gcse science combined b 21st century - scribble resources · 2019-01-14 · note, however, that...

Syllabus Snapshot

GCSE Science Combined B 21st

Century

Exam Board: OCR

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2a. OCR’s GCSE (9–1) in Combined Science B (Twenty First Century Science) (J260)

LearnersareenteredforeitherFoundationTier(components01–04)orHigherTier(components05–08).ThisqualificationisworthtwoGCSEs.

Content Overview Assessment Overview

Foundation Tier,grades1–1to5–5

Contentissplitintotwentyteachingchapters:

• ChapterB1:Youandyourgenes• ChapterB2:Keepinghealthy• ChapterB3:Livingtogether–foodand

ecosystems• ChapterB4:Usingfoodandcontrollinggrowth• ChapterB5:Thehumanbody–stayingalive• ChapterB6:LifeonEarth–past,presentand

future

• ChapterC1:Airandwater• ChapterC2:Chemicalpatterns• ChapterC3:Chemicalsofthenatural

environment• ChapterC4:Materialchoices• ChapterC5:Chemicalanalysis• ChapterC6:Makingusefulchemicals

• ChapterP1:Radiationandwaves• ChapterP2:Sustainableenergy• ChapterP3:Electriccircuits• ChapterP4:Explainingmotion• ChapterP5:Radioactivematerials• ChapterP6:Matter–modelsandexplanations

• ChapterBCP7:IdeasaboutScience• ChapterBCP8:PracticalSkills

Paper1assessescontentB1–B6andBCP7and8Paper2assessescontentC1–C6andBCP7and8Paper3assessescontentP1–P6andBCP7and8Paper4assessesallcontent

BiologyJ260/01

95marks

1hour45minutesWrittenpaper

26.4%oftotalGCSE

ChemistryJ260/02

95marks


26.4%oftotalGCSE

PhysicsJ260/03

95marks


26.4%oftotalGCSE

CombinedScienceJ260/04

75marks


20.8%oftotalGCSE

2 The specification overview

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GCSE (9–1) in Combined Science B (Twenty First Century Science)

Content Overview Assessment Overview

Higher Tier,grades4–4to9–9

Contentissplitintotwentyteachingchapters:

• ChapterB1:YouandyourGenes• ChapterB2:Keepinghealthy• ChapterB3:Livingtogether–foodand

ecosystems• ChapterB4:Usingfoodandcontrolling

growth• ChapterB5:Thehumanbody–stayingalive• ChapterB6:LifeonEarth–past,presentand

future

• ChapterC1:Airandwater• ChapterC2:Chemicalpatterns• ChapterC3:Chemicalsofthenatural

environment• ChapterC4:Materialchoices• ChapterC5:Chemicalanalysis• ChapterC6:Makingusefulchemicals

• ChapterP1:Radiationandwaves• ChapterP2:Sustainableenergy• ChapterP3:Electriccircuits• ChapterP4:Explainingmotion• ChapterP5:Radioactivematerials• ChapterP6:Matter–modelsand

explanations

• ChapterBCP7:IdeasaboutScience• ChapterBCP8:PracticalSkills

Paper5assessescontentB1–B6andBCP7and8Paper6assessescontentC1–C6andBCP7and8Paper7assessescontentP1–P6andBCP7and8Paper8assessesallcontent

BiologyJ260/05

95marks

1hour45minutes

Writtenpaper

26.4%oftotalGCSE

ChemistryJ260/06

95marks

1hour45minutes

Writtenpaper

26.4%oftotalGCSE

PhysicsJ260/07

95marks

1hour45minutes

Writtenpaper

26.4%oftotalGCSE

CombinedScienceJ260/08

75marks

1hour45minutes

Writtenpaper

20.8%oftotalGCSE

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2b. Content of GCSE (9–1) in Combined Science B (Twenty First Century Science) (J260)

Layout of specification content

Thespecificationcontentisdividedintotwentychapters.Therearesixchaptersforeachofbiology,chemistryandphysicsthatdescribethesciencecontenttobetaughtandassessed.ChapterBCP7describestheIdeas about Sciencethatshouldbetaught,andwillbeassessedincontextstakenfromanyoftheprecedingchapters.TheIdeas about SciencecovertherequirementsofWorking Scientifically.Thefinalchapterdescribestherequirementsforpracticalskills.

Inthespecification,thecontentthatisassessableispresentedintwocolumns:theteachingandlearningnarrativeandtheassessablelearningoutcomes.Thenarrativesummarisesthesciencestoryandprovidescontextfortheassessablelearningoutcomestherebysupportingtheteachingofthespecification.Theassessablelearningoutcomes

definetherequirementsforassessmentandanycontextsgiveninthenarrativesmayalsobeassessed.

Within each chapter:

Anoverview summarisesthescienceideasincludedinthechapter,explainingwhytheseideasarerelevanttolearnerslivinginthetwentyfirstcenturyandwhyitisdesirableforlearnerstounderstandthem.

FollowingtheoverviewisasummaryoftheknowledgeandunderstandingthatlearnersshouldhavegainedfromstudyatKeyStages1to3.Someoftheseideasarerepeatedinthecontentofthespecificationandwhilethismaterialneednotberetaught,itcanbedrawnupontodevelopideasatGCSE(9–1).

LearningatGCSE(9–1)isdescribedinthetablesthatfollow:

Teaching and learning narrative

Assessable learning outcomes Linked learning opportunities

Theteachingandlearningnarrativesummarisesthesciencestory,includingrelevantIdeas about Sciencetoprovidecontextsfortheassessablelearningoutcomes.Thenarrativeisintendedtosupportteachingandlearning.Therequirementsforassessmentaredefinedbytheassessablelearningoutcomesandanycontextgiveninthenarrativemayalsobeassessed.

Theassessablelearningoutcomessetoutthelevelofknowledgeandunderstandingthatlearnersareexpectedtodemonstrate.Thestatementsgiveguidanceonthebreadthanddepthoflearning.

Emboldened statements will only be assessed in Higher Tier papers.

ThemathematicalrequirementsinAppendix5darereferencedbytheprefixMtolinkthemathematicalskillsrequiredtotheareasofsciencecontentwherethosemathematicalskillscouldbelinkedtolearning.

OpportunitiesforcarryingoutpracticalactivitiesareindicatedthroughoutthespecificationandarereferencedasPAGB1toPAGP6(PracticalActivityGroup;seeChapterBCP8).

iAdvisory notes clarify the depth of cover required

ThelinkedlearningopportunitiessuggestwaystodevelopIdeas about Scienceandpracticalskillsincontext,andalsohighlightlinkstoideasinotherchapters.

Note,however,thatIdeas about Scienceandpracticalskillsmaybetaught,andwillbeassessed,inanycontext.

TheAssessmentObjectivesinSection3bmakecleartherangeofwaysinwhichlearnerswillberequiredtodemonstratetheirknowledgeandunderstanding

intheassessments,andtheSampleAssessmentMaterials(providedontheOCRwebsiteatwww.ocr.org.uk)provideexamples.

http://www.ocr.org.uk

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Biology key ideas

Biologyisthescienceoflivingorganisms(includinganimals,plants,fungiandmicroorganisms)andtheirinteractionswitheachotherandtheenvironment.Thestudyofbiologyinvolvescollectingandinterpretinginformationaboutthenaturalworldtoidentifypatternsandrelatepossiblecauseandeffect.Biologicalinformationisusedtohelphumansimprovetheirownlivesandstrivetocreateasustainableworldforfuturegenerations.

Learnersshouldbehelpedtounderstandhow,throughtheideasofbiology,thecomplexanddiversephenomenaofthenaturalworldcanbedescribedintermsofasmallnumberofkeyideaswhichareofuniversalapplication,andwhichinclude:

• lifeprocessesdependonmoleculeswhosestructureisrelatedtotheirfunction

• thefundamentalunitsoflivingorganismsarecells,whichmaybepartofhighlyadaptedstructuresincludingtissues,organsandorgansystems,enablinglivingprocessestobeperformedeffectively

• livingorganismsmayformpopulationsofsinglespecies,communitiesofmanyspeciesand

ecosystems,interactingwitheachother,withtheenvironmentandwithhumansinmanydifferentways

• livingorganismsareinterdependentandshowadaptationstotheirenvironment

• lifeonEarthisdependentonphotosynthesisinwhichgreenplantsandalgaetraplightfromtheSuntofixcarbondioxideandcombineitwithhydrogenfromwatertomakeorganiccompoundsandoxygen

• organiccompoundsareusedasfuelsincellularrespirationtoallowtheotherchemicalreactionsnecessaryforlife

• thechemicalsinecosystemsarecontinuallycyclingthroughthenaturalworld

• thecharacteristicsofalivingorganismareinfluencedbyitsgenomeanditsinteractionwiththeenvironment

• evolutionoccursbyaprocessofnaturalselectionandaccountsbothforbiodiversityandhoworganismsareallrelatedtovaryingdegrees.

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GCSE (9–1) in Combined Science B (Tw

enty First Century Science)

AsummaryofthecontentfortheGCSE(9–1)CombinedScienceB(TwentyFirstCenturyScience)courseisasfollows:

Chapter B1: You and your genes Chapter B2: Keeping healthy Chapter B3: Living together – food and ecosystems

B1.1 Whatisthegenomeandwhatdoesitdo?

B1.2 Howisgeneticinformationinherited?B1.3 Howcanandshouldgenetechnologybe

used?

B2.1 Whatarethecausesofdisease?B2.2 Howdoorganismsprotectthemselvesagainstpathogens?B2.3 Howcanwepreventthespreadofinfection?B2.4 Howcanlifestyle,genesandtheenvironmentaffectmy

health?B2.5 Howcanwetreatdisease?

B3.1 Whathappensduringphotosynthesis?B3.2 Howdoproducersgetthesubstances

theyneed?B3.3 Howareorganismsinanecosystem

interdependent?B3.4 Howarepopulationsaffectedby

conditionsinanecosystem?

Chapter B4: Using food and controlling growth Chapter B5: The human body – staying alive Chapter B6: Life on Earth – past,

present and future

B4.1 Whathappensduringcellularrespiration?

B4.2 Howdoweknowaboutmitochondriaandothercellstructures?

B4.3 Howdoorganismsgrowanddevelop?B4.4 Shouldweusestemcellstotreatdamage

anddisease?

B5.1 Howdosubstancesgetinto,outofandaroundourbodies?B5.2 Howdoesthenervoussystemhelpusrespondtochanges?B5.3 Howdohormonescontrolresponsesinthehumanbody?B5.4 Whydoweneedtomaintainaconstantinternal

environment?B5.5 Whatroledohormonesplayinhumanreproduction?B5.6 Whatcanhappenwhenorgansandcontrolsystemsstop

working?

B6.1 Howwasthetheoryofevolutiondeveloped?

B6.2 HowdoesourunderstandingofbiologyhelpusclassifythediversityoforganismsonEarth?

B6.3 Howisbiodiversitythreatenedandhowcanweprotectit?

Chapter BCP7: Ideas about Science

IaS1 Whatneedstobeconsideredwheninvestigatingaphenomenonscientifically?IaS2 Whatconclusionscanwemakefromdata?IaS3 Howarescientificexplanationsdeveloped?IaS4 Howdoscienceandtechnologyimpactsociety?

Chapter BCP8: Practical Skills

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Chemistry key ideas

Chemistryisthescienceofthecomposition,structure,propertiesandreactionsofmatter,understoodintermsofatoms,atomicparticlesandthewaytheyarearrangedandlinktogether.Itisconcernedwiththesynthesis,formulation,analysisandcharacteristicpropertiesofsubstancesandmaterialsofallkinds.

Learnersshouldbehelpedtoappreciatetheachievementsofchemistryinshowinghowthecomplexanddiversephenomenaofboththenaturalandman-madeworldscanbedescribedintermsofasmallnumberofkeyideaswhichareofuniversalapplication,andwhichinclude:

• matteriscomposedoftinyparticlescalledatomsandthereareabout100differentnaturallyoccurringtypesofatomscalledelements

• elementsshowperiodicrelationshipsintheirchemicalandphysicalproperties

• theseperiodicpropertiescanbeexplainedintermsoftheatomicstructureoftheelements

• atomsbondbyeithertransferringelectronsfromoneatomtoanotherorbysharingelectrons

• theshapesofmolecules(groupsofatomsbondedtogether)andthewaygiantstructuresarearrangedisofgreatimportanceintermsofthewaytheybehave

• therearebarrierstoreactionsoreactionsoccuratdifferentrates

• chemicalreactionstakeplaceinonlythreedifferentways:• protontransfer• electrontransfer• electronsharing

• energyisconservedinchemicalreactionssocanthereforebeneithercreatedordestroyed.

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Chapter C1: Air and water Chapter C2: Chemical patterns Chapter C3: Chemicals of the natural environment

C1.1 HowhastheEarth’satmospherechangedovertime,andwhy?

C1.2 Whyaretheretemperaturechangesinchemicalreactions?

C1.3 Whatistheevidenceforclimatechange,whyisitoccurring?

C1.4 Howcanscientistshelpimprovethesupplyofpotablewater?

C2.1 Howhaveourideasaboutatomsdevelopedovertime?

C2.2 WhatdoesthePeriodicTabletellusabouttheelements?

C2.3 Howdometalsandnon-metalscombinetoformcompounds?

C2.4 Howareequationsusedtorepresentchemicalreactions?

C3.1 Howaretheatomsheldtogetherinametal?

C3.2 Howaremetalswithdifferentreactivitiesextracted?

C3.3 Whatareelectrolytesandwhathappensduringelectrolysis?

C3.4 Whyiscrudeoilimportantasasourceofnewmaterials?

Chapter C4: Material choices Chapter C5: Chemical analysis Chapter C6: Making useful chemicals

C4.1 Howisdatausedtochooseamaterialforaparticularuse?

C4.2 Howdobondingandstructureaffectpropertiesofmaterials?

C4.3 Whyarenanoparticlessouseful?C4.4 Whathappenstoproductsattheendoftheir

usefullife?

C5.1 Howarechemicalsseparatedandtestedforpurity?

C5.2 Howaretheamountsofsubstancesinreactionscalculated?

C5.3 Howareamountsofchemicalsinsolutionmeasured?

C6.1 Whatusefulproductscanbemadefromacids?

C6.2 Howdochemistscontroltherateofreactions?

C6.3 Whatfactorsaffecttheyieldofchemicalreactions?




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Physics key ideas

Physicsisthescienceofthefundamentalconceptsoffield,force,radiationandparticlestructures,whichareinter-linkedtoformunifiedmodelsofthebehaviourofthematerialuniverse.Fromsuchmodels,awiderangeofideas,fromthebroadestissueofthedevelopmentoftheuniverseovertimetothenumerousanddetailedwaysinwhichnewtechnologiesmaybeinvented,haveemerged.Thesehaveenrichedbothourbasicunderstandingof,andourmanyadaptationsto,ourmaterialenvironment.

Learnersshouldbehelpedtounderstandhow,throughtheideasofphysics,thecomplexanddiversephenomenaofthenaturalworldcanbedescribedintermsofasmallnumberofkeyideaswhichareofuniversalapplicationandwhichinclude:

• theuseofmodels,asintheparticlemodelofmatterorthewavemodelsoflightandofsound

• theconceptofcauseandeffectinexplainingsuchlinksasthosebetweenforceandacceleration,orbetweenchangesinatomicnucleiandradioactiveemissions

• thephenomenaof‘actionatadistance’andtherelatedconceptofthefieldasthekeytoanalysingelectrical,magneticandgravitationaleffects

• thatdifferences,forexamplebetweenpressuresortemperaturesorelectricalpotentials,arethedriversofchange

• thatproportionality,forexamplebetweenweightandmassofanobjectorbetweenforceandextensioninaspring,isanimportantaspectofmanymodelsinscience

• thatphysicallawsandmodelsareexpressedinmathematicalform.

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Chapter P1: Radiation and waves Chapter P2: Sustainable energy Chapter P3: Electric circuits

P1.1 Whataretherisksandbenefitsofusingradiations?

P1.2 Whatisclimatechangeandwhatistheevidenceforit?

P1.3 Howdowavesbehave?

P2.1 Howmuchenergydoweuse?P2.2 Howcanelectricitybegenerated?

P3.1 Whatdeterminesthecurrentinanelectriccircuit?

P3.2 Howdoseriesandparallelcircuitswork?P3.3 Whatdeterminestherateofenergytransfer

inacircuit?P3.4 Whataremagneticfields?P3.5 Howdoelectricmotorswork?

Chapter P4: Explaining motion Chapter P5: Radioactive materials Chapter P6: Matter – models and explanations

P4.1 Whatareforces?P4.2 Howcanwedescribemotion?P4.3 Whatistheconnectionbetweenforcesand

motion?P4.4 Howcanwedescribemotionintermsofenergy

transfers?

P5.1 Whatisradioactivity?P5.2 Howcanradioactivematerialsbeusedsafely?

P6.1 Howdoesenergytransformmatter?P6.2 Howdoestheparticlemodelexplainthe

effectsofheating?P6.3 Howdoestheparticlemodelrelateto

materialsunderstress?




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2c. Content of chapters B1 to BCP8

Chapter B1: You and your genes

Overview

Theinheritanceofgeneticinformationfromeachgenerationtothenextisafundamentalideainscience;itcanhelpusanswerquestionsaboutwhywelookthewaywedo,andbuildsafoundationforlaterexplorationofideasaboutgeneticdiseases,celldivisionandgrowth,andevolution.

TopicB1.1exploresbasicconceptsofthegenomeandhowitaffectsanorganism’scharacteristics,throughideasaboutDNAandgenesastheunitsofgeneticinformation,thelinkbetweengenesandproteins,andhowtheinteractionbetweengenesandtheenvironmentaffectshowanindividuallooks,developsandfunctions.

TopicB1.2exploresinheritancebyconsideringtheeffectsofdominantandrecessivealleles,theinheritanceofcharacteristics,theprinciplesofinheritanceofsingle-genecharacteristicsandhowsexisdetermined.

Understandingofthegenomeandemerginggenetechnologiesareatthecuttingedgeofscience,andtheypromisepowerfulapplicationstobenefitpresentandfuturegenerations.Buttheyalsopresentethicalissuesforindividualsandsociety.TopicB1.3exploressomeoftheideaspeopleusetomakedecisionsaboutapplicationsofgenetechnologyincludinggenetictestingandgeneticengineering.

Learning about genes and inheritance before GCSE (9–1)

FromstudyatKeyStages1to3learnersshould:

• knowthatlivingthingsproduceoffspringofthesamekind,butnormallyoffspringvaryandarenotidenticaltotheirparents

• knowthatheredityistheprocessbywhichgeneticinformationistransmittedfromonegenerationtothenext

• knowthatgeneticinformationisstoredinthenucleus

• understandasimplemodelofchromosomes,genesandDNA

• knowaboutthepartplayedbyWatson,Crick,WilkinsandFranklininthedevelopmentoftheDNAmodel

• knowaboutsexualreproductioninanimals,includingtheroleofgametesandtheprocessoffertilisation

• knowaboutsexualandasexualreproductioninplants,includingflowerstructuresandtheprocessesofpollinationandfertilisation.

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Statementsshowninbold typewillonlybetestedintheHigherTierpapers.

AllotherstatementswillbeassessedinbothFoundationandHigherTierpapers.

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Learning about genes and inheritance at GCSE (9–1)

B1.1 What is the genome and what does it do?

Teaching and learning narrative Assessable learning outcomesLearners will be required to:

Linked learning opportunities

Allorganismscontaingeneticmaterial.Geneticmaterialcontainsinstructionsthatcontrolhowcellsandorganismsdevelopandfunction.Mostofanorganism’scharacteristicsdependontheseinstructionsandaremodifiedbyinteractionwiththeenvironment.

Geneticmaterialinplantandanimalcellsislocatedinthenucleus,oneofthemainsub-cellularstructures.Inorganismswhosecellsdonothaveanucleus(e.g.bacteria)thegeneticmaterialislocatedinthecytoplasm.

Allthegeneticmaterialofacellistheorganism’sgenome.Inmostorganismsthegenomeispackagedintochromosomes.ChromosomesarelongmoleculesofDNA.GenesaresectionsofthisDNA.

Inthecellsofplantsandanimals,chromosomesoccurinpairs.Thetwochromosomesinapaireachcarrythesamegenes.Thetwoversionsofeachgeneinthepairarecalledalleles,andcanbethesameordifferent.Adifferentversionofageneisageneticvariant.Thegenotypeofanorganismisthecombinationofallelesithasforeachgene;thephenotypeisthecharacteristicthatresultsfromthiscombinationandinteractionwiththeenvironment.Genestellacellhowtomakeproteinsbyjoiningtogetheraminoacidsinaparticularorder.

1. a) explainhowthenucleusandgeneticmaterialofeukaryoticcells(plantsandanimals)andthegeneticmaterial,includingplasmids,ofprokaryoticcellsarerelatedtocellfunctions

b) describehowtousealightmicroscopetoobserveavarietyofplantandanimalcells

Practical work:• Useamicroscope

tolookatavarietyofplantandanimalcells.

• ExtractDNAfromplanttissue.

Specification links:• Principlesof

polymerisation,andDNAandproteinsasexamplesofpolymers(C4.2).

2. describethegenomeastheentiregeneticmaterialofanorganism

3. describeDNAasapolymermadeupofnucleotides,formingtwostrandsinadoublehelix

4. describesimplyhowthegenomeanditsinteractionwiththeenvironmentinfluencethedevelopmentofthephenotypeofanorganism,includingtheideathatmostcharacteristicsdependoninstructionsinthegenomeandaremodifiedbyinteractionoftheorganismwithitsenvironment

iLearners are not expected to describe epigenetic effects

5. explainthetermschromosome,gene,allele,variant,genotypeandphenotype

6. explaintheimportanceofaminoacidsinthesynthesisofproteins,includingthegenomeasinstructionsforthepolymerisationofaminoacidstomakeproteins

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B1.2 How is genetic information inherited?



Duringsexualreproduction,eachoffspringinheritstwoallelesofeachgene;oneallelefromeachgamete.Thetwoallelescanbetwocopiesofthesamegeneticvariant(homozygous)ordifferentvariants(heterozygous).Avariantcanbedominantorrecessive,andthecombinationofallelesdetermineswhateffectthegenehas.

GeneticdiagramssuchasfamilytreesandPunnettsquarescanbeusedtomodelandpredictoutcomesoftheinheritanceofcharacteristicsthataredeterminedbyasinglegene(IaS3).However,mostcharacteristicsdependontheinstructionsinmultiplegenesandotherpartsofthegenome.

Ahumanindividual’ssexisdeterminedbytheinheritanceofgeneslocatedonsexchromosomes;specifically,genesontheYchromosometriggerthedevelopmentoftestes.

1. explainthetermsgamete,homozygous,heterozygous,dominantandrecessive

Practical work:• Microscopyofpollen

tubesonagar(nucleivisibleunderhighpower).

Ideas about Science:• Usegeneticdiagrams

(e.g.familytreesandPunnettsquares)tomodelandpredictoutcomesofsinglegeneinheritance(IaS3).

2. explainsinglegeneinheritance,includingdominantandrecessiveallelesanduseofgeneticdiagrams

3. predicttheresultsofsinglegenecrosses

4. usedirectproportionsandsimpleratiosingeneticcrosses M1c

5. usetheconceptofprobabilityinpredictingtheoutcomeofgeneticcrosses

M2e

6. recallthatmostphenotypicfeaturesaretheresultofmultiplegenesratherthansinglegeneinheritance

iLearners are not expected to describe epistasis and its effects

7. describesexdeterminationinhumans

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B1.3 How can and should gene technology be used?



Comparingthegenomesofindividualswithandwithoutadiseasecanhelptoidentifyallelesassociatedwiththedisease.Onceidentified,wecantestfortheseallelesinadults,children,fetusesandembryos,toinvestigatetheirriskofdevelopingcertaindiseases.Wecanalsoassesstheriskofadultspassingtheseallelelstotheiroffspring(includingtheidentificationof‘carriers’ofrecessivealleles).Genetictestingcanalsohelpdoctorstoprescribethecorrectdrugstoapatient(‘personalisedmedicine’),bytestingforallelesthataffecthowdrugswillworkintheirbody.

Anotherapplicationofgenetechnologyisgeneticengineering,inwhichthegenomeismodifiedtochangeanorganism’scharacteristics.Geneticengineeringhasbeenusedtointroducecharacteristicsusefultohumansintoorganismssuchasbacteriaandplants.

Genetechnologycouldhelpusprovidefortheneedsofsociety,byimprovinghealthcareandproducingenoughfoodforthegrowingpopulation.Butwithgenetictestingwemustalsoconsiderhowtheresultswillbeusedandbywhom,andtherisksoffalsepositives/negativesandmiscarriage(whensamplingamnioticfluid).Withgeneticengineeringthereareconcernsaboutthespreadofinsertedgenestootherorganisms,theneedforlong-termstudiestocheckforadversereactions,andmoralconcernsaboutmodifyinggenomesandtheapplicationofthetechnologytomodifyhumans(IaS4).

1. discussthepotentialimportanceformedicineofourincreasingunderstandingofthehumangenome,includingthediscoveryofallelesassociatedwithdiseasesandthegenetictestingofindividualstoinformfamilyplanningandhealthcare

Specification links:• Theinvolvementof

geneticandotherriskfactorsinthedevelopmentofdiseasessuchascardiovasculardisease,cancerandtype2diabetes(B2.5).

• Howcanwetreatdisease?(B2.5).

Ideas about Science:• Genetictestingand

geneticengineeringasapplicationsofsciencethathavemadeapositivedifferencetopeople’slives(IaS4).

• Discussrisks,benefits,ethicalissuesandregulationassociatedwithgenetechnology(IaS4).

2. describegeneticengineeringasaprocesswhichinvolvesmodifyingthegenomeofanorganismtointroducedesirablecharacteristics

3. describe the main steps in the process of genetic engineering including:

• isolating and replicating the required gene(s) • putting the gene(s) into a vector (e.g. a

plasmid) • using the vector to insert the gene(s) into

cells • selecting modified cells

4. explainsomeofthepossiblebenefitsandrisks,includingpracticalandethicalconsiderations,ofusinggenetechnologyinmodernagricultureandmedicine

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Chapter B2: Keeping healthy

Overview

Issuesofrisk,ethicsandsocialresponsibilityrelatedtodiseasepreventionandtreatmentinhumansandplantsareofteninthenews.Understandingthescienceofhealthanddiseaseenablesustoconsidertheissuescritically,andtoexplorepossibleanswers.

InTopicB2.1,learnersexplorehowdifferentpathogensarespreadandcausedisease,withreferencetosomecommoncommunicablediseasesofhumansandplants,theninTopicB2.2theyconsiderhowtheimmunesysteminhumansprotectsagainstinfection.

TopicB2.3looksatwaysinwhichindividualsandsocietycanreducethespreadofdiseases,linkedtoissuesofriskanddecisionmaking,forexamplewithregardtovaccinationandcontraception.

InTopicB2.4thewaythatlifestyleandgeneticfactorsincrease(ordecrease)theriskofdevelopingnon-communicablediseasesisexplored,withreferencetoideasaboutcorrelationandcause.Finally,learnerslearnaboutwaysoftreatingdiseasesinTopicB2.5andexploreissuesrelatedtothedevelopmentandtestingofnewtreatments.

Learning about health and disease before GCSE (9–1)


• appreciatethatgoodhygienehelpshumanskeephealthy

• beabletoidentifyandnamethemainpartsofthehumancirculatorysystem,anddescribethefunctionsoftheheart,bloodvesselsandblood

• appreciatetheimportanceofbacteriainthehumandigestivesystem

• knowthatanimals,includinghumans,needtherighttypesandamountofnutrition,andthata

healthyhumandietincludescarbohydrates,lipids(fatsandoils),proteins,vitamins,minerals,dietaryfibreandwater

• recallsomeoftheconsequencesofimbalancesinthediet,includingobesity,starvationanddeficiencydiseases

• recognisetheimpactofdiet,exercise,drugsandlifestyleonthewaytheirbodiesfunction

• recallsomeoftheeffectsofrecreationaldrugs(includingsubstancemisuse)onbehaviour,healthandlifeprocesses.

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Learning about health and disease at GCSE (9–1)

B2.1 What are the causes of disease?

Teaching and learning narrative Assessable learning outcomesLearnerswill be required to:


Thehealthofmostorganismswillbecompromisedbydiseaseduringtheirlifetime.Physicalandmentalhealthcanbecompromisedbydiseasecausedbyinfectionbyapathogen,anorganism’sallelesorlifestyle,ortrauma.Diseasedamageshostcellsandimpairsfunctions,causingsymptoms.However,anunhealthyorganismmaynotalwaysshowsymptomsofdisease,particularlyduringthe‘incubationperiod’afterinfectionwithapathogen.

Somediseasesarecommunicable:theyarecausedbypathogenicbacteria,viruses,protistsandfungi,andcanbespreadfromorganismtoorganisminbodilyfluids,onsurfaces,andinfoodandwater.Otherdiseasesarenon-communicable:theyarecausedbygeneticand/orlifestylefactorsandcannotbespreadfromoneorganismtoanother.

Somecommondiseasesillustratedifferenttypesofpathogenandcommonroutesofspreadandinfection,including:

Inhumans:influenza(viral),Salmonellafoodpoisoning(bacterial),Athlete’sfoot(fungal),malaria(protist)andHIV(viralSTI).

Inplants:tobaccomosaicvirus(viral),ashdieback(fungal)andcrowngalldisease(bacterial).

1. describetherelationshipbetweenhealthanddisease Practical work:• Modelthespread

ofinfectionusingliquids(whereoneis‘infected’withaninvisiblechemicalthatcanbedetectedexperimentally).

• Cultureandmicroscopyofswabsfromdifferentsurfaces.

2. describedifferenttypesofdiseases(includingcommunicableandnon-communicablediseases)

3. explainhowcommunicablediseases(causedbyviruses,bacteria,protistsandfungi)arespreadinanimalsandplants

4. describecommonhumaninfectionsincludinginfluenza(viral),Salmonella(bacterial),Athlete’sfoot(fungal)andmalaria(protist)andsexuallytransmittedinfectionsinhumansincludingHIV/AIDS(viral)

5. describeplantdiseasesincludingtobaccomosaicvirus(viral),ashdieback(fungal)andcrowngalldisease(bacterial)

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B2.2 How do organisms protect themselves against pathogens?



Humanshavephysical,chemicalandmicrobialdefencesthatmakeitdifficultforpathogenstoentertheblood.Theseincludetheskinandmucus,stomachacid,saliva,tears,andbacteriainthegut.

Thesedefencesarealwayspresent,andarenotproducedinresponsetoanyspecificpathogen.Plateletshelptosealwoundstoreducethechanceofpathogensenteringtheblood.

Theimmunesystemofthehumanbodyworkstoprotectusagainstdiseasecausedbypathogens.

Ifapathogenenterstheblood,whitebloodcellsdestroyit.Whitebloodcellshavereceptorsthatbindtoantigensonpathogens,todistinguishbetweennon-selfandself.Differenttypesofwhitebloodcellareadaptedtoeitheringestanddigestpathogens,orreleasechemicalsthatbreakthemdown,orproduceantibodiestodisablethemortagthemforattackbyotherwhitebloodcells.Anantibodyisspecificfor(onlybindsto)aparticularantigen.Oncethebodyhasmadeantibodiesagainstapathogen,memorycellsstayinthebodytomakeantibodiesquicklyuponre-infection(immunity).

