, horses, feral cats and prickly pear are just some of theintroduced species that have proven extremely damaging and hard to control. It isdebatable which one has caused the most damage as each has created a problem thatis significant in its own environment.15 The more food sources available to each organism, the less stress they are placedunder should one particular food item become scarce.16 Industry and transportation rely primarily on the burning of fossil fuels such as coaland petroleum products, which release carbon dioxide, methane, nitrous oxide andozone into the air. This has led to the enhanced greenhouse effect.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 617 a Short-term measures include:− physically removing as much of the oil as possible from seashores andaffected wildlife− preventing the oil from spreading. Skimmer booms are used on watersurfaces.b Long-term measures include:− reviewing the laws of how oil can be transported− reviewing oil tanker routes.18 An endangered species is one that will be lost from the ecosystem if steps are nottaken to stop those factors that are causing population numbers to be depleted. Anextinct species is one that is no longer present in any ecosystem on the Earth.19 Frogs are very susceptible to pollutants, and are usually the first organisms to showthe effects of pollution in the environment.20 For example, improved automobile mileage with a reduction in the amount ofpollution in exhaust emissions; reforestation projects; greater use of solar and windpower; more energy-efficient homes; and greater use of public transport.Skills21 Diagrammatic answer required.22 Many possibilities with such a large population, eg more deforestation, morepollution, global warming, less food, more extinction of species.Chapter 6 review questionsSummary questions1 Abiotic factors: the temperature, the humidity, the amount of oxygen in the air.Biotic factors: family and friends, the plants and animals that are around us.2 Temperature is an abiotic factor.3 a Animals that catch and eat other animals are called predators.b You would expect them to have sharp teeth for catching and tearing their food;they would have either speed and agility to catch their prey, or some form ofcamouflage that would allow them to sneak up on their prey. Some have false‘lures’. They might use ‘tools’—perhaps a web (spiders)—or work incooperative packs. They would probably have well-developed senses fordetecting their prey, ie good eyesight and/or good hearing.4 A pollutant is something that causes the environment to be unhealthy.5 Biodiversity refers to the number of different species that live in an ecosystem. Highbiodiversity means that there are many different species present; low biodiversitymeans that there are few different species present.6 a True. All living things require energy.b False. Carbon dioxide is obtained through the leaves.c True. Chlorophyll is the green pigment found in the leaves of plants.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 6d True. Humans are examples of omnivores.e False. Biodiversity refers to the number of different species (plants and animals)in the ecosystem.7 Phosphorus and nitrogen.8 Deforestation and irrigation cause increased salinisation.9 The term ‘desertification’ means that land that was once vegetated becomes desertlike.10 Four ways scientists can help include:a splitting the population into several groups. This means that if there is anoutbreak of disease, the whole population is not destroyed.b monitoring the organisms on a regular basis so that if help is needed in someway, it can be given quickly.c assisting in the birth of offspring, providing medical help if required.d releasing offspring into protected habitats, where introduced species have beenremoved.11 Human beings rely on the plants and animals around them for life—food, clothing,materials for houses, oxygen.12 An abiotic factor is a non-living factor that has an effect on an organism. A bioticfactor is a living organism, either plant or animal, that affects another.Thinking questions13 Common pollutants found around the schoolyard include food leftovers, which canattract flies and therefore cause disease. They can also include plastic wrappers andlunch bags. When these get into the stormwater drains, they can end up in the oceanand cause great damage to marine life, eg turtles often mistake them for jellyfish andeat them.14 Worms are detritivores, and assist in recycling elements such as carbon andnitrogen. This makes the soil more abundant in nutrients, which helps plants togrow.15 By keeping their leaves above water, water lilies can catch more sunlight, whichhelps them to photosynthesise.16 At deep levels under water, only the blue wavelengths of light can penetrate. Byhaving pigments that can absorb blue light, the algae can photosynthesise at a lowerdepth.17 The more chlorophyll the leaves contain, the more photosynthesis can take place.Plants having this feature can live in an environment that has less light.18 A range of behaviours in catching prey allows the carnivore to have the element ofsurprise when searching for food.19 This is fair, because not all animals need the same amount of food.20 By having a varied diet, the bilby has a greater chance of survival should any one ofthe foods it eats be removed from the ecosystem. Food sources are removed by fire,disease, human.21 By removing the plants, feral pigs are also removing the root systems which holdthe topsoil together. This causes erosion.