8E TEACHER GUIDE.pdf - swallowhillresources

8EIn the drink8EThis unit uses the context of safe water supplies to introduceand develop the idea that many everyday substances areactually mixtures and that these mixtures can be separated,using a variety of techniques, to produce useful materials.We recommend between 7.5 to 9 hours teaching time for this unit.From KS2 previous units most pupils will:• be able to explain why undissolved solids can be separated froma mixture by filtering• know that solids remain in the solution when they dissolve• know that a dissolved solid can be recovered by evaporation.This unit builds on ideas introduced in the QCA Scheme of Work forKS2: Unit 4D Solids, liquids and how they can be separated, Unit5C Gases around us, Unit 5D Changing state, Unit 6C More aboutdissolving and Unit 6D Reversible and irreversible changes.The unit considers ideas about mixtures in terms of differentmixtures that pupils should find familiar, in order to show the rangeof mixtures present in the world.• Topic 7Ha introduces the idea that the water we get from ourtaps has to be treated to make it clean, and then revisits mixturesand dissolving, which pupils will have met in KS2. Could levelwork looks at how our drinking water is treated.• Topic 7Hb looks at the particle model of matter to explaindissolving, filtering and the conservation of mass, and then looksat saturated solutions, and the effect of temperature on solubility.There is an optional Investigation Attainment Target 1 on theeffects of temperature on solubility. A set of level descriptions isprovided in the ASP. Could level work on the solubility of gases isprovided.• Topic 7Hc focuses on the evaporation of water from solutions andthe process used to do this in the laboratory, and also how this isapplied to the production of salt from brine. Could level work isprovided on Gandhi and the Salt Act.• Topic 7Hd focuses on chromatography and its applications. Couldlevel work looks at DNA ‘fingerprinting’.• Topic 7He looks at distillation, including an explanation of whyit works in terms of particles. Could level work is provided onwater supplies and desalination, and on fractional distillation. Theunit finishes with a discussion of whether and how we shouldconserve water supplies in the UK.ExpectationsKey conceptsAt the end of this unit…All pupils must:(WTL4) Recognise that we need safe drinking water.(L4) State that water is treated before being supplied to homes.Most pupils should:(L5) Use the particle model to describe what happens whensomething dissolves.(L6) Use the particle model to explain why mass is conserved whensomething dissolves.Some pupils could:(L7) Describe some of the human and environmental effects ofsupplying large quantities of water.(L7) Use particle models to explain how mixtures are separated bydistillation.(L8) Explain how the challenges of supplying and conserving waterare overcome when demand increases.Key processesAt the end of this unit…All pupils must:(WTL4) Measure temperature and mass.(WTL4) Use heating equipment safely.(L4) Identify patterns in data.(L4) Carry out filtering and chromatography safely in the laboratory.(L5) Describe how to obtain salt from rock salt.Most pupils should:(L5) Describe how to separate simple mixtures using filtration andchromatography.(L5) Present data from investigations as line graphs.(L5) Carry out evaporation and distillation safely in the laboratory.(L5) Explain what a chromatogram shows.Some pupils could:(L6) Point out patterns in their data using a line graph.(L6) Use patterns in data to make predictions.(L7) Evaluate experimental methods, explaining their strengths andweaknesses.Range and contentAt the end of this unit…All pupils must:(WTL4) Recall that mixtures can be separated.(L4) Recall some ways of conserving water supplies.(L4) Recall some examples of the uses of different separatingtechniques.(L5) Describe what happens in dissolving in terms of particles.(L5) Explain what a saturated solution is.(L5) Recall that solutes that are insoluble in water may dissolve inother solvents.Most pupils should:(L6) Describe how salt can be obtained from mines.(L6) Describe some of the ways in which water is treated beforebeing piped to our homes.Some pupils could:(L7) Describe how solubility increases with increasing temperaturefor most solutes.(L8) Explain how fractional distillation works.(L8) Describe how the solubility of gases changes with temperature.For a list of updated and vetted websites that can be used tosupport your teaching of this unit please visit the ExploringScience: How Science Works E-Forum (http://groups.google.co.uk/group/exploringscience.134Exploring Science edition © Pearson Education Limited 2008

In the drink8E8E NC statements coveredFrom KS2Sc3 2aSc3 2dSc3 3aSc3 3bSc3 3cSc3 3dSc3 3eStatementAt KS31 Key concepts1a2a2bTo describe changes that occur whenmaterials are mixed.About reversible changes, includingdissolving, melting, boiling, condensing,freezing and evaporating.How to separate solid particles ofdifferent sizes by sieving.That some solids dissolve in water to givesolutions, but some do not.How to separate insoluble solids fromliquids by filtering.How to recover dissolved solids byevaporating the liquid from the solution.To use knowledge of solids, liquids andgases to decide how mixtures might beseparated.StatementUsing scientific ideas and models to explainphenomena and developing them creatively togenerate and test theories.Exploring how the creative application ofscientific ideas can bring about technologicaldevelopments and consequent changes in theway people think and behave.Examining the ethical and moral implications ofusing and applying science.2 Key processes1a1b1c2a2b3aStatementUse a range of scientific methods and techniquesto develop and test ideas and explanations.Assess risk and work safely in the laboratory, fieldand workplace.Plan and carry out practical and investigativeactivities, both individually and in groups.Topic8Ea, 8Eb8Ea, 8Eb, 8Ec,8Ee8Ea8Ea8Ea8EcObtain, record and analyse data from a widerange of primary and secondary sources, includingICT sources, and use their findings to provideevidence for scientific explanations.Evaluate scientific evidence and workingmethods.Use appropriate methods, including ICT,to communicate scientific information andcontribute to presentations and discussions aboutscientific issues.AllTopic8Ea, 8Eb,8Ec8Ed, 8Ee8EeTopicall8Ea, 8Eb,8Ec, 8Eeall8Ea, 8Eb,8Ec, 8Ed8Ea, 8Eb,8Ec, 8Ed8Eb, 8Ec,8Ee4 Curriculum opportunitiesacdeghjStatementResearch, experiment, discuss and developarguments.Use real-life examples as a basis for finding outabout science.Study science in local, national and globalcontexts, and appreciate the connectionsbetween these.Experience science outside the schoolenvironment, including in the workplace, wherepossible.Recognise the importance of sustainability inscientific and technological developments.Explore contemporary and historical scientificdevelopments and how they have beencommunicated.Consider how knowledge and understanding ofscience informs personal and collective decisionsincluding those on substance abuse and sexualhealth.Links with other unitsTopic8Eaall8Ea, 8Ee8Ee8Ea, 8Ee8Ed8Ea, 8Ee7G Particle theory. 9B Importance of mineral saltsto humans.8AImportance of mineral saltsto humans.Cross-curricular linksTopic8Ec8EeLinks9DHistory – Gandhi and the Salt ActImportance of mineral saltsto plants.Geography – water (hydrological) cycleSkills opportunities for Personal, Learning and Thinking Skills (PLTS),literacy, numeracy and ICT are included in the individual topicnotes.8E3 Range and content2a4cStatementThe particle model provides explanations for thedifferent physical properties and behaviour ofmatter.Human activity and natural processes can lead tochanges in the environment.Topicall8Ee© Pearson Education Limited 2008 Exploring Science edition 135

8EIn the drinkFramework statements covered by Unit 8E1 How Science Works8E1.1 Explanations, arguments and decisionsCode Framework threads Year 8 Topic1.1b Applications, implications andcultural understanding1.1c Communication for audience andwith purposeRecognise that decisions about the use and application of science andtechnology are influenced by society and individuals, and how these couldimpact on people and the environment.Use a range of scientific vocabulary and terminology consistently indiscussions and written work.Adapt the stylistic conventions of a range of genres for different audiences andpurposes in scientific writing.8Eeall8Ea, 8Ee1.2 Practical and enquiry skillsCode Framework threads Year 8 Topic1.2a Using investigative approaches:planning an approach1.2b Using investigative approaches:selecting and managing variables1.2c Using investigative approaches:assessing risk and working safely1.2d Using investigative approaches:obtaining and presenting primaryevidence1.2e Working critically with primaryevidence1.2f Working critically with secondaryevidence3 Chemicals and material behaviourDescribe an appropriate approach to answer a scientific question usingsources of evidence and, where appropriate, making relevant observations ormeasurements using appropriate apparatus.Describe and identify key variables in an investigation and assign appropriatevalues to these.Explain how to take action to control the risks to themselves and others, anddemonstrate competence in their practical technique.Explain how the observation and recording methods are appropriate to thetask.Describe ways in which the presentation of experimental results through theroutine use of tables, charts and line graphs makes it easier to see patternsand trends.Describe how the patterns and trends in the results link to the conclusionsdrawn and whether the evidence is sufficient.Describe and suggest, with reasons, how planning and implementation couldbe improved.Describe what needs to be considered in the collection and manipulation ofsimple secondary evidence to evaluate the conclusion or interpretation made.Code Framework threads Year 8 Topic8Ea, 8Eb, 8Ec,8Ee8Eb, 8Ec8Eb, 8Ec8Ea, 8Eb, 8Ec8Ea, 8Eb, 8Ec8Eb, 8Ec, 8Ed8Ea, 8Eb, 8Ec3.1 Particle models Apply and use the particle model to describe a range of physical observations. 8Eb, 8EcApply and use the particle model to describe a range of separation techniques. all3.2 Chemical reactions Recognise that materials can be made up of one or more kinds of particles. 8Ea5 The environment, Earth and the UniverseCode Framework threads Year 8 Topic5.1 Changing environment andsustainabilityRecognise simple ideas of sustainable development.8Eb8Ee136Exploring Science edition © Pearson Education Limited 2008