1. describenon-specificdefencesystemsofthehumanbodyagainstpathogens,includingexamplesofphysical,chemicalandmicrobialdefences

2. explainhowplateletsareadaptedtotheirfunctionintheblood

3. explaintheroleoftheimmunesystemofthehumanbodyindefenceagainstdisease

4. explainhowwhitebloodcellsareadaptedtotheirfunctionsintheblood,includingwhattheydoandhowithelpsprotectagainstdisease

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B2.3 How can we prevent the spread of infection?



Reducingandpreventingthespreadofcommunicablediseasesinanimalsandplantshelpspreventlossoflife,destructionofhabitatsandlossoffoodsources.Forplants,strategiesincluderegulatingthemovementofplantmaterial,sourcinghealthyplantsandseeds,destroyinginfectedplants,polyculture,croprotationandchemicalandbiologicalcontrol.Foranimals,includinghumans,strategiesincludevaccination(toestablishimmunity),contraception,hygiene,sanitation,sterilisingwounds,restrictingtravel,anddestructionofinfectedanimals.

Thelikelyeffectiveness,benefits,risksandcostofeachstrategymustbeconsidered,andanindividual’srighttodecidebalancedwithwhatisbestforsociety(IaS4).

1. explainhowthespreadofcommunicablediseasesmaybereducedorpreventedinanimalsandplants,toincludeaminimumofonecommonhumaninfection,oneplantdiseaseandsexuallytransmittedinfectionsinhumansincludingHIV/AIDS

Practical work:• Investigatemicrobial

growthondifferentfoodsandsurfacesindifferentconditions.

Ideas about Science:• Discussriskand

decisionmakinginthecontextofdiseaseprevention(IaS4).

2. explaintheuseofvaccinesinthepreventionofdisease,includingtheuseofsafeformsofpathogensandtheneedtovaccinatealargeproportionofthepopulation

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B2.4 How can lifestyle, genes and the environment affect health?



Whetherornotapersondevelopsanon-communicablediseasedependsonmanyfactors,includingtheallelestheyinheritedandaspectsoftheirlifestyle.Theinteractionofgeneticandlifestylefactorscanincreaseordecreasetherisk.

Differenttypesofdiseasecaninteract,suchaswhenhavingadiseaseincreasesordecreasestheriskofdevelopingorcontractinganother.

1. a) describehowtheinteractionofgeneticandlifestylefactorscanincreaseordecreasetheriskofdevelopingnon-communicablehumandiseases,includingcardiovasculardiseases,manyformsofcancer,somelungandliverdiseasesanddiseasesinfluencedbynutrition,includingtype2diabetes

b) describehowtopracticallyinvestigatetheeffectofexerciseonpulserateandrecoveryrate

Specification links:• Whatcauses

cancer(B4.3).• Diseasescaused

bygenes(B1.2/3).

Practical work:• Investigatethe

amountsoffatandsugarinfoods/drinks.

• Measurebloodpressure,recoveryrate.

Ideas about Science:• Discusscorrelation,

causeandriskinthecontextofnon-communicablediseases(IaS3,IaS4).

2. usegivendatatoexplaintheincidenceofnon-communicablediseasesatlocal,nationalandgloballevelswithreferencetolifestylefactors,includingexercise,diet,alcoholandsmoking

3. inthecontextofdatarelatedtothecauses,spread,effectsandtreatmentofdisease:

a) translateinformationbetweengraphicalandnumericalforms

M4a b) constructandinterpretfrequencytablesanddiagrams,bar

chartsandhistograms M4a,M4c c) understandtheprinciplesofsamplingasappliedtoscientific

data M2d d) useascatterdiagramtoidentifyacorrelationbetweentwo

variables M2g

4. describeinteractionsbetweendifferenttypesofdisease

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B2.5 How can we treat disease?



Humanshavedevelopedmedicines,includingantibiotics,whichcancontroloreliminatethecauseofsomediseasesand/orreducethelengthorseverityofsymptoms.

Fornon-communicablediseasessuchascardiovasculardisease,strategiesthatlowertheriskofdevelopingthediseasehavebenefitscomparedtotreatmentsadministeredlater.

Manyfactorsneedtobeconsideredwhenprescribingtreatments,includingthelikelyeffectiveness,riskofadversereactions,patientconsent,andthecostsandbenefitstothepatientandothers(IaS4).

Studyingthegenomesandproteinsofpathogensandhostcellscansuggesttargetsfornewmedicines.Largelibrariesofchemicalsarescreenedfortheirabilitytoaffectatarget.Itisunlikelythataperfectmedicinewillbefoundduringscreening,butchemicalsareselectedformodificationandfurthertests.

Allnewmedicineshavetobetestedbeforetheyaremadewidelyavailable.Preclinicaltesting,forsafetyandeffectiveness,usesanimalsandculturedhumancells.Clinicaltestinguseshealthyhumanvolunteerstotestforsafety,andhumanswiththediseasetotestforsafetyandeffectiveness.‘Open-label’,‘blind’and‘double-blind’trialscanbeused.Thereareethicalquestionsaroundusingplacebosintestsonpeoplewithadisease(IaS4).

1. explaintheuseofmedicinesinthetreatmentofdisease

Specification links:• ‘Personalised

medicine’(B1.3).• Antibiotic

resistanceinmicroorganisms(B6.1).

Ideas about Science:• Riskanddecision

makinginthecontextofmedicinesandtreatment(IaS4).

2. calculatecross-sectionalareasofbacterialculturesandofclearzonesaroundantibioticdiscsonagarjellyusingπr2

M5c PAGB5

3. evaluatedifferentstrategiesforloweringtheriskofcardiovasculardiseaseandtreatingit,includinglifestylechanges,useofmedicinesandsurgery

4. describetheprocessofdiscoveryanddevelopmentofpotentialnewmedicinesincludingpreclinicalandclinicaltesting

Ideas about Science:• Ethicsinthe

contextofusingplacebosinclinicaltestingofnewmedicines(IaS4).

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Chapter B3: Living together – food and ecosystems

Overview

Alllivingorganismsdependontheabilityofphotosyntheticorganismstosynthesiseglucosefromcarbondioxideandwaterinthepresenceoflight,andonfeedingrelationshipstotransferbiomassthroughcommunities.

FromstudyatearlierKeyStages,learnerswillbefamiliarwiththereactantsandproductsofphotosynthesis,andtheneedforlightintheprocess.InTopicsB3.1andB3.2thecontextofphotosynthesisisusedtoexploreseveralfundamentalconceptsin

biology,includingenzymeactionandthemovementofchemicalsbydiffusion,osmosisandactivetransport.

LearnersexpandtheirknowledgeoftheinterdependenciesbetweenorganismswithinecosystemsinTopicB3.3,throughunderstandingoffoodwebs,competitionforresources,andthecyclingofchemicals.

Finally,TopicB3.4considerstheeffectsthatenvironmentalchangesandhumanactivitiescanhaveoninteractingpopulationswithinecosystems.

Learning about food and ecosystems before GCSE (9–1)


• understandthesimilaritiesanddifferencesbetweenplantandanimalcells

• knowthatsomeorganismsmaketheirownfoodusingphotosynthesis

• knowthatphotosynthesisinplantcellsoccursinthechloroplasts

• knowthereactantsin,andproductsof,photosynthesis,andbeabletowriteawordsummary

• knowthatphotosynthesisrequireslight• befamiliarwiththeadaptationsofleavesfor

photosynthesis,andtheroleofstomataingasexchange

• knowthatwaterandmineralsenteraplantthroughtheroots

• knowthatmoleculesofasolutemovethroughsolvent,andthroughcellmembranes,bydiffusion

• knowthatanimalsobtaintheirfoodfromplants(andotheranimalsthatateplants)

• understandthedifferencebetweencarnivores,herbivoresandomnivores,andbetweenproducersandconsumers

• knowthatindividualsofthesametypelivinginthesameplacemakeupapopulation,andthatalltheinteractingpopulationsinanecosystemmakeupthecommunity

• understandtheuseoffoodchainsandfoodwebsasmodelsofthefeedingrelationshipswithinacommunity

• appreciatetheinterdependenceoforganismsinacommunity,includingfoodwebs,thebreakdownandcyclingofmaterials,andanimalsaspollinators

• knowthatchangesinanecosystemcanaffectthesurvivalofindividualsandpopulations.

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Learning about food and ecosystems at GCSE (9–1)

B3.1 What happens during photosynthesis?



Producersmakeglucoseusingphotosynthesis.Someoftheglucoseisusedasthefuelforcellularrespiration,someisconvertedintostarchandthenstored,andtherestiscombinedwithelementsabsorbedfromtheenvironmenttomakecarbohydrates,lipidsandproteins(biomass)forgrowth.

Photosynthesisinvolvesmanychemicalreactions,butcanbesummarisedintwomainstages.Thefirststagerequireslightandchlorophyll(locatedinchloroplastsinplantcells)tosplitwatermoleculesintohydrogenandoxygen.Thehydrogenistransferredtothesecondstage,buttheoxygenisreleasedintotheatmosphereasawasteproduct.Thesecondstagecombinescarbondioxidewithhydrogentomakeglucose.

Thereactionsinphotosynthesisandmanyotherbiologicalprocessesarecatalysedbyenzymes.

Thelockandkeymodelcanbeusedtoexplainenzymeaction,andtomakepredictionsaboutandexplaintheeffectsontherateofenzyme-catalysedreactionswhenthesubstrateconcentration,temperatureandpHarechanged(IaS3).

1. a) describetheprocessofphotosynthesis,includingtheinputsandoutputsofthetwomainsstagesandtherequirementoflightinthefirststage,anddescribephotosynthesisasanendothermicprocess

b) describepracticalinvestigationsintotherequirementsandproductsofphotosynthesis

PAGB4

Practical work:• Onawholeplant,wrap

oneleafinfoil,andencloseanotherleafinaconicalflaskwithasmallamountofKOH(toremoveCO2);after24h,testleavesforstarch.

2. explainhowchloroplastsinplantcellsarerelatedtophotosynthesis

3. a) explainthemechanismofenzymeactionincludingtheactivesite,enzymespecificityandfactorsaffectingtherateofenzymecatalysedreactions,includingsubstrateconcentration,temperatureandpH

b) describepracticalinvestigationsintotheeffectofsubstrateconcentration,temperatureandpHontherateofenzymecontrolledreactions

M2b,M2f,M3d,M4a,M4b,M4c PAGB3

Practical work:• Investigateeffectsof

substrateconcentration,temperatureandpHonenzymeactivity.

Ideas about Science:• Lockandkeymodel

toexplainandmakepredictionsaboutenzymeactivity(IaS3).

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B3.1 What happens during photosynthesis?



Understandingofhowfactorsaffectenzymeactivityhelpstoexplaintheeffectsoftemperatureandcarbondioxideconcentrationontherateofphotosynthesis.Theeffectoflightintensityisexplainedbytheneedforlighttobringaboutreactionsinphotosynthesis.Light intensity is inversely proportional to the square of the distance from the light source (the inverse square law); this helps to explain why the rate of photosynthesis changes with distance from a point light source.

4. a) explaintheeffectoftemperature,lightintensityandcarbondioxideconcentrationontherateofphotosynthesis

b) describepracticalinvestigationsintotheeffectofenvironmentalfactorsontherateofphotosynthesis

PAGB4

Practical work:• Investigaterateof

photosynthesisbycollectinggasorcountingbubblesfrompondweed.

• Useadataloggertomeasureoxygenconcentration,pH,temperatureandlightintensityover24hforpondweed

5. use the inverse square law to explain why the rate of photosynthesis changes with distance from a light source

6. explain the interaction of temperature, light intensity and carbon dioxide concentration in limiting the rate of photosynthesis, and use graphs depicting the effects

7. inthecontextoftherateofphotosynthesis: a) understandandusesimplecompoundmeasuressuch

astherateofareaction M1a,M1c b) translateinformationbetweengraphicaland

numericalform M4a c) plotanddrawappropriategraphsselecting

appropriatescalesforaxes M4a,M4c d) extractandinterpretinformationfromgraphs,charts

andtables M2c

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B3.2 How do producers get the substances they need?



Thewaysinwhichphotosyntheticorganismstakeincarbondioxideandwaterforphotosynthesis,andreleasethewasteproductoxygen,illustratetheprinciplesofdiffusionandosmosis.Generally,moleculesmovefromaregionoftheirhigherconcentrationtoaregionoftheirlowerconcentration;thedifferenceinconcentrationdrivesachangetowardsequalconcentration.Carbondioxideandoxygenmoleculesmovebydiffusion,throughcellmembranesinsingle-cellular(prokaryotic)producers,andthroughstomataandcellmembranesinplants.Watermoleculesmovebyosmosisthroughcellmembranes;projectionsfromrootcells(‘roothairs’)ofplantsincreasethesurfaceareaforosmosis.

Thewayinwhichphotosyntheticorganismstakeinnitrogen(tomakeproteins)illustratestheprocessofactivetransport.Producersgetnitrogenfromnitrateions(NO3

–).Moleculesofwaterandgasescandiffusethroughpartially-permeablecellmembranesbutnitrateionscannot;producersuseenergyfrommoleculesofATPtotransportnitrateionsthroughthecellmembranebyactivetransport.

Plantsdonothavebloodtotransportsubstancesaroundtheorganism;theyhavetransportvesselsformedfromxylemandphloem.

Waterandions(e.g.nitrate)inaqueoussolutionaremovedthroughxylemfromtherootsandupthestem/trunkbytranspiration,toreplacewaterthatevaporatesfromopenstomata.

1. describesomeofthesubstancestransportedintoandoutofphotosyntheticorganismsintermsoftherequirementsofthoseorganisms,includingoxygen,carbondioxide,waterandmineralions

Practical work:• Investigatediffusion

usingdropsofinkinwaterandinagarinPetridishesongraphpaper.

• Investigatediffusionacrossapartiallypermeablemembraneusingstarchsuspensionindialysistubinginabeakerofwater;compareaddingiodinesolutioninsideversusoutsidethetubing.

• Investigatetheeffectofsoluteconcentrationonosmosisusingpotatocylindersinsugarsolution.

2. a) explainhowsubstancesaretransportedintoandoutofcellsthroughdiffusion,osmosisandactivetransport

b) describepracticalinvestigationsintotheprocessesofdiffusionandosmosis

iLearners are not expected to explain osmosis in terms of water potential

3. explainhowthepartiallypermeablecellmembranesofplantcellsandprokaryoticcellsarerelatedtocellfunctions

4. explainhowwaterandmineralionsaretakenupbyplants,relatingthestructureoftheroothaircellstotheirfunction

5. a) explainhowthestructureofthexylemandphloemareadaptedtotheirfunctionsintheplant

b) describehowtousealightmicroscopetoobservethestructureofthexylemandphloem

PAGB1

Practical work:• Useeosinstainto

observexyleminbroadbeanplantstemunderhandlensandmicroscope.

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B3.2 How do producers get the substances they need?



Sugarsaremovedthroughphloemfromphotosynthetictonon-photosynthetictissuesbytranslocation.Sugarsareloadedintophloembyactivetransport,thenwatermovesintotheconcentratedsolutionbyosmosisandpushesthesubstancesalongthetube.

Therateofwateruptakebyaplantcanbeaffectedbyenvironmentalfactors.Lightintensityandtemperatureaffecttherateofphotosynthesis(andthereforethedemandforwater),whileairmovementandtemperatureaffecttherateofwaterlossfromaerialpartsoftheplant.

6. a) describetheprocessesoftranspirationandtranslocation,includingthestructureandfunctionofthestomata

b) describehowtousealightmicroscopetoobservethestructureofstomata

PAGB1 c) describehowtouseasimplepotometer

iLearners are not expected to describe transpiration in terms of tension or pressure, and are not expected to describe translocation in terms of water potential or hydrostatic pressure

• Observestomata(painttwothinlayersofnailvarnishontoaleaf,putcleartapeoverthenpeeloff,sticktomicroscopeslide).

7. a) explaintheeffectofavarietyofenvironmentalfactorsontherateofwateruptakebyaplant,toincludelightintensity,airmovement,andtemperature

b) describepracticalinvestigationsintotheeffectofenvironmentalfactorsontherateofwateruptakebyaplant

8. inthecontextofwateruptakebyplants: a) usesimplecompoundmeasuressuchasrate M1a,M1c b) carryoutratecalculations M1a,M1c c) plot,drawandinterpretappropriategraphs M4a,M4b,M4c,M4d d) calculatepercentagegainandlossofmass M1c

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B3.3 How are organisms in an ecosystem interdependent?



Producerstakeincarbonandnitrogencompoundsfromtheirenvironmentandusethem(alongwithoxygen,hydrogenandotherelements)tomakesmallorganicmoleculesincludingsugars,fattyacids,glycerolandaminoacids.Thesesmallmoleculesareusedtomakelargerorganicmolecules,suchaslong-chaincarbohydrates,lipidsandproteins.Thelargermoleculesareusedtobuildnewstructures(e.g.membranes,organelles).

Consumerscanonlygettheirsupplyofcarbonandnitrogencompoundsbyeatingproducers(orotherconsumersthatateproducers)anddigestingthebiomass.Thisreleasesthesmallmoleculessotheycanbeabsorbedandthenusedtobuildbiomassintheconsumer.

Thetransferofbiomassbetweenorganismsisonewayinwhichthepopulationsinacommunityareinterdependent,andcanbemodelledusingafoodweb(IaS3).

Thesizeofeachpopulationinacommunityislimitedbypredationandcompetitionforfoodandotherresourcesincludingspace,water,light,shelter,mates,pollinatorsandseeddispersers.

Substancesessentialtolife,includingwaterandcarbon,cyclethroughthebioticandabioticcomponentsofecosystemssothattheycanbeusedandreusedbyorganisms.Watercyclesthroughprecipitation,foodchains,transpiration,excretion,run-off,flowthroughstreams/rivers/oceans,andevaporation.Carboncyclesthroughphotosynthesis,foodchains,cellularrespiration,decompositionandcombustion.Decompositioniscatalysedbyenzymesreleasedbymicroorganisms.

1. a) explaintheimportanceofsugars,fattyacidsandglycerol,andaminoacidsinthesynthesisandbreakdownofcarbohydrates,lipidsandproteins

b) describetheuseofqualitativetestsforbiologicalmolecules

Practical work:• Investigatethebreak

downofstarchintosugarsusingamylaseandteststrips.

Ideas about Science:• Useafoodwebasa

modeltoexplaininterdependenceinacommunity,identifylimitationsofthemodel,anduseittomakepredictionsabouttheeffectsthatachangeintheecosystemcouldhaveontheinteractingpopulations(IaS3).

2. describephotosyntheticorganismsasthemainproducersoffoodandthereforebiomassforlifeonEarth

3. describesomeofthesubstancestransportedintoorganismsintermsoftherequirementsofthoseorganisms,includingdissolvedfoodmolecules

4. describedifferentlevelsoforganisationinanecosystemfromindividualorganismstothewholeecosystem

5. explaintheimportanceofinterdependenceandcompetitioninacommunity

6. recallthatmanydifferentsubstancescyclethroughtheabioticandbioticcomponentsofanecosystem

Practical work:• Culturemicroorganisms

onstarchagar,stainwithiodinesolution;clearareasbeyondculturesshowdigestionbyextracellularamylase.

7. explaintheimportanceofthecarboncycleandthewatercycletolivingorganisms

8. explaintheroleofmicroorganismsinthecyclingofsubstancesthroughanecosystem

9. calculatethepercentageofmass,inthecontextoftheuseandcyclingofsubstancesinecosystems

M1c

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B3.4 How are populations affected by the conditions in an ecosystem?



Thedistributionandabundanceoforganismsinanecosystemdependsonabioticandbioticfactors.Thesizeofoneormorepopulationsinacommunitymaybeaffectediftheenvironmentalconditionschange,orifanewsubstance,competitor,predatororpathogenisintroduced.Asubstancecanbioaccumulateinafoodchaintotoxicconcentration,andsomecancauseeutrophication.Achangeinthesizeofapopulationwillaffectotherpopulationsinthesamecommunity.

Thedistributionandabundanceoforganisms,andchangingconditions,withinanecosystemcanbeinvestigatedusingtechniquesincluding:identificationkeys;transectsandquadrats;capture,mark,releaseandrecapture;samplinglivingindicators;andusinginstrumentstomeasureabioticfactorssuchastemperature,lightintensity,soilmoistureandpH.

1. explainhowsomeabioticandbioticfactorsaffectcommunities,includingenvironmentalconditions,toxicchemicals,availabilityoffoodandotherresources,andthepresenceofpredatorsandpathogens


distributionandabundanceoforganismsinanecosystem.

2. describehowtocarryoutafieldinvestigationintothedistributionandabundanceoforganismsinanecosystemandexplainhowtodeterminetheirnumbersinagivenarea

M2d PAGB2

3. inthecontextofdatarelatedtoorganismswithinapopulation: a) calculatearithmeticmeans M2b,M2f b) understandandusepercentiles M1c c) plotanddrawappropriategraphsselectingappropriate

scalesfortheaxes M4a,M4c d) extractandinterpretinformationfromcharts,graphsand

tables M2c

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Chapter B4: Using food and controlling growth

Overview

Alllivingorganismsdependonmoleculesofglucoseobtainedfromphotosynthesis(orfrombiomassobtainedthroughfoodchainsthatstartwithphotosyntheticorganisms).Theglucoseisusedforcellularrespirationandinthesynthesisoflargerorganicmoleculesusedforgrowth.

FromstudyatearlierKeyStages,learnerswillbefamiliarwiththereactantsandproductsofcellularrespiration.InTopicB4.1theyexplorehowcellularrespirationincreasestheamountofenergyassociatedwithcellularenergystores,inparticularmoleculesofATPthatareessentialformanylifeprocesses.InTopicB4.2theyconsiderbrieflyhowwecametoknowwhatwedoaboutorganellessuchas

mitochondria,usingthecontextofelectronmicroscopytoillustratetheideathatsomescientificexplanationswereonlydevelopedonceatechnologicaldevelopmentmadecertainobservationspossible.

TopicB4.3linksgrowthinmulticellularorganismstothedivisionofcellsduringthecellcycle,andexploresthenatureofstemcellsandtheroleofcelldifferentiation.Asadevelopmentofideas,learnersconsiderhowcancerresultsfromchangesinDNAthatcausealossofcontrolofcelldivision.

Finally,TopicB4.4exploresthequestionofwhetherstemcellsshouldbeusedtoregeneratetissueandtreatdisease.

Learning about cellular respiration and growth before GCSE (9–1)


• befamiliarwiththeprocessesofaerobicandanaerobicrespirationinlivingorganisms,andfermentationinmicroorganisms,includingwordsummariesofthereactions

• beabletorecallthedifferencesbetweenaerobicandanaerobicrespirationintermsofthereactants,productsandimplicationsfortheorganism

• befamiliarwiththetissuesandorgansofthehumandigestivesystem,includingadaptationstofunction

• understandinsimpletermsthatthehumandigestivesystemuseschemicals(includingenzymes)todigestfood

• appreciatetheimportanceofbacteriainthehumandigestivesystem

• knowhownutrientsandwateraretransportedwithinanimals,includinghumans.

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Learning about cellular respiration and growth at GCSE (9–1)

B4.1 What happens during cellular respiration?



Consumersgainbiomassfromotherorganismswhentheyeatthem.Someofthisbiomassisconvertedintomoleculesofglucose,thefuelforcellularrespiration.

CellularrespirationinvolvesmanychemicalreactionsandmakesmoleculesofATP.Itoccursinthecytoplasmandmitochondriaofanimalandplantcells,andinthecytoplasmofmicroorganisms.ATPisrequiredforprocessesthatareessentialforlife,includingbreakdownandsynthesisofmolecules,activetransportandmusclecontraction.

Aerobicrespirationbreaksdownglucoseandcombinesthebreakdownproductswithoxygen,makingwaterandcarbondioxide(awasteproduct).

Inconditionsoflowornooxygen(suchasinhumancellsduringvigorousexercise,plantrootcellsinwaterloggedsoilandbacteriainpuncturewounds)anaerobicrespirationoccurs.Thereisapartialbreakdownofglucose,producingfewermoleculesofATP.Inanimalcellsandsomebacteria,thisproduceslacticacid(awasteproduct).Inplantsandsomemicroorganisms,includingyeast,itproducesethanolandcarbondioxide.

1. comparetheprocessesofaerobicandanaerobicrespiration,includingconditionsunderwhichtheyoccur,theinputsandoutputs,andcomparativeyieldsofATP


amountofenergyreleasedfromdifferentfoods,byburningthemunderaboilingtubeofwaterwhere:

energy(kJ)=massofwater(kg)×changeintemperature(°C)×4.2kJ/kg(°C).

• InvestigaterespirationinmicroorganismsbycollectingCO2givenoff;whichsubstrateworksbest?

2. explainwhycellularrespirationoccurscontinuouslyinalllivingcells

3. explainhowmitochondriaineukaryoticcells(plantsandanimals)arerelatedtocellularrespiration

4. describecellularrespirationasanexothermicprocess

5. a) describepracticalinvestigationsintotheeffectofdifferentsubstratesontherateofrespirationinyeast(PAGB4)

b) carryoutratecalculationsforchemicalreactionsinthecontextofcellularrespiration

M1a,M1c

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B4.2 How do we know about mitochondria and other cell structures?



Scientificprogressoftenreliesontechnologicaldevelopmentswhichenablenewobservationstobemade.Theinventionoftheelectronmicroscopeenabledustoobservecellorganellessuchasmitochondriaandchloroplastsatmuchhighermagnificationthanhadpreviouslybeenpossiblewithlightmicroscopes,andthustodevelopexplanationsabouthowtheirstructuresrelatetotheirrolesincellularprocesses(IaS3).

1. explainhowelectronmicroscopyhasincreasedourunderstandingofsub-cellularstructures

Ideas about Science:• Explanationsabout

therolesofcellorganellesweredevelopedfromobservationsthatcouldonlybemadeusingelectronmicroscopy(IaS3).

2. inthecontextofcellsandsub-cellularstructures: a) demonstrateanunderstandingofnumber,sizeand

scaleandthequantitativerelationshipbetweenunits M2a,M2h b) useestimationsandexplainwhentheyshouldbeused M1d c) calculate with numbers written in standard form M1b

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B4.3 How do organisms grow and develop?



Growthofmulticellularorganismsinvolvesanincreaseinthenumberofbodycells.Allnewcellsarecreatedfromexistingcellswhentheydivide.Newbodycellsarecreatedaspartofthecellcycle.Duringinterphasethecellgrowslarger,thenumbersoforganellesincrease,andeachchromosomeiscopied;thenduringmitosisthechromosomecopiesseparate,thenucleusdivides,andthecelldividestoproducetwonewcellsthataregeneticallyidenticaltooneanother.

Cancerisanon-communicablediseaseinhumanscausedbychangesinaperson’sDNA.Thechangescauseacelltodividemanytimesbymitosis,whichcancreateatumour.

Gametesareproducedbymeiosis,adifferenttypeofcelldivision.Afterinterphase(duringwhichthechromosomenumberhasdoubled),twomeioticdivisionsoccur.Gametescontainhalfthenumberofchromosomesfoundinbodycells(onechromosomefromeachpair).Atfertilisation,maternalandpaternalchromosomespairup,sothezygotehasthenormalchromosomenumber.

Azygotedividesbymitosistoformanembryo.Allofthecellsinanembryoareinitiallyidenticalandunspecialised;theseareembryonicstemcells,andcanbecomespecialisedtoformanytypeofcell(differentiation)byswitchinggenesoffandon.Mostcellsinahumanembryobecomespecialisedaftertheeightcellstage.However,some(adultstemcells)remainunspecialisedandcanbecomespecialisedlatertobecomemany,butnotall,typesofcells.

Inplants,onlycellsinmeristemsundergomitosis,producingunspecialisedcellsthatcandevelopintoanykindofplantcell.

1. a) describetheroleofthecellcycleingrowth,includinginterphaseandmitosis

b) describehowtousealightmicroscopetoobservestagesofmitosis

PAGB1

iLearners are not expected to recall intermediate phases

Practical work:• Investigatemitosis

usingamicroscopetolookatstainedcellsfromonionroottip.

Specification links:• Factorsthat

increasetheriskofdevelopingcancer(B2.4).

2. describecancerastheresultofchangesincellsthatleadtouncontrolledgrowthanddivision

3. explaintheroleofmeioticcelldivisioninhalvingthechromosomenumbertoformgametes,includingthestagesofinterphaseandtwomeioticdivisions

i Learners are not expected to recall intermediate phases

4. describethefunctionofstemcellsinembryonicandadultanimalsandmeristemsinplants

5. explaintheimportanceofcelldifferentiation,inwhichcellsbecomespecialisedbyswitchinggenesoffandontoformtissueswithparticularfunctions

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B4.4 Should we use stem cells to treat damage and disease?



Stemcellsofferthepotentialtotreatpatientsbyreplacingdamagedtissuesorcells.Butthebenefitsmustbeweighedagainstrisksandethicalconcernsabouttheuseanddestructionofhumanembryostocollectembryonicstemcells.Forthesereasons,useofstemcellsinresearchandmedicineissubjecttogovernmentregulationinmanycountries(IaS4).

1. discusspotentialbenefits,risksandethicalissuesassociatedwiththeuseofstemcellsinmedicine

Ideas about Science:• Stemcelltherapyasan

applicationofsciencethatcouldchangelives(IaS4).

• Risks,benefitsandethicalissuesassociatedwithuseofstemcellsinmedicine(IaS4).

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Chapter B5: The human body – staying alive

Overview

Frompreviousstudy,learnersshouldappreciatethatcellsworktogetherinmulti-cellularorganisms–inahierarchyofcells,tissues,organsandsystems–tosupportthefunctioningofeachcellandoftheorganismasawhole.Thischapterdevelopsunderstandingofhowcellsandsystemsworktogethertosupportlifeinthehumanbody.

InTopicB5.1,learnersconsiderhowthesubstancesessentialforchemicalreactionsaretransportedinto,outofandaroundthehumanbody,andwhyexchangesurfacesarenecessary.

InTopicsB5.2andB5.3theyexplorehowthenervousandendocrinesystemshelpthebodytodetectandrespondtoexternalandinternalchanges.TopicB5.4illustratestheimportanceofmaintainingaconstantinternalenvironment.

TheessentialroleofhormonesinhumanreproductionisexploredinTopicB5.5,followedinTopicB5.6byconsiderationofwhatcanhappenwhencertainstructuresandsystems–includingtheregulationofbloodsugar,structuresintheeyeandneuronsinthenervoussystem–gowrong.

Learning about the human body before GCSE (9–1)


• appreciatethehierarchicalorganisationofmulticellularorganisms:fromcellstotissuestoorganstosystemstoorganisms

• beabletoidentify,name,drawandlabelthebasicpartsofthehumanbody

• haveabasicunderstandingofthefunctionofmuscles

• befamiliarwiththetissuesandorgansofthehumandigestivesystem,includingadaptationstofunction

• understandthebasicstructuresandfunctionsofthegasexchangesysteminhumans,includingadaptationstofunction

• understandthemechanismofbreathingtomoveairinandoutofthelungs,andbeabletouseapressuremodeltoexplainthemovementofgases

• understand,inoutline,hownutrientsandwateraretransportedwithinanimals,includinghumans

• beabletoidentifyandnamethemainpartsofthehumancirculatorysystem

• befamiliarwiththefunctionsoftheheart,bloodvesselsandblood

• knowwhichpartofthebodyisassociatedwitheachsense.