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 622 Increased biodiversity makes a community more adaptable to change. When oneorganism is removed from the food web, there is a greater chance that the otherorganisms that relied on it for food will be able to find something else to eat.23 The fungus is in a symbiotic relationship with the orchid. It provides the food for theorchid, while the orchid provides a frame for it to live on and water via its roots.Interpreting questions2415 Elizabeth Street (microhabitat)Broken HillNew South WalesAustraliaEarth(habitat)(biome)(biogeographical)(biosphere)25 a Those biomes that lie adjacent to the equator mainly have equatorial and tropicalrainforest biomes and some tropical savanna grasslands.b Plant life would be similar in all equatorial regions as the climate is tropical andwould mainly contain species typical of rainforest biomes.26 A species that lives in a specialised habitat has no other place to live if that habitat isharmed in any way. Species that can live in a variety of habitats have a better chanceof survival in adverse conditions.27 At each level of the food chain energy is lost. So the number of plankton needs to bemuch larger than the number of seals, hence the one seal shown in the food pyramid.28 Diagrammatic answer required.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 7Unit 7.1 Plant transport systemsCheckpoint1 Carbon dioxide and water are converted into glucose and oxygen in the presence ofsunlight.2 Carbon dioxide enters the leaf and oxygen leaves the leaf. Water is transported inand out of the leaf. Glucose is transported from the leaf to other parts of the plant.3 a Water is conducted up the plant stem through the xylem.b Glucose is transported around the plant in the phloem.c Xylem and phloem are grouped together in vascular bundles.d New xylem and phloem cells are made from cambium.4 a Phloem.b Xylem.5 Pressure in the roots pushes the water up and evaporation from the leaves sucks thewater upward.6 When plant cells lose water, the pressure in the cells decreases and the plant wilts(becomes flaccid).7 When there is sufficient water, the plant cells are under enough pressure to remainfirm or turgid.8 Phloem cells lie just under the bark and may be damaged by ringbarking. Thiscould kill the plant as nutrients are carried in the phloem cells.9 Xylem cells.Think10 Carbon dioxide from the air enters the leaves of the plant providing a source ofcarbon. In the leaf, carbon dioxide is converted into glucose, which is transported toother parts of the plant and stored as starch or cellulose. These compounds contain alot of carbon.11 Phloem cells.12 Water enters the stem, moves up the plant, enters and fills the plant cells, enablingthe stem to stand up right rather than wilt.13 Plants need photosynthesis in order to obtain food. Sunlight is essential forphotosynthesis so plants will face the Sun to receive maximum sunlight.14 The leaves do not directly face the Sun as they are hanging down. This reduceswater loss. It also allows both sides of the leaf to receive a good amount of light,maximising photosynthesis.15 Removing leaves from a plant will prevent evaporation of water from its leaves.This in turn will reduce water being drawn up through the stem. This will cause theplant to wilt.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 716 Needle-shaped leaves have smaller spaces through which water can escape. This isan adaptation which enables the plant to lose less water.AnalyseSunlight, chlorophyll17 water + carbon dioxide → glucose + oxygen18 About 15 growth rings are evident in the top left trunk, making the tree about 15years old.19 The root hairs are very numerous. This would result in a large increase of surfacearea, allowing a large amount of water to be absorbed.Unit 7.2 Photosynthesis and respirationCheckpoint1ScientistsDiscoveriesPriestleyOxygen is produced.IngenhouszLight is necessary.SenebierCarbon dioxide is used.de SaussureWater is used.2 a False.b False.c True.d False.3 Chlorophyll is needed because it contains chemicals that trap the correct amount ofthe Sun’s energy needed for photosynthesis.4 Light energy is converted to chemical energy.5 All living things require food in the form of glucose. Plants are able to produceglucose from carbon dioxide and water. Animals cannot do this so they aredependent on plants and therefore photosynthesis.6 a Carbon dioxide and water.b Chlorophyll and light.c Glucose and oxygen.7 To provide energy for animal cells.8 Carbon dioxide, water and energy.9 Lavoisier found