In the drink8E8E Routes through the unitThis page suggests routes through the unit at three different levels, using some of the tasks provided. Many other teaching sequences are possible using the alternative teaching materials and tasks provided orby adding your own materials. We recommend between 7.5 and 9 hours of teaching time for this unit.Topic Level Learning objectives Key words TasksStarter 1, Exploring 1&3, Explaining 1–2,Plenary 3, Homework 1dissolve, filtering, insoluble, mixture,opaque, soluble, solute, solution,solvent, transparent8Ea Must All pupils must: explain what a mixture is and what a solution is; describe how to filter a mixture;explain why filtering works and why it cannot separate soluble solids from a liquid; apply theirknowledge of filtering for a practical purpose; recall that there are a number of liquids that can beused as solvents; explain why we cannot drink sea water.filtrate, residue Starter 1&3, Exploring 1&3, Explaining 1–2,Plenary 2, Homework 3Should Most pupils should: appreciate that some mixtures are easier to separate than others; recall that soluteswhich are insoluble in water may dissolve in other solvents.Starter 1&3, Exploring 1&3, Explaining 1–3,Plenary 1, Homework 4Could Some pupils could: recall some of the ways in which our water is treated before it is supplied to homes;describe different mixtures of solids, liquids or gases.Starter 1, Explaining 1, Exploring 2,Plenary 3, Homework 18Eb Must All pupils must: explain that a dissolved solid breaks up into very tiny pieces; explain how to make asolid dissolve more quickly; recall that there is a limit to the amount of solid that will dissolve in water,and use a graph to find out how this varies with temperature.saturated, solubility Starter 1–2, Explaining 1, Exploring 2,Plenary 2, Homework 2Should Most pupils should: explain why the mass of a solution is the sum of the masses of the solute andsolvent; explain filtering using ideas about particles; recall that the limit of solubility will be different fordifferent solutes; recall that for most solutes, more solid will dissolve when the water is hotter.Starter 1–2, Explaining 1, Exploring 2,Plenary 1, Homework 3Could Some pupils could: recall that all solids dissolve to some extent; be able to use a quantitative definition ofsolubility; recall that gases dissolve in water, and that their solubility changes with temperature.common salt, evaporation, salts Starter 1, Explaining 1–2, Exploring 2,Plenary 4, Homework 18Ec Must All pupils must: recall that water usually contains dissolved chemicals; explain that a dissolved solid canbe obtained from a liquid by evaporating the liquid; carry out evaporation safely in the laboratory.Starter 1, Explaining 1–2, Exploring 2,Plenary 1–2, Homework 2brine, hard water, quality standards,rock salt, soft waterShould Most pupils should: recall that salt can be obtained from sea water by evaporation or from salt mines;explain how to obtain pure salt from rock salt; recall some differences between hard and soft water.Could Some pupils could: recall some facts about Gandhi and the Salt Act. Starter 1, Explaining 1–2, Exploring 2,Plenary 2–3, Homework 2–3chromatography Starter 1, Exploring 1, Explaining 1–2,Plenary 1–2, Homework 18Ed Must All pupils must: recall what chromatography is; be able to make a chromatogram; describe howchromatography can be used to separate colours in inks; interpret a chromatogram to draw a conclusion.chromatogram Starter 1, Exploring 1, Explaining 1–2,Exploring 3, Plenary 1, Homework 2Should Most pupils should: explain how chromatography works and what it is used for; recall that there aredifferent types of chromatography for different applications.Could Some pupils could: recall some applications of chromatography. Starter 1, Exploring 1, Explaining 1–2,Exploring 3, Plenary 1, Homework 3Starter 1–2, Exploring 1, Explaining 1&3,Plenary 1, Homework 1condensing, distillation, pure, steam,water vapour8Ee Must All pupils must: describe what ‘pure’ water is; recall that distillation can be used to separate a liquid fromanything dissolved in it; explain that distillation is evaporation followed by condensation; describe someapplications of distillation; describe some ways in which water supplies can be conserved.Should Most pupils should: be able to explain distillation using ideas about particles. still Starter 1–2, Exploring 1, Explaining 1&6,Plenary 3, Homework 2Starter 1, Explaining 1, Exploring 1,Explaining 4–6, Plenary 3, Homework 3Could Some pupils could: recall some of the human and environmental effects of supplying large quantities ofwater; explain how distillation of sea water provides water in some arid countries; explain that fractionaldistillation works because each liquid boils at a different temperature; recall some of the products madefrom crude oil.8E© Pearson Education Limited 2008 Exploring Science edition 137

8EIn the drink8E8E Background Information8Ea – Using water/The solution is clearDissolving is a topic that is superficially very simple, but canactually lead to some very complex ideas. One of the key ideasto be brought out is that true dissolving will only occur when thesolute is broken down into particles that are too small to be seenwith the naked eye. A common error will be to assume that anyform of dispersion is evidence of dissolving – the fact that ‘soluble’aspirins are often in fact only partially soluble may be a source ofthis misunderstanding. These mixtures are suspensions (though thisword is not used in the Pupil’s Book).Suspended substances may fall to the bottom of the liquid onstanding, or they may, if the particles are small enough, remainsuspended virtually indefinitely. In this case you get a colloidalsuspension, such as an emulsion, gel or aerosol. This is dealt withon Worksheet 8Ea(7).Another common error is the confusion between the meanings ofthe words ‘clear’ and ‘colourless’. The use of ‘clear’ as a descriptionof colourless glass bottles at the bottle bank will not help. In thePupil’s Book the word clear is used to mean transparent, withthe colour of the liquid being an independent description. A fulldescription of the liquid will therefore involve a minimum of twowords (e.g. clear blue, misty yellow, clear and colourless). It mayalso be worth stressing to some pupils the difference between‘colourless’ and ‘white’, perhaps by showing them a test tube full ofwater and one containing milk.Some common models based on solute particles filling up ‘gaps’ inthe liquid have come under critical scrutiny in recent years. At best,they are a gross oversimplification of the actual particle interactions.Particles in a liquid are closely packed, hence the difficulty incompressing a liquid into a smaller volume. These models usuallyoverstate the size of any gaps and/or distort the relative sizes ofsolvent and solute particles (sugar molecules, for example, aresignificantly larger than water molecules).Mixtures are collections of items or substances that have beenbrought together by some physical means and that can beseparated so that each of the constituent parts is obtained. Thisprocess of separation will form the thread through the remainderof this unit, but in every case the method required to separate amixture is a physical one – no chemical reactions are involved andno new chemicals are formed.Filtering is a way of sorting items by size – sieving is an examplethat pupils should be familiar with from KS2 work. Filter papersact in a similar fashion, allowing only tiny particles through andtrapping the rest.Filtering will only separate insoluble solids (which do not dissolve)from the liquid or solvent in which they are found, as dissolvedparticles are small enough to pass through the paper. In a watertreatment plant, filtration can only be used to separate the ‘lumps’from dirty water – floating branches, paper waste, solid humanwaste and particles of soil or dirt. Filtration will not remove thebacteria that live in the water (as they are too small) and it will notremove minerals that are dissolved in it.8Eb – SolubilityTechnically, solubility refers to the amount of solute that willdissolve in a particular mass or volume of solvent. In this topic, theonly solvent used is water, and the overwhelming majority of dataavailable will relate to aqueous solutions. There are potentially alarge number of possible combinations of mass and volume unitsin which solubility can be expressed, and the resulting values willbe concentrations, typically expressed in grams of solute per 100 gwater, or as moles of solute per cubic decimetre (i.e. one litre) ofsolution. This latter treatment is clearly well beyond the scope ofa KS3 course. Note also the subtle difference between specifyingthe volume or mass of solvent and the volume or mass of the finalsolution.8Ec – Salt of the EarthEvaporation is a way of extracting dissolved solids from a liquid.If a sample of pure water is evaporated, no solid residue will beleft behind, but if a solution (water containing a dissolved solid, ormixture of solids) is heated the water will evaporate leaving thesolids behind.Evaporation of solutions in the laboratory needs care. The solutionshould be heated until a little remains so that the solid can beformed as the heat stored in the watch glass or evaporating basinevaporates this remaining amount. This will help to stop the solidresidue from ‘spitting’ at the pupils and also limit the number ofbreakages. This process is known as ‘heating to dryness’. If the solidis heated beyond this point, it may ‘jump’ out of the container andmay also be changed by the heat.Copper sulphate is ideal for demonstrating evaporation as its bluecolour means that it can be easily seen. Also, the effect of heatingit too strongly is a very clear change in colour – anhydrous coppersulphate is produced, which is white if too much water (the waterof crystallisation) is removed. The blue colour returns if a little wateris added to the white crystals.Hard water is water with a high mineral content, mostly highlevels of magnesium or calcium carbonates, bicarbonates and/orsulphates. Some of the salts in hard water precipitate on heatingto form scale which blocks up central heating pipes and furs kettleelements. Soap initially reacts with the hardness salts to form ascum, and no lather is formed until all these salts have reacted.Detergents contain different salts, which form soluble compoundswith the hardness salts, and so do not leave scum.Drinking water standards in the UK are set by UK and EUlegislation. The standards set maximum values for concentrationsof various ions, organic molecules, specified microbes, compoundssuch as pesticides, and radioactivity. Sampling is carried out wherewater leaves the supply points, and also at consumers’ taps.8Ed – What’s in a solution?Chromatography is a way of separating different chemicals in aliquid. The chemicals must be soluble in the liquid being used. Atschool level, chromatography is typically used to separate colouredcompounds such as dyes in ink or food colouring. At higher levelsthe compounds being separated are not necessarily coloured – thechromatogram can be treated to make the separate chemicals visible.Different soluble chemicals form different-sized particles– the smaller the particle the more easily it can move duringchromatography. As the solvent soaks up the paper, the differentchemicals in the sample move at different speeds, resulting in aspread-out series of ‘spots’. If two samples on the chromatogramcontain the same chemical, that chemical will move up the samedistance from the start point as the chromatogram is made.Most dyes, pigments, paints, and so on, are mixed from a selectionof pure chemicals. Different manufacturers of paints/dyes usedifferent combinations of chemicals to achieve the desired colour.This fact is made use of when chromatography is used in policework: a sample of paint can be compared with standard samplesfrom different manufacturers to determine its origin.8Ee Still water/Focus on: Supplying water/Running out …Distillation is a process used to separate a liquid from a mixtureof either a liquid and a dissolved solid or several liquids, so that theliquid is not lost.138Exploring Science edition © Pearson Education Limited 2008