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Learning about the human body at GCSE (9–1)

B5.1 How do substances get into, out of and around our bodies?



Oxygen,waterandmoleculesfromfoodareessentialforchemicalreactionsincellsinthehumanbody,includingcellularrespirationandsynthesisofbiomass.Carbondioxideandureaarewasteproductsthatneedtoberemovedfromcellsbeforetheyreachtoxiclevels.Movingthesesubstancesinto,aroundandoutofthebodydependsuponinteractionsbetweenthecirculatory,gaseousexchange,digestiveandexcretorysystems.

Oxygenandcarbondioxidediffusebetweenbloodincapillariesandairinalveoli.Wateranddissolvedfoodmoleculesareabsorbedfromthedigestivesystemintobloodincapillaries.Wasteproductsincludingcarbondioxideandureadiffuseoutofcellsintotheblood.Ureaisfilteredoutofthebloodbythekidneysintourine.Partially-permeablecellmembranesregulatethemovementofthesesubstances;gasesmoveacrossthemembranesbydiffusion,waterbyosmosisandsomeothersubstancesbyactivetransport.

Theheart,bloodvessels,redbloodcellsandplasmaareadaptedtotransportsubstancesaroundthebody.

Tosustainallthelivingcellsinsidehumansandothermulti-cellularorganisms,exchangesurfacesincreasethesurfacearea:volumeratio,andthecirculatorysystemmovessubstancesaroundthebodytodecreasethedistancetheyhavetodiffusetoandfromcells.

1. describesomeofthesubstancestransportedintoandoutofthehumanbodyintermsoftherequirementsofcells,includingoxygen,carbondioxide,water,dissolvedfoodmoleculesandurea

Practical work:• Dissectlamb’sheart

toobserveatria,ventriclesandvalves.

• Investigatevalvesinanarmvein(tourniquetaroundbicep;whenveinsbecomeprominent,gentlytrytopushbloodineachdirection).

2. explainhowthepartially-permeablecellmembranesofanimalcellsarerelatedtodiffusion,osmosisandactivetransport

3. describethehumancirculatorysystem,includingitsrelationshipswiththegaseousexchangesystem,thedigestivesystemandtheexcretorysystem

4. explainhowthestructureoftheheartisadaptedtoitsfunction,includingcardiacmuscle,chambersandvalves

5. explainhowthestructuresofarteries,veinsandcapillariesareadaptedtotheirfunctions,includingdifferencesinthevesselwallsandthepresenceofvalves

6. explainhowredbloodcellsandplasmaareadaptedtotheirfunctionsintheblood

7. explaintheneedforexchangesurfacesandatransportsysteminmulticellularorganismsintermsofsurfacearea:volumeratio


effectofsurfacearea:volumeratioondiffusionofdyeintoagarcubes.

8. calculatesurfacearea:volumeratios M1c,M5c

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B5.2 How does the nervous system help us respond to changes?



Inordertosurvive,organismsneedtodetectandrespondtochangesintheirexternalandinternalenvironments.Thehighlyadaptedstructuresofthenervoussystemfacilitatefast,short-lastingresponsestostimuli.

Inastimulatedneuron,anelectricalimpulsepassesalongtheaxon.Mostaxonshaveafattysheathtoincreaseimpulsetransmissionspeed.Animpulseistransmittedfromoneneurontoanotheracrossasynapsebythereleaseoftransmittersubstances,whichdiffuseacrossthegapandbindtoreceptorsonthenextneuron,stimulatingit.

Reflexesproviderapid,involuntaryresponseswithoutinvolvingaprocessingcentre,andareessentialtothesurvivalofmanyorganisms.Insomecircumstancesthebraincanmodifyareflexresponseviaaneurontothemotorneuronofthereflexarc(e.g.tostopusdroppingahotobject).

1. explainhowthecomponentsofthenervoussystemworktogethertoenableittofunction,includingsensoryreceptors,sensoryneurons,theCNS,motorneuronsandeffectors

2. explainhowthestructuresofnervecellsandsynapsesrelatetotheirfunctions

iLearners are not expected to explain nerve impulse transmission in terms of membrane potentials

3. a) explainhowthestructureofareflexarc,includingtherelayneuron,isrelatedtoitsfunction

b) describepracticalinvestigationsintoreflexactions

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B5.3 How do hormones control responses in the human body?



Theendocrinesystemofhumansandotheranimalsuseshormones,secretedbyglandsandtransportedbytheblood,toenablethebodytorespondtoexternalandinternalstimuli.Hormonesbindtoreceptorsoneffectors,stimulatingaresponse.Theendocrinesystemprovidesslower,longer-lastingresponsesthanthenervoussystem.The production of hormones is regulated by negative feedback.

1. describetheprinciplesofhormonalcoordinationandcontrolbythehumanendocrinesystem

2. explain the roles of thyroxine and adrenaline in the body, including thyroxine as an example of a negative feedback system.

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B5.4 Why do we need to maintain a constant internal environment?



Cells,enzymesandlifeprocessesfunctiononlyincertainconditions,andoptimallywhenconditionsarewithinanarrowrange.Themaintenanceofaconstantinternalenvironmentishomeostasis,anddependsonreceptors,nerves,hormonesand(oftenantagonistic)effectorstocounteractchanges.

1. explaintheimportanceofmaintainingaconstantinternalenvironmentinresponsetointernalandexternalchange

Specification links:• Theeffectsoftemperatureon

enzymeactivity(B3.1).

Practical work:• Compareskintemperatureand

corebodytemperatureunderdifferentconditions.

• Modelthecontroloftemperaturebytryingtokeepabeakerofwaterat40°CusingjustaBunsenburner(singleeffector)comparedtoaBunsenburnerandice(antagonisticeffectors).

2. inthecontextofmaintainingaconstantinternalenvironment:

a) extractandinterpretdatafromgraphs,chartsandtables

M2c b) translateinformationbetweennumericaland

graphicalforms M4a

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B5.5 What role do hormones play in human reproduction?



Hormonesplayavitalroleinenablingsexualreproductioninhumans:theyregulatethemenstrualcycle,includingovulation,inadultfemales.Withoutthisprocess,sexualreproductionwouldnotbepossible.

A number of hormones interact to control the menstrual cycle:

• FSH causes the ovaries to develop a follicle containing an egg, and produce oestrogen

• oestrogen causes the uterus wall to thicken• LH causes the follicle to release the egg (ovulation)• the remains of the follicle secrete progesterone• progesterone prepares the lining of the uterus for implantation

of a fertilised egg• oestrogen and progesterone stop the production of LH and FSH• as progesterone levels fall, the thickened uterus wall breaks down

and is discharged (menstruation).

Themenstrualcyclecanbecontrolledartificiallybytheadministrationofhormones,oftenasanoralpill.Thehormonespreventovulation,socanbeusedasacontraceptive,buttheydonotdecreasetheriskofsexualtransmissionofcommunicablediseases(IaS4).

1. describetheroleofhormonesinhumanreproduction,includingthecontrolofthemenstrualcycle

2. explain the interactions of FSH, LH, oestrogen and progesterone in the control of the menstrual cycle

3. explaintheuseofhormonesincontraceptionandevaluatehormonalandnon-hormonalmethodsofcontraception

Specification links:• Sexuallytransmitted

disease(B2.1).

Ideas about Science:• Riskinthecontextof

sexandcontraception(IaS4).

Hormones can also be used to artificially manipulate the menstrual cycle as a treatment in certain cases of female infertility in which follicle development and ovulation do not occur successfully. The use of hormones to treat infertility is an example of an application of science that has made a significant positive difference to people’s lives (IaS4).

4. explain the use of hormones in modern reproductive technologies to treat infertility

Ideas about Science:• Infertility treatment as

an application of science that makes a positive difference to lives (IaS4).

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B5.6 What can happen when organs and control systems stop working?



Bloodsugarleveliscontrolledbyinsulinand glucagon acting antagonistically.Type1diabetesariseswhenthepancreasstopsmakinginsulin;bloodsugarcanberegulatedusinginsulininjections.Type2diabetesdevelopswhenthebodynolongerrespondstoitsowninsulinordoesnotmakeenoughinsulin;bloodsugarcanberegulatedusingdiet(highincomplexcarbohydrates),exerciseandinsulininjections.

1. explainhowinsulincontrolsthebloodsugarlevelinthebody

2. explain how glucagon and insulin work together to control the blood sugar level in the body

3. comparetype1andtype2diabetesandexplainhowtheycanbetreated

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Chapter B6: Life on Earth – past, present and future

Overview

Themodernexplanationofevolutionbynaturalselectionisoneofthecentralideasinbiology.ThehistoricaldevelopmentoftheexplanationanditsjourneytowidespreadacceptanceinthesciencecommunityillustratekeyIdeas about Science.

LearnersexploreideasaboutevolutioninKeyStages2and3,sobyKeyStage4theyshouldbefamiliarwiththeconceptsofvariation(atphenotypelevel),adaptation,advantage,competitionandnaturalselection.InTopicB6.1,learnersbegintoexpandtheirunderstandingbylinkingvariationtogenetics,andtheconceptofevolutionbynaturalselectionisexploredwithinthestoryofhowthetheorywasdeveloped,evaluatedandmodifiedbythescientificcommunity.Thetopicconsiderstheimportanceof

evidenceasthebasisforwidespreadscientificacceptanceofthetheory,andprobesreasonswhysomepeoplemaystillnotacceptit.

TheeffectsthatsexualandasexualreproductionhaveonevolutionareconsideredinTopicB6.2,followedbyabriefexaminationinTopicB6.3oftheimpactthatdevelopmentsinscientificunderstandinghavehadonthewayweclassifythediversityoflifeonEarthtoday.

Finally,inTopicB6.4learnersexaminetheimpactsofhumanactivitiesontheEarth’sbiodiversity,thetremendousimportanceofprotectingit,issuesthataffectdecisionmaking,andwaysinwhichourunderstandingofsciencecanhelpustointeractpositivelywithecosystemssothatbiodiversityandecosystemresourcesareconservedforthefuture.

Learning about evolution and biodiversity before GCSE (9–1)


• knowthattherearemanydifferenttypesoforganismslivinginmanydifferentenvironments,andthattherearesimilaritiesanddifferencesbetweenallorganisms

• recognisethatlivingorganismscanbegroupedandclassifiedinavarietyofwaysbasedoncommonalitiesanddifferences

• beabletouseclassificationkeys• recognisethatlivingorganismshavechanged

overtimeandthatfossilsprovideinformationaboutorganismsthatlivedmillionsofyearsago

• appreciatethatorganismsliveinhabitatstowhichtheyareadapted

• recognisethatorganismsproduceoffspringofthesamekind,butnormallyoffspringvaryandarenotidenticaltotheirparents

• knowthatthereisvariationbetweenindividualswithinaspecies,andthatvariationcanbedescribedascontinuousordiscontinuous

• understandthatthevariationmeanssomeorganismscompetemoresuccessfully,resultinginnaturalselection

• appreciatethatvariation,adaptation,competitionandnaturalselectionresultintheevolutionofspecies

• understandthatchangesintheenvironmentmayleaveorganismslesswelladaptedtocompetesuccessfullyandreproduce,whichcanleadtoextinction

• befamiliarwithsomeofthereasonswhyit’simportanttoprotectandconservebiodiversity,andsomewaysofdoingso.

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Learning about evolution and biodiversity at GCSE (9–1)

B6.1 How was the theory of evolution developed?



Themoderntheoryofevolutionbynaturalselectioncombinesideasaboutgenes,variation,advantageandcompetitiontoexplainhowtheinheritedcharacteristicsofapopulationcanchangeoveranumberofgenerations.Itincludestheideasthat:

MutationsinDNAcreategeneticvariants,whichmaybeinherited.Mostgeneticvariantsdonotaffectphenotype,butthosethatdomayincreaseanorganism’sabilitytosurviveinitsenvironmentsandcompeteforresources(i.e.conferanadvantage).Individualswithanadvantagearemorelikelytoreproduce;thus,bynaturalselection,theproportionofindividualspossessingbeneficialgeneticvariantsincreasesinsubsequentgenerations.

Anewspeciescanariseiftheorganismsinapopulationevolvetobesodifferentfromtheirancestorsthattheycouldnolongermatewiththemtoproducefertileoffspring.Speciationismorelikelytooccurwhentwopopulationsofanorganismareisolated.

CharlesDarwinnoticedthattheselectivebreedingofplantsandanimalshadproducednewvarietieswithmanybeneficialcharacteristics,quitedifferenttotheirwildancestors.Mostofwhatweeat,andourabilitytofeedthegrowinghumanpopulation,dependsonselectivelybredplantsandanimals.Darwinwonderedwhetherasimilarprocessofselectioninnaturecouldhavecreatednewspecies.

1. statethatthereisusuallyextensivegeneticvariationwithinapopulationofaspecies

2. recallthatgeneticvariantsarisefrommutations,andthatmost havenoeffectonthephenotype,someinfluencephenotypeandaveryfewdeterminephenotype

3. explainhowevolutionoccursthroughnaturalselectionofvariantsthatgiverisetophenotypesbettersuitedtotheirenvironment

4. explaintheimportanceofcompetitioninacommunity,withregardtonaturalselection

5. describeevolutionasachangeintheinheritedcharacteristicsofapopulationoveranumberofgenerationsthroughaprocessofnaturalselectionwhichmayresultintheformationofnewspecies

6. explaintheimpactoftheselectivebreedingoffoodplantsanddomesticatedanimals

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B6.1 How was the theory of evolution developed?



ThetheoryofevolutionbynaturalselectionwasdevelopedtoexplainobservationsmadebyDarwin,Wallaceandotherscientists,including:

• theproductionofnewvarietiesofplantsandanimalsbyselectivebreeding

• fossilswithsimilaritiesanddifferencestolivingspecies• thedifferentcharacteristicsshownbyisolatedpopulationsofthe

samespecieslivingindifferentecosystems.

Thetheoryofevolutionbynaturalselectionillustrateshowscientistscontinuetotestaproposedexplanationbymakingnewobservationsandcollectingnewevidence,andhowiftheexplanationisabletoexplaintheseitcanbecomewidelyacceptedbythescientificcommunity(IaS3).Forexample,thespreadofantibioticresistanceinbacteriacanbeexplainedbymutation,advantageandnaturalselection.

7. describehowfossilsprovideevidenceforevolution Ideas about Science:• Thetheoryof

evolutionbynaturalselectionasanexampleofhowscientificexplanationsaredeveloped(IaS3).

8. describemodernexamplesofevidenceforevolutionincludingantibioticresistanceinbacteria

Ideas about Science:• Thetheoryof

evolutionbynaturalselectionasascientificexplanationmodifiedinlightofnewbservationsandideas(IaS3).

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B6.2 How does our understanding of biology help us classify the diversity of organisms on Earth?



TheenormousdiversityoforganismsonEarthcanbeclassifiedintogroupsonthebasisofobservedsimilaritiesanddifferencesintheirphysicalcharacteristicsand,morerecently,theirDNA.Wearemorelikelytoclassifyspeciesintothesamegroupiftherearelotsofsimilaritiesintheirgenomes(i.e.iftheyhavemanygenes,andgeneticvariants,incommon).Genomeanalysiscanalsosuggestwhetherdifferentgroupshaveacommonancestor,andhowrecentlyspeciationoccurred.

1. describetheimpactofdevelopmentsinbiologyonclassificationsystems,includingtheuseofDNAanalysistoclassifyorganisms

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B6.3 Why is biodiversity threatened and how can we protect it?



ThebiodiversityoftheEarth,orofaparticulararea,isthecombinationofthediversityoflivingorganisms,thediversityofgenestheseorganismshave,andthediversityofecosystems.

Thebiodiversityofmanyareasisbeingreducedbyactivitiesrelatedtoincreasinghumanpopulationsize,industrialisationandglobalisation.Suchinteractionscanresultinecosystemsbeingdamagedordestroyed,populationsdyingout,andspeciesbecomingextinctwhenconditionschangemorequicklythantheycanadapt.Humanscaninteractwithecosystemspositivelybyusingecosystemresourcesinasustainableway(atthesamerateastheycanbereplaced),andbyprotectingandconservingbiodiversity.

Allorganisms,includinghumans,dependonotherorganismsandtheenvironmentfortheirsurvival.Protectingandconservingbiodiversitywillhelpensurewecancontinuetoprovidethehumanpopulationwithfood,materialsandmedicines.

Biodiversitycanbeprotectedatdifferentlevels,includingprotectionofindividualspecies,protectionofecosystems,andcontrolofactivitiesthatcontributetoglobalclimatechange.Decisionsaboutprotectingandconservingbiodiversityareaffectedbyecological,economic,moralandpoliticalissues(IaS4).

1. describebothpositiveandnegativehumaninteractionswithinecosystemsandexplaintheirimpactonbiodiversity

Specification links:• Greenhousegases

andglobalwarming(P1.3,C1.1).

Ideas about Science:• Theimpactsofscience

onbiodiversity,includingnegativeimpactsandpotentialsolutions(IaS4).

• Decisionmakinginthecontextoftheprotectionandconservationofbiodiversity(IaS4).

Practical work:• Measurelivingand

non-livingindicatorstoassesstheeffectofpollutiononorganisms.

2. explainsomeofthebenefitsandchallengesofmaintaininglocalandglobalbiodiversity

3. extractandinterpretinformationrelatedtobiodiversityfromcharts,graphsandtables

M2c,M4a

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Chapter C1: Air and water

Overview

Thequalityofourairandwaterisamajorworldconcern.Chemistsmonitorourairandwater,andworktominimisetheimpactofhumanactivitiesontheirquality.

InTopicC1.1,thecontextofchangesintheEarth’satmosphereisusedtoexploretheparticlemodelanditslimitationswhenexplainingchangesofstate,andtheprinciplesofbalancingequationsforcombustionreactions.

Asadevelopmentofideasaboutburningfuels,TopicC1.2considersbondinginsmall

moleculesandtemperaturechangesinchemicalreactions.

TopicC1.3explorestheevidenceforclimatechange,askingwhyitmightbeoccurringandhowseriousathreatitis.Learnersconsiderenvironmentalandhealthconsequencesofsomeairpollutantsandclimatechange,andlearnhowscientistsarehelpingtoprovideoptionsforimprovingairqualityandcombattingglobalwarming.

Finally,TopicC1.4explorestheneedforincreasingtheamountofpotablewaterworldwide,andtechniquesforobtainingpotablewaterfromground,wasteandsaltwater.

Learning about air and water before GCSE (9–1)


• beabletoexplainthepropertiesofthedifferentstatesofmatter(solid,liquidandgas)intermsoftheparticlemodel,includinggaspressure

• appreciatethedifferencesbetweenatoms,elementsandcompounds

• befamiliarwiththeuseofchemicalsymbolsandformulaeforelementsandcompounds

• knowaboutconservationofmass,changesofstateandchemicalreactions

• beabletoexplainchangesofstateintermsoftheparticlemodel

• knowthatthereareenergychangesonchangesofstate(qualitative)

• knowaboutexothermicandendothermicchemicalreactions(qualitative)

• understandthecarboncycle• knowthecompositionoftheEarth’s

atmospheretoday• knowabouttheproductionofcarbondioxide

byhumanactivityanditsimpactonclimate.

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Learning about air and water at GCSE (9–1)

C1.1 How has the Earth’s atmosphere changed over time, and why?



TheEarth,itsatmosphereanditsoceansaremadeupfromelementsandcompoundsindifferentstates.Theparticlemodelcanbeusedtodescribethestatesofthesesubstancesandwhathappenstotheparticleswhentheychangestate.Theparticlemodelcanberepresentedindifferentways,but these are limited because they do not accurately represent the scale or behaviour of actual particles, they assume that particles are inelastic spheres, and they do not fully take into account the different interactions between particles.

Theformationofourearlyatmosphereandoceans,andthestatechangesinvolvedinthewatercycle,canbedescribedusingtheparticlemodel.

Explanationsabouthowtheatmospherewasformedandhaschangedovertimearebasedonevidence,includingthetypesandchemicalcompositionofancientrocks,andfossilevidenceofearlylife(IaS3).

ExplanationsincludeideasaboutearlyvolcanicactivityfollowedbycoolingoftheEarthresultinginformationoftheoceans.Theevolutionofphotosynthesisingorganisms,formationofsedimentaryrocks,oilandgas,andtheevolutionofanimalsledtochangesintheamountsofcarbondioxideandoxygenintheatmosphere.

1. recallandexplainthemainfeaturesoftheparticlemodelintermsofthestatesofmatterandchangeofstate,distinguishingbetweenphysicalandchemicalchangesandrecognisethattheparticlesthemselvesdonothavethesamepropertiesasthebulksubstances

Practical work:• Measure

temperatureagainsttimeandplotacoolingcurveforstearicacidorheatingcurveforice.

Ideas about Science:• Usetheparticle

modeltoexplainstatechanges(IaS3).

2. explain the limitations of the particle model in relation to changes of state when particles are represented by inelastic spheres

3. useideasaboutenergytransfersandtherelativestrengthofforcesbetweenparticlestoexplainthedifferenttemperaturesatwhichchangesofstateoccur

4. usedatatopredictstatesofsubstancesundergivenconditions

5. interpretevidenceforhowitisthoughttheatmospherewasoriginallyformed

Ideas about Science:• Distinguishdata

fromexplanatoryideasinaccountsofhowtheatmospherewasformed(IaS3).

6. describehowitisthoughtanoxygen-richatmospheredevelopedovertime

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C1.1 How has the Earth’s atmosphere changed over time, and why?



Ourmodernlifestylehascreatedahighdemandforenergy.Combustionoffossilfuelsfortransportandenergygenerationleadstoemissionsofpollutants.

Carbonmonoxide,sulfurdioxide,nitrogenoxidesandparticulatesdirectlyharmhumanhealth.Somepollutantscauseindirectproblemstohumansandtheenvironmentbytheformationofacidrainandsmog.Scientistsmonitortheconcentrationofthesepollutantsintheatmosphereandstrivetodevelopapproachestomaintainingairquality(IaS4).

Thecombustionreactionsoffuelsandtheformationofpollutantscanberepresentedusingwordandsymbolequations.Theformulaeinvolvedinthesereactionscanberepresentedbymodels,diagramsorwrittenformulae.Theequationsshouldbebalanced.

Whenasubstancechemicallycombineswithoxygenitisanexampleofoxidation.Combustionreactionsarethereforeoxidation.

Somegasesinvolvedincombustionreactionscanbeidentifiedbytheirchemicalreactions.

7. describethemajorsourcesofcarbonmonoxideandparticulates(incompletecombustion),sulfurdioxide(combustionofsulfurimpuritiesinfuels),oxidesofnitrogen(oxidationofnitrogenathightemperaturesandfurtheroxidationintheair)

Ideas about Science:• Unintendedimpacts

ofburningfossilfuelsonairquality(IaS4).

• Catalyticconverters,lowsulfurpetrolandgasscrubbersaspositiveapplicationsofscience(IaS4).

8. explaintheproblemscausedbyincreasedamountsofthesesubstancesanddescribeapproachestodecreasingtheemissionsofthesesubstancesintotheatmosphereincludingtheuseofcatalyticconverters,lowsulfurpetrolandgasscrubberstodecreaseemissions

9. usechemicalsymbolstowritetheformulaeofelementsandsimplecovalentcompounds

10. usethenamesandsymbolsofcommonelementsandcompoundsandtheprincipleofconservationofmasstowriteformulaeandbalancedchemicalequations

11. usearithmeticcomputationsandratioswhenbalancingequations

M1a,M1c

12. describeteststoidentifyoxygen,hydrogenandcarbondioxide

PAGC2

13. explainoxidationintermsofgainofoxygen

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C1.2 Why are there temperature changes in chemical reactions?



Whenafuelisburnedinoxygenthesurroundingsarewarmed;thisisanexampleofanexothermicreaction.Therearealsochemicalreactionsthatcooltheirsurroundings;theseareendothermicreactions.

Energyhastobesuppliedbeforeafuelburns.Forallreactions,thereisacertainminimumenergyneededtobreakbondssothatthereactioncanbegin.Thisistheactivationenergy.Theactivationenergy,andtheamountofenergyassociatedwiththereactantsandproducts,canberepresentedusingareactionprofile.

Atomsarerearrangedinchemicalreactions.Thismeansthatbondsbetweentheatomsmustbebrokenandthenreformed.Breakingbondsrequiresenergy(theactivationenergy)whilstmakingbondsgivesoutenergy.

Energy changes in a reaction can be calculated if we know the bond energies involved in the reaction.

1. distinguishbetweenendothermicandexothermicreactionsonthebasisofthetemperaturechangeofthesurroundings

Practical work:• Investigate

differentchemicalreactionstofindoutiftheyareexothermicorendothermic.

2. drawandlabelareactionprofileforanexothermicandanendothermicreaction,identifyingactivationenergy

3. explainactivationenergyastheenergyneededforareactiontooccur

4. interpretchartsandgraphswhendealingwithreactionprofiles

5. calculate energy changes in a chemical reaction by considering bond breaking and bond making energies

M1a,M1c,M1d

6. carryoutarithmeticcomputationswhencalculatingenergychanges

M1a,M1c,M1d

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C1.3 What is the evidence for climate change, why is it occurring?



SomeelectromagneticradiationfromtheSunpassesthroughtheatmosphereandisabsorbedbytheEarthwarmingit.ThewarmEarthemitsinfraredradiationwhichsomegases,includingcarbondioxideandmethane,absorbandre-emitinalldirections;thiskeepstheEarthwarmerthanitwouldotherwisebeandiscalledthegreenhouseeffect.WithoutthegreenhouseeffecttheEarthwouldbetoocoldtosupportlife.

TheproportionofgreenhousegasesintheEarth’satmospherehasincreasedoverthelast200yearsasaresultofhumanactivities.Therearecorrelationsbetweenchangesinthecompositionoftheatmosphere,consumptionoffossilfuelsandglobaltemperaturesovertime.Althoughthereareuncertaintiesinthedata,mostscientistsnowacceptthatrecentclimatechangecanbeexplainedbyincreasedgreenhousegasemissions.

Patternsinthedatahavebeenusedtoproposemodelstopredictfutureclimatechanges.Asmoredataiscollected,theuncertaintiesinthedatadecrease,andourconfidenceinmodelsandtheirpredictionsincreases(IaS3).

Scientistsaimtoreduceemissionsofgreenhousegases,forexamplebyreducingfossilfueluseandremovinggasesfromtheatmospherebycarboncaptureandreforestation.Theseactionsneedtobesupportedbypublicregulation.Evenso,itisdifficulttomitigatetheeffectofemissionsduetotheverylargescalesinvolved.Eachnewmeasuremayhaveunforeseenimpactsontheenvironment,makingitdifficulttomakereasonedjudgmentsaboutbenefitsandrisks(IaS4).

1. describethegreenhouseeffectintermsoftheinteractionofradiationwithmatter

Specification links:• Whatisglobalwarmingand

whatistheevidenceforit?(P1.3)

Practical work:• Investigateclimatechange

models–bothphysicalmodelsandcomputermodels.

Ideas about Science: • Useideasaboutcorrelation

andcause,aboutmodelsandthewayscienceexplanationsaredevelopedwhendiscussingclimatechange(IaS3).

• Risks,costsandbenefitsoffueluseanditssustainabilityandeffectsonclimate(IaS4).

• Publicregulationoftargetsforemissionsandreasonswhydifferentdecisionsonissuesrelatedtoclimatechangemightbemadeinviewofdifferencesinpersonal,social,oreconomiccontext(IaS4).

2. evaluatetheevidenceforadditionalanthropogeniccausesofclimatechange,includingthecorrelationbetweenchangeinatmosphericcarbondioxideconcentrationandtheconsumptionoffossilfuels,anddescribetheuncertaintiesintheevidencebase

3. describethepotentialeffectsofincreasedlevelsofcarbondioxideandmethaneontheEarth’sclimateincludingwherecropscanbegrown,extremeweatherpatterns,meltingofpolariceandfloodingoflowland

4. describehowtheeffectsofincreasedlevelsofcarbondioxideandmethanemaybemitigated,includingconsiderationofscale,riskandenvironmentalimplications

5. extractandinterpretinformationfromcharts,graphsandtables

M2c,M4a

6. useordersofmagnitudetoevaluatethesignificanceofdata

M2h

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C1.4 How can scientists help improve the supply of potable water?



Theincreaseinglobalpopulationmeansthereisagreaterneedforpotablewater.Obtainingpotablewaterdependsontheavailabilityofwaste,groundorsaltwaterandtreatmentmethods.

Chlorineisusedtokillmicroorganismsinwater.Thebenefitsofaddingchlorinetowatertostopthespreadofwaterbornediseasesoutweighrisksoftoxicity.Insomecountriesthechlorinationofwaterissubjecttopublicregulation,butotherpartsoftheworldarestillwithoutchlorinatedwaterandthisleadstoahigherriskofdisease(IaS4).

1. describetheprincipalmethodsforincreasingtheavailabilityofpotablewaterintermsofseparationtechniquesused,includingtheeaseoftreatingwaste,groundandsaltwaterincludingfiltrationandmembranefiltration;aeration,useofbacteria;chlorinationanddistillation(forsaltwater)

Ideas about Science:• Technologiestoincreasethe

availabilityofpotablewatercanmakeapositivedifferencetopeople’slives(IaS4).

• Accesstotreatedwaterraisesissuesaboutrisk,costandbenefitandprovidingtreatedwaterforallraisesethicalissues(IaS4).

Practical work:• Identifyunknowngases.

2. describeatesttoidentifychlorine(usingbluelitmuspaper)

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Chapter C2: Chemical patterns

Overview

Thischapterfeaturesacentralthemeofmodernchemistry:ittracesthedevelopmentofideasaboutthestructureoftheatomandthearrangementofelementsinthemodernPeriodicTable.Bothstoriesshowhowscientifictheoriesdevelopasnewevidenceismadeavailablethateithersupportsorcontradictscurrentideas.

Atomicstructureisusedtohelpexplainthebehaviouroftheelements.Trendsandpatternsshownbythephysicalandchemicalpropertiesingroupsandinthetransitionmetalsarestudied.

Thefirsttwotopicsofthechaptergiveopportunitiesforlearnerstodevelopunderstandingofideasaboutscience;howscientificknowledgedevelops,the

relationshipbetweenevidenceandexplanations,andhowthescientificcommunityrespondstonewideas.Thelatertopicspresentsomeofthemostimportantmodelswhichunderpinanunderstandingofatoms,chemicalbehaviourandpatternsandhowreactionsarerepresentedinchemicalequations.

TopicC2.1looksatthedevelopmentofideasabouttheatomandintroducesthemodernmodelforatomicstructure,includingelectronarrangements.TopicC2.2considersthedevelopmentofthemodernPeriodicTableandthepatternsthatexistwithinit,focusingonGroups1and7,withsomereferencetoGroup0.TopicC2.3focusesonextendinganunderstandingofatomicstructuretoexplaintheionicbondingbetweenionsinioniccompound.ThisleadsontoTopicC2.4whichstudiesusingequationsandsymbolstosummarisereactions.