that humans, as well as guinea pigs produce heat by ‘burning’ food.10 Other experiments that have supported Lavoisier’s findings include:• placing a mouse in a bell jar to measure how the oxygen and carbon dioxidecontent changes© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 7• providing a mouse in a bell jar with a fuel other than glucose (such as fat) todetermine how efficiently the fuel is used.11 The products of photosynthesis become the reactants for respiration.12 Photosynthesis occurs in chloroplasts and respiration occurs in mitochondria.Think13 Photosynthesis does not occur as one reaction. There are many enzymes required tospeed up the individual chemical reactions that go together to make up the overallequation of photosynthesis. It is not possible to cause these individual steps tohappen in one test tube.14 Growth and repair.Analyse15 a Starch.b No blue/black colour.c No photosynthesis occurs because no carbon dioxide is available.d To remove any previously stored starch.16 a H 2 O + light energy → O 2 + H +b CO 2 + H + → C 6 H 12 O 6c Stage one.17 a Photosynthesis.b More light energy is available, so a greater rate of photosynthesis occurs.c For example, higher carbon dioxide level, higher temperature.18 a Reactions speed up at higher temperatures.b Enzymes are affected at high temperatures. If they are altered, enzyme activityslows and finally stops.19 a Oxygen.b Oxygen relights a glowing splint test.c 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2 (chlorophyll and light needed).d More gas would be produced by the larger plant mass.Unit 7.3 LeavesCheckpoint1 a True.b False.c True.d False.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 72StructuresEpidermisCuticleStomataGuard cellsMesophyll cellsPalisade cellsXylem cellsFunctionsOuter layer of cells of the leaf.Waxy, waterproof covering of the leaf.Allow gases to enter and exit the leaf.Control the size of openings in the leaf.Loosely packed cells with air spaces between them.Tightly packed cells containing large numbers ofchloroplasts.Specialised water-conducting cells.3 Palisade tissue.4 a Stomata.b Guard cells change shape to close the stomata.5 a Water via xylem cells, carbon dioxide by diffusion through stomata.b Glucose via phloem cells, oxygen by diffusion through stomata.6 a Green.b We know that green is not absorbed as the plant looks green. The green light isreflected to our eye making the plant appear green.c Red and blue.7 Xanthophylls, carotene.8 Red, yellow and orange accessory pigments in autumn leaves remain afterchlorophyll is broken down.9 Plants are found in surface layers, additional pigments.Think10 Gases are more easily able to diffuse in and out of the leaf.11 Allows maximum exposure to sunlight.12 a Prevents water loss; protects from bacterial and fungal invasion.b It does not allow gases to pass through it.13 Accessory pigments become visible when chlorophyll is broken down.Skills14 Diagrammatic answer required.15 a X, the palisade cells as they have a higher concentration of chloroplasts.b Oxygen is the gas moving in the direction of the arrow. This is produced byphotosynthesis and exits the leaf to enter the air.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 7Chapter 7 review questionsSummary questions1 Photosynthesis is the process in which plants make their own food, using energyfrom the Sun and chlorophyll to convert carbon dioxide and water into glucose andoxygen.2 a Water in the roots.b Thick walls of xylem vessels, and water in cell walls.3 Glucose and starch.4 a 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2 (chlorophyll and light needed).b Converts light energy to the chemical energy needed by all living things.Replaces the oxygen used in respiration.5 Dead xylem cells.6 a Light intensity, carbon dioxide concentration and temperature.b More light provides more energy. Carbon dioxide is a reactant. Increasingreactant concentration increases rate. Higher temperatures usually mean fasterreactions.7 For respiration and for conversion to other substances such as starch and cellulose.8 Plants photosynthesise during the day and respire at all times of the day and night.9 a Starch.b Glycogen.Thinking questions10 Xylem carries water and minerals, while phloem carries food.11 Chemosynthetic bacteria also convert carbon dioxide and water to glucose andoxygen, but use energy from a chemical reaction rather than light energy.12 The stages in each process are not the reverse of each other. They involve differentsteps and different enzymes. Even though the overall equation is the opposite thereactions that take place are quite different.13 Refer to the comparison table and equations for respiration and photosynthesis onpage 195 of Science Focus 2.14 Autumn leaves have accessory pigments that are left behind as the leaf dies.15 See Unit 7.2, Prac 2 Green leaves and photosynthesis, on page 198 of Science Focus2.16 Plants in the desert will have less stomata to conserve water.17 Similarity: product and reactant names are the same. Difference: photosynthesis inplants but not animals.Interpreting questions18 a viib iv© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 7c id ve iif vig iii19 a C and D.b B, C and D.cB—respiration occurring to produce carbon dioxide (no photosynthesis to lowercarbon dioxide).d D—oxygen is produced, but there are no fish present to use it up.20 a Water levels, carbon dioxide concentration and temperature.b Plant C, because red light is most strongly absorbed by chlorophyll. More lightmeans more photosynthesis.