In the drink8ESimple distillation involves separating a liquid from dissolvedsolids. The method is effectively the same as evaporation, exceptthat the vapour is collected and condensed to form a liquid.When using a Liebig condenser in distillation, ensure that thecooling water goes in at the bottom and out at the top. This ensuresthat the cooling jacket remains full of water. When demonstratingthe Liebig condenser to pupils it is worth setting it up the wrongway round to show them that if water is fed in at the top it just runsdown the lower surface and does not remain in contact with thecentral tube.8E When heating liquids in a flask, anti-bumping granules mustbe used. These help small bubbles of gas to form as the liquidboils. In the absence of anti-bumping granules, large bubbles ofsteam can form and shake the flask.Fractional distillation involves the separation of two or moreliquids with different boiling points. If the mixture is heated sothat one of the liquids boils, this liquid will turn into a gas andleave the boiling flask. If this gas is then channelled so that it canno longer return to the hot flask, it can be cooled. As a result,it will condense and turn back into a liquid, which can then becollected. If the original mixture contained several different liquids,the mixture can be heated further until the next liquid boils. Thegas produced can then be condensed and collected in a differentcontainer. This process of collecting different liquids from the samemixture is known as fractional distillation and is used to separatethe different chemicals found in crude oil into fractions. Note thatpure liquids are not formed during fractional distillation becauseliquids will evaporate when heated, whether or not they are boiling.So when the mixture in the flask reaches the boiling point of oneliquid, other liquids in the mixture will also be evaporating to someextent.Desalination can be carried out by evaporating sea water andthen condensing the vapour, but this is energy-intensive. Reverseosmosis forces water through a semipermeable membrane at highpressure. Only water molecules, or other molecules of similar size,can pass through the membrane.© Pearson Education Limited 2008 Exploring Science edition 139

8EaUsing water8EaPupil’s materialsNumber and title Level Location Type TasksUsing water All PB p63 Classwork Exploring 1The solution is clear Must PB pp64–65 Classwork Explaining 18E Quick Quiz Must/Should ASP Classwork Starter 48E Quick Quiz Answer Sheet Must/Should ASP Classwork Starter 48Ea Quick Check Must/Should ASP Classwork Plenary 18Ea Word Sheet Must ASP Classwork8Ea(1) The solution is clear Must CHAP Access Explaining 18Ea(2) Operation survival 1 Must CHAP Practical Exploring 28Ea(3) Operation survival 2 Should CHAP Practical Exploring 28Ea(4) A soluble puzzle Must CHAP Homework Homework 18Ea(5) Filtering Must/Should CHAP Homework Homework 28Ea(6) Water for life Should CHAP Homework Homework 38Ea(7) Treating our water Could CHAP Homework Homework 4Learning objectivesExemplar topic plansAll pupils must:(1) explain what a mixture is and what a solution is(2) describe how to filter a mixture(3) explain why filtering works and why it cannot separatesoluble solids from a liquid(4) apply their knowledge of filtering for a practical purpose(5) recall that there are a number of liquids that can be used assolvents(6) explain why we cannot drink sea water.Correctly use the words dissolve, filtering, insoluble,mixture, opaque, soluble, solute, solution, solvent,transparent.Most pupils should:(7) appreciate that some mixtures are easier to separate thanothers(8) recall that solutes which are insoluble in water may dissolvein other solvents.Correctly use the words filtrate, residue.Some pupils could:(9) recall some of the ways in which our water is treated beforeit is supplied to homes(10) describe different mixtures of solids, liquids or gases.MUSTPB pages63–65COULDPB pages63–65Starter 1Exploring 1Exploring 3Explaining 1Explaining 2Plenary 3Homework 1Starter 1Starter 3Exploring 1Exploring 3Explaining 1Explaining 2Explaining 3Plenary 1Homework 4*This table is repeated in 8Eb.SHOULDPB pages63–65SHOULDPB pages64–67Starter 1Starter 3Exploring 1Exploring 3Explaining 1Explaining 2Plenary 2Homework 32 Yr KS3*8Ea Starter 18Ea Explaining 18Eb Explaining 18Eb Exploring 28Eb Plenary 28Eb Homework 2Topic notes• Targets for the topic can be accessed via the ActiveBook orActiveTeach from the link next to the initiator question.• Pupils should have covered solutions and dissolving at Key Stage2, but will not have been introduced to all the key words in thistopic.Be prepared: 8EaStarter 1: cafetiere or coffee filter.Exploring 2: moss or grass.140Exploring Science edition © Pearson Education Limited 2008

Using water8EaTopic task plannerUse these tasks to adapt the Exemplar topic plan to your own needs. Many tasks can be adapted to become different types (e.g. ‘starter’rather than ‘exploring’). AB or AB/AT at the top of a task means that the task depends on using the ActiveBook and/or ActiveTeach;where these symbols appear in brackets it indicates that the task can be carried out with or without their use.Task Level NC Type Objectives Skills 1 KC 2 KP 3 RC 4 COStarter 1 M/S 4 Practical 1–3 PLTS (Ct, Ep) 1a 2a cStarter 2 M/S 4 Classwork 1–3 PLTS (Ct) 2aStarter 3 M/S 4–6 Classwork 1–3, 4, 8 PLTS (Rl) 1a 2aStarter 4 M/S 4–6 Classwork whole unit PLTS (Rl) 2aExploring 1 M/S 4 Classwork 4, 6 ICT (SS) 2a c, eExploring 2 M/S/C 4–5 Practical 2, 3, 4, 7 1a, 1b, 1c, 2a, 2b 2a cExploring 3 M/S/C 4 Practical 1 Lit (WF) 1a, 1b, 1c, 2a 2aExploring 4 M/S 4–5 Practical 1, 5, 8 1b 1a, 1b, 1c, 2a 2aExplaining 1 M/S 4–5 Classwork 1–3, 5, 7, 8 Lit (WF) 2a cExplaining 2 M/S 4 Practical 2 1c 2aExplaining 3 C 6 Classwork 10 3a 2a a, cPlenary 1 M/S/C 4 Classwork 1–3 PLTS (Ct) 2aPlenary 2 M/S 4–6 Classwork 1–3, 4, 8 PLTS (Rl) 1a 2a aPlenary 3 M 4 Classwork 1–3, 5 Lit (WF) 2aHomework 1 M 4 Homework 1, 2 Lit(WF) 2aHomework 2 M 4 Homework 1–4 2a cHomework 3 S 4 Homework 2–6 Lit (EC) 2a cHomework 4 C 4–6 Homework 9 Lit(EC) 2a c8EaStarters1: Practical: Making teaMake a cup of tea in a beaker by pouring hot or boiling water ontoa tea bag. Then write a list of questions on the board and ask pupilsto discuss the answers in pairs. After a few minutes, ask each pairto join with another pair, and each group of four should decideon the best answers to each question before having a whole-classfeedback session. Suitable questions include:• Describe what you saw happening (elicit words such astransparent, colourless, coloured if necessary).• What is the tea bag for?• Why can the coloured water get through the tea bag?• What other things at home need separating? (Answers couldinclude filters for making ‘real’ coffee, or sieves for getting lumpsout of flour or chips from fat.)A possible alternative is making coffee from ground beans using afilter or a cafetiere. But no drinking it in the lab! Take care when using hot water.ResourcesBeaker; tea bag. Optional: ground coffee, cafetiere or coffee filter.2: Thinking about dissolving (AT)Afl Use some or all of the following thinking skills questions tofind out how much pupils recall about dissolving and filtering fromKey Stage 2.• OOO: solution, solvent, solute. (Possible answers: the solute isthe only solid (although, technically, a liquid such as ethanol canbe said to dissolve in water); the solution is the only one thatcontains more than one substance, or it is the only mixture; thesolute is the only one that can be a solid.)• OOO: sand, salt, sugar. (Possible answers: sand is the only onethat is not soluble in water, it is the only one we do not eat; sugaris the only one not found naturally at the seaside.)• OOO: tea, instant coffee, filter coffee. (Possible answers: instantcoffee is the only one that dissolves completely in water and it isthe only one that does not need a filter; tea is the only one madefrom leaves.)• OOO: flour, chalk, sugar. (Possible answers: sugar is the only onethat dissolves in water; chalk is the only one that is not a food,and is the only one made from a rock.)• OOO: tea bag, chip basket, sieve, saucepan. (Possible answers:the saucepan is the only one that cannot filter mixtures; tea bag isthe only one made of paper, and is the only one containing a foodsubstance.)• PMI: sand should be soluble. (Possible answers: P – sand couldbe transported more easily in a solution; M – beaches woulddisappear as the sand would dissolve in the sea; I – what wouldpeople do for holidays?)The second AT presentation link on page 65 opens Thinking aboutdissolving – a PowerPoint presentation version of this task.3: Ideas about mixtures and solutions ATAfl The second AT presentation link on page 64 opens Ideasabout mixtures and solutions – a presentation with different ideasabout mixtures and solutions, some of which are correct and someare not. The presentation also includes answers. This presentationcan also be used for Plenary 2, in which case you may just wishpupils to jot down answers to be referred to later.4: Quick QuizAfl Use the 8E Quick Quiz for baseline assessment for this unit.Pupils could record their answers on the 8E Quick Quiz AnswerSheet.© Pearson Education Limited 2008 Exploring Science edition 141