Learning about chemical patterns before GCSE (9–1)


• knowthepropertiesofthedifferentstatesofmatter(solid,liquidandgas)intermsoftheparticlemodel,includinggaspressure

• knowchangesofstateintermsoftheparticlemodel

• beawareofasimple(Dalton)atomicmodel• knowdifferencesbetweenatoms,elements

andcompounds• knowchemicalsymbolsandformulaefor

elementsandcompounds• knowconservationofmassinchangesofstate

andchemicalreactions

• understandchemicalreactionsastherearrangementofatoms

• beabletorepresentchemicalreactionsusingformulaeandusingequations

• knowsomedisplacementreactions• knowwhatcatalystsdo• beawareoftheprinciplesunderpinningthe

MendeleevPeriodicTable• knowsomeideasaboutthePeriodicTable:

periodsandgroups;metalsandnon-metals• knowhowsomepatternsinreactionscanbe

predictedwithreferencetothePeriodicTable• knowsomepropertiesofmetalsand

non-metals.

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C2.1 How have our ideas about atoms developed over time?



Themodernmodeloftheatomdevelopedovertime.StagesinthedevelopmentofthemodelincludedideasbytheancientGreeks(4elementideas),Dalton(firstparticlemodel),Thomson(‘plumpudding’model),Rutherford(ideaofatomicnucleus)andBohr(shellsofelectrons).Modelswererejected,modifiedandextendedasnewevidencebecameavailable.Thedevelopmentoftheatomicmodelinvolvedscientistssuggestingexplanations,makingandcheckingpredictionsbasedontheirexplanations,andbuildingoneachother’swork(IaS3).

ThePeriodicTablecanbeusedtofindtheatomicnumberandrelativeatomicmassofanatomofanelement,andthenworkoutthenumbersofprotons,neutronsandelectrons.Thenumberofelectronsineachshellcanberepresentedbysimpleconventionssuchasdotsincirclesorasasetofnumbers(forexample,sodiumas2.8.1).

Atomsaresmall–about10–10macross,andthenucleusisatthecentre,aboutahundred-thousandthofthediameteroftheatom.Moleculesarelarger,containingfromtwotohundredsofatoms.Objectsthatcanbeseenwiththenakedeyecontainmillionsofatoms.

1. describehowandwhytheatomicmodelhaschangedovertimetoincludethemainideasofDalton,Thomson,RutherfordandBohr

Specification links:• Atomsandradiation

(P5.1).

Ideas about Science:• Understandinghow

scientificexplanationsandmodelsdevelopinthecontextofchangingideasabouttheatomicmodel(IaS3).

2. describetheatomasapositivelychargednucleussurroundedbynegativelychargedelectrons,withthenuclearradiusmuchsmallerthanthatoftheatomandwithmostofthemassinthenucleus

3. recallrelativechargesandapproximaterelativemassesofprotons,neutronsandelectrons

4. estimatethesizeandscaleofatomsrelativetootherparticles M1d

5. recallthetypicalsize(orderofmagnitude)ofatomsandsmallmolecules

6. relatesizeandscaleofatomstoobjectsinthephysicalworld M1d

7. calculatenumbersofprotons,neutronsandelectronsinatoms,givenatomicnumberandmassnumberofisotopesorbyextractingdatafromthePeriodicTable

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C2.2 What does the Periodic Table tell us about elements?



ElementsinthemodernPeriodicTablearearrangedinperiodsandgroups,basedontheiratomicnumbers.Elementsinthesamegrouphavethesamenumberofelectronsintheiroutershells.Thenumberofelectronshellsincreasesdownagroupbutstaysthesameacrossaperiod.

MendeleevproposedthefirstarrangementofelementsinthePeriodicTable.Althoughhedidnotknowaboutatomicstructure,hereversedtheorderofsomeelementswithrespecttotheirmasses,leftgapsforundiscoveredelementsandpredictedtheirproperties.Hisideaswereacceptedbecausewhencertainelementswerediscoveredtheyfittedhisgapsandthedevelopmentofamodelforatomicstructuresupportedhisarrangement.Thelaterdeterminationofthenumberofprotonsinatomsprovidedanexplanationfortheorderheproposed(IaS3).

ThePeriodicTableshowsrepeatingpatternsinthepropertiesoftheelements.Metalsandnon-metalscanbeidentifiedbytheirpositioninthePeriodicTableandbycomparingtheirproperties(physicalpropertiesincludingelectricalconductivity).

Propertiesofelementswithinagroupshowtrends.ThereactivityofGroup1metalselementsincreasesdownthegroup,shownbytheirreactivitywithmoistair,waterandchlorine.

TheGroup7halogensarenon-metalsandbecomelessreactivedownthegroup.Thisisshowninreactionssuchastheirdisplacementreactionswithcompoundsofotherhalogensinthegroup.

1. explainhowthepositionofanelementinthePeriodicTableisrelatedtothearrangementofelectronsinitsatomsandhencetoitsatomicnumber

Practical work:• Reactionsof

Group1(demonstration)andGroup7(forexampledisplacement).

Ideas about Science:• Understanding

howscientificexplanationsandmodelsdevelop,inthecontextofthePeriodicTable(IaS3).

Ideas about Science: • Makingand

testingpredictionsabouttrendsandpatternsinthePeriodicTable(IaS1).

2. describehowMendeleevorganisedtheelementsbasedontheirpropertiesandrelativeatomicmasses

3. describehowdiscoveryofnewelementsandtheorderingelementsbyatomicnumbersupportsMendeleev’sdecisionstoleavegapsandreordersomeelements

4. describemetalsandnon-metalsandexplainthedifferencesbetweenthemonthebasisoftheircharacteristicphysicalandchemicalproperties,includingmeltingpoint,boilingpoint,stateandappearance,density,formulaeofcompounds,relativereactivityandelectricalconductivity

5. recallthesimplepropertiesofGroup1elementsincludingtheirreactionwithmoistair,water,andchlorine

6. recallthesimplepropertiesofGroup7elementsincludingtheirstatesandcoloursatroomtemperatureandpressure,theircoloursasgases,theirreactionswithGroup1elementsandtheirdisplacementreactionswithothermetalhalides

7. predictpossiblereactionsandprobablereactivityofelementsfromtheirpositionsinthePeriodicTable

8. describeexperimentstoidentifythereactivitypatternofGroup7elementsincludingdisplacementreactions

9. describeexperimentstoidentifythereactivitypatternofGroup1elements

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C2.3 How do metals and non-metals combine to form compounds?



Group0containselementswithafulloutershellofelectrons.Thisarrangementislinkedtotheirinert,unreactiveproperties.Theyexistassingleatomsandhencearegaseswithlowmeltingandboilingpoints.

Group1elementscombinewithGroup7elementsbyionicbonding.Thisinvolvesatransferofelectronsleadingtochargedions.Atomsandionscanberepresentedusingdotandcrossdiagramsassimplemodels(IaS3).Metals,suchasGroup1elements,loseelectronsfromtheoutershelloftheiratomstoformionswithcompleteoutershellsandwithapositivecharge.Non-metals,suchasGroup7elements,formionswithanegativechargebygainingelectronstofilltheiroutershell.Thenumberofelectronslostorgaineddeterminesthechargeontheion.

Thepropertiesofioniccompoundssuchasgroup1halidescanbeexplainedintermsoftheionicbonding.Positiveionsandnegativeionsarestronglyattractedtogetherandformgiantlattices.Ioniccompoundshavehighmeltingpointsincomparisontomanyothersubstancesduetothestrongattractionbetweenionswhichmeansalargeamountofenergyisneededtobreaktheattractionbetweentheions.Theydissolveinwaterbecausetheirchargesallowthemtointeractwithwatermolecules.Theyconductelectricitywhenmoltenorinsolutionbecausethechargedionscanmove,butnotwhensolidbecausetheionsareheldinfixedpositions.

1. recallthesimplepropertiesofGroup0includingtheirlowmeltingandboilingpoints,theirstateatroomtemperatureandpressureandtheirlackofchemicalreactivity

Practical work:• Testthepropertiesof

ioniccompounds.

Ideas about Science:• Dotandcrossdiagrams

asmodelsofatomsandions,andthelimitationsofthesemodels(IaS3).

• 2-Dand3-Drepresentationsassimplemodelsofthearrangementofions,andthelimitationsofthesemodels(IaS3).

2. explainhowobservedsimplepropertiesofGroups1,7and0dependontheoutershellofelectronsoftheatomsandpredictpropertiesfromgiventrendsdownthegroups

3. explainhowthereactionsofelementsarerelatedtothearrangementofelectronsintheiratomsandhencetotheiratomicnumber

4. explainhowtheatomicstructureofmetalsandnon-metalsrelatestotheirpositioninthePeriodicTable

5. describethenatureandarrangementofchemicalbondsinioniccompounds

6. explainionicbondingintermsofelectrostaticforcesandtransferofelectrons

7. calculatenumbersofprotons,neutronsandelectronsinatomsandions,givenatomicnumberandmassnumberorbyusingthePeriodicTableM1a

8. constructdotandcrossdiagramsforsimpleionicsubstances

9. explainhowthebulkpropertiesofionicmaterialsarerelatedtothetypeofbondstheycontain

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C2.3 How do metals and non-metals combine to form compounds?



Thearrangementofionscanberepresentedinbothtwo-dimensionsandthree-dimensions.Theserepresentationsaresimplemodelswhichhavelimitations,forexampletheydonotfullyshowthenatureormovementoftheelectronsorions,theinteractionbetweentheions,theirarrangementinspace,theirrelativesizesorscale(IaS3).

10. useideasaboutenergytransfersandtherelativestrengthofattractionbetweenionstoexplainthemeltingpointsofioniccompoundscomparedtosubstanceswithothertypesofbonding

11. describethelimitationsofparticularrepresentationsandmodelsofionsandionicallybondedcompoundsincludingdotandcrossdiagrams,and3-Drepresentations

12. translateinformationbetweendiagrammaticandnumericalformsandrepresentthreedimensionalshapesintwodimensionsandviceversawhenlookingatchemicalstructuresforioniccompounds

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C2.4 How are equations used to represent chemical reactions?



ThereactionsofGroup1andGroup7elementscanberepresentedusingwordequationsandbalancedsymbolequationswithstatesymbols.

Theformulaeofioniccompounds,includingGroup1andGroup7compoundscanbeworkedoutfromthechargesontheirions.Balancedequationsforreactionscanbeconstructedusingtheformulaeofthesubstancesinvolved,includinghydrogen,water,halogens(chlorine,bromineandiodine)andthehydroxides,chlorides,bromidesandiodides(halides)ofGroup1metals.

1. usechemicalsymbolstowritetheformulaeofelementsandsimplecovalentandioniccompounds

2. usetheformulaeofcommonionstodeducetheformulaofGroup1andGroup7compounds

3. usethenamesandsymbolsofthefirst20elements,Groups1,7and0andothercommonelementsfromasuppliedPeriodicTabletowriteformulaeandbalancedchemicalequationswhereappropriate

4. describethephysicalstatesofproductsandreactantsusingstatesymbols(s,l,gandaq)

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Chapter C3: Chemicals of the natural environment

Overview

Ourwayoflifedependsonawiderangeofproductsmadefromnaturalresources.TheEarth’scrustprovidesuswithmetaloresandcrudeoilandouruseoftheseimpactsonthenaturalenvironment.Chemistryisfundamentaltoanunderstandingofthescaleandsignificanceofthishumanactivity.

InTopicC3.1thepropertiesofmetalsarerelatedtotheirstructureandbondingandinTopicC3.2learnersdiscoverwhythereactivityofametaldetermineshowitisextractedfromitsoresandhownew

technologiesenableustoextractmetalsfrompoorqualityores.

ElectrolysisisexplainedinTopicC3.3,andlearnerslearnaboutthewidevarietyofproductsmadebyelectrolysis.

Finally,TopicC3.4coverstheseparationofcrudeoilintofractionsandtheuseofthesefractionstomakeotherchemicalsandpolymers.Withinthiscontextlearnersstudythepropertiesofsimplemoleculesinrelationtocovalentbondingandintermolecularforces.

Learning about chemicals of the natural environment before GCSE (9–1)


• knowthedifferencesbetweenatoms,elementsandcompounds

• befamiliarwiththeuseofchemicalsymbolsandformulaeforelementsandcompounds

• befamiliarwiththeuseofformulaeandequationstorepresentchemicalreactions

• understandchemicalreactionsastherearrangementofatoms

• knowaboutreactionsofacidswithmetalstoproduceasaltplushydrogen

• knowsomedisplacementreactions• knowtheorderofmetalsandcarboninthe

reactivityseries• knowthatcarbonisusedtoobtainmetalsfrom

metaloxides.

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C3.1 How are the atoms held together in a metal?



Chemistsuseamodelofmetalstructuretoexplainthepropertiesofmetals(IaS3).Inthemodel,metalatomsarearrangedcloselytogetherinagiantstructure,heldtogetherbyattractionbetweenthepositivelychargedatomsanda‘sea’ofnegativelychargedelectrons.Metalsaremalleableandductilebecausetheionscanslideovereachotherbutstillbeheldtogetherbytheelectrons;theyconductelectricityandheatbecausetheirelectronsarefreetomove;andtheyhavehighboilingpointsandmeltingpointsduetothestrongelectrostaticattractionbetweenmetalionsandtheelectrons.Thesepropertiesofmetalsmakethemuseful.

1. describethenatureandarrangementofchemicalbondsinmetals

Ideas about Science: • Usethemodelof

metalstructuretoexplainpropertiesofmetals(IaS3).

2. explainhowthebulkpropertiesofmetalsarerelatedtothetypeofbondstheycontain

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C3.2 How are metals with different reactivities extracted?



Metalscanbeplacedinanorderofreactivitybylookingattheirreactionswithwater,diluteacidandcompoundsofothermetals.Therelativereactivityofmetalsenablesustomakepredictionsaboutwhichmetalsreactfastestorwhichmetalwilldisplaceanother.

Whenmetalsreacttheyformioniccompounds.Themetalatomsloseoneormoreelectronstobecomepositiveions.Themoreeasilythishappensthemorereactivethemetal.

Thesereactionscanberepresentedbywordandsymbolequationsincludingstatesymbols. Ionic equations show only the ions that change in the reaction and show the gain or loss of electrons. They are useful for representing displacement reactions because they show what happens to the metal ions during the reaction.

Thewayametalisextracteddependsonitsreactivity.Somemetalsareextractedbyreactingthemetalcompoundintheiroreswithcarbon.

Carbonisanon-metalbutcanbeplacedinthereactivityseriesofthemetalsbetweenaluminiumandzinc.

Metalsbelowcarboninthereactivityseriesareextractedfromtheiroresbydisplacementbycarbon.Themetalintheoreisreducedandcarbonisoxidised.

Highlyreactivemetalsabovecarboninthereactivityseriesareextractedbyelectrolysis.

Scientists are developing methods of extracting the more unreactive metals from their ores using bacteria or plants. These methods can extract metals from waste material, reduce the need to extract ‘new’ ores, reduce energy costs, and reduce the amount of toxic metals in landfill. However, these methods do not produce large quantities of metals quickly (IaS4).

1. deduceanorderofreactivityofmetalsbasedonexperimentalresultsincludingreactionswithwater,diluteacidanddisplacementreactionswithothermetals


reactivityofdifferentmetalswithwateranddiluteacid.

• InvestigatethereactivityofZn,FeandCubyheatingeachmetalwithoxidesofeachoftheothertwometals.

Specification links:• Introducesoxidation

andreduction(C1.1).

Ideas about Science: • Impactsofmetal

extractionontheenvironment,themeasuresscientistsaretakingtomitigatethem,andtherisks,costsandbenefitsofdifferentcoursesofaction(IaS4).

2. explainhowthereactivityofmetalswithwaterordiluteacidsisrelatedtothetendencyofthemetaltoformitspositiveiontoincludepotassium,sodium,calcium,aluminium,magnesium,zinc,iron,lead,[hydrogen],copper,silver

3. usethenamesandsymbolsofcommonelementsandcompoundsandtheprincipleofconservationofmasstowriteformulaeandbalancedchemicalequationsand ionic equations

4. explain,usingthepositionofcarboninthereactivityseries,theprinciplesofindustrialprocessesusedtoextractmetals,includingtheextractionofzinc

5. explainwhyelectrolysisisusedtoextractsomemetalsfromtheirores

6. evaluate alternative biological methods of metal extraction (bacterial and phytoextraction)

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C3.3 What are electrolytes and what happens during electrolysis?



Electrolysisisusedtoextractreactivemetalsfromtheirores.Electrolysisisthedecompositionofanelectrolytebyanelectriccurrent.Electrolytesincludemoltenanddissolvedioniccompounds.Inbothcasestheionsarefreetomove.

Duringelectrolysisnon-metalionsloseelectronstotheanodetobecomeneutralatoms.Metal(orhydrogen)ionsgainelectronsatthecathodetobecomeneutralatoms.The addition or removal of electrons can be used to identify which species are reduced and which are oxidised. These changes can be summarised using half equations.

Electrolysisisusedtoextractreactivemetalsfromtheirmoltencompounds.Duringtheelectrolysisofaluminium,aluminiumoxideisheatedtoaveryhightemperature.Positivelychargedaluminiumionsgainelectronsfromthecathodetoformatoms.Oxygenionsloseelectronsattheanodeandformoxygenmoleculeswhichreactwithcarbonelectrodestoformcarbondioxide.Theprocessusesalargeamountofenergyforboththehightemperatureandtheelectricityinvolvedinelectrolysis.

Someextractionmethods,suchastherecoveryofmetalsfromwasteheaps,giveadiluteaqueoussolutionofmetalsions.

Whenanelectriccurrentispassedthroughanaqueoussolutionthewateriselectrolysedaswellastheioniccompound.Lessreactivemetalssuchassilverorcopperformonthenegativeelectrode.Ifthesolutioncontainsionsofmorereactivemetals,hydrogengasformsfromthehydrogenionsfromthewater.Similarly,oxygenusuallyformsatthepositiveelectrodefromhydroxideionsfromthewater.Aconcentratedsolutionofchlorideionsformschlorineatthepositiveelectrode.

1. describeelectrolysisintermsoftheionspresentandreactionsattheelectrodes

Practical work:• Investigatewhattype

ofsubstancesareelectrolytes.

2. predicttheproductsofelectrolysisofbinaryioniccompoundsinthemoltenstate

3. recallthatmetals(orhydrogen)areformedatthecathodeandnon-metalsareformedattheanodeinelectrolysisusinginertelectrodes

4. use the names and symbols of common elements and compounds and the principle of conservation of mass to write half equations

5. explain reduction and oxidation in terms of gain or loss of electrons, identifying which species are oxidised and which are reduced

6. explainhowelectrolysisisusedtoextractsomemetalsfromtheiroresincludingtheextractionofaluminium

7. describecompetingreactionsintheelectrolysisofaqueoussolutionsofioniccompoundsintermsofthedifferentspeciespresentincludingtheformationofoxygen,chlorineandthedischargeofmetalsorhydrogenlinkedtotheirrelativereactivity

Practical work:• Investigatetheeffects

ofconcentrationofaqueoussolution,current,voltageontheelectrolysisofsodiumchloride.

8. describethetechniqueofelectrolysisofanaqueoussolutionofasalt

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C3.4 Why is crude oil important as a source of new materials?



Crudeoilismixtureofhydrocarbons.Itisusedasasourceoffuelsandasafeedstockformakingchemicals(includingpolymers)foraverywiderangeofconsumerproducts.Almostalloftheconsumerproductsweuseinvolvetheuseofcrudeoilintheirmanufactureortransport.

Crudeoilisfinite.Ifwecontinuetoburnitatourpresentrateitwillrunoutinthenearfuture.Crudeoilmakesasignificantpositivedifferencetoourlives,butourcurrentuseofcrudeoilisnotsustainable.Decisionabouttheuseofcrudeoilmustbalanceshort-termbenefitswiththeneedtoconservethisresourceforfuturegenerations(IaS4).

Crudeoilisamixture.Itneedstobeseparatedintogroupsofmoleculesofsimilarsizecalledfractions.Thisisdonebyfractionaldistillation.Fractionaldistillationdependsonthedifferentboilingpointsofthehydrocarbons,whichinturnisrelatedtothesizeofthemoleculesandtheintermolecularforcesbetweenthem.

Thefractionsaremixtures,mainlyofalkanes,withanarrowrangeofboilingpoints.Thefirstfouralkanesshowtypicalpropertiesofahomologousseries:eachsubsequentmemberincreasesinsizebyCH2,theyhaveageneralformulaandshowtrendsintheirphysicalandchemicalproperties.

Themolecularformulaofanalkaneshowsthenumberofatomspresentineachmolecule.Theseformulaecanbesimplifiedtoshowthesimplestratioofcarbontohydrogenatoms.Thistypeofformulaisanempiricalformula.

1. recallthatcrudeoilisamainsourceofhydrocarbonsandisafeedstockforthepetrochemicalindustry

Ideas about Science:• Decisionmakinginthe

contextoftheuseofcrudeoilforfuelsandasafeedstock(IaS4).

2. explainhowmodernlifeiscruciallydependentuponhydrocarbonsandrecognisethatcrudeoilisafiniteresource

3. describeandexplaintheseparationofcrudeoilbyfractionaldistillation

PAGC2

4. describethefractionsofcrudeoilaslargelyamixtureofcompoundsofformulaCnH2n+2whicharemembersofthealkanehomologousseries

5. useideasaboutenergytransfersandtherelativestrengthofchemicalbondsandintermolecularforcestoexplainthedifferenttemperaturesatwhichchangesofstateoccur

6. deducetheempiricalformulaofacompoundfromtherelativenumbersofatomspresentorfromamodelordiagramandviceversa

7. usearithmeticcomputationandratiowhendeterminingempiricalformulae

M1c

8. describethearrangementofchemicalbondsinsimplemolecules

Ideas about Science: • Theuseandlimitations

ofmodelstorepresentbondinginsimplemolecules(IaS3).

9. explaincovalentbondingintermsofthesharingofelectrons

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C3.4 Why is crude oil important as a source of new materials?



SmallmoleculeslikealkanesandmanyofthosemetinchapterC1containnon-metalatomswhicharebondedtoeachotherbycovalentbonds.Acovalentbondisastrongbondbetweentwoatomsthatformedfromasharedpairofelectrons.

Acovalentbondcanberepresentedbyadotandcrossdiagram.Moleculescanbeshownasmolecularorempiricalformulae,displayedformulae(whichshowallofthebondsinthemolecule)orina3dimensional‘ballsandstick’model.

Simplemoleculeshavestrongcovalentbondsjoiningtheatomswithinthemolecule,buttheyonlyhaveweakintermolecularforces.Nocovalentbondsarebrokenwhensimplemoleculesboil.Themoleculesmoveapartwhengivenenoughenergytoovercometheintermolecularforces.Thisexplainstheirlowmeltingandboilingpoints.

Crackinglongchainalkanesmakessmallermoreusefulmoleculesthatareingreatdemandasfuels(forexamplepetrol).Crackingalsoyieldsalkenes–hydrocarbonswithcarbon–carbondoublebonds.Alkenesaremuchmorereactivethanalkanesandcanreacttomakeaverywiderangeofproductsincludingpolymers.Withoutcracking,wewouldneedtoextractalotmorecrudeoiltomeetdemandforpetrolandwouldwastesomelongerchainalkaneswhicharenotasuseful.

10. constructdotandcrossdiagramsforsimplecovalentsubstances

11. representthreedimensionalshapesintwodimensionsandviceversawhenlookingatchemicalstructuresforsimplemolecules

M5b

12. describethelimitationsofdotandcrossdiagrams,ballandstickmodelsandtwoandthreedimensionalrepresentationswhenusedtorepresentsimplemolecules

13. translateinformationbetweendiagrammaticandnumericalforms

M4a

14. explainhowthebulkpropertiesofsimplemoleculesarerelatedtothecovalentbondstheycontainandtheirbondstrengthsinrelationtointermolecularforces

15. describetheproductionofmaterialsthataremoreusefulbycracking

Ideas about Science:• Crackingasapositive

applicationofscience,toreduceextractionofcrudeoilandsoconservesoilreserves(IaS4).

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Chapter C4: Material choices

Overview

Oursocietyusesalargerangeofmaterialsandproductsthathavebeendeveloped,testedandmodifiedbytheworkofchemists.Materialsusedtomakeaparticularproductneedtomeetaspecificationwhichdescribesthepropertiesthematerialneedstomakeitsuitableforaparticularuse.Thischapterlooksatarangeofdifferentmaterialsandinvestigatestheirpropertiesinthecontextoftheirsuitabilityformakingconsumerproducts.Thechapteralsoconsidershowthelifecycleofaproductisassessedinitsjourneyfromrawmaterialtofinaldisposal.

TopicC4.1considersthevarietyofmaterialsthatweuse.Learnersusedataandinformationaboutthepropertiesof‘pure’andcompositematerialstoconsidertheirsuitabilityformakingconsumerproducts.Ceramics,glass,materialswithgiantstructureandpolymersareallconsidered.

TopicC4.2extendsthestudyofpropertiestolookingatbondingandstructureinordertoexplainwhyaparticularmaterialbehavesasitdoes.Learnerslearnaboutthebondinginmetals,polymersandgiantcovalentstructuresandlinkthebondingandstructuretothepropertiesofthematerials.Theyconsidertheusefulnessofdiagramsandmodelsofbondingandstructuretochemistswhoneedtoinvestigateandpredictpropertiesofmaterialssothattheycanmakejudgementsabouttheirusefulnessormodellikelychangesintheirpropertiesiftheirstructuresaremodified.Arangeofmaterialsarestudied,includingnewmaterialssuchasfullerenesandgraphene.

TopicC4.3looksspecificallyatthenatureandusesofnanoparticles.

TopicC4.4considersthelifecycleofmaterials.Theylearnhowtheimpactofourmanufacture,useanddisposalofconsumerproductsisassessedusinglifecycleassessments.

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Learning about material choices before GCSE (9–1)

FromstudyatKeyStages1to3Learnersshould:

• distinguishbetweenanobjectandthematerialfromwhichitismade

• identifyandnameavarietyofeverydaymaterials,includingwood,plastic,glass,metal,water,androck

• describethesimplephysicalpropertiesofavarietyofeverydaymaterials

• compareandgrouptogetheravarietyofeverydaymaterialsonthebasisoftheirsimplephysicalproperties

• haveobservedthatsomematerialschangestatewhentheyareheatedorcooled,andmeasuredthetemperatureatwhichthishappensindegreesCelsius(°C)

• compareandgrouptogethereverydaymaterialsonthebasisoftheirproperties,includingtheirhardness,solubility,transparency,conductivity(electricalandthermal),andresponsetomagnets

• identifyandcomparethesuitabilityofavarietyofeverydaymaterials,includingwood,metal,plastic,glass,brick,rock,paperandcardboardforparticularuse

• knowthedifferencesbetweenatoms,elementsandcompounds

• recognisechemicalsymbolsandformulaeforsomeelementsandcompounds

• knowaboutthepropertiesofceramics,polymersandcomposites(qualitative).

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C4.1 How is data used to choose a material for a particular use?



Oursocietyusesalargerangeofmaterialsandproductsdevelopedbychemists.Chemistsassessmaterialsbymeasuringtheirphysicalproperties,andusedatatocomparedifferentmaterialsandtomatchmaterialstothespecificationofausefulproduct(IaS4).

Compositeshaveaverybroadrangeofusesastheyallowthepropertiesofseveralmaterialstobecombined.Compositesmayhavematerialscombinedonabulkscale(forexample,usingsteeltoreinforceconcrete)orhavenanoparticlesincorporatedinamaterialorembeddedinamatrix.

1. comparequantitativelythephysicalpropertiesofglassandclayceramics,polymers,compositesandmetalsincludingmeltingpoint,softeningtemperature(forpolymers),electricalconductivity,strength(intensionorcompression),stiffness,flexibility,brittleness,hardness,density,easeofreshaping

Practical work:• Practicalinvestigationofa

rangeofmaterialsleadingtoclassificationintocategories.

Ideas about Science:• Therangeofmaterials

developedbychemistsenhancesthequalityoflife(IaS4).

• Useandlimitationsofamodeltorepresentstructures(IaS3).

2. explainhowthepropertiesofmaterialsarerelatedtotheirusesandselectappropriatematerialsgivendetailsoftheusagerequired

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C4.2 How do bonding and structure affect properties of materials?



Differentmaterialscanbemadefromthesameatomsbuthavedifferentpropertiesiftheyhavedifferenttypesofbondingorstructures.Chemistsuseideasaboutbondingandstructurewhentheypredictthepropertiesofanewmaterialorwhentheyareresearchinghowanexistingmaterialcanbeadaptedtoenhanceitsproperties.

Carbonisanunusualelementbecauseitcanformchainsandringswithitself.Thisleadstoavastarrayofnaturalandsyntheticcompoundsofcarbonwithaverywiderangeofpropertiesanduses.‘Families’ofcarboncompoundsarehomologousseries.

Polymermoleculeshavethesamestrongcovalentbondingassimplemolecularcompounds,buttherearemoreintermolecularforcesbetweenthemoleculesduetotheirlength.Thestrengthoftheintermolecularforcesaffectsthepropertiesofthesolid.

Giantcovalentstructurescontainmanyatomsbondedtogetherina3dimensionalarrangementbycovalentbonds.Theabilityofcarbontobondwithitselfgivesrisetoavarietyofmaterialswhichhavedifferentgiantcovalentstructuresofcarbonatoms.Theseareallotropes,andincludediamondandgraphite.Thesematerialshavedifferentpropertieswhicharisefromtheirdifferentstructures.

1. explainhowthebulkpropertiesofmaterials(includingstrength,meltingpoint,electricalandthermalconductivity,brittleness,flexibility,hardnessandeaseofreshaping)arerelatedtothedifferenttypesofbondstheycontain,theirbondstrengthsinrelationtointermolecularforcesandthewaysinwhichtheirbondsarearranged,recognisingthattheatomsthemselvesdonothavetheseproperties

Specification links• Ionicbondingand

structure(C2.3).• Simplemolecules

(C2.3)andmetallicbonding(C3.1).

• Covalentbondsandintermolecularforces(C3.4).

Practical work:• Testingpropertiesof

simplecovalentcompounds,giantionicandgiantcovalentsubstances,metalsandpolymers.

Ideas about Science:• Identifypatternsin

datarelatedtopolymersandallotropesofcarbon(IaS2).

• Useandlimitationsofamodeltorepresentthestructuresofarangeofmaterials(IaS3).

2. recallthatcarboncanformfourcovalentbonds

3. explainthatthevastarrayofnaturalandsyntheticorganiccompoundsoccursduetotheabilityofcarbontoformfamiliesofsimilarcompounds,chainsandrings

4. describethenatureandarrangementofchemicalbondsinpolymerswithreferencetotheirpropertiesincludingstrength,flexibilityorstiffness,hardnessandmeltingpointofthesolid

5. describethenatureandarrangementofchemicalbondsingiantcovalentstructures

6. explainthepropertiesofdiamondandgraphiteintermsoftheirstructuresandbondingincludingmeltingpoint,hardnessand(forgraphite)conductivityandlubricatingaction

7. representthreedimensionalshapesintwodimensionsandviceversawhenlookingatchemicalstructurese.g.allotropesofcarbon

M5b

8. describeandcomparethenatureandarrangementofchemicalbondsinioniccompounds,simplemolecules,giantcovalentstructures,polymersandmetals

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C4.3 Why are nanoparticles so useful?



Nanoparticleshaveasimilarscaletoindividualmolecules.Theirextremelysmallsizemeanstheycanpenetrateintobiologicaltissuesandcanbeincorporatedintoothermaterialstomodifytheirproperties.Nanoparticleshaveaveryhighsurfaceareatovolumeratio.Thismakesthemexcellentcatalysts.