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 8Unit 8.1 Space rocksCheckpoint1 Minor planet.2 In the asteroid belt between Mars and Jupiter.3 a One metre to hundreds of kilometres.b One kilometre or more in diameter.4 Firestorms, earthquakes and tsunamis.5 a A shooting star forms when a meteoroid burns as it enters the Earth’satmosphere.b A meteor is a burning meteoroid.c Meteorites burn on impact with the Earth’s atmosphere.6 Several meteors travelling together.7 Meteors appear to come from one point called a ‘radiant’ and are named after theconstellation in which the radiant is located.8 A comet is a snowball made of ice mixed with a large amount of dust, frozen carbondioxide and organic matter. Comets are a few kilometres in diameter and orbit theSun.9 a False.b True.c True.d True.10 2062.11 Comets have a dark outer layer, making their presence difficult to detect.12 Deflect the comet by exploding a nuclear device near it.Think13 a Astronomy is the study of the universe.b A shooting star is not really a star.c Meteors and meteorites are both meteoroids.d All meteorites hit the ground.e Meteors may be caused by comets.14 They end in ‘ids’.15 Asteroids of the order of metres in size do not cause widespread damage whereasthose of the order of kilometres can cause major catastrophes.16 With a diameter of 930 kilometres it was large and easily visible.17 It would collide with the Trojan group of asteroids.18 The dust is attracted more towards the Sun than the gas is, so two tails are formed.19 Jupiter’s size and strong gravity may cause a space rock to hit it instead of the Earth.20 They are easier to spot against a white background.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 821 The Earth and Psyche may have been formed from the same material when the solarsystem was formed, or perhaps Psyche was made when another object smashed intothe Earth.22 Diagrammatic answer required.23 a The crater is many times bigger than the meteorite that caused it.b It disintegrated into smaller particles, which were largely dispersed into theatmosphere in a dust cloud.Skills24 a 43 000 kilometres.b One-tenth the distance to the Moon.Unit 8.2 The night skyCheckpoint1 The Sun and Alpha Centauri.2 42 000 000 000 000 kilometres.3 The distance light travels in one year.4 Approximately 9 500 000 000 000 kilometres.5 Celestial means ‘of the sky’.6 An imaginary globe surrounding the Earth on which we imagine the stars to be.7 Because the Earth rotates.8 The ecliptic is the line followed by the Sun as it moves across the sky. It helpsdistinguish between the skies of the southern and northern hemispheres.9 A constellation is a group of stars, eg the Southern Cross, Aquarius.10 Crux.Think11 c suns (stars) are mostly visible.12 Because of the curvature of the Earth.13 a Scorpius.b Triangulum Australe.c Pegasus.d Hercules.14 a Hydra.b Phoenix.Analyse15 Diagrammatic answer required.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 8Skills16 a 64 000 000 000 000 years.b 6 400 000 000 000 years.c 640 000 000 000 years.d 159 817 years.17 147 light years.18 Various answers, eg Achernar, Vega.19 a Diagrammatic answer required.b Diagrammatic answer required.20 +2, 0, –0.5, –1.21 See Figure 8.2.5 in Science Focus 2.22 Distance sound travels in one second = 330 metres. In one minute is 60 × 330metres = 19800 metres = 19.8 km per minute. In one hour is 60 × 19.8 km = 1188km per hour. Distance light travels in a day is 24 × 1188 km = 28 512 km per day.Distance light travels in a year is 365 × 475.2 = 10 406 880 kilometres per year orone sound year = 10 406 880 kilometres.Unit 8.3 The Milky Way and other galaxiesCheckpoint1 A vast quantity of stars held together by gravity.2 Barred spiral, spiral, elliptical, irregular.3 a Quasar.b Radio galaxy.4 a The Milky Way galaxy is a spiral galaxy.b The Milky Way galaxy contains over 100 billion stars.c The Earth is located away from the centre of the Milky Way galaxy.d Omega Centauri is a globular cluster than can be seen with the naked eye.5 It is flat and looks like two dinner plates facing each other.6 The Earth is located in one of the spirals in the outer region of the Milky Way, about30 000 light years from the centre.7 It exhibits unusual activity in its centre.8 Quasar, radio galaxy.9 a Keck.b Hubble.c The Australian compact array near Narrabri.10 It provided information about the size, composition and movement of stars andgalaxies.11 The Milky Way galaxy is part of a group of more than thirty galaxies known as ‘theLocal Group’. This in turn is part of the ‘Local Supercluster’.