8EaUsing water8EaExploring tasks1: Pupil’s Book page 63 (AT)This page introduces the idea that we have a plentiful supply ofclean, safe water in the UK, but that people in other countries arenot always so fortunate. The questions should help pupils to reviseearlier work on the water cycle and filtering.• The AT video link opens Water companies – a clip showing TinaDijkstal from Southern Water talking about how she became ahydrogeologist and what she does. She also gives some examplesof how much water is used and how much the company supplies.• The AT spreadsheet link opens Using water – a spreadsheet tohelp pupils to calculate how much water their household usesand to draw pie charts showing the volumes used for differentuses. You could follow this up by asking pupils to estimate usagesfor families in different circumstances (e.g. more young children,an elderly person living alone, etc).2: Practical: Soil filterThe Practical box on page 65 of the Pupil’s Book suggests that pupilsdesign a soil filter that could be used for survival in the countryside.• Must: pupils follow the instructions on Worksheet 8Ea(2) to buildtheir filter, and then complete the exercise at the bottom of thesheet to explain how it works.• Should: Worksheet 8Ea(3) provides brief instructions for theconstruction of the filter, and then asks pupils to investigate howfast their filter works.• Could: pupils could be asked to design their own filter based onlyon the prompt in the Pupil’s Book and/or materials provided, andasked to design their own investigation. They should evaluateeach other’s filters based on scientific tests to award one group/pupil with a ‘best design’ award. Do not allow pupils to drink their water. It could still becontaminated.Resources (per group)Plastic drinks bottle (bottom removed – ensure there are nosharp edges); moss or grass; ruler; small stones; sand (or soil);muddy/dirty water to filter (with bits of grass, twigs, etc.);stopclock; beakers; bucket to collect waste; Worksheets 8Ea(2)or 8Ea(3).3: Practical: Testing solubilityProvide pupils with a selection of solids and ask them to mixa spatula of each with water in a test tube or boiling tube. Themixture can be stirred with a spatula or glass rod. Pupils should beencouraged to use appropriate vocabulary to describe the resultingmixture, and then come to a judgement about whether the solid issoluble or insoluble.• Should: ask pupils to explain how they are making judgementsabout what is soluble and what is not.With some groups it may be appropriate to introduce additionalgradations such as ‘partially soluble’, ‘mostly soluble’, and so on.You could also include some liquids.• Could: a light meter could be used to measure the amount oflight coming through each test tube.Note that Exploring 1 in Topic 8Eb looks at solubility in a morequantitative manner. Aspirin can be harmful.Resources (per group)8 test tubes or boiling tubes; glass rods; spatulas.Suggested list of solids: sugar, salt, flour, instant coffee or tea,aspirin*, soap, pepper, baking soda.(*A brand such as Aspro Clear TM will dissolve completely.)4: Practical: Effectiveness of solventsPupils compare the effectiveness of solvents in removing differenttypes of marks. It is suggested that you keep a class set of ‘offcuts’for this practical – for example material from discarded worksurfaces, whiteboards or polished wood. A piece of the board(about 20 cm × 10 cm would be a suitable size) can be markedusing a variety of substances, for example ball point pen, washablemarker pen, permanent marker, wax crayon and liquid paper, andthe marks labelled. Pupils should be given the opportunity to seewhich of these can be removed easily with a damp cloth. For thosemarks that are not easily removed in this way, other solvents shouldbe tried, for example ‘meths’ (now called Industrial DenaturedAlcohol), white spirit or propanone (acetone). Industrial Denatured Alcohol is highly flammable and harmful.Propanone is an irritant and highly flammable. White spirit isharmful and flammable. Ensure there are no naked flames inthe lab. This practical should be carried out in a well-ventilatedlaboratory. Eye protection should be worn.Resources (per group)Wooden or work surface ‘offcuts’ (about 20 cm × 10 cm)marked with (at least three from) biro, marker pens, nail varnish,liquid paper, wax crayon; access to solvents (e.g. IndustrialDenatured Alcohol, propanone, white spirit); cloths; disposablegloves (preferably nitrile, not latex); eye protection.Explaining tasks1 Pupil’s Book pages 64–65 (AT)These pages look at mixtures, filtering and dissolving. Worksheet8Ea(1) is the Access Sheet.• Must: read through the text with pupils and ask them to answerthe questions.• Should: pupils should remember most of this work from KS2.However, it is worth confirming this before moving on to the restof the unit. This can be done by giving pupils the top half of theAccess Sheet only, and asking them to write their own definitionsof the words. They should try this without reference to the book atfirst, but could then use the book to check their definitions.• The AT video link on page 64 opens Filtering water supplies – aclip showing Tina Dijkstal explaining how river water is filteredat the treatment works before being disinfected and fed into thewater supply.• The second AT presentation link on page 64 opens Ideas aboutmixtures and solutions – see Starter 3 and Plenary 2.• The AB document link on page 64 opens Other mixtures – seeExplaining 3.2: Practical: How to filterDemonstrate how to use filter paper and a funnel to filter in the lab.Let pupils practise this to produce clean water from pure water plusdirt or from salt solution plus dirt. The products from this processcould then be kept to use in the following topic.Resources (per group)Funnel; filter paper; beaker; conical flask; samples of dirty water.142Exploring Science edition © Pearson Education Limited 2008

Using water8Ea3: Other mixtures ATThe AB document link on page 64 opens Other mixtures – whichexplains how scientists classify mixtures of solids, liquids andgases. Pupils are asked to create a document giving examples ofthe different kinds of mixtures, and a few photos are provided tohelp them to get started. Alternatively, they could make posters orcomputer presentations.Plenaries1: Quick CheckAfl The Quick Check sheet provides a set of answers – ask pupilsto suggest what the questions were. In some cases, pupils may beable to suggest more than one question that would result in theanswer given. Encourage pupils to use the key words from thistopic in their questions. Give pupils a few minutes to work on thisalone or in groups, then report back to the rest of the class.8Ea• Must: pupils write questions for answers 1 to 5.• Should: pupils write questions for all answers on the sheet.• Could: pupils attempt to write at least two different questions foreach answer on the sheet.2: Mixtures and solutions revisited ATAfl The AT presentation link on page 64 opens Ideas aboutmixtures and solutions – a concept cartoon with different ideasabout mixtures and solutions, some of which are correct and someare not. The presentation also includes answers. If this presentationhas already been used in Starter 3, ask pupils to look at their earlieranswers and amend them as necessary before discussing theanswers with them.3: I can… cloze exercise AB/ATAfl The AB document link on page 65 opens a cloze exercisecovering the material on pages 64–65. There is also an ATpresentation version with answers.Homework tasks1: Worksheet 8Ea(4) provides a crossword to help consolidatepupil’s knowledge of the scientific vocabulary covered in thistopic.2: Worksheet 8Ea(5) provides questions on filtering in domesticsituations.3: Worksheet 8Ea(6) provides questions based on water and itsimportance for life.4: Worksheet 8Ea(7) looks at how our water is treated beforebeing supplied to homes.© Pearson Education Limited 2008 Exploring Science edition 143

Solubility8EbTopic task plannerUse these tasks to adapt the Exemplar topic plan to your own needs. Many tasks can be adapted to become different types (e.g. ‘starter’rather than ‘exploring’). AB or AB/AT at the top of a task means that the task depends on using the ActiveBook and/or ActiveTeach;where these symbols appear in brackets it indicates that the task can be carried out with or without their use.Also consider using one of the plenaries from the previous topic as a starter task in this topic.Task Level NC Type Objectives Skills 1 KC 2 KP 3 RC 4 COStarter 1 M/S/C 4–5 Practical 3, 4 1a 2aStarter 2 M/S 4–5 Classwork 3, 4 1a, 1b, 1c, 2a, 2b 2aExploring 1 M/S 4–5 Practical 3, 6 1a, 1b, 2aExploring 2 M/S/C 4–8 Practical 3, 6, 7 PLTS (Tw) 1a, 1b, 1c, 2a, 2b, 3a 2aExploring 3 M/S 4–5 Practical 3 PLTS (Tw) 1a, 1b, 1c, 2a 2aExplaining 1 M/S 4–5 Classwork 1, 3–7 2aExplaining 2 S/C 5–6 Classwork 6, 7, 9 Num (L) 2aPlenary 1 S/C 5–6 Practical 6, 7 1a 2aPlenary 2 M/S 4–5 Classwork 1, 3, 7 PLTS (Rl) 2aPlenary 3 M 4–5 Classwork 1, 3–7 Lit (WF) 2aHomework 1 M 4–5 Homework 3 Num (L) 2aHomework 2 S 4–5 Homework 3, 6, 7 Num (L) 2aHomework 3 C 5–6 Homework 10 Num (L), Lit (EC) 2a c8EbStarters1: Practical: Dissolving and massHave a couple of beakers of water ready and a balance. Let pupilssee you finding the mass of the beaker of water, and the mass ofsome sand and some salt.Ask pupils to work in groups of 2 to 4 to discuss the answers toquestions such as:• Must: what will happen to the sand if I add it to the water? Whatwill happen if I put the salt in the water? What will happen if Ikeep adding more salt? Will this change if I heat up the water?• Should: what will the mass be if I add the sand to the water?What will happen to the mass when I add the salt to the water?Explain these answers. Will more sugar dissolve or more salt?• Could: how will the amount that dissolved change if there ismore water?Ask for feedback on each question as you work through thedemonstrations, if necessary eliciting the idea that all the originalparticles of salt (sodium chloride) are still present in a solution,even if they cannot be seen. Pupils may realise from their ownexperience, or from KS2 work, that there is a limit to the amount ofa solute that will dissolve in a certain volume of water.ResourcesBeakers of water; sand; salt; balance; stirring rod.2: Solvents and solutions (AT)Afl Worksheet 8Eb(2) provides a set of drawings of solvents andsolutions for pupils to cut out and match up. Pupils’ responses willlet you see if they have grasped the idea of conservation of masson dissolving, and the idea of saturated solutions.The second AT presentation link on page 66 opens Solutions beforeand after – this provides the same drawings as on the worksheetso that this activity can be done as a class discussion.Exploring tasks1: Practical: How much salt/sugar will dissolve?Salt and sugar are suggested in the Pupil’s Book as suitableexamples of solutes which might dissolve in different amounts.Note that the solubility of sodium chloride at 25 °C is approximately36 g/100 ml, whereas the solubility of sucrose is over 200 g/100 ml.You may therefore wish to encourage pupils to use small volumesof water.• Must: pupils can follow a simple method based on, for example,counting the number of spatulas of solid that will dissolve in agiven volume of water.• Should: pupils should be encouraged to develop a moresophisticated approach based on measuring out masses of solid.The solid should be added until no more dissolves.Resources (per group)Salt; sugar; beaker (10 cm 3 ); spatula. Optional: access tobalances.2: Practical: Temperature and solubilityPupils can be asked to investigate the effect of the temperature of asolvent on the solubility of a solute. A variety of methods are possible.• Must: Worksheet 8Eb(3) presents the simplest method,whereby students find out how many spatulas of potassiumchloride (referred to as ‘salt’ on the worksheet, for simplicity)dissolve in a fixed quantity of water at different temperatures.Ensure that pupils understand that it is the quantity of solutethey are investigating, not how fast it dissolves. If you havewater baths available, pupils should stand their beakers inwater at appropriate temperatures. If not, then pupils shouldbe encouraged to realise that if they heat the water to theappropriate temperature, and then put salt in, the water will becooling down while they carry out their experiment.• Should: a more accurate method is to prepare hot solutionswith different quantities of solute, and cool them until crystalsstart to appear. This method is outlined on Worksheet 8Eb(4),which suggests using copper sulphate, as the formation ofcoloured crystals will be easier to see. If time permits, pupils canprepare a range of solutions, or each group can be allocated aparticular mass of solute and results can be pooled. Alternatively,© Pearson Education Limited 2008 Exploring Science edition 145