Fullerenesformnanotubesandballs.Theballstructureenablesthemtocarrysmallmolecules,forexamplecarryingdrugsintothebody.Thesmallsizeoffullerenenanotubesenablesthemtobeusedasmolecularsievesandtobeincorporatedintoothermaterials(forexampletoincreasestrengthofsportsequipment).Graphenesheetshavespecialisedusesbecausetheyareonlyasingleatomthickbutareverystrongwithhighelectricalandthermalconductivity.

Developingtechnologiesbasedonfullerenesandgraphenerequiredleapsofimaginationfromcreativethinkers(IaS3).

Thereareconcernsaboutthesafetyofsomenanoparticlesbecausenotmuchisknownabouttheireffectsonthehumanbody.Judgementsaboutaparticularusefornanoparticlesdependonbalancingtheperceivedbenefitandrisk(IaS4).

1. compare‘nano’dimensionstotypicaldimensionsofatomsandmolecules

Ideas about Science:• Discussthe

potentialbenefitsandrisksofdevelopmentsinnanotechnology(IaS4).

• Developmentofnanoparticlesandgraphenereliedonimaginativethinking(IaS3).

2. describethesurfaceareatovolumerelationshipfordifferent-sizedparticlesanddescribehowthisaffectsproperties

3. describehowthepropertiesofnanoparticulatematerialsarerelatedtotheirusesincludingpropertieswhicharisefromtheirsize,surfaceareaandarrangementofatomsintubesorrings

4. explainthepropertiesfullerenesandgrapheneintermsoftheirstructures

5. explainthepossiblerisksassociatedwithsomenanoparticulatematerials,including:

a) possibleeffectsonhealthduetotheirsizeandsurfacearea b) reasonsthatthereismoredataaboutusesofnanoparticles

thanaboutpossiblehealtheffects c) therelativerisksandbenefitsofusingnanoparticlesfor

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C4.3 Why are nanoparticles so useful?



6. estimatesizeandscaleofatomsandnanoparticlesincludingtheideasthat:

a) nanotechnologyistheuseandcontrolofstructuresthatareverysmall(1to100nanometresinsize)

b) dataexpressedinnanometresisusedtocomparethesizesofnanoparticles,atomsandmolecules

M1d

7. interpret,orderandcalculatewithnumberswritteninstandardformwhendealingwithnanoparticles

M1b

8. useratioswhenconsideringrelativesizesandsurfaceareatovolumecomparisons

M1c

9. calculatesurfaceareasandvolumesofcubes M5c

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C4.4 What happens to products at the end of their useful life?



Ironisthemostwidelyusedmetalintheworld.Theusefullifeofproductsmadefromironislimitedbecauseironcorrodes.Thisinvolvesanoxidationreactionwithoxygenfromtheair.

Lifecycleassessments(LCAs)areusedtoconsidertheoverallimpactofourmaking,usinganddisposingofaproduct.LCAsinvolveconsideringtheuseofresourcesandtheimpactontheenvironmentofallstagesofmakingmaterialsforaproductfromrawmaterials,makingthefinishedproduct,theuseoftheproduct,transportandthemethodusedforitsdisposalattheendofitsusefullife.

ItisdifficulttomakesecurejudgmentswhenwritingLCAsbecausethereisnotalwaysenoughdataandpeopledonotalwaysfollowrecommendeddisposaladvice(IaS4).

Someproductscanberecycledattheendoftheirusefullife.Inrecycling,theproductsarebrokendownintothematerialsusedtomakethem;thesematerialsarethenusedtomakesomethingelse.Reusingproductsuseslessenergythanrecyclingthem.ReusingandrecyclingbothaffectstheLCA.

Recyclingconservesresourcessuchascrudeoilandmetalores,butwillnotbesufficienttomeetfuturedemandfortheseresourcesunlesshabitschange.

Theviabilityofarecyclingprocessdependsonanumberoffactors:thefinitenatureofsomedepositsofrawmaterials(suchasmetaloresandcrudeoil),availabilityofthematerialtoberecycled,economicandpracticalconsiderationsofcollectionandsorting,removalofimpurities,energyuseintransportandprocessing,scaleofdemandfornewproduct,environmentalimpactoftheprocess.

Productsmadefromrecycledmaterialsdonotalwayshavealowerenvironmentalimpactthanthosemadefromnewresources(IaS4).

1. explainreductionandoxidationintermsoflossorgainofoxygen,identifyingwhichspeciesareoxidisedandwhicharereduced

Practical work:• Investigatingthe

factorsneededforrustingofironorcorrosionofothermetals.

• Investigatingtheeffectivenessofcorrosionprevention(barrierandsacrificialprotectionmethods).

Ideas about Science:• Usetheexampleof

applyingscientificsolutionstotheproblemofcorrosionofmetalstoexplaintheideaofimprovingsustainability(IaS4).

• Uselife-cycleassessmentstocomparethesustainabilityofproductsandprocesses(IaS4).

2. explain reduction and oxidation in terms of gain or loss of electrons, identifying which species are oxidised and which are reduced

3. describethebasicprinciplesincarryingoutalife-cycleassessmentofamaterialorproductincluding:

a) theuseofwater,energyandtheenvironmentalimpactofeachstageinalifecycle,includingitsmanufacture,transportanddisposal

b) incineration,landfillandelectricitygenerationschemes

c) biodegradableandnon-biodegradablematerials

4. interpretdatafromalife-cycleassessmentofamaterialorproduct

5. describetheprocesswherePETdrinksbottlesarereusedandrecycledfordifferentuses,andexplainwhythisisviable

6. evaluatefactorsthataffectdecisionsonrecyclingwithreferencetoproductsmadefromcrudeoilandmetalores

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Chapter C5: Chemical analysis

Overview

Thischapterlooksathowchemicalsareanalysed.Chemicalanalysisisimportantinchemistryforthequalitycontrolofmanufacturedproductsandalsotoidentifyorquantifycomponentsintestingofnewproducts,mineralextraction,forensicsandenvironmentalmonitoring.Chemistsneedtobothidentifywhichsubstancesarepresent(qualitativeanalysis)andthequantityofeachsubstance(quantitativeanalysis).Measuringpurityandseparatingmixturesisimportantinmanufacturingtoensurequalityandtoseparateusefulproductsfrombi-productsandwaste.Beingabletoanalysequantitiesofchemicalsenableschemiststoplanfortheamountsofreactantstheyneedtousetomakeaproduct,orpredictquantitiesofproductsfromknownamountsofreactants.

ThechapterbeginsinTopicC5.1byconsideringwhyitisnecessarytopurifychemicalsandhowthe

componentsofmixturesareseparated.Methodsoftestingforpurityandseparatingmixturesarestudied,includingchromatographyandarangeofpracticalseparationtechniques.

TopicC5.2introducesquantitativework.Themoleisusedasameasureofamountsofsubstanceandlearnersprocessdatafromformulaeandequationstoworkoutquantitiesofreactantsandproducts.

TopicC5.3developsquantitativeworkfurthertoshowhowtheconcentrationsofsolutionsaredetermined.Thishasapplicationsforthetestingandqualitycontrolofmanufacturedchemicalproductsandalsoallowstheanalysisofunknownchemicalsforarangeofpurposes(forexampleinforensics,indrugproduction,mineralexplorationandenvironmentalmonitoring).Learnersmakeastandardsolutionandanalysetheconcentrationofunknownsolutionsusingtitrations.

Learning about chemical analysis before GCSE (9–1)


• useknowledgeofsolids,liquidsandgasestodecidehowmixturesmightbeseparated,includingthroughfiltering,sievingandevaporating

• understandtheconceptofapuresubstanceandhowtoidentifyapuresubstance

• knowaboutsimpletechniquesforseparatingmixtures:filtration,evaporation,distillationandchromatography

• knowaboutthepHscaleformeasuringacidity/alkalinity;andindicators.

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Learning about chemical analysis at GCSE (9–1)

C5.1 How are chemicals separated and tested for purity?



Manyusefulproductscontainmixtures.Itisimportantthatconsumerproductssuchasdrugsorpersonalcareproductsdonotincludeimpurities.Mixturesinmanyconsumerproductscontainpuresubstancesmixedtogetherindefiniteproportionscalledformulations.

Puresubstancescontainasingleelementorcompound.Chemiststestsubstancesmadeinthelaboratoryandinmanufacturingprocessestocheckthattheyarepure.Onewayofassessingthepurityofasubstanceisbytestingitsmeltingpoint;puresubstanceshavesharpmeltingpointsandcanbeidentifiedbymatchingmeltingpointdatatoreferencevalues.

Chromatographyisusedtoseeifasubstanceispureortoidentifythesubstancesinamixture.Componentsofamixtureareidentifiedbytherelativedistancetravelledcomparedtothedistancetravelledbythesolvent.Rfvaluescanbecalculatedandusedtoidentifyunknowncomponentsbycomparisontoreferencesamples.Somesubstancesareinsolubleinwater,soothersolventsareused.Chromatographycanbeusedoncolourlesssubstancesbutlocatingagentsareneededtoshowthespots.

1. explainthatmanyusefulmaterialsareformulationsofmixtures

Specification links:• Particlemodeland

changesofstate(C1.1).

• Fractionaldistillationofcrudeoilonanindustrialscale(C3.4).

Ideas about Science• Usetheparticlemodel

toexplaintheideaofapuresubstance.

2. explainwhatismeantbythepurityofasubstance,distinguishingbetweenthescientificandeverydayuseoftheterm‘pure’

3. usemeltingpointdatatodistinguishpurefromimpuresubstances

4. recallthatchromatographyinvolvesastationaryandamobilephaseandthatseparationdependsonthedistributionbetweenthephases

5. interpretchromatograms,includingcalculatingRfvalues M3c

6. suggestchromatographicmethodsfordistinguishingpurefromimpuresubstances

PAGC3

Includingtheuseof: a) paperchromatography b) aqueousandnon-aqueoussolvents c) locatingagents

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C5.1 How are chemicals separated and tested for purity?



Preparationofchemicalsoftenproducesimpureproductsoramixtureofproducts.Separationprocessesinboththelaboratoryandinindustryenableusefulproductstobeseparatedfromby-productsandwasteproducts.Thecomponentsofmixturesareseparatedusingprocessesthatexploitthedifferentpropertiesofthecomponents,(forexamplestate,boilingpoints,orsolubilityindifferentsolvents).

Separationprocessesarerarelycompletelysuccessfulandmixturesoftenneedtogothroughseveralstagesorthroughrepeatedprocessestoreachanacceptablepurity.

7. describe,explainandexemplifytheprocessesoffiltration,crystallisation,simpledistillation,andfractionaldistillation

PAGC2, PAGC4

8. suggestsuitablepurificationtechniquesgiveninformationaboutthesubstancesinvolved

PAGC2, PAGC4

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C5.2 How are the amounts of substances in reactions calculated?



Duringreactions,atomsarerearrangedbutthetotalmassdoesnotchange.Reactionsinopensystemsoftenappeartohaveachangeinmassbecausesubstancesaregainedorlost,usuallytotheair.

Chemistsuserelativemassestomeasuretheamountsofchemicals.RelativeatomicmassesforatomsofelementscanbeobtainedfromthePeriodicTable.

Therelativeformulamassofacompoundcanbecalculatedusingitsformulaandtherelativeatomicmassesoftheatomsitcontains.

Relative masses are based on the mass of carbon 12. Counting atoms or formula units of compounds involves very large numbers, so chemists use a mole as a unit of counting. One mole contains the same number of particles as there are atoms in 12g of carbon-12, and has the value 6.0 × 1023 atoms; this is the Avogadro constant. It is more convenient to count atoms as ‘numbers of moles’.

The number of moles of a substance can be worked out from its mass, this is useful to chemists because they can use the equations for reactions to work out the amounts of reactants to use in the correct proportions to make a particular product, or to work out which reactant is used up when a reaction stops.

1. recallandusethelawofconservationofmass Specification links• Theparticlemodel(C1.1).• Maximisingindustrial

yields(C6.3).

Practical work:• Comparisonoftheoretical

andactualyieldfromthepreparationofanorganiccompound(introducedinC3)orasalt(introducedinC5).

Practical work:• Makingandtesting

predictions.Carryingoutinvestigations.Analysingandevaluatingdata.Usingmeasuringapparatus.Safehandlingofchemicals.

2. explainanyobservedchangesinmassinnon-enclosedsystemsduringachemicalreactionandexplainthemusingtheparticlemodel

3. calculaterelativeformulamassesofspeciesseparatelyandinabalancedchemicalequation

4. recall and use the definitions of the Avogadro constant (in standard form) and of the mole

5. explain how the mass of a given substance is related to the amount of that substance in moles and vice versa and use the relationship:

number of moles = mass of substance (g) relative formula mass (g) M2a,M3c

6. deduce the stoichiometry of an equation from the masses of reactants and products and explain the effect of a limiting quantity of a reactant

7. use a balanced equation to calculate masses of reactants or products

M1a,M1c

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C5.2 How are the amounts of substances in reactions calculated?



The equation for a reaction can also be used to work out how much product can be made starting from a known amount of reactants. This is useful to determine the amounts of reacting chemicals to be used in industrial processes so that processes can run as efficiently as possible.

8. usearithmeticcomputation,ratio,percentageandmultistepcalculationsthroughoutquantitativechemistry

M1a,M1c,M1d

Ideas about Science:• Usingdatatomake

quantitativepredictionsaboutyieldsandcomparingthemtoactualyields(IaS1,IaS2).

9. carry out calculations with numbers written in standard form when using the Avogadro constant

M1b

10. changethesubjectofamathematicalequation M3c

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C5.3 How are the amounts of chemicals in solution measured?



Quantitative analysis is used by chemists to make measurements and calculations to show the amounts of each component in a sample.

Concentrations sometimes use the units g/dm3 but more often are expressed using moles, with the units mol/dm3. Expressing concentration using moles is more useful because it links more easily to the reacting ratios in the equation.

Theconcentrationofacidsandalkaliscanbeanalysedusingtitrations.Alkalisneutraliseacids.Anindicatorisusedtoidentifythepointwhenneutralisationisjustreached.Duringthereaction,hydrogenionsfromtheacidreactwithhydroxideionsfromthealkalitoformwater.ThereactioncanberepresentedusingtheequationH+(aq)+OH–(aq)→H2O(l)

Aswithallquantitativeanalysistechniques,titrationsfollowastandardproceduretoensurethatthedataiscollectedsafelyandisofhighquality,includingselectingsamples,makingroughandmultiplerepeatreadingsandusingequipmentofanappropriateprecision(suchasaburetteandpipette).

Datafromtitrationscanbeassessedintermsofitsaccuracy,precisionandvalidity.Aninitialroughmeasurementisusedasanestimateandtitrationsarerepeateduntilalevelofconfidencecanbeplacedinthedata;thereadingsmustbe

1. explain how the mass of a solute and the volume of the solution is related to the concentration of the solution and calculate concentration using the formulae:

concentration (g/dm3) =

mass of solute (g)

volume (dm3) M3c

Specification links:• Strongandweakacid

chemistry(C6.1)

Practical work:• Makingupastandard

solution.

Practical work• Acid-basetitrations. Useofappropriate

measuringapparatus,measuringpH,useofavolumetricflasktomakeastandardsolution,titrationsusingburettesandpipettes,useofacid-baseindicators,safehandlingofchemicals.

2. explain how the concentration of a solution in mol/dm3 is related to the mass of the solute and the volume of the solution and calculate the molar concentration using the formula

concentration (mol/dm3) =

number of moles of solute volume (dm3) M3c

3. describeneutralisationasacidreactingwithalkalitoformasaltpluswaterincludingthecommonlaboratoryacidshydrochloricacid,nitricacidandsulfuricacidandthecommonalkalis,thehydroxidesofsodium,potassiumandcalcium

4. recallthatacidsformhydrogenionswhentheydissolveinwaterandsolutionsofalkaliscontainhydroxideions

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C5.3 How are the amounts of chemicals in solution measured?



closetogetherwithanarrowrange.Thetruevalueofatitrationmeasurementcanbeestimatedbydiscardingroughsandtakingameanoftheresultswhichareincloseagreement.

Theresultsofatitrationandtheequationforthereactionareusedtoworkouttheconcentrationofanunknownacidoralkali.

5. recognisethataqueousneutralisationreactionscanbegeneralisedtohydrogenionsreactingwithhydroxideionstoformwater

Ideas about Science:• Justifyatechniquein

termsofprecision,accuracyandvalidityofdatatobecollected,minimisingrisk.Useofrangeandmeanwhenprocessingtitrationresults,analysisofdata(IaS1,IaS2).

6. describeandexplaintheprocedureforatitrationtogiveprecise,accurate,validandrepeatableresults

7. evaluatethequalityofdatafromtitrations

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Chapter C6: Making useful chemicals

Overview

Thisunitconsidersthelaboratoryandlargescaleproductionofusefulchemicals.TopicC6.1beginswiththelaboratorysynthesisofsaltsfromacidreactions,andalsolooksatthecharacteristicsofbothacidsandbases.

InTopicC6.2,thestorymovesontostudyhowchemistsmanagetherateofreactionwhenthese

reactionstakeplace,inthecontextofmanagingconditionsbothinthelaboratoryandinindustry.Thistopicgivestheopportunityforawiderangeofpracticalinvestigationandmathematicalanalysisofrates.

TopicC6.3looksatreversiblereactions,withparticularemphasisonthelargescaleproductionofammonia.

Learning about making useful chemicals before GCSE (9–1)

FromstudyatKeyStages1to3Learnersshould:

• explainthatsomechangesresultintheformationofnewmaterials,andthatthiskindofchangeisnotusuallyreversible

• representchemicalreactionsusingformulaeandusingequations

• defineacidsandalkalisintermsofneutralisationreactions

• describethepHscaleformeasuringacidity/alkalinity;andindicators

• recallreactionsofacidswithmetalstoproduceasaltplushydrogenandreactionsofacidswithalkalistoproduceasaltpluswater

• knowwhatcatalystsdo• knowaboutenergychangesonchangesof

state(qualitative)• knowaboutexothermicandendothermic

chemicalreactions(qualitative).

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C6.1 What useful products can be made from acids?



Manyproductsthatweuseeverydayarebasedonthechemistryofacidreactions.Productsmadeusingacidsincludecleaningproducts,pharmaceuticalproductsandfoodadditives.Inaddition,acidsaremadeonanindustrialscaletobeusedtomakebulkchemicalssuchasfertilisers.

Acidsreactinneutralisationreactionswithmetals,hydroxidesandcarbonates.Allneutralisationreactionsproducesalts,whichhaveawiderangeofusesandcanbemadeonanindustrialscale.

The strength of an acid depends on the degree of ionisation and hence the concentration of H+ ions, which determines the reactivity of the acid. The pH of a solution is a measure of the concentration of H+ ions in the solution. Strong acids ionise completely in solution, weak acids do not. Both strong and weak acids can be prepared at a range of different concentrations (i.e. different amounts of substance per unit volume).

Weak acids and strong acids of the same concentration have different pH values. Weak acids are less reactive than strong acids of the same concentration (for example they react more slowly with metals and carbonates).

1. recallthatacidsreactwithsomemetalsandwithcarbonatesandwriteequationspredictingproductsfromgivenreactants

Specification links• Writingformulae,

balancedsymbolandionicequations(C3.2).

• Concentrationofsolutions(C5.4).

Practical work:• Reactionsofacids

andpreparationofsalts.

• pHtesting• Investigatingstrong

andweakacidreactivity.

• Useofindicatorstoteststrongandweakacids,makingstandardsolutionsusingvolumetricflasks.

2. describepracticalprocedurestomakesaltstoincludeappropriateuseoffiltration,evaporation,crystallisationanddrying

PAGC4

3. usetheformulaeofcommonionstodeducetheformulaofacompound

4. recallthatrelativeacidityandalkalinityaremeasuredbypHincludingtheuseofuniversalindicatorandpHmeters

5. use and explain the terms dilute and concentrated (amount of substance) and weak and strong (degree of ionisation) in relation to acids including differences in reactivity with metals and carbonates

6. use the idea that as hydrogen ion concentration increases by a factor of ten the pH value of a solution decreases by one

7. describe neutrality and relative acidity and alkalinity in terms of the effect of the concentration of hydrogen ions on the numerical value of pH (whole numbers only)

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C6.2 How do chemists control the rate of reactions?



Controllingrateofreactionenablesindustrialchemiststooptimisetherateatwhichachemicalproductcanbemadesafely.

Therateofareactioncanbealteredbyalteringconditionssuchastemperature,concentration,pressureandsurfacearea.Amodelofparticlescollidinghelpstoexplainwhyandhoweachofthesefactorsaffectsrate;forexample,increasingthetemperatureincreasestherateofcollisionsand,moresignificantly,increasestheenergyavailabletotheparticlestoovercometheactivationenergyandreact.

Acatalystincreasestherateofareactionbutcanberecovered,unchanged,attheend.Catalystsworkbyprovidinganalternativerouteforareactionwithaloweractivationenergy.Energychangesforuncatalysedandcatalysedreactionshavedifferentreactionprofiles.

Theuseofacatalystcanreducetheeconomicandenvironmentalcostofanindustrialprocess,leadingtomoresustainable‘green’chemicalprocesses.

1. describetheeffectonrateofreactionofchangesintemperature,concentration,pressure,andsurfacearea

Specification links• Endothermicand

exothermicreactionsandenergyleveldiagrams(C1).

Practical work:• Investigatetheeffectof

temperatureandconcentrationonrateofreactions.

• Comparemethodsoffollowingrate

Ideas about Science: • Usetheparticlemodelto

explainfactorsthataffectratesofreaction(IaS3).

• Theuseofcatalystssupportsmoresustainableindustrialprocesses(IaS4).

2. explaintheeffectsonratesofreactionofchangesintemperature,concentrationandpressureintermsoffrequencyandenergyofcollisionbetweenparticles

3. explaintheeffectsonratesofreactionofchangesinthesizeofthepiecesofareactingsolidintermsofsurfaceareatovolumeratio

4. describethecharacteristicsofcatalystsandtheireffectonratesofreaction

5. identifycatalystsinreactions

6. explaincatalyticactionintermsofactivationenergy

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Rateofreactioncanbedeterminedbymeasuringtherateatwhichaproductismadeortherateatwhichareactantisused.Some reactions involve a colour change or form a solid in a solution; the rate of these reactions can be measured by timing the changes that happen in the solutions by eye or by using apparatus such as a colorimeter.Reactionsthatmakegasescanbefollowedbymeasuringthevolumeofgasorthechangeinmassovertime.

Ongraphsshowingthechangeinavariablesuchasconcentrationovertime,thegradientofatangenttothecurveisanindicatorofrateofchangeatthattime.Theaveragerateofareactioncanbecalculatedfromthetimetakentomakeafixedamountofproduct.

7. suggestpracticalmethodsfordeterminingtherateofagivenreactionincluding:

forreactionsthatproducegases: i) gassyringesorcollectionoverwatercanbe

usedtomeasurethevolumeofgasproduced ii) masschangecanbefollowedusingabalance measurement of physical factors: iii) colour change iv) formation of a precipitate PAGC5

Practical work:• Designingandcarryingout

investigationsintorates.Analysingandinterpretingdata.Useofapparatustomakemeasurements.Useofheatingequipment.Safehandlingofchemicals.Measuringratesofreactionusingtwodifferentmethods. 8. interpretrateofreactiongraphs

M4a,M4b

9. usearithmeticcomputationandratioswhenmeasuringratesofreaction

M1a,M1c

10. drawandinterpretappropriategraphsfromdatatodeterminerateofreaction

M2b,M4b,M4c

11. determinegradientsofgraphsasameasureofrateofchangetodeterminerate

M4b,M4d,M4e

12. useproportionalitywhencomparingfactorsaffectingrateofreaction

M1c

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Enzymesareproteinsthatcatalyseprocessesinlivingorganisms.TheyworkattheiroptimumwithinanarrowrangeoftemperatureandpH.Enzymescanbeadaptedandsometimessynthesisedforuseinindustrialprocesses.Enzymeslimittheconditionsthatcanbeusedbutthiscanbeanadvantagebecauseifaprocesscanbedesignedtouseanenzymeatalowertemperaturethanatraditionalprocess,thisreducesenergydemand.

13. describetheuseofenzymesascatalystsinbiologicalsystemsandsomeindustrialprocesses

Specification link:• Enzymesinbiological

processes(B3.1).

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C6.3 What factors affect the yield of chemical reactions?



Industrialprocessesaremanagedtogetthebestyieldasquicklyandeconomicallyaspossible.Chemistsselecttheconditionsthatgivethebesteconomicoutcomeintermsofsafety,maintainingtheconditionsandequipment,andenergyuse.

Thereactionsinsomeprocessesarereversible.Thiscanbeproblematicinindustrybecausethereactantsnevercompletelyreacttomaketheproducts.Thiswastesreactantsandmeansthattheproductshavetobeseparatedoutfromthereactants,whichrequiresextrastagesandcosts.

Data about yield and rate of chemical processes are used to choose the best conditions to make a product. On industrial scales, very high temperatures and pressures are expensive to maintain due to the cost of energy and because equipment may fail under extreme conditions. Catalysts can be used to increase the rate of reaction without affecting yield.

Chemicalengineerschoosetheconditionsthatwillmaketheprocessassafeandefficientaspossible,reducetheenergycostsandreducethewasteproducedatallstagesoftheprocess.

1. recallthatsomereactionsmaybereversedbyalteringthereactionconditionsincluding:

a) reversiblereactionsareshownbythesymbol? b) reversiblereactions(inclosedsystems)donot

reach100%yield

Specification links:• Calculationsofyields(C5.1).

Practical work:• Investigatingreversible

reactions.

Ideas about Science:• Makepredictionsfromdata

andgraphsaboutyieldofchemicalproducts(IaS1).

• Considertherisksandcostsofdifferentoperatingconditionsinanammoniaplant(IaS4).

Practical work• Analyseandevaluatedata

aboutyieldandrateofammoniaproduction.

2. recallthatdynamicequilibriumoccurswhentheratesofforwardandreversereactionsareequal

3. predict the effect of changing reaction conditions (concentration, temperature and pressure) on equilibrium position and suggest appropriate conditions to produce a particular product, including:

a) catalysts increase rate but do not affect yield b) the disadvantages of using very high

temperatures or pressures

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Chapter P1: Radiation and waves

Overview

Therearetwokeyscienceideasinthischapter–thefirstconsiderstheusesofelectromagneticradiationandthepossiblehealthrisksofradiation,bothinnatureandfromtechnologicaldevices,whicharebecomingofincreasingconcern.Thesecondpartofthechapterconsidersawavemodelforlightandsound.

TopicP1.1describesthemodelofradiation,animportantscientificmodelforexplaininghowoneobjectcanaffectanotheratadistance,andlinksthistotheideathatallpartsoftheelectromagneticspectrumbehaveinthisway.Itthengoesontousetheradiationmodeltoexplainhowelectromagneticradiationbehavesandtoconsidertherisksandbenefitsofthetechnologiesthatuseelectromagneticradiation.Insomecases,misunderstandingtheterm‘radiation’generatesunnecessaryalarm.Throughconsideringtheevidenceconcerningthepossible

harmfuleffectsoflowintensitymicrowaveradiationfromdevicessuchasmobilephones,learnerslearntoevaluatereportedhealthstudiesandinterpretlevelsofrisk.

TopicP1.2introducestheideathatallbodiesemitradiationtoexplainthegreenhouseeffect.Evidenceforglobalwarmingisexplored;scientificexplanationsforclimatechangedrawonideasaboutthewaythatradiationisemittedandabsorbedbydifferentmaterials.Thereisanopportunitytousebothphysicalanalogiesandcomputermodellingtodemonstratetheexplanatorypowerofmodelsinscience.

Allwaveshavepropertiesincommonandawavemodelcanbeusedtoexplainagreatmanyphenomena,bothnaturalandartificial.InTopicP1.3thereflectionandrefractionofwavesonwaterprovideevidencethatlightandsoundcanbemodelledaswaves.

Learning about light, sound, and waves, before GCSE (9–1)


• haveobservedwavesonwater,spring,andstrings

• knowthemeaningofthetermslongitudinal,transverse,superposition,andfrequency,inthecontextofwaves

• knowthatsoundwavesarelongitudinalandneedamediumtotravelthroughandthatsoundtravelsatdifferentspeedsinsolids,inwater,andinair

• knowthatsoundisproducedwhenobjectsvibrateandthatsoundwavesaredetectedbythevibrationstheycause

• knowthatlighttravelsataveryhighspeedandcanpassthroughavacuum

• knowsomeofthesimilaritiesanddifferencesbetweenlightwavesandwavesinmatter

• beabletousearaymodeloflighttodescribeandexplainreflectioninmirrors,refractionanddispersionbyglassandtheactionofconvexlenses

• knowthatlightincidentonasurfacemaybeabsorbed,scattered,orreflected,andthatlighttransfersenergyfromasourcetoanabsorber,whereitmaycauseachemicalorelectricaleffect.

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P1.1 What are the risks and benefits of using radiations?



Amodelofradiationcanbeusedtodescribeandpredicttheeffectsofsomeprocessesinwhichoneobjectaffectsanothersomedistanceaway.Oneobject(asource)emitsradiation(ofsomekind).Thisspreadsoutfromthesourceandtransfersenergytootherobject(s)somedistanceaway.

Lightisoneofafamilyofradiations,calledtheelectromagneticspectrum.Allradiationsintheelectromagneticspectrumtravelatthesamespeedthroughspace.

Whenradiationstrikesanobject,somemaybetransmitted(passthroughit),orbereflected,orbeabsorbed.Whenradiationisabsorbeditceasestoexistasradiation;usuallyitheatstheabsorber.

Sometypesofelectromagneticradiationdonotjustcauseheatingwhenabsorbed;X-rays,gammaraysandhighenergyultravioletradiationhaveenoughenergytoremoveanelectronfromanatomormolecule(ionisation)whichcanthentakepartinotherchemicalreactions.

1. describethemaingroupingsoftheelectromagneticspectrum–radio,microwave,infrared,visible(redtoviolet),ultraviolet,X-raysandgammarays,thattheserangefromlongtoshortwavelengths,fromlowtohighfrequencies,andfromlowtohighenergies

Practical work:• Estimatethespeedof

microwavesusingamicrowaveoven.

• Investigatehowtheintensityofradiationchangeswithdistancefromthesource.

2. recallthatoureyescanonlydetectaverylimitedrangeoffrequenciesintheelectromagneticspectrum

3. recallthatallelectromagneticradiationistransmittedthroughspacewiththesameveryhigh(butfinite)speed

4. explain,withexamples,thatelectromagneticradiationtransfersenergyfromsourcetoabsorber

5. recallthatdifferentsubstancesmayabsorb,transmit,orreflectelectromagneticradiationinwaysthatdependonwavelength

Specification links:• Whyaresomematerials

radioactive?(P6.1)• Howcanradioactive

materialsbeusedsafely(P6.2).

• Howhasourunderstandingoftheatomdevelopedovertime?(C2.1)

6. recallthatineachatomitselectronsarearrangedatdifferentdistancesfromthenucleus,thatsucharrangementsmaychangewithabsorptionoremissionofelectromagneticradiation,andthatatomscanbecomeionsbylossofouterelectrons

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Exposuretolargeamountsofionisingradiationcancausedamagetolivingcells;smalleramountscancauseschangestocellswhichmaymakethemgrowinanuncontrolledway,causingcancer.

Oxygenisactedonbyradiationtoproduceozoneintheupperatmosphere.Thisozoneabsorbsultravioletradiation,andprotectslivingorganisms,especiallyanimals,fromitsharmfuleffects.