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 812 Planets, stars, galaxies.Think13 To reduce the amount of interference by particles in the atmosphere.14 Light from a celestial object does not have to pass through any atmosphere.15 By collecting more light using a dish, and over a long period of time.16 Because light from a galaxy may take billions of years to reach the telescope whichproduces the image.Analyse17 a Spiral.b Irregular.c Barred spiral.d Elliptical.Skills18 Diagrammatic answer required.19 Diagrammatic answer required.Unit 8.4 Satellites and remote sensingCheckpoint1 Various answers, eg Mercury, Venus, Earth.2 Diagrammatic answer required.3 Telephone calls, television signals, Internet data.4 Intelsat 5 is a satellite in a geostationary orbit 35 900 kilometres above the Earth. Itis capable of relaying communications information rapidly around the globe.5 Sensors mounted onto satellites can study and monitor the Earth’s features.6 False colour is added to computer images to make various parts of informationclearer.7 a Images, temperature, pressure and humidity data, etc.b Land clearance, ocean temperatures, crop health, extent of floods and mineraldeposits, etc.8 Electronic maps, locating position.9 Observing the solar system.10 Panoramic cameras, spectrometers, magnets, a microscope.11 Easier and more cost-effective than sending humans. Remote-sensing spacecraft canbe smaller, do not need to provide food, air or accommodation and they do not needto return to Earth. Able to collect huge amounts of information.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 8Think12 It must be a geostationary one.13 Geostationary satellites are above the same point on the Earth, which means theywill not move out of range and lose contact during a communication. They alsoboost the signal to make sure it is clear. They allow communication over very longdistances with little delay as the message travels at the speed of light.14 a Solid fuel booster rockets fall into the Atlantic Ocean.b The main stage rocket disintegrates in the atmosphere.15 So all parts of the Earth have GPS coverage.16 It would slow down, burn up and fall to the Earth.17 Sunlight can reach them without having to penetrate the atmosphere.18 So that its signal can be received by a receiver in a fixed position on the Earth.Skills19 Diagrammatic answer required.Chapter 8 review questionsSummary questions1 Asteroids are irregularly shaped rocky objects; they are covered in craters and rangein size from 30 metres to over 900 metres.2 Meteor showers are named after the constellation in which the radiant is located.3 Comets are huge, dirty snowballs which form a head and two tails when near theSun.4 A comet can be a threat as it is dark in colour and can be difficult to see until lit upby the Sun.5 Light years are used, ie the distance travelled by light in a year (9.5 trillionkilometres).6 Right ascension is measured in hours and describes how far around the celestialequator a star is. Declination is the angle in degrees we then move to locate a star.7 Civilisations 5000 years ago aided their memories of star patterns by naming themafter mythical beings and animals.8 Observe objects in space, collect experimental data and analyse using computers,command space missions, pilot space shuttles.9 Elliptical, spiral, barred spiral, irregular.10 Quasar.11 Visible light, radio waves.12 Geostationary orbit, asynchronous orbit, polar orbit.13 Many answers possible, eg weather patterns, shape of land surface, trackinganimals, nagivation.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 814 Information can be received quickly and accurately about position on the Earth.Thinking questions15 Twin robot geologists equipped with sensors and tools that enabled information tobe collected about Mars.16 a Comet.b Meteor.c Asteroid.17 A meteorite is a meteor that hits the Earth.18 a Many more stars are visible in the country.b Light from stars in the country is less obscured by pollution and city lights.19 It remains in the same position.20 Nebulae.21 A pulsar is a star that emits a stream of radio waves, while a quasar is a galaxy(huge collection of stars) with a very bright centre.22 All are satellites.Interpreting questions23 Diagrammatic answer required.24 RA 23h and DEC 30°.25 Those of the zodiac.26 Diagrammatic answer required.