8EbSolubility8Ebdifferent groups can investigate the solubility of different saltswith temperature. Pupils can produce graphs of solubility againsttemperature.If there is time, pupils could be encouraged to plan this practicalbefore they are given the method on Worksheet 8Eb(4). Pupilsshould attempt to identify the variables in this experiment andalso any possible safety issues. You could discuss with them thedifficulty of deciding on an end point and how they will record theirresults. At the end of practical lesson, you could discuss with pupilsthe reliability of their results and if they have sufficient data to beable to draw a conclusion. Any suggestions about improvements tothe practical should be accompanied by a reason for the suggestedchange. Pupils could also be encouraged to pool their results andthink about how these could be manipulated to help providefurther evidence for their conclusion.• Could: pupils could be asked to extend their investigation to thesolubility of various substances in different solvents.This practical can be used to carry out an AT1 investigation. A setof level descriptions is provided on pages 153–154 of the ASP. Eye protection should be worn. Copper sulphateis harmful.Resources (per group)Potassium chloride; boiling tube; spatula; heating apparatusor access to kettle; access to balances (optional); Worksheets8Eb(3) or 8Eb(4); eye protection.3: Practical: How fast does sugar dissolve?The time taken for materials to dissolve can be investigated in thelaboratory using sugar as an example. In this case a number ofvariables could be investigated, e.g. temperature, amount of solute,volume of solvent, type of sugar (granulated, caster, lump, etc.).This experiment can also be adapted to be carried out at home.Note that most pupils will have carried out an experiment into thespeed of dissolving at KS2, but may not have investigated all thevariables listed.Resources (per group)Sugar (granulated, caster, lump, etc.); water; stopclock; beakers;heating apparatus; thermometer; spatulas; access to balance;mortar and pestle; copper sulphate.Explaining tasks1: Pupil’s Book pages 66–67 (AT)These pages introduce the idea that the total mass of a solutionis the sum of the masses of the solvent and solute, and explaindissolving in terms of particles. The idea of saturated solutions anddifferent solubilities is then introduced. Worksheet 8Eb(1) is theAccess Sheet.• The first AT animation link on page 66 opens Dissolving – ananimation showing what happens to particles when somethingdissolves.• The second AT animation link on page 66 opens Filtering – ananimation showing filtering in terms of what happens to theparticles.• The second AT presentation link on page 66 opens Solutionsbefore and after – see Starter 2.• The first AB document link on page 67 opens Different solubilities– see Explaining 2.2: Solubility AB/ATThe AB document link on page 67 opens Different solubilities– this document provides a graph showing how the solubilitiesof different salts change with temperature, and includescomprehension questions. This is best used after pupils haveworked through the material in the Pupil’s Book.• Should: project the graph using an interactive whiteboard, anddiscuss the answers to the questions.• Could: pupils can work through the questions individually or inpairs.Plenaries1: Practical: Snowstorm in a test tubeLead iodide provides a very good visual demonstration of thechange of solubility with temperature, although this does notlead to the production of large crystals. Heat a little lead iodide ina boiling tube about half full of distilled water. Alternatively, thelead iodide may be precipitated by mixing equal volumes of dilutepotassium iodide and lead nitrate solutions. The solid will dissolvewhen the water is close to boiling point. Allow the solution tocool slowly and crystals of lead iodide will precipitate as a ‘goldensnowstorm’ effect – the glittering crystals give quite a spectaculareffect as they float in the water. Once a set of tubes has been setup, they can be re-used repeatedly.Show pupils the demonstration, and ask them to explain why ithappens. Lead compounds are toxic. Wash hands after handling them.Eye protection should be worn.ResourcesBoiling tubes; lead iodide (solid); 250 cm 3 beakers. Alternatively,use dilute lead nitrate and potassium iodide solutions(0.005 mol dm –3 ); eye protection.2: Quick CheckAfl The 8Eb Quick Check sheet provides a set of questions forpupils to classify as true or false. Pupils should write a correctversion of any statements they decide are false, or be asked toexplain their reasoning.• Must: pupils answer questions 1 to 4.• Should: pupils answer all questions.3: I can… cloze exercise AB/ATAfl The AB document link on page 67 opens a cloze exercisecovering the material on pages 66–67. There is also an ATpresentation version with answers.Homework tasks1: Worksheet 8Eb(5) provides data handling questions onsolubility.2: Worksheet 8Eb(6) provides data handling questions onsolubility. Pupils will also need a sheet of graph paper.3: Worksheet 8Eb(7) looks at the solubility of gases in water, andat how places such as power stations that put warm water backinto waterways can affect wildlife.146Exploring Science edition © Pearson Education Limited 2008

8EcSalt of the EarthPupil’s materialsNumber and title Level Location Type TasksSalt of the Earth All PB pp68–69 Classwork Explaining 28Ec Quick Check Must/Should ASP Classwork Plenary 18Ec Word Sheet Must ASP Classwork8Ec(1) Salt of the Earth Must CHAP Access Explaining 28Ec(2) Investigating water 1 Must CHAP Practical Exploring 18Ec(3) Investigating water 2 Should CHAP Practical Exploring 18Ec(4) Evaporating Must/Should CHAP Practical Explaining 18Ec(5) Making salt from rock salt 1 Must CHAP Practical Exploring 28Ec(6) Making salt from rock salt 2 Should CHAP Practical Exploring 28Ec(7) Hard water? 1 Must CHAP Homework Homework 18Ec(8) Hard water? 2 Should CHAP Homework Homework 28Ec(9) Gandhi and the Salt Act Could CHAP Homework Homework 38EcLearning objectivesExemplar topic plansAll pupils must:(1) recall that water usually contains dissolved chemicals(2) explain that a dissolved solid can be obtained from a liquidby evaporating the liquid(3) carry out evaporation safely in the laboratory.Correctly use the words common salt, evaporation, salts.Most pupils should:(4) recall that salt can be obtained from sea water byevaporation or from salt mines(5) explain how to obtain pure salt from rock salt(6) recall some differences between hard and soft water.Correctly use the words brine, hard water, qualitystandards, rock salt, soft water.Some pupils could:(7) recall some facts about Gandhi and the Salt Act.Topic notes• Targets for the lesson can be accessed via the ActiveBook orActiveTeach from the link next to the initiator question.• Pupils should have covered the evaporation of a solution toobtain a dissolved solid at KS2, but may not have carried out theprocedure with standard laboratory equipment.MUSTPB pages68–69COULDPB pages68–69Starter 1Explaining 1Explaining 2Exploring 2Plenary 4Homework 1Starter 1Explaining 1Explaining 2Exploring 2Plenary 2Plenary 3Homework 2Homework 3*This table is repeated in 8Ed.SHOULDPB pages68–69SHOULDPB pages68–71Starter 1Explaining 1Explaining 2Exploring 2Plenary 2Plenary 1Homework 22 Yr KS3*8Ec Starter 18Ec Explaining 18Ec Explaining 28Ed Explaining 28Ed Exploring 28Ed Plenary 18Ed Homework 2Be prepared: 8EcStarter 2: samples of hard and soft water.Explaining 3: dried peas or lentils.© Pearson Education Limited 2008 Exploring Science edition 147

8EcSalt of the Earth8EcTopic task plannerUse these tasks to adapt the Exemplar topic plan to your own needs. Many tasks can be adapted to become different types (e.g. ‘starter’rather than ‘exploring’). AT or AB/AT at the top of a task means that the task depends on using the ActiveBook and/or ActiveTeach;where these symbols appear in brackets it indicates that the task can be carried out with or without their use.Also consider using one of the plenaries from the previous topic as a starter task in this topic.Task Level NC Type Objectives Skills 1 KC 2 KP 3 RC 4 COStarter 1 M/S 4 Practical 2 PLTS (Ct) 1a 2aStarter 2 M/S 4 Practical 1, 6 2aExploring 1 M/S 4–5 Practical 1-3 1a, 1b, 1c, 2a, 2b, 2aExploring 2 M/S/C 4–5 Practical 2, 3, 5 1b, 1c, 2a 2aExploring 3 M/S 4–5 Practical 1, 6 1a, 1b, 1c, 2a, 2b, 2aExploring 4 M/S 4–5 Classwork 1 ICT (SS), Num (B) 2aExplaining 1 M/S 4 Practical 3 1c 2aExplaining 2 M/S 4–5 Classwork 1, 2, 4, 6 2a cExplaining 3 M/S 5–7 Practical 1, 6 PCTS (Tw) 1a, 1c, 2a, 2b, 3a 2a aPlenary 1 M/S 4–5 Classwork 2, 3, 5 2aPlenary 2 M/S 4–5 Classwork 2, 3, 5 1b 2b 2aPlenary 3 S/C 5–6 Classwork 2, 4 2a cPlenary 4 M 4–5 Classwork 1, 2, 4, 6 Lit (WF) 2aHomework 1 M 4–5 Homework 1 Num (B) 2b 2aHomework 2 S 4–5 Homework 1, 6 Lit (EC) 2b 2a cHomework 3 C 5 Homework 7 Lit (EC) 2a c, kStarters1: Practical: Separating sand and saltShow pupils a small pile of salt, then mix it with some sand and askpupils to work in small groups to suggest a way of separating thesalt and sand again.• Must: show pupils a beaker of water, filtering and heatingapparatus to act as a hint.• Should: pupils should work out a method without seeing theapparatus.Pupils will have allowed solutions to evaporate to dryness at KS2,but may not remember the details of what they did, or have hadthe opportunity to heat a solution to obtain a dissolved solid. Eye protection must be worn when heating.ResourcesSalt; sand; beaker of water; heating apparatus; eye protection.2: Practical: Hard water (demonstration)Put pupils into groups and give each group samples of hardwater and soft water mixed with soap solution. Put this intocontext by telling them that the different samples have come fromdifferent parts of the country. Ask the groups to shake the tubesand to comment on what they observe. Elicit the idea that thetwo samples of water must have different chemicals dissolved inthem, and ask for suggestions as to how this can be determined. Ifnecessary, ask what will happen if the water is heated. Pupils willhave allowed solutions to evaporate to dryness at KS2, but may notremember the details of what they did, and may not have had theopportunity to heat a solution to obtain a dissolved solid.Resources (per group)Samples of hard and soft water; soap solution; boiling tubes.If you are in a hard water area, use distilled water for your softwater. If you are in a soft water area, add approximately 0.45 gof calcium sulphate per litre of water to make up the hard watersample.Exploring tasks1: Practical: Investigating waterPupils analyse three or more different water samples to determinehow pure they are – the most pure will contain the least dissolvedsolid. Heating a known and fixed volume of each of the watersamples will enable a fair comparison to be made. If you make upwater samples for use (from distilled water plus different quantitiesof salts), keep a note of the quantities used to help you to assessthe accuracy of pupils’ findings.You may wish to carry out Explaining 1 (demonstrating how toevaporate a solution to dryness safely) before pupils carry this out.• Must: instructions are provided on Worksheet 8Ec(2).• Should: an apparatus list and hints for pupils to plan their ownmethod are provided on Worksheet 8Ec(3). Check pupils’ plans before they start. Eye protection mustbe worn.Resources (per group)Measuring cylinder; balance; labelled water samples (made upwith different quantities of dissolved salts); evaporating basin;heating apparatus; eye protection; Worksheet 8Ec(2) or 8Ec(3).2: Practical: Salt from rock saltPupils can obtain samples of pure salt from rock salt. Thiswill provide further practice in the techniques of filtering andevaporation.You can give this practical a context by providing ‘samples’ ofrock salt from different mines, and ask pupils to determine whichwould be the best ‘mine’ to use for making salt. They should beencouraged to use distilled water to avoid any salts in tap wateraffecting their results.You may wish to carry out Explaining 1 (demonstrating how toevaporate a solution to dryness safely) before pupils carry this out.• Must: show pupils how to do the practical, and then ask them touse Worksheet 8Ec(5) to explain the process.• Should: pupils follow the instructions on Worksheet 8Ec(6) andanswer the questions.148Exploring Science edition © Pearson Education Limited 2008