Radiowavesareproducedwhenthereisanoscillatingcurrentinanelectricalcircuit.Radiowavesaredetectedwhenthewavescauseanoscillatingcurrentinaconductor.

Differentpartsoftheelectromagneticspectrumareusedfordifferentpurposesduetodifferencesinthewaystheyarereflected,absorbed,ortransmittedbydifferentmaterials.

Developmentsintechnologyhavemadeuseofallpartsoftheelectromagneticspectrum;everydevelopmentmustbeevaluatedforthepotentialrisksaswellasthebenefits(IaS4).Dataandscientificexplanationsofmechanisms,ratherthanopinion,shouldbeusedtojustifydecisionsaboutnewtechnologies(IaS3).

7. recallthatchangesinmolecules,atomsandnucleicangenerateandabsorbradiationsoverawidefrequencyrange,including:

a) gammaraysareemittedfromthenucleiofatoms b) X-rays,ultravioletandvisiblelightaregenerated

whenelectronsinatomsloseenergy c) highenergyultraviolet,gammaraysandX-rays

haveenoughenergytocauseionisationwhenabsorbedbysomeatoms

d) ultravioletisabsorbedbyoxygentoproduceozone,whichalsoabsorbsultraviolet,protectinglifeonEarth

e) infraredisemittedandabsorbedbymolecules

Ideas about Science:• Usetheradiationmodelto

predictandexplainthebehaviourofelectromagneticradiation(IaS3).

Practical work• Investigateabsorption,

transmissionandreflectionofelectromagneticradiatione.g.absorptionofultravioletbysunscreens,reflectionandabsorptionofmicrowaves,ormobilephonesignals.

Ideas about Science• Discussthedifferentrisks

andbenefitsoftechnologiesthatuseelectromagneticradiation(IaS4).

8. describehowultra-violetradiation,X-raysandgammarayscanhavehazardouseffects,notablyonhumanbodilytissues

9. giveexamplesofsomepracticalusesofelectromagneticradiationintheradio,microwave,infrared,visible,ultraviolet,X-rayandgammarayregionsofthespectrum

10. recall that radio waves can be produced by, or can themselves induce, oscillations in electrical circuits

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P1.2 What is climate change and what is the evidence for it?

Teaching and learning narrative Assessable learning outcomesLearners will be able to:

Linked opportunities

Allobjectsemitelectromagneticradiationwithaprincipalfrequencythatincreaseswithtemperature.TheEarthissurroundedbyanatmospherewhichallowssomeoftheelectromagneticradiationemittedbytheSuntopassthrough;thisradiationwarmstheEarth’ssurfacewhenitisabsorbed.TheradiationemittedbytheEarth,whichhasalowerprincipalfrequencythanthatemittedbytheSun,isabsorbedandre-emittedinalldirectionsbysomegasesintheatmosphere;thiskeepstheEarthwarmerthanitwouldotherwisebeandiscalledthegreenhouseeffect.

OneofthemaingreenhousegasesintheEarth’satmosphereiscarbondioxide,whichispresentinverysmallamounts;othergreenhousegasesincludemethane,presentinverysmallamounts,andwatervapour.Duringthepasttwohundredyears,theamountofcarbondioxideintheatmospherehasbeensteadilyrising,largelytheresultofburningincreasedamountsoffossilfuelsasanenergysourceandcuttingdownorburningforeststoclearland.

Computerclimatemodelsprovideevidencethathumanactivitiesarecausingglobalwarming.Asmoredataiscollectedusingarangeoftechnologies,themodelcanberefinedfurtherandbetterpredictionsmade(IaS3).

1. explainthatallbodiesemitradiation,andthattheintensityandwavelengthdistributionofanyemissiondependsontheirtemperatures

Specification Links• Whatistheevidencefor

climatechange?(C1.2)

Practical work:• Investigateclimate

changemodels–bothphysicalmodelsandcomputermodels

Ideas about Science• Useideasabouttheway

scienceexplanationsaredevelopedwhendiscussingclimatechange(IaS3).

• Useideasaboutcorrelationandcausewhendiscussingevidenceforclimatechange(IaS3).

2. explain how the temperature of a body is related to the balance between incoming radiation, absorbed radiation and radiation emitted; illustrate this balance, using everyday examples including examples of factors which determine the temperature of the Earth

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P1.3 How do waves behave?



Awaveisaregulardisturbancethattransfersenergyinthedirectionthatthewavetravels,withouttransferringmatter.

Forsomewaves(suchaswavesalongarope),thedisturbanceofthemediumasthewavepassesisatright-anglestoitsdirectionofmotion.Thisiscalledatransversewave.Forotherwaves(suchasaseriesofcompressionpulsesonaslinkyspring),thedisturbanceofthemediumasthewavepassesisparalleltoitsdirectionofmotion.Thisiscalledalongitudinalwave.

Thespeedofawavedependsonthemediumitistravellingthrough.Itsfrequencyisthenumberofwaveseachsecondthataremadebythesource.Thewavelengthofwavesisthedistancebetweenthesamepointsontwoadjacentdisturbances.

Thewaysinwhichlightandsoundwavesreflectandrefractwhentheymeetataninterfacebetweentwomaterialscanbemodelledwithwaterwaves.

Awavemodelforlightandsoundcanbeusedtodescribeandpredictsomebehaviouroflightandsound.

Refraction of light and sound can be explained by a change in speed of waves when they pass into a different medium; a change in the speed of a wave causes a change in wavelength since the frequency of the waves cannot change, and that this may cause a change in direction.

1. describewavemotionintermsofamplitude,wavelength,frequencyandperiod

Ideas about Science• Usethewavemodelto

predictandexplaintheobservedbehaviouroflight(IaS3).

Practical work:• Carryoutexperiments

tomeasurethespeedofwavesonwaterandthespeedofsoundinair.

2. describeevidencethatforbothripplesonwatersurfacesandsoundwavesinair,itisthewaveandnotthewaterorairitselfthattravels

3. describethedifferencebetweentransverseandlongitudinalwaves

4. describehowwavesonaropeareanexampleoftransversewaveswhilstsoundwavesinairarelongitudinalwaves

5. definewavelengthandfrequency

6. recallandapplytherelationshipbetweenspeed,frequencyandwavelengthtowaves,includingwavesonwater,soundwavesandacrosstheelectromagneticspectrum:

wavespeed(m/s)=frequency(Hz)×wavelength(m) M1a,M1c,M3c,M3d

7. a) describehowthespeedofripplesonwatersurfacesandthespeedofsoundwavesinair,maybemeasured

b) describehowtousearippletanktomeasurethespeed/frequencyandwavelengthofawave

PAGP4

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P1.3 How do waves behave?



8. a) describetheeffectsofreflectionandrefractionofwavesatmaterialinterfaces

b) describehowtomeasuretherefractionoflightthroughaprism

c) describehowtoinvestigatethereflectionoflightoffaplanemirror

PAGP4

9. recall that waves travel in different substances at different speeds and that these speeds may vary with wavelength

10. explain how refraction is related to differences in the speed of the waves in different substances

11. recallthatlightisanelectromagneticwave

12. recallthatelectromagneticwavesaretransverse

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Chapter P2: Sustainable energy

Overview

Energysupplyisoneofthemajorissuesthatsocietymustaddressintheimmediatefuture.

Citizensarefacedwithcomplexchoicesandavarietyofmessagesfromenergysupplycompanies,environmentalgroups,themedia,scientistsandpoliticians.Somemaintainthatrenewableresourcesarecapableofmeetingourfutureneeds,someadvocatenuclearpower,andsomearguethatdrasticlifestylechangesarerequired.Decisionsaboutenergyuse,whetheratapersonaloranationallevel,needtobeinformedbyaquantitativeunderstandingofthe

situation,andthisisanunderlyingthemeofthechapter.

TopicP2.1quantifiestheenergyusedbyelectricaldevicesintroducescalculationsofefficiencyandconsiderswaysofreducingdissipationinavarietyofcontexts.InTopicP2.2nationaldataonenergysourcesintroducesastudyofelectricitygenerationanddistribution;nuclearpowergeneration,theburningoffossilfuelsandrenewableresourcesarecomparedandcontrasted.Electricalsafetyinthehomeandareviewoftheenergychoicesavailabletoindividuals,organisationsandsocietyarealsoincluded.

Learning about energy before GCSE (9–1)


• havecomparedenergyusesandcostsindomesticcontexts,includingcalculationsusingavarietyofunits

• haveconsideredavarietyofprocessesthatinvolvetransferringenergy,includingheating,changingmotion,burningfuelsandchangingpositioninafield.

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P2.1 How much energy do we use?



Energyisconsideredasbeingstoredinalimitednumberofways:chemical,nuclear,kinetic,gravitational,elastic,thermal,electrostaticandelectromagneticandcanbetransferredfromonetoanotherbyprocessescalledworkingandheating.

Electricityisaconvenientwaytotransferenergyfromsourcetotheconsumerbecauseitiseasilytransmittedoverdistancesandcanbeusedtodoworkinmanyways,includingheatinganddrivingmotorswhichmakethingsmoveortoliftweights.

Whenenergyisusedtodoworksomeenergyisusuallywastedindoingthingsotherthantheintendedoutcome,itisdissipatedintothesurroundings,ultimatelyintoinaccessiblethermalstores.

Thepowerofanapplianceordeviceisameasureoftheamountofenergyittransferseachsecond,i.e.therateatwhichittransfersenergy.

Sankeydiagramsareusedtoshowalltheenergytransfersinasystem,includingenergydissipatedtothesurroundings;thedatacanbeusedtocalculatetheefficiencyofenergytransfers.

1. describehowenergyinchemicalstoresinbatteries,orinfuelsatthepowerstation,istransferredbyanelectriccurrent,doingworkondomesticdevices,suchasmotorsorheaters

Practical work• Comparethepower

consumptionofavarietyofdevicesandrelateittothechangesinstoredenergy.

• Investigatetheeffectsofinsulationontherateofcooling.

Maths• Calculatethecostof

energysuppliedbyelectricitygiventhepowerrating,thetimeandthecostperkWh(IaS2.2).

2. explain,withreferencetoexamples,therelationshipbetweenthepowerratingsfordomesticelectricalappliances,thetimeforwhichtheyareinuseandthechangesinstoredenergywhentheyareinuse

3. recallandapplythefollowingequationinthecontextofenergytransfersbyelectricalappliances:

energytransferred(J,kWh)=power(W,kW)×time(s,h) M3c,M3d

4. describe,withexamples,wherethereareenergytransfersinasystem,thatthereisnonetchangetothetotalenergyofaclosedsystem

qualitative only

5. describe,withexamplessystemchanges,whereenergyisdissipated,sothatitisstoredinlessusefulways

6. explainwaysofreducingunwantedenergytransfere.g.throughlubrication,thermalinsulation

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7. describetheeffects,ontherateofcoolingofabuilding,ofthicknessandthermalconductivityofitswalls

qualitative only

8. recallandapplytheequation: efficiency=usefulenergytransferred÷totalenergy

transferred tocalculateenergyefficiencyforanyenergytransfer,and

describe ways to increase efficiency M1c

9. interpretandconstructSankeydiagramstoshowunderstandingthatenergyisconserved

M4a

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P2.2 How can electricity be generated?



Themainenergyresourcesthatareavailabletohumansarefossilfuels(oil,gas,coal),nuclearfuels,biofuels,wind,water,andradiationfromtheSun.

Inmostpowerstationsgeneratorsproduceavoltageacrossawirebyspinningamagnetnearthewire.Oftenanenergysourceisusedtoheatwater;thesteamproduceddrivesaturbinewhichiscoupledtoanelectricalgenerator.Otherenergysourcesdrivethegeneratordirectly.

Themainssupplytoourhomesisanalternatingvoltage,at50Hz,230volts,butelectricityisdistributedthroughtheNationalGridatmuchhighervoltagestoreduceenergylosses.Transformersareusedtoincreasethevoltagefortransmissionandthendecreasethevoltagefordomesticuse.

Mostmainsappliancesareconnectedbyathreecorecable,containinglive,neutralandearthwires.

Thedemandforenergyiscontinuallyincreasingandthisraisesissuesabouttheavailabilityandsustainabilityofenergysourcesandtheenvironmentaleffectsofusingthesesources.Theintroductionanddevelopmentofnewenergysourcesmayprovidenewopportunitiesbutalsointroducestechnologicalandenvironmentalchallenges.Thedecisionsabouttheenergysourcesthatareusedmaybedifferentfordifferentpeopleindifferentcontexts(IaS4).

1. describethemainenergyresourcesavailableforuseonEarth(includingfossilfuels,nuclearfuel,biofuel,wind,hydroelectricity,thetidesandtheSun)

Specification links• Whatdeterminestherateof

energytransferinacircuit?(P3.4)

• What is the process inside a generator? (P3.7)

Practical work• Investigatefactorsaffecting

theoutputfromsolarpanelsandwindturbines.

Maths• Useideasaboutprobability

inthecontextofrisk.• Extractandinterpret

informationaboutelectricitygenerationandenergyusepresentedinavarietyofnumericalandgraphicalforms.

Ideas about Science• Discusstherisksandbenefits

ofdifferentwaysofgeneratingelectricityandwhydifferentdecisionsonthesameissuemightbeappropriate(IaS4.3–4.9,4.11).

2. explainthedifferencesbetweenrenewableandnon-renewableenergyresources

3. comparethewaysinwhichthemainenergyresourcesareusedtogenerateelectricity

M2c

4. recallthatthedomesticsupplyintheUKisa.c.,at50Hzandabout230voltsandexplainthedifferencebetweendirectandalternatingvoltage

5. recallthat,intheNationalGrid,transformersareusedtotransferelectricalpowerathighvoltagesfrompowerstations,tothenetworkandthenusedagaintotransferpoweratlowervoltagesineachlocalityfordomesticuse

6. recallthedifferencesinfunctionbetweenthelive,neutralandearthmainswires,andthepotentialdifferencesbetweenthesewires;henceexplainthatalivewiremaybedangerousevenwhenaswitchinamainscircuitisopen,andexplainthedangersofprovidinganyconnectionbetweenthelivewireandanyearthedobject

7. explainpatternsandtrendsintheuseofenergyresourcesindomesticcontexts,workplacecontexts,andnationalcontexts

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Chapter P3: Electric circuits

Overview

Knownonlybyitseffects,electricityprovidesanidealvehicletoillustratetheuseandpowerofscientificmodels.Duringthecourseofthe20thcentury,electricalengineerscompletelychangedwholesocieties,bydesigningsystemsforelectricalgenerationanddistribution,andawholerangeofelectricaldevices.

Inthischapter,learnerslearnhowscientistsvisualisewhatisgoingoninsidecircuitsandpredictcircuitbehaviour.InTopicP3.1,modelsofchargemovingthroughcircuitsdrivenbyavoltageandagainstaresistanceareintroduced.AmoregeneralunderstandingofvoltageaspotentialdifferenceisthendevelopedinTopicP3.2,whichthencontinues

withanexplorationofthedifferencebetweenseriesandparallelcircuits,leadingontoinvestigatingthebehaviourofvariouscomponentsind.c.seriescircuits.TopicP3.3concentratesonquantifyingtheenergytransferredinelectriccircuitsandhowthisisdeterminedbyboththepotentialdifferenceandthecurrent.

AreminderofearlierworkonmagnetsandmagneticfieldsinTopicP3.4leadsintoanintroductiontotheelectricmotorinTopicP3.5.Applicationsofelectromagnetismandinparticulartheelectricmotorhaverevolutionisedpeople’slivesinsomanyways–fromverysmallmotorsusedinmedicalcontexts,toverylargemotorsusedtopropelshipsorpumpwaterinpumpedstorageschemes.

Learning about electricity and magnetism before GCSE (9–1)


• befamiliarwiththebasicpropertiesofmagnets,andusethesetoexplainandpredictobservations

• knowthatthereisamagneticfieldclosetoanywirecarryinganelectriccurrent

• beawareoftheexistenceofelectriccharge,andunderstandhowsimpleelectrostaticphenomenacanbeexplainedintermsofthemovementofelectronsbetweenandwithinobjects

• understandtheideaofanelectriccircuit(aclosedconductingloopcontainingabattery)

thatconductsanelectriccurrentandbeabletopredictthecurrentinbranchesofaparallelcircuit

• understandtheideaofvoltageasameasureofthe‘strength’ofabatteryorpowersupply

• knowthatelectricalresistanceismeasuredinohmsandcanbecalculatedbydividingthevoltageacrossthecomponentbythecurrentthroughit

• knowthatthepowerratingsofelectricalappliancesarerelatedtotherateatwhichtheappliancestransfersenergy.

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P3.1 What determines the current in an electric circuit?



Anelectriccurrentistherateofflowofcharge;inanelectriccircuitthemetalconductors(thecomponentsandwires)containmanychargesthatarefreetomove.Whenacircuitismade,thebatterycausesthesefreechargestomove,andthesechargesarenotusedupbutflowinacontinuousloop.

Inagivencircuit,thelargerthepotentialdifferenceacrossthepowersupplythebiggerthecurrent.Components(forexample,resistors,lamps,motors)resisttheflowofchargethroughthem;theresistanceofconnectingwiresisusuallysosmallthatitcanbeignored.Thelargertheresistanceinagivencircuit,thesmallerthecurrentwillbe.

Representationalmodelsofelectriccircuitsusephysicalanalogiestohelpthinkabouthowanelectriccircuitworks,andtopredictwhathappenswhenavariableischanged(IaS3).

1. recallthatcurrentisarateofflowofcharge,thatforachargetoflow,asourceofpotentialdifferenceandaclosedcircuitareneededandthatacurrenthasthesamevalueatanypointinasingleclosedloop

Ideas about Science• Identifylimitations

inanalogiesusedtorepresentelectriccircuits(IaS3)

Practical work• Designand

constructelectriccircuitstoinvestigatetheelectricalpropertiesofrangeofcircuitcomponents.

2. recallandusetherelationshipbetweenquantityofcharge,currentandtime:

charge(C)=current(A)×time(s) M1c,M3c,M3d

3. recallthatcurrent(I)dependsonbothresistance(R)andpotentialdifference(V),andrecalltheunitsinwhichthesequantitiesaremeasured

4. a) recallandapplytherelationshipbetweenI,R,andV,tocalculatethecurrents,potentialdifferencesandresistancesind.c.seriescircuits

potentialdifference(V)=current(A)×resistance(Ω) M1c,M3c,M3d b) describeanexperimenttoinvestigatetheresistanceofa

wireandbeabletodrawthecircuitdiagramofthecircuitused

PAGP6

5. recallthatforsomecomponentsthevalueofRremainsconstant(fixedresistors)butthatinothersitcanchangeasthecurrentchanges(e.g.heatingelements,lampfilaments)

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P3.1 What determines the current in an electric circuit?



6. a) usegraphstoexplorewhethercircuitelementsarelinearornon-linearandrelatethecurvesproducedtotheirfunctionandproperties

M4c,M4d b) describeexperimentstoinvestigatetheI-Vcharacteristics

ofcircuitelements.Toinclude:lamps,diodes,LDRsandthermistors.Beabletodrawcircuitdiagramsforthecircuitsused

PAGP6

7. representcircuitswiththeconventionsofpositiveandnegativeterminals,andthesymbolsthatrepresentcommoncircuitelements,includingfilamentlamps,diodes,LDRsandthermistors

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P3.2 How do series and parallel circuits work?



Whenelectricchargeflowsthroughacomponent(ordevice),workisdonebythepowersupplyandenergyistransferredfromittothecomponentand/oritssurroundings.Potentialdifferencemeasurestheworkdoneperunitcharge.

Inaseriescircuitthechargepassesthroughallthecomponents,sothecurrentthrougheachcomponentisthesameandtheworkdoneoneachunitofchargebythebatterymustequalthetotalworkdonebytheunitofchargeonthecomponents.Thepotentialdifference(p.d.)islargestacrossthecomponentwiththegreatestresistanceandachangeintheresistanceofonecomponentwillresultinachangeinthepotentialdifferencesacrossallthecomponents.

Inaparallelcircuiteachchargepassesthroughonlyonebranchofthecircuit,sothecurrentthrougheachbranchisthesameasifitweretheonlybranchpresentandtheworkdonebyeachunitofchargeisthesameforeachbranchandequaltotheworkdonebythebatteryoneachcharge.Thecurrentislargestthroughthecomponentwiththesmallestresistance,becausethesamebatteryp.d.causesalargercurrenttoflowthroughasmallerresistancethanthroughabiggerone.

Whentwoormoreresistorsareplacedinseriestheeffectiveresistanceofthecombination(equivalentresistance)isequaltothesumoftheirresistances,becausethebatteryhastomovechargesthroughallofthem.

1. relatethepotentialdifferencebetweentwopointsinthecircuittotheworkdoneon,orby,agivenamountofchargeasitmovesbetweenthesepoints:

potentialdifference(V)= workdone(energytransferred)(J)÷charge(C) M1c,M3c,M3d

Ideas about Science• Linkthefeaturesof

amodeloranalogytofeaturesinanelectriccircuit,identifyevidenceforspecificaspectsofamodelandlimitationsinrepresentationsofamodel(IaS3).

Practical work• Used.c.series

circuits,includingpotentialdividercircuitstoinvestigatethebehaviourofavarietyofcomponents.

• Designandconstructelectriccircuitstouseasensorforaparticularpurpose.

2. a) describethedifferencebetweenseriesandparallelcircuits:toincludeideasabouthowthecurrentthrougheachcomponentandthepotentialdifferenceacrosseachcomponentisaffectedbyachangeinresistanceofacomponent

b) describehowtopracticallyinvestigatethebrightnessofbulbsinseriesandparallelcircuits.Beabletodrawcircuitdiagramsforthecircuitsused

PAGP6

3. explain,why,iftworesistorsareinseriesthenetresistanceisincreased,whereaswithtwoinparallelthenetresistanceisdecreased

qualitative only

4. solveproblemsforcircuitswhichincluderesistorsinseries,usingtheconceptofequivalentresistance

M1c,M3c,M3d

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P3.2 How do series and parallel circuits work?



Two(ormore)resistorsinparallelprovidemorepathsforchargestomovealongthaneitherresistoronitsown,sotheeffectiveresistanceisless.

Somecomponentsaredesignedtochangeresistanceinresponsetochangesintheenvironmente.g.theresistanceofanLDRvarieswithlightintensity,theresistanceofathermistorvarieswithtemperature;thesepropertiesareusedinsensingsystemstomonitorchangesintheenvironment.

5. explainthedesignanduseofd.c.seriescircuitsformeasurementandtestingpurposesincludingexploringtheeffectof:

a) changingcurrentinfilamentlamps,diodes,thermistorsandLDRs

b) changinglightintensityonanLDR c) changingtemperatureofathermistor(NTConly)

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P3.3 What determines the rate of energy transfer in a circuit?



Theenergytransferredwhenelectricchargeflowsthroughacomponent(ordevice),dependsontheamountofchargethatpassesandthepotentialdifferenceacrossthecomponent.

Thepowerrating(inwatts,W)ofanelectricaldeviceisameasureoftherateatwhichanelectricalpowersupplytransfersenergytothedeviceand/oritssurroundings.Therateofenergytransferdependsonboththepotentialdifferenceandthecurrent.Thegreaterthepotentialdifference,thefasterthechargesmovethroughthecircuit,andthemoreenergyeachchargetransfers.

TheNationalGridusestransformerstostepdownthecurrentforpowertransmission.Thepoweroutputfromatransformercannotbegreaterthanthepowerinput,thereforeifthecurrentincreases,thepotentialdifferencemustdecrease.Transmittingpowerwithalowercurrentthroughthecablesresultsinlesspowerbeingdissipatedduringtransmission.

1. describetheenergytransfersthattakeplacewhenasystemischangedbyworkdonewhenacurrentflowsthroughacomponent

Practical work• Comparethepower

consumptionofavarietyofdevicesandrelateittothecurrentpassingthroughthedevice.

2. explain,withreferencetoexamples,howthepowertransferinanycircuitdeviceisrelatedtotheenergytransferredfromthepowersupplytothedeviceanditssurroundingsoveragiventime:power(W)=energy(J)÷time(s)

M1c,M3c,M3d

3. recallandusetherelationshipbetweenthepotentialdifferenceacrossthecomponentandthetotalchargetocalculatetheenergytransferredinanelectriccircuitwhenacurrentflowsthroughacomponent:

energytransferred(workdone)(J)=charge(C)×potentialdifference(V)

M1c,M3c,M3d

4. recallandapplytherelationshipsbetweenpowertransferredinanycircuitdevice,thepotentialdifferenceacrossit,thecurrentthroughit,anditsresistance:

a) power(W)=potentialdifference(V)×current(A) b) power(W)=(current(A))2×resistance(Ω) M1c,M3c,M3d

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P3.3 What determines the rate of energy transfer in a circuit?



5. usetheideaofconservationofenergytoshowthatwhenatransformerstepsupthevoltage,theoutputcurrentmustdecreaseandviceversa

selectandusetheequation: potentialdifferenceacrossprimarycoil×currentinprimarycoil

=potentialdifferenceacrosssecondarycoil×currentinsecondarycoil

M1c,M3b,M3c,M3d

6. explainhowtransmittingpowerathighervoltagesismoreefficientwaytotransferenergy

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P3.4 What are magnetic fields?



Aroundanymagnetthereisaregion,calledthemagneticfield,inwhichanothermagnetexperiencesaforce.Themagneticeffectisstrongestatthepoles.Thefieldgetsgraduallyweakerwithdistancefromthemagnet.

Thedirectionandstrengthofamagneticfieldcanberepresentedbyfieldlines.TheseshowthedirectionoftheforcethatwouldbeexperiencedbytheNpoleofasmallmagnet,placedinthefield.

ThemagneticfieldaroundtheEarth,withpolesnearthegeographicnorthandsouth,providesevidencethatthecoreoftheEarthismagnetic.TheN-poleofamagneticcompasswillpointtowardsthemagneticnorthpole.

Magneticmaterials(suchasironandnickel)canbeinducedtobecomemagnetsbyplacingtheminamagneticfield.Whenthefieldisremovedpermanentmagnetsretaintheirmagnetisationwhilstothermaterialslosetheirmagnetisation.

Whenthereisanelectriccurrentinawire,thereisamagneticfieldaroundthewire;thefieldlinesformconcentriccirclesaroundthewire.Windingthewireintoacoil(solenoid)makesthemagneticfieldstronger,asthefieldsofeachturnaddtogether.Windingthecoilaroundanironcoremakesastrongermagneticfieldandanelectromagnetthatcanbeswitchedonandoff.

The19th-centurydiscoveryofthiselectromagneticeffectledquicklytotheinventionofanumberofmagneticdevices,includingelectromagneticrelays,whichformedthebasisofthetelegraphsystem,leadingtoacommunicationsrevolution(IaS4.1).

1. describetheattractionandrepulsionbetweenunlikeandlikepolesforpermanentmagnets

Specification links• Soundwaves(P1.4).

Practical work• Useplottingcompassesto

mapthemagneticfieldnearapermanentbarmagnet,betweenfacinglike/oppositepolesoftwomagnets,asinglewire,aflatcoilofwireandasolenoid.

• Investigatetherelationshipbetweenthenumberofturnsonasolenoidandthestrengthofthemagneticfield.

Ideas about Science• Developmentsof

electromagnetshaveledtomajorchangesinpeople’slives,includingapplicationsincommunicationssystems,MRIscannersandoncranesinscrapyards.

2. describethecharacteristicsofthemagneticfieldofamagnet,showinghowstrengthanddirectionchangefromonepointtoanother

3. explainhowthebehaviourofamagneticcompassisrelatedtoevidencethatthecoreoftheEarthmustbemagnetic

4. describethedifferencebetweenpermanentandinducedmagnets

5. describehowtoshowthatacurrentcancreateamagneticeffect

6. describethepatternanddirectionsofthemagneticfieldaroundaconductingwire

7. recallthatthestrengthofthefielddependsonthecurrentandthedistancefromtheconductor

8. explainhowthemagneticeffectofasolenoidcanbeincreased

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P3.5 How do electric motors work?



The magnetic fields of a current-carrying wire and a nearby permanent magnet will interact and the wire and magnet exert a force on each other. This is called the ‘motor effect’.

If the current-carrying wire is placed at right angles to the magnetic field lines, the force will be at right angles to both the current direction and the lines of force of the field. The direction of the force can be inferred using Fleming’s left-hand rule.

The size of the force is proportional to the length of wire in the field, the current and the strength of the field.

The motor effect can result in a turning force on a rectangular current-carrying coil placed in a uniform magnetic field; this is the principle behind all electric motors.

The invention and development of practical electric motors have made an impact on almost every aspect of daily life (IaS4.1).

1. describe the interaction forces between a magnet and a current-carrying conductor to include ideas about magnetic fields

Practical work• Investigatethemotoreffect

forasinglewireinamagneticfieldandapplytheprinciplestobuildasimpleelectricmotor.

• Buildasimpleelectricmotorandexplainhowitworks.

Ideas about Science• Describeandexplainexamples

ofusesofelectricmotorsthathavemadesignificantimprovementstopeople’slives(IaS4.1).

2. show that Fleming’s left-hand rule represents the relative orientations of the force, the conductor and the magnetic field

3. select and apply the equation that links the force (F) on a conductor to the strength of the field (B), the size of the current (I) and the length of conductor (I) to calculate the forces involved

force (N) = magnetic flux density (T) × current (A) × length of conductor (m)

M1b,M1c,M3c,M3d

4. explain how the force on a conductor in a magnetic field is used to cause rotation in the rectangular coil of a simple electric motor

i Detailed knowledge of the construction of motors not required

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Chapter P4: Explaining motion

Overview

Simplebutcounterintuitiveconceptsofforcesandmotion,developedbyGalileoandNewton,cantransformyoungpeople’sinsightintoeverydayphenomena.Theseideasalsounderpinanenormousrangeofmodernapplications,includingspacecraft,urbanmasstransitsystems,sportsequipmentandridesatthemeparks.

TopicP4.1reviewstheideaofforces:identifying,describingandusingforcestoexplainsimplesituations.TopicP4.2looksathowspeedismeasuredandrepresentedgraphicallyandintroducesthe

vectorquantitiesofvelocityanddisplacement.Therelationshipsbetweendistance,speed,accelerationandtimeareanexampleofsimplemathematicalmodellingthatcanbeusedtopredictthespeedandpositionofamovingobject.

TherelationshipbetweenforcesandmotionisdevelopedinTopicP4.3,whereresultantforcesandchangesinmomentumaredescribed.Theseideasarethenappliedinthecontextofroadsafety.

TopicP4.4considershowwecandescribemotionintermsofenergychanges.

Learning about force and motion before GCSE (9–1)


• describemotionusingwordsandwithdistance–timegraphs

• usetherelationshipaveragespeed=distance÷time

• identifytheforceswhentwoobjectsincontactinteract;pushing,pulling,squashing,friction,turning

• usearrowstoindicatethedifferentforcesactingonobjects,andpredictthenetforcewhentwoormoreforcesactonanobject

• knowthattheforcesduetogravity,magnetismandelectricchargeareallnon-contactforces

• understandhowtheforcesactingonanobjectcanbeusedtoexplainitsmotion.

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P4.1 What are forces?



Forcearisesfromaninteractionbetweentwoobjects,andwhentwoobjectsinteract,bothalwaysexperienceaforceandthesetwoforcesformaninteractionpair.Thetwoforcesinaninteractionpairarethesamekindofforce,equalinsizeandoppositeindirection,andactondifferentobjects(Newton’sThirdLaw).