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9Unit 9.1 Teamwork and topicsCheckpoint1 Surgical team, construction workers, newspaper production.2 a False.b False.c True.3 a Being able to plan an investigation—this allows you to describe a problem anddevelop a hypothesis.b Being able to carry out an Internet search—allows you to access any materialthat has been done previously.c Being able to think creatively—having an imagination will allow for varyingways of solving any problems.4 Varying answers depending on student—refer to Science Focus 2 page 234 andFigure 9.1.2.5 Varying answers depending on student—refer to Science Focus 2 page 234 andFigure 9.1.2.6 The team would not function as everyone will be doing the same thing. For exampleif everyone was a researcher then there would be no actual first-hand investigations.7 Archimedes would be an explorer/creator due to the fact that he solved problems inunusual ways at unusual times.8 a It is a problem that can not be answered with a yes/no or true/false.b Which ball bounces the highest—a golf ball or squash ball, and by what amount.9 a Do 12 eggs make a dozen?b Are all chicken eggs brown?c How many days are there in December?d What is the first colour in a rainbow?10 Closed question.11 Various answers.Think12 Varying answers depending on student—refer to Science Focus 2 page 233.13 Varying answers depending on student—refer to Science Focus 2 page 233.14 Sapper would be an explorer.15 Varying answers depending on student—refer to Science Focus 2 page 234 andFigure 9.1.2.16 Closed question—Is a basketball larger that a tennis ball? Open-ended question—What factors affect the bounce of a tennis ball?© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9Unit 9.2 Planning your investigationCheckpoint1 a False.b True.2 This will allow you to gather information about what other scientists have foundabout your question or problem.3 Why was the information written and when was the information gathered and bywhom?4 A variable is a factor that can change in an experiment.5 A hypothesis is a prediction or ‘educated guess’ about what you may find in anexperiment. A hypothesis is something that can be tested by an experiment.6 The aim outlines what a team wants to investigate whereas a hypothesis is aprediction of what may be found in the investigation.7 The three types of variables are:• independent variable: the variable that is changed• dependent variable: the variable that is being measured• controlled variables: the variables that are kept the same throughout anexperiment.8 You should change only one variable in an individual experiment.9 The experimental procedure should include:• a title• an aim• a hypothesis• a list of variables• a list of equipment that you will need• a step-by-step outline of what to do• an outline of how results or observations are to be recorded. This could includeusing a chart, table, photographs, description or other recording method.10 Your experimental method should be repeated a number of times so that a moreaccurate conclusion can be made. If you are collecting numerical data, thenrepeating it will allow an average to be calculated. This is more accurate than just aonce off.Think11 a Probably reliable—.net tells you it is a public network and .au that it is anAustralian site—but you need to find out more about who produced the site andwhere they got their information.b Unreliable—the ~ indicates it’s a personal site of billbembers and may reflectbiased views of the members.c Could be reliable—edu.au tells you that it is an Australian education site, butyou need to find out more about who produced the site and where they got theirinformation.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9d Reliable—csiro.au tells you that it’s the site of the CSIRO, an Australiangovernment-backed scientific research organisation that bases it findings onscientific evidence.e Unreliable—boycottwoodchipping tells you that the site only has one viewpoint.f Reliable—gov.au indicated that it is an Australian Government site.12 The web address will give you an indication but by checking information on anumber of sites will allow you to determine accuracy.Analyse13 a Other variables that may be controlled include the mass of the egg, the shape ofthe egg.b Appears to have the required design features.c Possibly the experiment could have been repeated more times.Skills14 a Aim: To evaluate the effect of two months sunlight on various types of plastic.b Aim: To find the growth of seedlings over a three-week period that are fed withdifferent brands of fertiliser.c Aim: To find the bounce height of a tennis ball at different temperatures.d Aim: To test different shaped dog bowls and measure how much waterevaporated from each over three days.15 a Experiment 1i independent variable—types of plasticii dependent variable—effect of sunlight on plasticiii controlled variables—position in Sun, time.b Experiment 2i independent variable—different brands of fertiliser.ii dependent variable—growth (height) of seedlings.iii controlled variables—amount of fertiliser, type of seedling, amount of waterand sunlight, position in Sun.c Experiment 3i independent variable—temperature of tennis ballii dependent variable—height of bounceiii controlled variables—type of tennis ball, surface bounced on, height ofrelease.d Experiment 4i independent variable—different shaped drinking bowlsii dependent variable—amount of water evaporated from bowlsiii controlled variables—amount of water in bowl at start, position of bowl inSun, time, temperature of water at the start.16 a The alcohol contains more energy than methylated spirits.b The Bio Battery was the best value battery for use in a torch.c Fast paste was the strongest glue when gluing icy-pole sticks together.17 a Aim: To test the effect that different amounts of fertiliser have on tomato plantgrowth.