Salt of the Earth8Ec• Could: ask pupils to work in groups to plan their own method, andto explain the reasons for each step. Eye protection must be worn. Do NOT heat the salt to dryness inthe evaporating basin. Hot specks of salt will spit out. Stop heatingwhen crystals are forming at the edge and let the lastof the water evaporate without heating.Resources (per group)Rock salt, or a variety of rock salt samples (see below); accessto electronic top pan balance; mortar and pestle; evaporatingbasin; filter funnels and papers; beaker; conical flask; stirringrod; heating apparatus; eye protection; Worksheet 8Ec(5).‘Mine’ 4 1 6 3 5 2sand (g) 975 900 850 800 750 700salt (g) 25 100 150 200 250 300If possible, different grades and/or colours of sand should be used toalter the appearance of the samples.3: Practical: Testing water for hardness (AT)Ask pupils to test different samples of water for hardness, by shakingup a sample of water with some soap solution and measuring theheight of the lather produced. Pupils will have seen what happensif you have carried out Starter 2. If this has not been done, the firstAT presentation link on page 69 opens Testing water for hardness– which shows the effects of adding different quantities of soapsolution to different water samples. Pupils should discuss how tomeasure the results of the practical and how the observations areappropriate to the task.• Must: show pupils what to do, and ask them to test and rank thesamples in terms of hardness.• Should: ask pupils to plan a fair, quantitative investigation, andwrite a report stating the relative hardness of the different samplesin terms of the height of lather formed.Resources (per group)Numbered water samples made up using distilled waterand calcium sulphate (see below); boiling tubes; measuringcylinders; soap solution; ruler.Water sample 5 1 3 2 4 5Mass of calciumsulphate per litre (mg)0 40 80 120 160 1804: Salts in water AB/ATThe AT spreadsheet link on page 69 opens Salts in water – whichprovides details of the masses of different salts found in differentsamples of water. Pupils are asked to use this to plot different kindsof chart to compare the different waters and to decide which kind ofchart shows the data most effectively.Explaining tasks1: Practical: EvaporatingDemonstrate or let pupils practise evaporation of a solution todryness. Instructions are provided on Worksheet 8Ec(4).Heat a solution until a little remains so that the solid can be formedas the heat stored in the watch glass or evaporating basin evaporatesthis remaining amount. This will stop the solid residue from ‘spitting’at the pupils and also limit the number of breakages! This process isknown as heating to dryness. If the solid is heated beyond this point,it may ‘jump’ out of the container and be changed by the heat. Copper sulphate is harmful when solid or in concentratedsolution. Eye protection must be worn.Resources (per group)Evaporating basin; copper sulphate solution; heating apparatus;beaker; eye protection; Bunsen burners; Worksheet 8Ec(4).2: Pupil’s Book pages 68–69 (AB/AT)These pages explain that almost all water contains some dissolvedsalts, and introduces evaporation as a way of finding out howmuch salt is in the water. Worksheet 8E(1) is the Access Sheet.• The AT video link on page 69 opens Hard and soft water – thevideo shows Tina Dijkstal talking about why some areas havehard water and some have soft water.• The first AT presentation link on page 69 opens Testing water forhardness – see Exploring 3.• The AT spreadsheet link on page 69 opens Salts in water – seeExploring 4.• The third AT presentation link on page 69 opens Extracting salt– see Plenary 2.• The first AT document link on page 69 opens Solution mining –see Plenary 3.3: Practical: Modelling filtration and evaporation (demonstration)This demonstration can be linked to Exploring 2 which asks pupils toextract salt from rock salt. Show pupils a mixture of flour, powderedcopper sulphate and dried pea or lentils. The flour represents thewater, the copper sulphate is the salt and the peas represent thesand and dirt. Shake the mixture in a sieve, collecting the flour andcopper sulphate in a basin below. Pupils should understand that thesieve is acting as the filter paper would. Ask pupils to think about thisas a model and to relate it to their knowledge of particles.Resources (per demonstration)Flour, powdered copper sulphate (or other coloured powder),dried peas or lentils, sieve, basin.Plenaries1: Quick CheckThe 8E Quick Check sheet contains a set of cards that can be sortedto describe how to separate salt from rock salt, and to explain whathappens at each stage. These should be cut up beforehand. Pupilscan sort the cards individually or in groups.2: Extracting salt ATThe third AT presentation link on page 69 opens Extracting salt – thisshows two groups of pupils extracting salt from rock salt.Show pupils all the cartoons, and ask them to note on the final onewhich group has produced the most salt from their original sampleof rock salt (Group A). Then go through the cartoons again one byone, asking what Group A did better than Group B, and why thiswould make a difference. This is an opportunity to revise aspects ofdissolving and filtering as well as evaporation.3: Solution mining ATThe first AT document link on page 69 opens Solution mining – thispresents a diagram of solution mining, and poses questions aimed atrevising aspects of dissolving and evaporation.4: I can… cloze exercise AB/ATAfl The AB document link on page 69 opens a cloze exercisecovering the material on pages 68–69. There is also an ATpresentation version with answers.Homework tasks1: Worksheet 8Ee(7) provides simple questions on hard water.2: Worksheet 8Ee(8) provides questions on hard water, with anelement of comprehension.3: Worksheet 8Ec(9) looks at Gandhi and the Salt Act.8Ec© Pearson Education Limited 2008 Exploring Science edition 149

8EdWhat’s in a solution?8EdPupil’s materialsNumber and title Level Location Type TasksWhat’s in a solution? All PB pp70–71 Classwork Explaining 28Ed Quick Check Must/Should ASP Classwork Plenary 18Ed Word Sheet Must ASP Classwork8Ed(1) What’s in a solution? Must CHAP Access Explaining 28Ed(2) Chromatography of ink Must CHAP Classwork Explaining 38Ed(3) Getting it right Should/Could CHAP Classwork Exploring 38Ed(4) Chromatography Must CHAP Homework Homework 18Ed(5) Who scraped the gatepost? Should CHAP Homework Homework 28Ed(6) Forensic evidence Could CHAP Homework Homework 3SS54 Chromatography All Year 7 CHAP Skills Sheet Exploring 1, Exploring 3Learning objectivesExemplar topic plansAll pupils must:(1) recall what chromatography is(2) be able to make a chromatogram(3) describe how chromatography can be used to separatecolours in inks(4) interpret a chromatogram to draw a conclusion.Correctly use the word chromatography.Most pupils should:(5) explain how chromatography works and what it is used for(6) recall that there are different types of chromatography fordifferent applications.Correctly use the word chromatogram.Some pupils could:(7) recall some applications of chromatography.Topic notes• Targets for the topic can be accessed via the ActiveBook orActiveTeach from the link next to the initiator question.• Although specialist chromatography paper can be obtained,the practicals suggested work just as well with filter paper. Forsimplicity, the worksheets accompanying this topic refer to ‘filterpaper’ as opposed to ‘chromatography paper’.MUSTPB pages70–71COULDPB pages68–71Starter 1Exploring 1Explaining 2Explaining 1Plenary 1Plenary 2Homework 1Starter 1Exploring 1Explaining 2Explaining 1Exploring 3Plenary 1Homework 3*This table is repeated in 8Ec.SHOULDPB pages70–71SHOULDPB pages68–71Starter 1Exploring 1Explaining 2Explaining 1Exploring 3Plenary 1Homework 22 Yr KS3*8Ec Starter 18Ec Explaining 18Ec Explaining 28Ed Explaining 28Ed Exploring 28Ed Plenary 18Ed Homework 2Be prepared: 8EdStarter 1: pre-prepared chromatogram (optional).Exploring 1, 2 and Practical 3: access to means of drying filterpapers.Exploring 2 and Practical 3: a range of food colourings.150Exploring Science edition © Pearson Education Limited 2008