Frictionistheinteractionbetweentwosurfacesthatslide(ortendtoslide)relativetoeachother:eachsurfaceexperiencesaforceinthedirectionthatprevents(ortendstoprevent)relativemovement.

Thereisaninteractionbetweenanobjectandthesurfaceitisrestingon:theobjectpushesdownonthesurface,thesurfacepushesupontheobjectwithanequalforce,andthisiscalledthenormalcontactforce.

Ineverydaysituations,adownwardforceactsoneveryobject,duetothegravitationalattractionoftheEarth.Thisiscalleditsweight.Itcanbemeasured(inN)usingaspring(ortop-pan)balance.Theweightofanobjectisproportionaltoitsmass.NeartheEarth’ssurface,theweightofa1kgobjectisroughly10N.TheEarth’sgravitationalfieldstrengthistherefore10N/kg.

Newton’sinsightthatlinkedtheforcethatcausesobjectstofalltoEarthwiththeforcethatkeepstheMooninorbitaroundtheEarthledtothefirstuniversallawofnature.

1. recallandapplyNewton’sThirdLaw Practical work• Investigatethe

effectofdifferentcombinationsofsurfacesonthefrictionalforces.

Ideas about science• Explainhow

Newton’sdiscoveryoftheuniversalnatureofgravityisanexampleoftheroleofimaginationinscientificdiscovery.(IaS3).

2. recallexamplesofwaysinwhichobjectsinteract:bygravity,electrostatics,magnetismandbycontact(includingnormalcontactforceandfriction)

3. describehowexamplesofgravitational,electrostatic,magneticandcontactforcesinvolveinteractionsbetweenpairsofobjectswhichproduceaforceoneachobject

4. representinteractionforcesasvectors

5. defineweight

6. describehowweightismeasured

7. recallandapplytherelationshipbetweentheweightofanobject,itsmassandthegravitationalfieldstrength:

weight(N)=mass(kg)×gravitationalfieldstrength(N/kg) M1c,M3c

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P4.2 How can we describe motion?



Themotionofamovingobjectcanbedescribedusingthespeedtheobjectismoving,thedirectionitistravellingandwhetherthespeedischanging.

Thedistanceanobjecthastravelledatagivenmomentismeasuredalongthepathithastaken.

Thedisplacementofanobjectatagivenmomentisitsnetdistancefromitsstartingpointtogetherwithanindicationofdirection.

Thevelocityofanobjectatagivenmomentisitsspeedatthatmoment,togetherwithanindicationofitsdirection.

Distanceandspeedarescalarquantities;theygivenoindicationofdirectionofmotion.

Displacementandvelocityarevectorquantities,andincludeinformationaboutthedirection.

Ineverydaysituations,accelerationisusedtomeanthechangeinspeedofanobjectinagiventimeinterval.

Distance–timegraphsandspeed–timegraphscanbeusedtodescribemotion.Theaveragespeedcanbecalculatedfromtheslopeofadistance-timegraph.

Theaverageaccelerationofanobjectmovinginastraightlinecanbecalculatedfromaspeed-timegraph.Thedistancetravelledcanbecalculatedfromtheareaunderthelineonaspeed-timegraph.

1. recallandapplytherelationship: averagespeed(m/s)=distance(m)÷time(s) M1a,M1c,M3b,M3c,M3d

Practical work:• Useavarietyof

methodstomeasuredistances,speedsandtimesandtocalculateacceleration.

• Comparemethodsofmeasuringtheaccelerationduetogravity.

Ideas about Science• Usemathematicaland

computationalmodelstomakepredictionsaboutthemotionofmovingobjects(IaS3).

• Exploreusingsimplecomputermodelstopredictmotionofamovingobject.

2. recalltypicalspeedsencounteredineverydayexperienceforwind,andsound,andforwalking,running,cyclingandothertransportationsystems

3. a) makemeasurementsofdistancesandtimes,andcalculatespeeds

b) describehowtouseappropriateapparatusandtechniquestoinvestigatethespeedofatrolleydownaramp

M2b,M2f PAGP3

4. makecalculationsusingratiosandproportionalreasoningtoconvertunits,toincludebetweenm/sandkm/h

M1c,M3c

5. explainthevector–scalardistinctionasitappliestodisplacementanddistance,velocityandspeed

6. a) recallandapplytherelationship: acceleration(m/s2)=changeinspeed(m/s)÷

timetaken(s) M1c,M3b,M3c,M3d b) explainhowtouseappropriateapparatusand

techniquestoinvestigateacceleration PAGP3

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Themathematicalrelationshipsbetweenacceleration,speed,distance,andtimeareasimpleexampleofacomputationalmodel.Themodelcanbeusedtopredictthespeedandpositionofanobjectmovingatconstantspeedorwithconstantacceleration.

7. selectandapplytherelationship:(finalspeed(m/s))2–(initialspeed(m/s))2=2×acceleration(m/s2)×distance(m)

M1a,M1c,M3b,M3c,M3d

8. drawandusegraphsofdistancesandspeedsagainsttimetodeterminethespeedsandaccelerationsinvolved

9. interpretdistance–timeandvelocity–timegraphs,includingrelatingthelinesandslopesinsuchgraphstothemotionrepresented

M4a,M4b,M4c,M4d

10. Interpret enclosed areas in velocity–time graphs M4a,M4b,M4c,M4d,M4f

11. recallthevalueofaccelerationinfreefallandcalculatethemagnitudesofeverydayaccelerationsusingsuitableestimatesofspeedsandtimes

M2h

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P4.3 What is the connection between forces and motion?



Whenforcesactonanobjecttheresultantforceisthesumofalltheindividualforcesactingonit,takingtheirdirectionsintoaccount. If a resultant force acts on an object, it causes a change of momentum in the direction of the force.

The size of the change of momentum of an object is proportional to the size of the resultant force acting on the object and to the time for which it acts (Newton’s Second Law).

Foranobjectmovinginastraightline:

• iftheresultantforceiszero,theobjectwillmoveatconstantspeedinastraightline(Newton’sFirstLaw)

• iftheresultantforceisinthedirectionofthemotion,theobjectwillspeedup(accelerate)

• iftheresultantforceisintheoppositedirectiontothemotion,theobjectwillslowdown.

In situations involving a change in momentum (such as a collision), the longer the duration of the impact, the smaller the average force for a given change in momentum.

Insituationswheretheresultantforceonamovingobjectisnotinthelineofmotion,theforcewillcauseachangeindirection.

1. describeexamplesoftheforcesactingonanisolatedsolidobjectorsystem

Practical work• Investigatefactors

thatmightaffecthumanreactiontimes.

• Investigatetheuseofcrumplezonestoreducethestoppingforces.

2. describe,usingfreebodydiagrams,exampleswhereseveralforcesleadtoaresultantforceonanobjectandthespecialcaseofbalancedforces(equilibrium)whentheresultantforceiszero

qualitative only

3. use scale drawings of vector diagrams to illustrate the resolution of two or more forces, in situations when there is a net force, or equilibrium

i Limited to parallel and perpendicular vectors only M4a,M5a,M5b

4. recall and apply the equation for momentum and describe examples of the conservation of momentum in collisions: momentum (kg m/s) = mass (kg) × velocity (m/s)

M1c,M3c,M3d

5. select and apply Newton’s Second Law in calculations relating force, change in momentum and time:

change of momentum (kg m/s) = resultant force (N) × time for which it acts (s)

M1c,M3c,M3d

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If the force is perpendicular to the direction of motion the object will move in a circle at a constant speed – the speed doesn’t change but the velocity does. For example, a planet in orbit around the Sun – gravity acts along the radius of the orbit, at right angles to the planet’s path.

Themassofanobjectcanbethoughtofastheamountofmatterinanobject–thesumofalltheatomsthatmakeitup.Massismeasuredinkilograms.The mass of an object is also a measure of its resistance to any change in its motion (its inertia); using this definition the inertial mass is the ratio of the force applied to the resulting acceleration.

Newtonwroteabouthowthelengthoftimeaforceactedonanobjectwouldchangetheobject’s‘amountofmotion’,andthewayheusedthetermmakesitclearthatheisdescribingwhatwenowcallmomentum,thishasledtoNewton’sSecondLawbeingexpressedintwoways:in terms of change in momentumandintermsofacceleration.

Newton’sexplanationofmotionisoneofthegreatintellectualleapsofhumanity.Itisagoodexampleoftheneedforcreativityandimaginationtodevelopascientificexplanationofsomethingthathadbeenobservedanddiscussedformanyyears(IaS3).

6. applyNewton’sFirstLawtoexplainthemotionofobjectsmovingwithuniformvelocityandalsothemotionofobjectswherethespeedand/ordirectionchanges

7. explain with examples that motion in a circular orbit involves constant speed but changing velocity

qualitative only

8. explain that inertial mass is a measure of how difficult it is to change the velocity of an object and that it is defined as the ratio of force over acceleration

9. recallandapplyNewton’sSecondLaw,relatingforce,massandacceleration:

force(N)=mass(kg)×acceleration(m/s2) M1c,M3c,M3d

Ideas about Science• ExplainwhyNewton’s

explanationofmotionisanexampleoftheneedforcreativethinkingindevelopingnewscientificexplanations(IaS3).

10. useandapplyequationsrelatingforce,mass,velocity,accelerationandmomentumtoexplainrelationshipsbetweenthequantities

M3b,M3c,M3d

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Ideasaboutforceandmomentumcanbeusedtoexplainroadsafetymeasures,suchasstoppingdistances,carseatbelts,crumplezones,airbags,andcycleandmotorcyclehelmets.

ImprovementsintechnologybasedonNewton’slawsofmotion(togetherwiththedevelopmentofnewmaterials)havemadeallformsoftravelmuchsafer.

11. explainmethodsofmeasuringhumanreactiontimesandrecalltypicalresults

12. explainthefactorswhichaffectthedistancerequiredforroadtransportvehiclestocometorestinemergenciesandtheimplicationsforsafety

M2c

13. explainthedangerscausedbylargedecelerations Ideas about Science• Describeandexplain

examplesofhowapplicationofNewton’slawsofmotionhasleddevelopmentsinroadsafety(IaS4).

• Discusspeople’swillingnesstoacceptriskinthecontextofcarsafetyandexplainwaysinwhichtheriskscanbereduced(IaS4).

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P4.4 How can we describe motion in terms of energy transfers?



Energyisalwaysconservedinanyeventorprocess.Energycalculationscanbeusedtofindoutifsomethingispossibleandwhatwillhappen,butnotexplainwhyithappens.

Thestoreofenergyofamovingobjectiscalleditskineticenergy.

Asanobjectisraised,itsstoreofgravitationalpotentialenergyincreases,andasitfalls,itsgravitationalpotentialenergydecreases.

Whenaforcemovesanobject,itdoesworkontheobject,energyistransferredtotheobject;whenworkisdonebyanobject,energyistransferredfromtheobjecttosomethingelse,forexample:

• whenanobjectisliftedtoahigherpositionabovetheground,workisdonebytheliftingforce;thisincreasesthestoreofgravitationalpotentialenergy

• whenaforceactingonanobjectmakesitsvelocityincrease,theforcedoesworkontheobjectandthisresultsinanincreaseinitsstoreofkineticenergy.

Iffrictionandairresistancecanbeignored,anobject’sstoreofkineticenergychangesbyanamountequaltotheworkdoneonitbyanappliedforce;inpracticeairresistanceorfrictionwillcausethegaininkineticenergytobelessthantheworkdoneonitbyanappliedforceinthedirectionofmotion,becausesomeenergyisdissipatedthroughheating.

1. describetheenergytransfersinvolvedwhenasystemischangedbyworkdonebyforcesincluding:

a) toraiseanobjectabovegroundlevel b) tomoveanobjectalongthelineofactionoftheforce

Specification links: • Sustainable

energy (P2).

Practical work• Usedatalogging

softwaretocalculatetheefficiencyofenergytransferswhenworkisdoneonamovingobject.

• Measuretheworkdonebyanelectricmotorliftingaload,andcalculatetheefficiency.

2. recallandapplytherelationshiptocalculatetheworkdone(energytransferred)byaforce:workdone(NmorJ)=force(N)×distance(m)(alongthelineofactionoftheforce)

M1a,M3c,M3d

3. recalltheequationandcalculatetheamountofenergyassociatedwithamovingobject:kineticenergy(J)=0.5×mass(kg)×(speed(m/s))2

M1a,M3c,M3d

4. recalltheequationandcalculatetheamountofenergyassociatedwithanobjectraisedabovegroundlevel:gravitationalpotentialenergy(J)=mass(kg)×gravitationalfieldstrength(N/kg)×height(m)

M1a,M3c,M3d

5. makecalculationsoftheenergytransfersassociatedwithchangesinasystem,recallingrelevantequationsformechanicalprocesses

M1a,M1c,M3c

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P4.4 How can we describe motion in terms of energy transfers?



Calculatingtheworkdonewhenclimbingstairsorliftingaload,andthepoweroutput,makesalinkbacktotheusefulnessofelectricalappliancesfordoingmanyeverydaytasks.

6. calculaterelevantvaluesofstoredenergyandenergytransfers;convertbetweennewton-metresandjoules

M1c,M3c

7. describeallthechangesinvolvedinthewayenergyisstoredwhenasystemchanges,forcommonsituations:includinganobjectprojectedupwardsorupaslope,amovingobjecthittinganobstacle,anobjectbeingacceleratedbyaconstantforce,avehicleslowingdown

8. explain,withreferencetoexamples,thedefinitionofpowerastherateatwhichenergyistransferred(workdone)inasystem

9. recallandapplytherelationship:power(W)=energytransferred(J)÷time(s)

M1a,M3c,M3d

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Chapter P5 Radioactive materials

Overview

Theterms‘radiation’and‘radioactivity’areofteninterchangeableinthepublicmind.Becauseofitsinvisibility,radiationiscommonlyfeared.Amoreobjectiveevaluationofrisksandbenefitsisencouragedthroughdevelopinganunderstandingofthemanypracticalusesofradioactivematerials.

TopicP5.1beginsbyconsideringtheevidenceofanuclearmodeloftheatom,includingRutherford’salphaparticlescatteringexperiment.Itthenusesthenuclearmodeltoexplainwhathappensduring

radioactivedecay.Thepropertiesofalpha,betaandgammaradiationareinvestigatedandideasabouthalf-lifearedeveloped.

InTopicP5.2learnerslearnaboutthepenetrationpropertiesofionisingradiationwhichleadstoaconsiderationoftheuseofradioactivematerialsinthehealthsector,andhowtheycanbehandledsafely.Inthecontextofhealthrisksassociatedwithirradiationand/orcontaminationbyradioactivematerial,theyalsolearnabouttheinterpretationofdataonrisk.

Learning about radioactivity before GCSE (9–1)

ThereisnoformallearningaboutradioactivitybeforeKeyStage4,butlearnerswillhaveideasaboutradioactivity,nuclearenergyandradiationfromeverydaylanguage.FromTopicP1.2learnersshould:

• recallthatineachatomitselectronsarearrangedatdifferentdistancesfromthenucleus

• recallthatgammaraysareemittedfromthenucleiofatoms

• beabletodescribehowionisingradiationcanhavehazardouseffects,notablyonhumanbodilytissues.

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P5.1 What is radioactivity?



Anatomhasanucleus,madeofprotonsandneutrons,whichissurroundedbyelectrons.

Themodernmodeloftheatomdevelopedovertimeasscientistsrejectedearliermodelsandproposednewonestofitthecurrentlyavailableevidence.

Eachstagereliedonscientistsusingreasoningtoproposemodelswhichfittedtheevidenceavailableatthetime.Modelswererejected,modifiedandextendedasnewevidencebecameavailable(IaS3).

Afterthediscoveryoftheelectroninthe19thcenturybyThomson,scientistsimaginedthatatomsweresmallparticlesofpositivematterwiththenegativeelectronsspreadthrough,likecurrantsinacake.

Thiswasthemodeluseduntil1910whentheresultsoftheRutherford-Geiger-Marsdenalphaparticlescatteringexperimentprovidedevidencethatagoldatomcontainsasmall,massive,positiveregion(thenucleus).

Atomsaresmall–about10–10macross,andthenucleusisatthecentre,aboutahundred-thousandthofthediameteroftheatom.

Eachatomhasanucleusatitscentreandthatnucleusismadeofprotonsandneutrons.Foranelement,thenumberoftheprotonsisalwaysthesamebutthenumberofneutronsmaydiffer.Formsofthesameelementwithdifferentnumbersofneutronsarecalledtheisotopesoftheelement.

1. describetheatomasapositivelychargednucleussurroundedbynegativelychargedelectrons,withthenuclearradiusmuchsmallerthanthatoftheatomandwithalmostallofthemassinthenucleus

Specification links• Howhasour

understandingofthestructureofatomsdevelopedovertime?(C2.1)

Ideas about Science• Explainhowthe

developmentofthenuclearmodeloftheatomisanexampleofhowscientificexplanationsbecomeaccepted(IaS3).

Practical work• Collectdatato

calculatethehalf-lifeofaradioactiveisotope.

• Usearandomeventsuchasdice-throwingtomodelradioactivedecay.

2. describehowandwhytheatomicmodelhaschangedovertime,toincludethemainideasofDalton,Thomson,RutherfordandBohr

3. recallthetypicalsize(orderofmagnitude)ofatomsandsmallmolecules

4. recallthatatomicnucleiarecomposedofbothprotonsandneutrons,andthatthenucleusofeachelementhasacharacteristicpositivecharge

5. recallthatnucleiofthesameelementcandifferinnuclearmassbyhavingdifferentnumbersofneutrons,thesearecalledisotopes

6. usetheconventionalrepresentationtoshowthedifferencesbetweenisotopes,includingtheiridentity,chargeandmass

7. recallthatsomenucleiareunstableandmayemitalphaparticles,betaparticles,orneutrons,andelectromagneticradiationasgammarays

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P5.1 What is radioactivity?



InterpretingtheunexpectedresultsoftheRutherford-Geiger-Marsdenexperimentrequiredimaginationtoconsideranewmodeloftheatom.

Somesubstancesemitionisingradiationallthetimeandarecalledradioactive.Theionisingradiation(alpha,beta,gamma,andneutron)isemittedfromtheunstablenucleusoftheradioactiveatoms,whichasaresultbecomemorestable.

Alphaparticlesconsistoftwoprotonsandtwoneutrons,andbetaparticlesareidenticaltoelectrons.Gammaradiationisveryhighfrequencyelectromagneticradiation.

Radioactivedecayisarandomprocess.Foreachradioactiveisotopethereisadifferentconstantchancethatanynucleuswilldecay.Overtimetheactivityofradioactivesourcesdecreases,asthenumberofundecayednucleidecreases.

Thetimetakenfortheactivitytofalltohalfiscalledthehalf-lifeoftheisotopeandcanbeusedtocalculatethetimeittakesforaradioactivematerialtobecomerelativelysafe.

8. relateemissionsofalphaparticles,betaparticles,orneutrons,andgammaraystopossiblechangesinthemassorthechargeofthenucleus,orboth

9. usenamesandsymbolsofcommonnucleiandparticlestowritebalancedequationsthatrepresenttheemissionofalpha,beta,gamma,andneutronradiationsduringradioactivedecay

M1b,M1c,M3c

10. explaintheconceptofhalf-lifeandhowthisisrelatedtotherandomnatureofradioactivedecay

11. calculate the net decline, expressed as a ratio, in a radioactive emission after a given (integral) number of half-lives

M1c,M3d

12. interpretactivity-timegraphstofindthehalf-lifeofradioactivematerials

M1c,M2g,M4a,M4c

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P5.2: How can radioactive materials be used safely?



Ionisingradiationcandamagelivingcellsandthesemaybekilledormaybecomecancerous,soradioactivematerialsmustbehandledwithcare.Inparticular,aradioactivematerialtakenintothebody(contamination)posesahigherriskthanthesamematerialoutsideasthematerialwillcontinuetoemitionisingradiationuntilitleavesthebody.

Whilstionisingradiationcancausecancer,itcanalsobeusedforimaginginsidethebodyandtokillcancerouscells.

Doctorsandpatientsneedtoconsidertherisksandbenefitswhenusingionisingradiationtotreatdiseases.

1. recallthedifferencesinthepenetrationpropertiesofalphaparticles,betaparticlesandgammarays

Specification links: • Whataretherisksand

benefitsofusingelectromagneticradiations?(P1.2)

Practical work• Collectandinterpretdatato

showthepenetrationpropertiesofionisingradiations.

Ideas about Science• Discussideasabout

correlationandcauseinthecontextoflinksbetweenionisingradiationandcancer(IaS3).

• Discusstheusesofionisingradiation,withreferencetoitsrisksandbenefits(IaS4).

2. recallthedifferencesbetweencontaminationandirradiationeffectsandcomparethehazardsassociatedwitheachofthese

3. describethedifferentusesofnuclearradiationsforexplorationofinternalorgans,andforcontrolordestructionofunwantedtissue

4. explainhowionisingradiationcanhavehazardouseffects,notablyonhumanbodilytissues

5. explainwhythehazardsassociatedwithradioactivematerialdifferaccordingtotheradiationemittedandthehalf-lifeinvolved

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Chapter P6: Matter – models and explanations

Overview

RichardFeynmansaid:“If,insomecataclysm,allofscientificknowledgeweretobedestroyed,andonlyonesentencepassedontothenextgenerationsofcreatures,whatstatementwouldcontainthemostinformationinthefewestwords?Ibelieveitistheatomichypothesis(ortheatomicfact,orwhateveryouwishtocallit)thatallthingsaremadeofatoms—littleparticlesthatmovearoundinperpetualmotion,attractingeachotherwhentheyarealittledistanceapart,butrepellinguponbeingsqueezedintooneanother.Inthatonesentence,youwillsee,thereisanenormousamountofinformationabouttheworld,ifjustalittle

imaginationandthinkingareapplied.”(Six Easy Pieces,p.4).

InthischaptertheparticlemodeldescribedbyFeynmanisusedtopredictandexplainsomepropertiesofmatter.TopicP6.1explorestherelationshipbetweenenergyandtemperatureandthewaysinwhichenergytransfertransformsmatter.TopicP6.2considershowtheparticlemodelexplainsthedifferencesindensitiesbetweensolids,liquidsandgasesandtheeffectofheatingbothintermsoftemperaturechangesandchangesofstate.TopicP6.3considersthebehaviourofmaterialsunderstressandhowtheparticlemodelcanexplaindifferencesinbehaviour.

Learning about matter and the particle model before GCSE (9–1)


• beabletouseaparticulatemodelofmattertoexplainstatesofmatterandchangesofstate

• haveinvestigatedstretchingandcompressingmaterialsandidentifyingthosethatobeyHooke’slaw

• beabletodescribehowtheextensionorcompressionofanelasticmaterialchangesasa

forceisapplied,andmakealinkbetweentheworkdoneandenergytransferduringcompressionorextension

• haveinvestigatedpressureinliquidsandrelatedthistofloatingandsinking

• beabletorelateatmosphericpressuretotheweightofairoverhead.

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Learning about Matter at GCSE (9–1)

P6.1 How does energy transform matter?



Ittooktheinsightofanumberofeighteenthandnineteenthcenturyscientiststoappreciatethatheatandworkweretwoaspectsofthesamequantity,whichwecallenergy.CarefulexperimentsdevisedbyJouleshowedthatequalamountsofmechanicalworkwouldalwaysproducethesametemperaturerise.

Energycanbesuppliedtoraisethetemperatureofasubstancebyheatingusingafuel,oranelectricheater,orbydoingworkonthematerial.

Mass–theamountofmatterinanobject–dependsonitsvolumeandthedensityofthematerialofwhichitconsists.

Thetemperatureriseofanobjectwhenitisheateddependsonitsmassandtheamountofenergysupplied.Differentsubstancesstoredifferentamountsofenergyperunitmassforthesametemperaturerise–thisiscalledthespecificheatcapacityofthematerial.

Whenasubstanceinthesolidstateisheated,itstemperaturerisesuntilitreachesthemeltingpointofthesubstance,butenergymustcontinuetobesuppliedforthesolidtomelt.Itstemperaturedoesnotchangewhileitmelts,andthechangeindensityonmeltingisverysmall.Similarlyasasubstanceintheliquidstateisheateditstemperaturerisesuntilitreachesboilingpoint;itstemperaturedoesnotchange,althoughenergycontinuestobesuppliedwhileitboils.Thechangeindensityonboilingisverygreat;asmallvolumeofliquidproducesalargevolumeofvapour.

1. a) definedensity b) describehowtodeterminethedensitiesofsolid

andliquidobjectsusingmeasurementsoflength,massandvolume

M1c,M5c PAGP1

Specification links• Howmuchenergydowe

use?(P2.1)• Whatdeterminestherateof

energytransferinacircuit(P3.4).

• Howcanwedescribemotionintermsofenergytransfers(P4.4).

Practical work• Deviseamethodtomeasure

thedensityofirregularobjects.

• Measurethespecificheatcapacityofarangeofsubstancessuchaswater,copper,aluminium.

• Measurethelatentheatoffusionofasubstanceinthesolidstateandthelatentheatofvaporisationofasubstanceintheliquidstate.

• Showthatthesameamountofworkalwaysresultsinthesametemperaturerise.

2. recallandapplytherelationshipbetweendensity,massandvolumetochangeswheremassisconserved:

density(kg/m3)=mass(kg)÷volume(m3) M1a,M1b,M1c,M3c

3. describetheenergytransfersinvolvedwhenasystemischangedbyheating(intermsoftemperaturechangeandspecificheatcapacity)

4. definethetermspecificheatcapacityanddistinguishbetweenitandthetermspecificlatentheat

5. a) selectandapplytherelationshipbetweenchangeininternalenergyofamaterialanditsmass,specificheatcapacityandtemperature:

changeininternalenergy(J)=mass(kg)×specificheatcapacity(J/kg/°C)×changeintemperature(°C)

M1a,M1c,M3d b) explainhowtosafelyuseapparatustodetermine

thespecificheatcapacityofmaterials PAGP5

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P6.1 How does energy transform matter?



Differentsubstancesrequiredifferentamountsofenergyperkilogramtochangethestateofthesubstance–thisiscalledthespecificlatentheatofthesubstance.

6. selectandapplytherelationshipbetweenenergyneededtocauseachangeinstate,specificlatentheatandmass:

energytocauseachangeofstate(J)=mass(kg)×specificlatentheat(J/kg)

M1a,M1c,M3c,M3d

• Collectdata,plotandinterpretgraphsthatshowhowthetemperatureofasubstancechangeswhenheatedbyaconstantsupplyofenergy.

Ideas about Science • Describeandexplainhow

carefulexperimentalstrategycanyieldhighqualitydata(IaS1).

• Describeandexplainanexampleofhowadevelopinganewscientificexplanationtakescreativethinking(IaS3).

7. describeallthechangesinvolvedinthewayenergyisstoredwhenasystemchanges,andthetemperaturerises,forexample:amovingobjecthittinganobstacle,anobjectslowingdown,waterbroughttoaboilinanelectrickettle

8. makecalculationsoftheenergytransfersassociatedwithchangesinasystemwhenthetemperaturechanges,recallingorselectingtherelevantequationsformechanical,electrical,andthermalprocesses

M1a,M1c,M2a,M3c,M3d

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P6.2 How does the particle model explain the effects of heating?



Theparticlemodelofmatterdescribesthearrangementsandbehavioursofparticles(atomsandmolecules);itcanbeusedtopredictandexplainthedifferencesinpropertiesbetweensolids,liquidsandgases.Inthismodel:

• allmatterismadeofverytinyparticles• thereisnoothermatterexcepttheseparticles(inparticular,no

matterbetweenthem)• particlesofanygivensubstanceareallthesame• particlesofdifferentsubstanceshavedifferentmasses• thereareattractiveforcesbetweenparticles.Thesedifferin

strengthfromonesubstancetoanother• inthesolidstate,theparticlesareclosetogetherandunableto

moveawayfromtheirneighbours• intheliquidstate,theparticlesarealsoclosetogether,butcan

slidepasteachother• inthegasstate,theparticlesarefurtherapart,andcanmove

freely.

Theparticlemodelisanexampleofhowscientistsusemodelsastoolsforexplainingobservedphenomena.

1. explainthedifferencesindensitybetweenthedifferentstatesofmatterintermsofthearrangementsoftheatomsormolecules

Ideas about Science• Usetheparticle

modeltoexplainfamiliarorunfamiliarphenomenaandmakepredictions(IaS3).

2. usetheparticlemodelofmattertodescribehowmassisconserved,whensubstancesmelt,freeze,evaporate,condenseorsublimate,butthatthesechangesdifferfromchemicalchangesandthematerialrecoversitsoriginalpropertiesifthechangeisreversed

3. usetheparticlemodeltodescribehowheatingasystemwillchangetheenergystoredwithinthesystemandraiseitstemperatureorproducechangesofstate

4. explainhowthemotionofthemoleculesinagasisrelatedbothtoitstemperatureanditspressure:henceexplaintherelationbetweenthetemperatureofagasanditspressureatconstantvolume

qualitative only

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P6.2 How does the particle model explain the effects of heating?



Theparticlemodelcanbeusedtodescribeandpredictphysicalchangeswhenmatterisheated.

• Theparticlesarealwaysmoving:inthesolidstate,theyarevibrating;intheliquidstate,theyarevibratingandjostlingaround;inthegasstate,theyaremovingfreelyinrandomdirections.

• Asubstanceinthegasstateexertspressureonitscontainerbecausethemomentumoftheparticleschangeswhentheycollidewithwallsofthecontainer.

• Thehottersomethingis,thehigheritstemperatureisandthefasteritsparticlesarevibratingormoving.

Carefulexperimentationandmathematicalanalysisshowedthatthetemperatureofasubstancewaslinkedtothekineticenergyofitsatomsormolecules.

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P6.3 How does the particle model relate to materials under stress?



Whenmorethanoneforceisappliedtoasolidmaterialitmaybecompressed,stretchedortwisted.Whentheforcesareremoveditmayreturntoitsoriginalshapeorbecomepermanentlydeformed.

Theseeffectscanbeexplainedusingideasaboutparticlesinthesolidstate.Asubstanceinthesolidstateisafixedshapeduetotheforcesbetweentheparticles.

Compressingorstretchingthematerialchangestheseparationoftheparticles,andtheforcesbetweentheparticles.

Elasticmaterialsspringbacktotheiroriginalshape.Iftheforcesaretoolargethematerialbecomesplasticandispermanentlydistorted.

Forsomematerials,theextensionisproportionaltotheappliedforce,butinothersystems,suchasrubberbandstherelationshipisnotlinear,eventhoughtheyareelastic.

Whenworkisdonebyaforcetocompressorstretchaspringorothersimplesystem,energyisstored,thisenergycanberecoveredwhentheforceisremoved.

1. explain,withexamples,thattostretch,bendorcompressanobject,morethanoneforcehastobeapplied

Practical work• Investigatethe

force-extensionpropertiesofavarietyofmaterials,identifyingthosethatobeyHooke’slaw,thosethatbehaveelastically,andthosethatshowplasticdeformation.