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9b Hypothesis: The greater the amount of fertiliser the greater the growth.c Independent—amount of fertiliser, dependent—height of plant.d Controlled variables—amount of water, position in and amount of sunlight,height of original plant, type and amount of soil, type and size of pot.e Observations—height of plant, colour and number of leaves.f Height of plant, number of leaves.g Method:i Plant the 20 tomato seedling into identical plastic pots.ii Measure the height of all plants and record.iii Make up solutions of 1 per cent, 2 per cent, 5 per cent and 10 per cent of thefertiliser and pour 20 mL of each into five different pots.iv Place all pots in the same area, and record their heights every day for oneweek.v Need 4 tables—1 for each fertiliser solution strength.hDay %fertiliser1Plant 1(cm)Plant 2(cm)Plant 3(cm)Plant 4(cm)Plant 5(cm)234567Unit 9.3 Testing and evaluationCheckpoint1 Results or data that are numerical (with numbers) are called quantitative, as theyusually measure amounts or quantities. Observations that are a written as adescription or recorded as a picture or diagram are called qualitative.2 Different types of measurements can be how tall something is, the time for achemical reaction to occur or the time it takes.3 Different types of observation could include the colour of a reaction, a smell of achemical or whether there was a sound released during the experiment.4 The hypothesis, variables and procedure should be reviewed to see if theexperimental design could be improved.5 Other things that may be recorded include the time of day and the air temperature.6 a Dependent variables.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 97 You may include the following: any trends or patterns that occur in your results,whether you need to calculate averages, how to present your data or observations toshow any patterns or trends and how accurate your results were.8 The title is the discussion.9 The following should be included in your conclusion: whether your team’shypothesis was right or wrong, what data or observations showed your hypothesis tobe wrong/right, any experimental errors or mistakes that affected your results andother important things that your team learnt.10 The final section is where you include a list of any resources used during yourresearch. This is sometimes called a bibliography.Think11 Experimental errors are things that are unavoidable, whereas mistakes are things thatcould have been avoided if you took a little more care.12 Graph types may include: line, column, histogram, pie or bar graphs.13 Since it was an initial ‘educated guess’ if it is incorrect you still have learntsomething.Analyse14 a Their discussion is good as it covers all aspects, including how the experimentcould be improved.b Possibly define what indicated a cracked egg, eg were very fine cracks accepted?c The discussion is very good as it covered the main points required.15 a The conclusion covered most of the important points but failed to include theerror that occurred in the experiment using two layers of bubble wrap.b An indication of the above mistake.c Our experiment supported the hypothesis that the amount of bubble wrap aroundan egg will stop it breaking when dropped 5 metres. Three layers of bubble wrapwill prevent a raw egg from breaking. None of the five eggs protected by thisamount of bubble wrap were damaged. Since we observed cracking andbreakage in the one and two layer tests, it is apparent this amount of packagingis not sufficient to protect the egg. Experimental error affected our results. In test3A it was found that the bubble wrap had been used for a second time.Additionally, design errors were found to have been present. The styrofoamprotective package was only designed for a maximum of two layers of bubblewrap.Skills16 a The results do not show that brown sugar dissolves faster than white. The timesfor brown sugar was 2 seconds more than for white sugar.b Yes, because the time for sugar cube dissolving was five times longer than foricing sugar.c No, there is no specified amount for either.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9d The volume of water should be measured with a measuring cylinder and themass of sugar should be measured using a balance to accurately weigh thecorrect amount.e The temperature of the water needs to be kept constant, the amount of stirringshould be controlled and the tests should have been repeated at least five times.f Various answers but should address the above problems.17 a See column 2 of table below.b See final column of table below.cTime taken for egg to fall (seconds)dParachutesize (cm)Area ofparachute(cm 2 )Test 1 Test 2 Test 3 Averagetime0 0 0.5 0.6 0.5 0.515 x 15 225 2.6 2.4 2.5 2.525 x 25 625 4.8 4.4 4.6 4.635 x 35 1225 6.7 6.4 6.5 6.545 x 45 2025 8.5 8.4 8.4 8.4Area vs time for parachute fall2500Area of parachute (cm 2 )20001500100050000 2 4 6 8 10Average time (s)efAs the area of the parachute increases, the time taken to fall increases also.The larger the area of the parachute, the longer the time taken for it to reach theground.