What’s in a solution?8EdTopic task plannerUse these tasks to adapt the Exemplar topic plan to your own needs. Many tasks can be adapted to become different types (e.g. ‘starter’rather than ‘exploring’). AB or AB/AT at the top of a task means that the task depends on using the ActiveBook and/or ActiveTeach;where these symbols appear in brackets it indicates that the task can be carried out with or without their use.Also consider using one of the plenaries from the previous topic as a starter task in this topic.Task Level NC Type Objectives Skills 1 KC 2 KP 3 RC 4 COStarter 1 M/S 4–5 Practical 1, 3 2aStarter 2 M/S 4 Classwork PLTS (Ep) 2aExploring 1 M/S 4–5 Practical 1–5 1c, 2a? 2aExploring 2 M/S 4–5 Practical 1–5 1c, 2a 2aExploring 3 S/C 4–6 Practical 1–5 1a, 1c 2a cExploring 4 M/S/C 4–6 Classwork 5–7 ICT (IR) 2a cExplaining 1 M 4–5 Practical 5 2aExplaining 2 M/S 4–5 Classwork 1–5, 7 2a 2a cExplaining 3 M 4 Classwork 3 2aPlenary 1 M/S 4–5 Classwork 1–5 2aPlenary 2 M 4–5 Classwork 1–3 Lit (WF) 2aPlenary 3 M/S 4–6 Classwork 1–7, previous topics PLTS (Rl) 2aHomework 1 M 4–5 Homework 3 2aHomework 2 S 4–6 Homework 4, 5, 7 2a 2a cHomework 3 C 5–6 Homework 4, 5, 7 Lit (EC) 2a, 2b 2a c, j8EdStarters1: Practical: Chromatography introductionDemonstrate chromatography to the whole class as a starteractivity. Use a dark-coloured ink that includes a range of differentcolours to make the chromatogram more interesting (either testdifferent pens containing water soluble inks to find one with agood mix of colours, or make up a mixture of different colouredinks). If time is short, you may wish to have a ready-preparedchromatogram made from the same ink, so that you do not have towait too long for the water to travel up the paper.Some pupils may have used chromatography at KS2 to investigatethe mix of colours in ink or in the dye used to colour Smarties, sothis starter is a good way of finding out what pupilsalready know.ResourcesMix of coloured ink; chromatography paper or filter paper;beaker of water; support for paper; pipette.OR: pre-prepared chromatogram made from a mix of colouredinks.2: Colour mixturesShow pupils three pots of paint – red, yellow and blue, or tell themthat you are about to paint something and have only those threecolours. Ask what you should do if you want to paint somethingorange, purple or green. Follow this up asking pupils to work insmall groups to discuss how the police can identify the make (andsometimes model) of a car from a scraping of paint left at a crimescene, or the type of pen used to write a letter or sign a fraudulentcheque. Give pupils 5 minutes to discuss the questions in groups,and then ask them to report back. If necessary, elicit the idea thatmany colours are made from mixtures of other colours, and couldbe identified if the component colours could be separated.Exploring tasks1: Practical: Chromatography of inksThe easiest way to set this up is as shown on Skills Sheet 54 fromYear 7 CHAP. Remember to check that you have a variety of felttippedpens that have water-soluble inks. It is possible to get arange of black pens that are all water soluble, but that containdifferent mixtures of coloured inks. The use of a non-watersolublebased black pen will make the point about the solubilityof the ink used, but do not get pupils to try this one as their onlychromatogram – they will only get frustrated if they have no patternto see at the end.Ensure that chromatograms are removed from the solvent beforethe water soaks to the top/edge. Any labels/marks on the papershould be made in pencil so they are unaffected bythe solvent.Resources (per group)100 cm 3 beaker; water; filter paper; scissors; water-soluble ink;access to means of drying filter papers; Year 7 CHAP SkillsSheet 54.2: Practical: Chromatography using food colouringsThis is similar to Exploring 1, but more easily set up using thesecond method shown on Skills Sheet 54 from Year 7 CHAP. Asmall spot of each food colouring should be placed on a differentspot along the pencil line. Make sure that the pencil line on thechromatography paper is at least 0.5 cm above the water level inthe beaker.Resources (per group)100 cm 3 beaker; water; filter paper; scissors; a range of foodcolourings; access to means of drying filter papers; Year 7 CHAPSkills Sheet 54.© Pearson Education Limited 2008 Exploring Science edition 151

8EdWhat’s in a solution?8Ed3: Practical: Getting it rightWorksheet 8Ec(3) lists some mistakes that could be made whencarrying out chromatography, and asks pupils to suggest whatcould happen if these mistakes are made. This sheet could justform the basis for individual work or a class discussion, or theanswers to the questions could be treated as predictions thatpupils can then check.Resources (per group)Water-soluble and permanent inks; large beakers/jars; pencilsand rulers; water; square filter paper or chromatography paper;samples of food colourings with fine pipettes; access to meansof drying filter papers; Year 7 CHAP Skills Sheet 54.4: Research different types of chromatography (AB/AT)Ask pupils to find out about different types of chromatography.The first AB document link on page 71 opens Chromatograms– this gives pupils some details and illustrations of different kindsof chromatography and asks them to match up the diagramsand explanations to make posters. Pupils will not be expected torecall details of different techniques, but should appreciate thatthe chromatograms they have made in the lab are just one way ofseparating different dissolved substances.• Must: use the worksheet from the ActiveBook and scissorsand glue, and ask pupils to cut out the titles, descriptions anddiagrams. Help them to sort them out and briefly discuss whydifferent techniques are needed.• Should: give pupils the sheet from the ActiveBook and ask themto work in groups to sort the statements and diagrams. Theycould use the internet to find out more details of the differentmethods, or find out some applications.• Could: give pupils a list of the different techniques only, andask them to find out how each type works, and its strengths,weaknesses and applications. The phrases given on theworksheet are paper chromatography, thin layer chromatography,chromatograms with colourless substances, gas-liquidchromatography.Plenaries1: Revision notesThe Quick Check sheet provides a set of ‘revision notes’ withmistakes. Ask pupils to spot the mistakes and correct them.2: I can… cloze exercise AB/ATAfl The AT document link on page 71 opens a cloze exercisecovering the material on pages 70–71. There is also an ATpresentation version with answers.3: Beg of my neighbourAfl Ask each pupil to write down three things that they think theperson sitting next to them should have learnt during this topic (orduring the unit so far), and when they would have learnt it. Thenask pupils to ask each other in pairs whether they agree on thethings they should have learnt. Ask them to agree a final list of thethree most important points.Homework tasks1: Worksheet 8Ed(4) provides simple questions on chromatography.2: Worksheet 8Ed(5) provides questions on chromatography, in aforensics setting.3: Worksheet 8Ed(6) looks at the use of chromatography inforensic analysis of DNA samples.Explaining tasks1: Practical: Biro inkDemonstrate that a chromatogram can be made from a non-watersolubleink by using a solvent in which the inks do dissolve. Ethanol is highly flammable. Industrial Denatured Alcohol ishighly flammable and harmful.Resources100 cm 3 beaker; ethanol (or Industrial Denatured Acohol);biro pen or a ‘permanent’ marker pen.2: Pupil’s Book pages 70–71 (AT)These pages introduce chromatography as a way of separatingdifferent substances that are dissolved in water. Worksheet 8Ed(1)is the Access Sheet.• The AT video link on page 70 opens Chromatography – theanimation shows the procedure for producing a chromatogramfrom orange drinks.• The first AB document link on page 71 opens Chromatograms– see Exploring 4.3: Analysing chromatogramsWorksheet 8Ed(2) provides drawings of several differentchromatograms, to give pupils further practice in analysing simplechromatograms.152Exploring Science edition © Pearson Education Limited 2008

8EeStill waterPupils’ materialsNumber and title Level Location Type TasksStill water Must/Should PB p72–73 Classwork Explaining 1Focus on: Reservoirs and desalination Could PB p74–75 Classwork Explaining 5Running out … Must/Should PB p76 Classwork Explaining 68E Quick Quiz Must/Should ASP Classwork Plenary 68E Quick Quiz Answer Sheet Must/Should ASP Classwork Plenary 68E End of Unit Test Must/Should ASP Classwork Plenary 78E Level Ladder Must/Should ASP Classwork Plenary 58Ee Quick Check Must/Should ASP Classwork Plenary 18Ee Word Sheet Must ASP Classwork8Ee(1) Still water Must CHAP Access Explaining 18Ee(2) Supplying water Should CHAP Access Explaining 58Ee(3) Distillation Must/Should CHAP Classwork Explaining 28Ee(4) Separating mixtures Should CHAP Classwork Plenary 28Ee(5) A solar pump 1 Must CHAP Homework Homework 18Ee(6) A solar pump 2 Should CHAP Homework Homework 28Ee(7) Fractional distillation Could CHAP Homework Homework 3SS41 Debates and speaking Must/Should Year 7 CHAP Classwork Explaining 68EeLearning objectivesExemplar topic plansAll pupils must:(1) describe what ‘pure’ water is(2) recall that distillation can be used to separate a liquid fromanything dissolved in it(3) explain that distillation is evaporation followed bycondensation(4) describe some applications of distillation(5) describe some ways in which water supplies can beconserved.Correctly use the words condensing, distillation, pure,steam, water vapour.Most pupils should:(6) be able to explain distillation using ideas about particles.Correctly use the word still.Some pupils could:(7) recall some of the human and environmental effects ofsupplying large quantities of water(8) explain how distillation of sea water provides water in somearid countries(9) explain that fractional distillation works because each liquidboils at a different temperature(10) recall some of the products made from crude oil.MUSTPB pages72–73COULDPB pages72–76Starter 1Starter 2Exploring 1Explaining 1Explaining 3Plenary 1Homework 1Starter 1Explaining 1Exploring 1Explaining 4Explaining 5Explaining 6Plenary 3Homework 3SHOULDPB pages72–73,76SHOULDPB pages72–73,76Starter 1Starter 2Exploring 1Explaining 1Explaining 6Plenary 3Homework 22 Yr KS38Ee Starter 18Ee Starter 28Ee Exploring 18Ee Explaining 18Ee Explaining 68Ee Plenary 38Ee Homework 2Topic notes• Targets for the topic can be accessed via the ActiveBook orActiveTeach from the link next to the initiator question.Be prepared: 8EeExploring 2: garden trowel, canes/sticks, stones, access toopen ground.© Pearson Education Limited 2008 Exploring Science edition 153