2. describeand use the particle model to explainthedifferencebetweenelasticandplasticdeformationcausedbystretchingforces

3. a) describetherelationshipbetweenforceandextensionforaspringandothersimplesystems

b) describehowtomeasureandobservetheeffectofforcesontheextensionofaspring

M2b,M2f PAGP2

4. describethedifferencebetweentheforce-extensionrelationshipforlinearsystemsandfornon-linearsystems

5. recallandapplytherelationshipbetweenforce,extensionandspringconstantforsystemswheretheforce-extensionrelationshipislinear

forceexertedbyaspring(N)=extension(m)×springconstant(N/m)

M1c,M3c

6. a) calculatetheworkdoneinstretchingaspringorothersimplesystem,bycalculatingtheappropriateareaontheforce-extensiongraph

M4f b) describehowtosafelyuseapparatustodetermine

theworkdoneinstretchingaspring PAGP2

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P6.3 How does the particle model relate to materials under stress?



7. selectandapplytherelationshipbetweenenergystored,springconstantandextensionforalinearsystem:energystoredinastretchedspring(J)=½×springconstant(N/m)×(extension(m))2

M1c,M3b,M3c,M3d

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Overview

Inordertomakesenseofthescientificideasthatlearnersencounterinlessonsandineverydaylifeoutsideofschool,theyneedanunderstandingofhowscienceexplanationsaredeveloped,thekindsofevidenceandreasoningbehindthem,theirstrengthsandlimitations,andhowfarwecanrelyonthem.

Learnersalsoneedopportunitiestoconsidertheimpactsofscienceandtechnologyonsociety,andhowwerespondindividuallyandcollectivelytonewideas,artefactsandprocessesthatsciencemakespossible.

ItisintendedthattheIdeas about Sciencewillhelplearnersunderstandhowscientificknowledgeisobtained,howtorespondtosciencestoriesandissuesintheworldoutsidetheclassroom,andtheimpactsofscientificknowledgeonsociety.

Notethat:

• althoughparticularIdeas about Sciencehavebeenlinkedtoparticularcontextsthroughoutthespecificationasexamples,theassessablelearningoutcomesinthischaptershouldbedeveloped,andwillbeassessed,inanycontextfromchaptersB1–B6,C1-C6,andP1-P6.

• theassessablelearningoutcomesinthischapterwillbeassessedinallofthewrittenexaminationpapers

• termsassociatedwithmeasurementanddataanalysisareusedinaccordancewiththeirdefinitionsintheAssociationofScienceEducationpublicationThe Language of Measurement(2010).

Learning about How Science Works before GCSE (9–1)


• understandthatscienceexplanationsarebasedonevidenceandthatasnewevidenceisgathered,explanationsmaychange

• havedevisedandcarriedoutscientificenquiries,inwhichtheyhaveselectedthemostappropriatetechniquesandequipment,collectedandanalyseddataanddrawnconclusions.

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IaS1 What needs to be considered when investigating a phenomenon scientifically?



Theaimofscienceistodevelopgoodexplanationsfornaturalphenomena.Thereisnosingle‘scientificmethod’thatleadstogoodexplanations,butscientistsdohavecharacteristicwaysofworking.Inparticular,scientificexplanationsarebasedonacycleofcollectingandanalysingdata.

Usually,developinganexplanationbeginswithproposingahypothesis.Ahypothesisisatentativeexplanationforanobservedphenomenon(“thishappensbecause…”).

Thehypothesisisusedtomakeapredictionabouthow,inaparticularexperimentalcontext,achangeinafactorwillaffecttheoutcome.Apredictioncanbepresentedinavarietyofways,forexampleinwordsorasasketchgraph.

Inordertotestaprediction,andthehypothesisuponwhichitisbased,itisnecessarytoplananexperimentalstrategythatenablesdatatobecollectedinasafe,accurateandrepeatableway.

1. ingivencontextsusescientifictheoriesandtentativeexplanationstodevelopandjustifyhypothesesandpredictions

Making and testing predictions:

TrendsandpatternsinthePeriodicTable(C2)

Reactivityofmetals(C3.2)

2. suggestappropriateapparatus,materialsandtechniques,justifyingthechoicewithreferencetotheprecision,accuracyandvalidityofthedatathatwillbecollected

3. recognisetheimportanceofscientificquantitiesandunderstandhowtheyaredetermined

4. identifyfactorsthatneedtobecontrolled,andthewaysinwhichtheycouldbecontrolled

5. suggestanappropriatesamplesizeand/orrangeofvaluestobemeasuredandjustifythesuggestion

M2d

6. planexperimentsordeviseproceduresbyconstructingclearandlogicallysequencedstrategiesto:

– makeobservations – produceorcharacteriseasubstance – testhypotheses – collectandcheckdata – explorephenomena

7. identifyhazardsassociatedwiththedatacollectionandsuggestwaysofminimizingtherisk

8. useappropriatescientificvocabulary,terminologyanddefinitionstocommunicatetherationaleforaninvestigationandthemethodsusedusingdiagrammatic,graphical,numericalandsymbolicforms

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IaS2 What processes are needed to draw conclusions from data?

Teaching and learning narrative Assessable learning outcomes Learners will be required to:


Thecycleofcollecting,presentingandanalysingdatausuallyinvolvestranslatingdatafromoneformtoanother,mathematicalprocessing,graphicaldisplayandanalysis;onlythencanwebegintodrawconclusions.

Asetofrepeatmeasurementscanbeprocessedtocalculatearangewithinwhichthetruevalueprobablyliesandtogiveabestestimateofthevalue(mean).

Displayingdatagraphicallycanhelptoshowtrendsorpatterns,andtoassessthespreadofrepeatedmeasurements.

Mathematicalcomparisonsbetweenresultsandstatisticalmethodscanhelpwithfurtheranalysis.

1. presentobservationsandotherdatausingappropriateformats P6.2(mechanicalequivalentofheat)

Describeandexplainhowcarefulexperimentalstrategycanyieldhighqualitydata.

2. whenprocessingdatauseSIunitswhereappropriate(e.g.kg,g,mg;km,m,mm;kJ,J)andIUPACchemicalnomenclatureunlessinappropriate

3. whenprocessingdatauseprefixes(e.g.tera,giga,mega,kilo,centi,milli,microandnano)andpowersoftenforordersofmagnitude

4. beabletotranslatedatafromoneformtoanother M2c,M4a

5. whenprocessingdatainterconvertunits

6. whenprocessingdatauseanappropriatenumberofsignificantfigures

M2a

7. whendisplayingdatagraphicallyselectanappropriategraphicalform,useappropriateaxesandscales,plotdatapointscorrectly,drawanappropriatelineofbestfit,andindicateuncertainty(e.g.rangebars)

M2c,M4a,M4c

8. whenanalysingdataidentifypatterns/trends,usestatistics(rangeandmean)andobtainvaluesfromalineonagraph(includinggradient,interpolationandextrapolation),

M2b,M2f,M2g,M4b,M4d,M4e,M4f

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IaS2 What processes are needed to draw conclusions from data?



Dataobtainedmustbeevaluatedcriticallybeforewecanmakeconclusionsbasedontheresults.Therecouldbemanyreasonswhythequality(accuracy,precision,repeatabilityandreproducibility)ofthedatacouldbequestioned,andanumberofwaysinwhichtheycouldbeimproved.

Datacanneverbereliedoncompletelybecauseobservationsmaybeincorrectandallmeasurementsaresubjecttouncertainty(arisingfromthelimitationsofthemeasuringequipmentandthepersonusingit).Aresultthatappearstobeanoutliershouldbetreatedasdata,unlessthereisareasontorejectit(e.g.measurementorrecordingerror)

9. inagivencontextevaluatedataintermsofaccuracy,precision,repeatabilityandreproducibility,identifypotentialsourcesofrandomandsystematicerror,anddiscussthedecisiontodiscardorretainanoutlier

Drawing conclusions from data:

PatternsinthePeriodicTable(C2)

Propertiesofpolymers(C4.2)

10. evaluateanexperimentalstrategy,suggestimprovementsandexplainwhytheywouldincreasethequality(accuracy,precision,repeatabilityandreproducibility)ofthedatacollected,andsuggestfurtherinvestigations

Agreementbetweenthecollecteddataandtheoriginalpredictionincreasesconfidenceinthetentativeexplanation(hypothesis)uponwhichthepredictionisbased,butdoesnotprovethattheexplanationiscorrect.Disagreementbetweenthedataandthepredictionindicatesthatoneorotheriswrong,anddecreasesourconfidenceintheexplanation.

11. inagivencontextinterpretobservationsandotherdata(presentedindiagrammatic,graphical,symbolicornumericalform)tomakeinferencesandtodrawreasonedconclusions,usingappropriatescientificvocabularyandterminologytocommunicatethescientificrationaleforfindingsandconclusions

12. explaintheextenttowhichdataincreaseordecreaseconfidenceinapredictionorhypothesis

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IaS3 How are scientific explanations developed?



Scientistsoftenlookforpatternsindataasameansofidentifyingcorrelationsthatcansuggestcause-effectlinks–forwhichanexplanationmightthenbesought.

Thefirststepistoidentifyacorrelationbetweenafactorandanoutcome.Thefactormaythenbethecause,oroneofthecauses,oftheoutcome.Inmanysituations,afactormaynotalwaysleadtotheoutcome,butincreasesthechance(ortherisk)ofithappening.Inordertoclaimthatthefactorcausestheoutcomeweneedtoidentifyaprocessormechanismthatmightaccountfortheobservedcorrelation.

1. useideasaboutcorrelationandcauseto: – identifyacorrelationindatapresented

astext,inatable,orasagraph M2g – distinguishbetweenacorrelationanda

cause-effectlink – suggestfactorsthatmightincreasethe

chanceofaparticularoutcomeinagivensituation,butdonotinvariablyleadtoit

– explainwhyindividualcasesdonotprovideconvincingevidencefororagainstacorrelation

– identifythepresence(orabsence)ofaplausiblemechanismasreasonablegroundsforaccepting(orrejecting)aclaimthatafactorisacauseofanoutcome

Considering correlation and cause:

EvidenceforrisksofX-rays(P1.2)

Evidenceforhumanactivitiescausingglobalwarming(P1.3)

Riskfactorsfornon-communicabledisease(B2.4)

Identifyingcausalrelationshipstoexplainclimatechange(C1.2).

Scientificexplanationsandtheoriesdonot‘emerge’automaticallyfromdata,andareseparatefromthedata.Proposinganexplanationinvolvescreativethinking.Collectingsufficientdatafromwhichtodevelopanexplanationoftenreliesontechnologicaldevelopmentsthatenablenewobservationstobemade.

Asmoreevidencebecomesavailable,ahypothesismaybemodifiedandmayeventuallybecomeanacceptedexplanationortheory.

Ascientifictheoryisageneralexplanationthatappliestoalargenumberofsituationsorexamples(perhapstoallpossibleones),whichhasbeentestedandusedsuccessfully,andiswidelyacceptedbyscientists.Ascientificexplanationofaspecificeventorphenomenonisoftenbasedonapplyingascientifictheorytothesituationinquestion.

2. describeandexplainexamplesofscientificmethodsandtheoriesthathavedevelopedovertimeandhowtheorieshavebeenmodifiedwhennewevidencebecameavailable

Developing scientific explanations:

Climatechange(P1.3)

Big Bang model (P4.5)

Nuclearmodeloftheatom(P5.1)

Thelinkbetweenwork,heatandtemperature(P6.2)

Thetheoryofnaturalselection(B6.1)

Explanatoryaccountsofhowtheatmospherewasformed(C1.1)

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IaS3 How are scientific explanations developed?



Findingsreportedbyanindividualscientistorgrouparecarefullycheckedbythescientificcommunitybeforebeingacceptedasscientificknowledge.Scientistsareusuallyscepticalaboutclaimsbasedonresultsthatcannotbereproducedbyanyoneelse,andaboutunexpectedfindingsuntiltheyhavebeenrepeated(bythemselves)orreproduced(bysomeoneelse).

Two(ormore)scientistsmaylegitimatelydrawdifferentconclusionsaboutthesamedata.Ascientist’spersonalbackground,experienceorinterestsmayinfluencehis/herjudgments.

Anacceptedscientificexplanationisrarelyabandonedjustbecausenewdatadisagreewithit.Itusuallysurvivesuntilabetterexplanationisavailable.

3. describeinbroadoutlinethe‘peerreview’process,inwhichnewscientificclaimsareevaluatedbyotherscientists

Explanations that relied on technological development:

Telescopes and the Big Bang model (P4.5)

Rolesofcellorganelles(B4.2)

Developmentofnanoparticles,andgraphene(C4.3)

Modelsareusedinsciencetohelpexplainideasandtotestexplanations.Amodelidentifiesfeaturesofasystemandrulesbywhichthefeaturesinteract.Itcanbeusedtopredictpossibleoutcomes.Representationalmodelsusephysicalanalogiesorspatialrepresentationstohelpvisualisescientificexplanationsandmechanisms.Descriptivemodelsareusedtoexplainphenomena.Mathematicalmodelsusepatternsindataofpastevents,alongwithknownscientificrelationships,topredictbehaviour;oftenthecalculationsarecomplexandcanbedonemorequicklybycomputer.

Modelscanbeusedtoinvestigatephenomenaquicklyandwithoutethicalandpracticallimitations,buttheirusefulnessislimitedbyhowaccuratelythemodelrepresentstherealworld.

4. useavarietyofmodels(includingrepresentational,spatial,descriptive,computationalandmathematicalmodels)to:

– solveproblems – makepredictions – developscientificexplanationsand

understanding – identifylimitationsofmodels

Examples of models:

Radiationmodeloflight(P1.2)

Wavemodeloflight(P1.3)

Equationsofmotion(P4.2)

Atomicmodel(P5.1)

Particlemodelofmatter(P6.1,P6.2)

Lockandkeyforenzymeaction(B3.1)

Usingmodelsofstructureofmaterialstoexplainproperties(C3.1,C4.1,C4.2,C4.3).

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IaS4 How do science and technology impact society?



Scienceandtechnologyprovidepeoplewithmanythingsthattheyvalue,andwhichenhancetheirqualityoflife.Howeversomeapplicationsofsciencecanhaveunintendedandundesirableimpactsonthequalityoflifeortheenvironment.Scientistscandevisewaysofreducingtheseimpactsandofusingnaturalresourcesinasustainableway(atthesamerateastheycanbereplaced).

Everythingwedocarriesacertainriskofaccidentorharm.Newtechnologiesandprocessescanintroducenewrisks.

Thesizeofariskcanbeassessedbyestimatingitschanceofoccurringinalargesample,overagivenperiodoftime.

Tomakeadecisionaboutacourseofaction,weneedtotakeaccountofboththerisksandbenefitstothedifferentindividualsorgroupsinvolved.Peoplearegenerallymorewillingtoaccepttheriskassociatedwithsomethingtheychoosetodothansomethingthatisimposed,andtoacceptrisksthathaveshort-livedeffectsratherthanlong-lastingones.People’s perception of the size of a particular risk may be different from the statistically estimated risk.Peopletendtoover-estimatetheriskofunfamiliarthings(likeflyingascomparedwithcycling),andofthingswhoseeffectisinvisibleorlong-term(likeionisingradiation).

Someformsofscientificresearch,andsomeapplicationsofscientificknowledge,haveethicalimplications.Indiscussionsofethicalissues,acommonargumentisthattherightdecisionisonewhichleadstothebestoutcomeforthegreatestnumberofpeople.

Scientistsmustcommunicatetheirworktoarangeofaudiences,includingthepublic,otherscientists,andpoliticians,inwaysthatcanbeunderstood.Thisenablesdecision-makingbasedoninformationaboutrisks,benefits,costsandethicalissues.

1. describeandexplaineverydayexamplesandtechnologicalapplicationsofsciencethathavemadesignificantpositivedifferencestopeople’slives

Positive applications of science:

Useoftheelectromagneticspectrum(P1.2)

Generatinganddistributingelectricity(P3.3)

Geneticengineering(B1.3)

Infertilitytreatment(B5.5)

Catalyticconverters,lowsulfurpetrolandgasscrubbers(C1.1)

Sustainability:

Energydemandsandchoicesofsourcestogenerateelectricity(P3.2)

Lifecycleassessment(C4.4)

Risks, benefits and ethical issues:

Biodiversity(B6.4)technologiesthatuseionisingradiation(P1.2,P5.2)

Genetechnology(B1.3)

Managingglobalwarming(C1.2)

2. identifyexamplesofrisksthathavearisenfromanewscientificortechnologicaladvance

3. foragivensituation: – identifyrisksandbenefitstothedifferent

individualsandgroupsinvolved – discussacourseofaction,takingaccountof

whobenefitsandwhotakestherisks – suggestreasonsforpeople’swillingnessto

accepttherisk – distinguish between perceived and

calculated risk

4. suggestreasonswhydifferentdecisionsonthesameissuemightbeappropriateinviewofdifferencesinpersonal,social,economicorenvironmentalcontext,andbeabletomakedecisionsbasedontheevaluationofevidenceandarguments

5. distinguishquestionsthatcouldinprinciplebeansweredusingascientificapproach,fromthosethatcouldnot;whereanethicalissueisinvolvedclearlystatewhattheissueisandsummarisethedifferentviewsthatmaybeheld

6. explainwhyscientistsshouldcommunicatetheirworktoarangeofaudiences.

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Chapter BCP8: Practical skills

Compliance with the requirements for practical work

Itiscompulsorythatlearnerscompleteatleastsixteen practicalactivities.

OCRhassplittherequirementsfromtheDepartmentforEducation‘GCSEsubjectcontentandassessmentobjectives’–Appendix4intosixteenPracticalActivityGroupsorPAGs,five biology, five chemistry and six physics.

ThePracticalActivityGroupsallowcentresflexibilityintheirchoiceofactivity.WhethercentresuseOCRsuggestedpracticalsorcentre-substitutedpracticals,theymustensurecompletionofatleastsixteenpracticalactivitiesandeachlearnermusthavehadtheopportunitytousealloftheapparatusandtechniquesdescribedinthefollowingtablesofthischapter.

ThetablesillustratetheapparatusandtechniquesrequiredforeachPAGandanexamplepracticalthatmaybeusedtocontributetothePAG.ItshouldbenotedthatsomeapparatusandtechniquescanbeusedinmorethanonePAG.It is therefore important that teachers take care to ensure that learners do have the opportunity to use all of the required apparatus and techniques during the course with the activities chosen by the centre.

Withinthespecificationthereareanumberofpracticalsthataredescribedinthe‘Assessable

learningoutcomes’column.ThesecancounttowardseachPAG.Weareexpectingthatcentreswillprovidelearnerswithopportunitiestocarryoutawiderangeofpracticalactivitiesduringthecourse.Thesecanbetheonesdescribedinthespecificationorcanbepracticalsthataredevisedbythecentre.Activitiescanrangefromwholeinvestigationstosimplestartersandplenaries.

Itshouldbenotedthatthepracticalsdescribedinthespecificationneedtobecoveredinpreparationforthequestionsinthewrittenexaminationsthatwillassesspracticalskills.Nolessthan15%ofthequestionswillassesspracticalskills.Learnersalsoneedtobepreparedtoanswerquestionsusingtheirknowledgeandunderstandingofpracticaltechniquesandproceduresinwrittenpapers.

Safetyisanoverridingrequirementforallpracticalwork.Centresareresponsibleforensuringappropriatesafetyproceduresarefollowedwhenevertheirlearnerscompletepracticalwork.

Useandproductionofappropriatescientificdiagramstosetupandrecordapparatusandproceduresusedinpracticalworkiscommontoallsciencesubjectsandshouldbeincludedwhereverappropriate.

Revision of the requirements for practical work

OCRwillreviewthepracticalactivitiesdetailedinChapterBCP8ofthisspecificationfollowinganyrevisionbytheSecretaryofStateoftheapparatusortechniquespublishedspecifiedinrespectoftheGCSECombinedScienceB(TwentyFirstCenturyScience)qualification.

OCRwillrevisethepracticalactivitiesifappropriate.

Ifanyrevisiontothepracticalactivitiesismade,OCRwillproduceanamendedspecificationwhichwillbepublishedontheOCRwebsite.OCRwillthenusethefollowingmethodstocommunicatetheamendmenttoCentres:NoticetoCentressenttoallExaminationsOfficers,e-alertstoCentresthathaveregisteredtoteachthequalificationandsocialmedia.

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Thefollowinglistincludesopportunitiesforchoiceanduseofappropriatelaboratoryapparatusforavarietyofexperimentalproblem-solvingand/orenquirybasedactivities.

Practical Activity Group(PAG)

Apparatus and techniques that the practical must use or cover

Example of a suitable biology activity (a range of practicals are included in the

specification and centres can

devise their own activity) *

B1Microscopy

Useofappropriateapparatus,techniquesandmagnification,includingmicroscopes,tomakeobservationsofbiologicalspecimensandproducelabelledscientificdrawings7

Investigatedifferentmagnificationtechniquestodrawscientificdiagramsfromanumberofbiologicalspecimens.

Useofappropriateapparatustomakeandrecordarangeofmeasurementsaccurately,includinglength,area,mass,time,temperature,volumeofliquidsandgases,andpH1

B2Samplingtechniques

Applicationofappropriatesamplingtechniquestoinvestigatethedistributionandabundanceoforganismsinanecosystemviadirectuseinthefield(toinclude:bioticandabioticfactors)

Investigationthedifferencesinhabitatsusingecologicalsamplingtechniques.


B3Ratesofenzyme-controlledreactions

SafeuseofappropriateheatingdevicesandtechniquesincludinguseofaBunsenburnerandawaterbathorelectricheater2

Investigatethefactorsthatcanaffecttherateofenzymeactivity.

Useofappropriateapparatusandtechniquesfortheobservationandmeasurementofbiologicalchangesand/orprocesses3

Measurementofratesofreactionbyavarietyofmethodsincludingproductionofgas,uptakeofwaterandcolourchangeofindicator5


B4Photosynthesis


InvestigatethefactorsthatcanaffecttherateofphotosynthesisonCabomba

Safeandethicaluseoflivingorganisms(plantsoranimals)tomeasurephysiologicalfunctionsandresponsestotheenvironmentMeasurementofratesofreactionbyavarietyofmethodsincludingproductionofgas,uptakeofwaterandcolourchangeofindicator5



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134© OCR 2016




Example of a suitable biology activity (a range of practicals are included in the

specification and centres can devise their

own activity) *

B5Microbiologicaltechniques


Investigatetheeffectivenessofantimicrobialagentsonthegrowthofabacteriallawn.

Useofappropriateapparatus,techniquesandmagnification,includingmicroscopes,tomakeobservationsofbiologicalspecimensandproducelabelledscientificdrawings7



* Centres are free to substitute alternative practical activities that also cover the apparatus and techniques from DfE: Combined Science GCSE subject content, July 2015 Appendix 4.1, 2, 3, 5, 7 These apparatus and techniques may be covered in any of the groups indicated. Number corresponds to that used in DfE: Combined Science GCSE subject content, July 2015 Appendix 4.

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Thefollowing list includesopportunities forchoiceanduseofappropriate laboratoryapparatus foravarietyofexperimentalproblem-solvingand/orenquirybasedactivities.



Example of a suitable chemistry activity (a range of

practicals are included in the



C1Electrolysis

Useofappropriateapparatusandtechniquestodraw,setupanduseelectrochemicalcellsforseparationandproductionofelementsandcompounds

Electrolysisofaqueoussodiumchlorideoraqueouscoppersulfatesolutiontestingforthegasesproduced

C2Distillation

Safeuseofarangeofequipmenttopurifyand/orseparatechemicalmixturesincludingevaporation,filtration,crystallisation,chromatographyanddistillation4

Distillationofamixture,forexampleorangejuice,cherrycola,hydrocarbons,inks


Useofappropriateapparatustomakeandrecordarangeofmeasurementsaccurately,includingmass,time,temperature,andvolumeofliquidsandgases1

C3SeparationTechniques


Usingchromatographytoidentifythemixturesofdyesinasampleofanunknowncomposition

C4Productionofsalts


ProductionofapuredrysampleofaninsolubleandsolublesaltUseofappropriateapparatustomakeandrecordarangeof

measurementsaccurately,includingmass,time,temperature,andvolumeofliquidsandgases1

Safeuseandcarefulhandlingofgases,liquidsandsolids,includingcarefulmixingofreagentsundercontrolledconditions,usingappropriateapparatustoexplorechemicalchangesand/orproducts

Useofappropriateapparatusandtechniquesforconductingandmonitoringchemicalreactions,includingappropriatereagentsand/ortechniquesforthemeasurementofpHindifferentsituations


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136© OCR 2016




Example of a suitable chemistry activity (a range of

practicals are included in the



C5Measuring

ratesofreaction

Useofappropriateapparatustomakeandrecordarangeofmeasurementsaccurately,includingmass,time,temperature,andvolumeofliquidsandgases1

Investigatetheeffectofsurfacearea,concentrationandtemperatureontherateofachemicalreaction

Makingandrecordingofappropriateobservationsduringchemicalreactionsincludingchangesintemperatureandthemeasurementofratesofreactionbyavarietyofmethodssuchasproductionofgasandcolourchange

* Centres are free to substitute alternative practical activities that also cover the apparatus and techniques from DfE: Combined Science GCSE subject content, July 2015 Appendix 4.1, 2, 4 These apparatus and techniques may be covered in any of the groups indicated. Number corresponds to that used in DfE: Combined Science GCSE subject content, July 2015 Appendix 4.

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Thefollowinglistincludesopportunitiesforchoiceanduseofappropriatelaboratoryapparatusforavarietyofexperimentalproblem-solvingand/orenquirybasedactivities.



Example of a suitable physics

activity (a range of practicals are

included in the specification and

centres can devise their own activity)*

P1Materials

Useofappropriateapparatustomakeandrecordarangeofmeasurementsaccurately,includinglength,area,mass,time,volumeandtemperature1

Determinethedensitiesofavarietyofobjects,bothsolidandliquidUseofsuchmeasurementstodeterminedensitiesofsolidand

liquidobjects

P2Forces


Investigatetheeffectofforcesonsprings

Useofappropriateapparatustomeasureandobservetheeffectsofforcesincludingtheextensionofsprings

P3Motion


Investigateaccelerationofatrolleydownaramp

Useofappropriateapparatusandtechniquesformeasuringmotion,includingdeterminationofspeedandrateofchangeofspeed(acceleration/deceleration)

P4Waves


Useofarippletanktomeasurethespeed,frequencyandwavelengthofawave

Makingobservationsofwavesinfluidsandsolidstoidentifythesuitabilityofapparatustomeasurespeed/frequency/wavelength.Makingobservationsoftheeffectsoftheinteractionofelectromagneticwaveswithmatter.

Investigatethereflectionoflightoffaplanemirrorandtherefractionoflightthroughprisms

P5Energy


Determinethespecificheatcapacityofamaterial

Safeuseofappropriateapparatusinarangeofcontextstomeasureenergychanges/transfersandassociatedvaluessuchasworkdone

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138© OCR 2016




Example of a suitable physics

activity (a range of practicals are

included in the specification and

centres can devise their own activity)*

P6Circuits

Useofappropriateapparatustomeasurecurrent,potentialdifference(voltage)andresistance,andtoexplorethecharacteristicsofavarietyofcircuitelements

InvestigatetheI-Vcharacteristicsofcircuitelements

Useofcircuitdiagramstoconstructandcheckseriesandparallelcircuitsincludingavarietyofcommoncircuitelements

* Centres are free to substitute alternative practical activities that also cover the apparatus and techniques from DfE: Combined Science GCSE subject content, July 2015 Appendix 4.1 These apparatus and techniques may be covered in any of the groups indicated. Number corresponds to that used in DfE: Combined Science GCSE subject content, July 2015 Appendix 4.

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Choice of activity

Centrescanincludeadditionalapparatusandtechniqueswithinanactivitybeyondthoselistedastheminimumintheabovetables.Learnersmust completeaminimumofsixteenpracticalscoveringalltheapparatusandtechniqueslisted.

Theapparatusandtechniquescanbecovered:(i) byusingOCRsuggestedactivities(providedas

resources)(ii) throughactivitiesdevisedbytheCentre.

Centrescanreceiveguidanceonthesuitabilityoftheirownpracticalactivitiesthroughourfreecourseworkconsultancyservice.Email:[email protected]

WhereCentresdevisetheirownpracticalactivitiestocovertheapparatusandtechniqueslistedabove,thepracticalmustcoveralltherequirementsandbeofalevelofdemandappropriateforGCSE.EachsetofapparatusandtechniquesdescribedinthemiddlecolumncanbecoveredbymorethanoneCentredevisedpracticalactivitye.g.“measurementofratesofreactionbyavarietyofmethodsincludingproductionofgas,uptakeofwaterandcolourchangeofindicator”couldbesplitintotwoormoreactivities(ratherthanone).

NEA Centre Declaration Form: Practical Science Statement

Centresmustprovideawrittenpractical science statementconfirmingthatreasonableopportunitieshavebeenprovidedtoalllearnersbeingsubmittedforentrywithinthatyear’ssetofassessmentstoundertakeatleastsixteenpracticalactivities.

ThepracticalsciencestatementiscontainedwithintheNEACentreDeclarationFormwhichcanbefoundontheOCRwebsiteatwww.ocr.org.uk/formsfinder.Bysigningtheform,thecentreisconfirmingthattheyhavetakenreasonablestepstosecurethateachlearner:

a) hascompletedthepracticalactivitiessetbyOCRasdetailedinChapterBCP8

b) hasmadeacontemporaneousrecordof: (i) theworkwhichthelearnerhasundertaken

duringthosepracticalactivities,and (ii) theknowledge,skillsandunderstanding

whichthatlearnerhasderivedfromthosepracticalactivities.

Centresshouldretainrecordsconfirmingpoints(a)to(b)aboveastheymayberequestedaspartoftheJCQinspectionprocess.Centresmustprovidepracticalscienceopportunitiesfortheirlearners.Thisdoesnotgosofarastoobligecentrestoensurethatalloftheirlearnerstakepartinallofthepracticalscienceopportunities.Thereisalwaysariskthatanindividuallearnermaymissthearrangedpracticalsciencework,forexamplebecauseofillness.Itcouldbecostlyforthecentretorunadditionalpracticalscienceopportunitiesforthelearner.

However,theopportunitiestotakepartinthespecifiedrangeofpracticalworkmustbegiventoalllearners.LearnerswhodonottakeupthefullrangeofopportunitiesmaybedisadvantagedastherewillbequestionsonpracticalscienceintheGCSE(9–1)CombinedScienceB(TwentyFirstCenturyScience)assessment.PleaseseetheJCQpublicationInstructions for conducting non-examination assessmentsforfurtherinformation.

AnyfailurebyacentretoprovideapracticalsciencestatementtoOCRinatimelymanner(bymeansofanNEACentreDeclarationForm)willbetreatedasmalpracticeand/ormaladministration[underGeneralConditionA8(Malpractice and maladministration)].

mailto:[email protected]

http://www.ocr.org.uk/formsfinder

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140© OCR 2016


2d. Prior knowledge, learning and progression

• LearnersinEnglandwhoarebeginningaGCSE(9–1)coursearelikelytohavefollowedaKeyStage3programmeofstudy.

• TherearenopriorqualificationsrequiredinorderforlearnerstoenterforaGCSE(9–1)inCombinedScienceB(TwentyFirstCenturyScience).

• GCSEs(9–1)arequalificationsthatenablelearnerstoprogresstofurtherqualificationseitherVocationalorGeneral.

ThereareanumberofSciencespecificationsatOCR.

Findoutmoreatwww.ocr.org.uk

http://www.ocr.org.uk

gcse science combined b 21st century - scribble resources · 2019-01-14 · note, however, that...

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