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9Chapter 9 review questionsSummary questions1OrganiserScientistLeaderResearcherExplorer/CreatorLikes organisation and planning and is a hard worker wholikes to get things done.Provides explanation on how things work and is good at usingequipment.Keeps the team together, and make sure goals are met.Provides information from many sources and is a goodcommunicator.Uses imagination to create new ideas and looks for better waysto do things.2 a True.b False.c True.d False.e False.f True.g False.h True.i True.3 To control variables they must be kept the same throughout an experiment.4 Title, aim, hypothesis, equipment or materials, method, results and observations,discussion or analysis, conclusion, bibliography.5 • The colour of new chemical formed.• Any smells that may have been released by a reaction.• The sound made during and experiment.• A description of a shape change.6 • The volume of a gas released.• The temperature rise due to a reaction.• The angle of a ramp.• The weight of an object.• The time it takes for something to happen.7 The analysis should include the following: any trends or patterns that occur in yourresults, whether you need to calculate averages, how to present your data orobservations to show any patterns or trends and how accurate your results were.8 A good conclusion should include: whether your team’s hypothesis was right orwrong, what data or observations showed your hypothesis to be wrong/right, anyexperimental errors or mistakes that affected your results and other important thingsthat your team learnt.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9Thinking questions9 The relationship is that when the independent variable is being changed, it causesthe dependent variable to change also.10 a Open-ended.b Open-ended.c Open-ended.d Open-ended.e Closed.f Open-ended.11 • Aim: To investigate whether amount of sunlight affects the growth of plants.• Hypothesis: That the plants in a dark cupboard will have less growth.Interpreting questions12 a Aim: To find the best hat for keeping your head warm.b Independent—type of hats.Dependent—the temperature of bottles of hot water.c Controlled variables—temperature of water in bottle, shape and size of bottle,material the bottle is made from, amount of the hot water, outside airtemperature.d To control these variables, measure the temperature of the water, use the sametype and size of bottle and do the experiment inside a room.e The best hat is the one that has the bottle with the highest temperature after afixed time or the hat that takes the longest time to reach a specified lowertemperature.13 a The colour of the light reaching the plants.b The increase in height of the plants.c The amount of light and water to the plants. The height of the original beanseedling and the size of the pot.d The plant exposed to green light grows more rapidly than those in blue and redlight.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.

Answers to coursebook questions Chapter 9e1614Growth vs light colourHeight (cm)12108642RedGreenBlue0Day 0 Day 2 Day 4 Day 6 Day 8 Day 10f The plant exposed to red light grew the most, the green light plant not as muchand the one exposed to blue light stopped growing somewhere between 2 and 4days.g Conclusion: The hypothesis was rejected because the red light was the bestcolour for the growth of bean seedlings and blue the worst.h The results cannot be relied on as they only represent the growth of one plantand there is no control using white light.ijIt is a fair test if it was repeated a number of times to confirm the initial results.The improvements would include a control using white light and to repeat theexperiment a number of times with various different plant seedlings. The amountof light reaching each plant needs to also be controlled, not only the colour.14 a The amount of bubble wrap.b Survival of the egg.c The number and size of the helium balloons.d Three helium-filled balloons and one layer of bubble wrap will stop an eggbreaking when it is dropped from a height of 5 metres.e Procedure:i Measure a height of 5 metres where the egg can be safely dropped.ii Place a new egg in a plastic bag and seal it with a twist tie.iii Wrap the egg in two layers of bubble wrap.iv Secure the wrapped egg in the polystyrene foam outer container.v Secure one helium-filled balloon to the container.vi Release the wrapped egg and balloon, repeating the drop five times.vii Record the results.viii Increase the number of helium balloons to two then to three, with theexperiment being repeated.© Pearson Education Australia (a division of Pearson Australia Group Pty Ltd) 2005.This page from the Science Focus 2 Teacher’s Resource on CD may be photocopied for classroom use.