8EeStill water8EeTopic task plannerUse these tasks to adapt the Exemplar topic plan to your own needs. Many tasks can be adapted to become different types (e.g. ‘starter’rather than ‘exploring’). AB or AB/AT at the top of a task means that the task depends on using the ActiveBook and/or ActiveTeach;where these symbols appear in brackets it indicates that the task can be carried out with or without their use.Also consider using one of the plenaries from the previous topic as a starter task in this topic.Task Level NC Type Objectives Skills 1 KC 2 KP 3 RC 4 COStarter 1 M 4–5 Classwork 1–4 PLTS (Ep) 2aStarter 2 M/S/C 4–5 Practical 1–4 PLTS (Ct) 2a AExploring 1 M 4–5 Practical 1–4 1c 2aExploring 2 S 6 Practical 1–4 1b, 1c 2a cExplaining 1 M 4–5 Classwork 1–4, 6 2a cExplaining 2 M/S 4–5 Classwork 3 2aExplaining 3 M/S 4–5 Practical 3 2aExplaining 4 S/C 5 Practical 3, 6 2aExplaining 5 S/C 5 Classwork 7, 8 Lit (EC) 2a, 2b 2a c, d, j, gExplaining 6 M/S 4 Classwork 5 Lit (DS) 2a c, e, gPlenary 1 M/S 4–5 Classwork whole unit 2aPlenary 2 S/C 4–6 Classwork whole unit 1a 2aPlenary 3 S/C 4–5 Classwork whole unit 1a 3a 2aPlenary 4 M 4–5 Classwork 1–3 Lit (WF) 2aPlenary 5 M/S 4–6 Classwork whole unit PLTS (Rl, Sm) 2aPlenary 6 M/S 4–6 Classwork whole unit PLTS (Rl) 2aPlenary 7 M/S 3–6 Classwork whole unit PLTS (Rl) 2aHomework 1 M 4–5 Homework 1–4 Lit (EC) 2a cHomework 2 S 4–5 Homework 1–4 Lit (EC) 2a cHomework 3 C 5–6 Homework 9, 10 Lit (EC) 2a 2a cStarters1: The water cyclePupils will have studied the water cycle at KS2, and many willremember that most rain was originally water evaporated from thesea. Give pupils one minute to draw a diagram to show the watercycle. You could give them a start by drawing, on the board, a cloudwith some raindrops below it and a sloping line under the cloud.Then ask pupils to share their ideas about the water cycle in groupsand explain why rain is not salty. Ask one pupil from each group togive their answer to the rest of the class.2: Practical: Distillation brainstormStart by asking pupils to think about evaporating a solution andwhat is left in the basin, and what they would need to do if it wasthe water from the solution they wanted to keep, rather than thesolute. Put pupils into groups and pose questions for them todiscuss in their groups before having a class feedback session.• Must: show pupils the apparatus needed for simple distillationand ask them to suggest how it works, including any safetyprecautions they should take.• Should: ask pupils to work out how to obtain water from asolution without showing them the apparatus first. They shoulddescribe the kind of apparatus they would need and how to use it.• Could: as for Should, but have a further discussion session to seeif pupils can work out how to separate two liquids with differentboiling points.ResourcesBunsen burner; tripod; gauze; evaporating basin; heatproof mat.Exploring tasks1: Practical: Distilling inkPupils distil ink using side-arm test-tubes. Ensure that the tubeor flask is not allowed to boil dry. (If boiling tubes with deliverytubes are used, bungs with two holes will be needed so that athermometer can be used.) Pupils should be instructed to heat theinky water gently to avoid it bubbling over into the delivery tube.Note that if the apparatus has been used for distilling ink by earlierclasses, the water produced may not be clear if earlier users haveallowed the ink to boil over. Eye protection should be worn. Do not fill the boiling tubemore than 1 / 3 full.Resources (per group)Side-arm test-tubes, or boiling tubes with delivery tubes; heatingapparatus; heatproof mat; inky water; anti-bumping granules;thermometer and bung (to fit test tubes); collecting beaker; eyeprotection.2: Practical: Survival stillPupils produce a survival ‘still’ using a black plastic bag and a cleancontainer. Support the black bag (in a bowl shape), just abovesome freshly dug/exposed earth on a hot day, with the containerunder the plastic to catch the drips of condensation. Some possiblemethods are illustrated below. Ensure that pupils wash their hands after contact with the soil.154Exploring Science edition © Pearson Education Limited 2008

Still water8Eeblack plasticfreshlydug holesmallstonecleancontainerlargestonessmall stoneto weigh downcentre of plasticframe madefrom canesand stringblack plasticfastened to caneswith sticky tapefreshly dug earth Ethanol is highly flammable. Completely Denatured Alcoholis highly flammable and harmful. Eye protection should be worn.Ensure that pupils smell the distillate following the recommendedmethod.Resources (per group)Long neck, side-arm conical flask; Liebig condenser; watersupply; anti-bumping granules; thermometer and bung;electric heating mantle; mixture of 20 cm 3 ethanol or CompletelyDenatured Alcohol to 150 cm 3 water; heatproof mat; eyeprotection.8EeResources (per group)Black bin liners; garden trowel; string; canes/sticks; stones;sticky tape; clean container (e.g. plastic cup/jam jar); access toopen ground.Explaining tasks1: Pupil’s Book pages 72–73Start by discussing evaporation, and the fact that it separates aliquid from a dissolved solid, but is only any use if you want thesolid. What happens if it is the pure liquid you want? Discusswhere the liquid has gone when it evaporates, and how it could be‘trapped’ and condensed.These pages look at the process of distillation. Worksheet 8Ee(1) isthe Access Sheet.2: Distillation (AT)Worksheet 8Ee(3) provides a diagram of the distillation apparatusfor pupils to label and to add their own explanations of how it works.• The AT video link on page 72 opens Distilling inky water – thisprovides an activity where labels have to be dragged and droppedonto a diagram of the distillation apparatus.• The AT animation link on page 72 opens Distillation – thisprovides an animation of distillation in terms of particles.3: Practical: Liebig condenserDemonstrate the distillation of inky water, using a Liebig condenser.Pupils should be told that ink is often made by dissolving solids inwater. Heat the flask gently whilst the mixture boils. Point out thereading on the thermometer, condensation inside the condenserand collection of the pure water. Discuss with pupils the reasonwhy the water in the cooling jacket goes in at the bottom. Eye protection should be worn.ResourcesLong neck, side-arm round-bottomed flask; Liebig condenser;water supply; anti-bumping granules; thermometer andbung; Bunsen burner; ink/water mixture; heatproof mat; eyeprotection.4: Practical: Distilling alcohol/waterDemonstrate the distillation of an alcohol/water mixture using anelectric heating mantle to avoid alcohol fumes igniting and givinga flash flame. Demonstrate to pupils how to smell chemicals safely(fill the lungs with clean air, then wave a hand above the containerto waft the smell towards you). Identify alcohol by smell (do notallow pupils to take a large sniff or taste it). This demonstration canbe more effective if Completely Denatured Alcohol (CDA) is used(but be aware that this is very smelly!) – the dye remains in theflask.5: Pupil’s Book pages 74–75 (AB/AT)These pages look at how cities are supplied with water, looking firstat where the water for Manchester comes from and consideringthe environmental and human consequences of different meansof supplying water. They then go on to briefly discuss the use ofdesalination plants for supplying drinking water.Worksheet 8Ee(2) is the Access Sheet.• The AT video link on page 74 opens Supplying water – the clipshows Tina Dijkstal explaining where Southern Water gets itswater and contrasts this with water companies in the south westof England.• The AT animation link on page 75 opens Desalination – this is adiagram of a desalination plant with labels selected from dropdownmenus.6: Pupil’s Book page 76This page looks at different opinions about the use of water in theUK, and how we can make sure that water supplies in the futureare adequate.• The AT video link on page 76 opens Saving water – this showsTina Dijkstal talking about why there are sometimes watershortages and about some of the ways in which people can useless water in their homes.The Have Your Say box on this page asks pupils to consider howthe government could make sure that the UK has enough water.This can be used as the basis for group discussions or a debate.Refer to Skills Sheet 41 from the Year 7 CHAP for ideas on how torun a debate.Plenaries1: Quick CheckThe Quick Check sheet provides a set of cards summarising thedifferent separation techniques covered in this unit for pupils tomatch up. Incorrect explanations are also included to test theirunderstanding.2: Explaining separation techniques (AB/AT)The AB document link on page 72 opens Separation summary– which provides a table for pupils to complete to summarise thefour different separation methods covered in this unit.Worksheet 8Ee(4) provides a diagram illustrating how filteringworks using the particle model. Pupils are asked to draw similardiagrams to explain how the other ways of separating mixtures work.3: Water purificationTell pupils that the local water company has been receivingcomplaints about the quality of the water, so it is having an openday at its laboratories. It wants to have some information boardsexplaining how it treats water, but it also wants to explain thescience behind the different ways of purifying water or analysing itto see what salts it contains.© Pearson Education Limited 2008 Exploring Science edition 155

8EeStill water8EeAsk pupils to prepare some labelled diagrams explaining howeach separation technique works. They should include ideas aboutparticles in their diagrams and/or labels, and information aboutwhat each method can be used for. This activity can be done as anassessed task. A set of level descriptions is provided on page 151 ofthe ASP.4: I can… cloze exercise AB/ATAfl The AB document link on page 73 opens a cloze exercisecovering the material on pages 72–73. There is also an ATpresentation version with answers.5: Level LadderAfl Pupils should tick the boxes on the Level Ladder to recordthose statements that they feel they know. Alternatively theycan use a traffic light system or the CRI index (see Introduction,page 17) to record degrees of certainty. Ideally pupils should becertain of all statements at a level to be sure they are working atthat level. Encourage pupils to plan how to do further work on thethings about which they remain unsure.6: Quick Quiz revisitedAfl Revisit the 8E Quick Quiz to test pupils’ knowledge of thecontent of this unit. If you have the ASP on CD-ROM use QuickQuiz 2, which provides the same activity but with the answersarranged in a different order. Pupils could fill in their answers onthe 8E Quick Quiz Answer Sheet. Encourage pupils to identifyfor themselves areas where their understanding is still weak anddecide how they are going to remedy this.7: End of Unit TestAfl Use the End of Unit Test. A marking guide is given in theASP. Encourage pupils to identify areas that are still weak and toformulate plans to strengthen those areas.Homework tasks1: Worksheet 8Ee(5) provides questions in the context of a solarpoweredwater pump that produces distilled water.2: Worksheet 8Ee(6) provides questions in the context of a solarpoweredwater pump that produces distilled water.3: Worksheet 8Ee(7) looks at the use of fractional distillation forseparating the components in crude oil.156Exploring Science edition © Pearson Education Limited 2008