* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Building Circuits Overview Directions
Survey
Document related concepts
Power engineering wikipedia , lookup
Alternating current wikipedia , lookup
Ground (electricity) wikipedia , lookup
Electrical substation wikipedia , lookup
Electronic engineering wikipedia , lookup
Fault tolerance wikipedia , lookup
History of electric power transmission wikipedia , lookup
Electrification wikipedia , lookup
History of electromagnetic theory wikipedia , lookup
Regenerative circuit wikipedia , lookup
Earthing system wikipedia , lookup
Opto-isolator wikipedia , lookup
Flexible electronics wikipedia , lookup
Circuit breaker wikipedia , lookup
Transcript
Thiswebsitewouldliketoremindyou:Yourbrowser(AppleSafari7)isoutofdate.Updateyourbrowserformore security,comfortandthebestexperienceonthissite. Activitydevelop BuildingCircuits Whattypesofworkingcircuitsarethere? Overview Studentsexperimentwithbatteries,wires,bulbs,andswitchestoassembleseries andparallelcircuitsandtotestforconductivityinsampleitems. Forthecompleteactivitywithmediaresources,visit: http://nationalgeographic.org/activity/building-circuits/ Program Directions 1.Activatestudents’priorknowledgeaboutelectricity. Findoutwhatstudentsalreadyknowaboutelectricity.Encouragethemtoidentify objectsintheroomthatuseelectricity.Ask:Doyouknowhowelectricitytravelsto powerthesedevices?(Electricitytravelsthroughcircuits.)Ask:Howiselectricity usedinmorecomplicatedprojects,likepoweringarobot?Explainthatelectricityis usedtoprovidepowertovariouspartsoftherobot,suchasmovingmechanical parts,systemsthatprovidecontrolfortherobot(liketheCPU),anddatagatheringcomponents(likesensors). 1of13 × 2.Introducetheconceptofacircuit. Drawacircleontheboard.Ask:Istheshapeopenorclosed?(Itisclosed.)Now drawacircularshapethatisnotcomplete,likea“u,”ontheboard.Ask:Isthis shapeopenorclosed?(Itisopen.)Informstudentsthatinorderforelectricityto flowandpoweradevice,theremustbeanunbroken,orclosed,pathway.Doa quickdemonstrationusingtheroom’slights.Flipthelightoffintheclassroom.Tell studentswhenthelightgoesoff,thecircuitisopenandelectricitycannotreach thebulbtoproducelight.Referencetheshapespreviouslydrawnontheboard. Flipthelightbackon.Tellstudentsthecircuitisnowclosedandelectricityisfreeto travelandilluminatethebulb. 3.Studentsbuildasimplecircuittolightabulbwiththehelpofadiagramand demonstration. Telltheclasstheywillnowbuildaclosedsimplecircuittolightabulb.Showthe classtheseparatepiecestheywilluse:aDcellbattery;theholderfortheDcell battery;fouralligatorclipleads;a2.5volt,0.2amp,orsmallerbulbswithascrewtypebase;andtwobulbholders.Separatetheclassintoworkinggroupsof2-4 studentsanddistributethepartslistedabovetoeachgroup.Explainthattheir groupgoalistoworktogethertobuildasimplecircuitthatwilllightthebulb. Explainthatyouwilldemonstratehowtobuildacircuitandtheywillfollowalong, butlaterontheywillneedtoworkintheirgroupstobuildacircuitontheirown. Drawasimplecircuitdiagramontheboard,andlabelandexplainalloftheparts, usingtheprovideddiagram.Walktheclassthroughbuildingthecircuitusingthe HowtoBuildaSimpleCircuithandout. Aftergroupshavesuccessfullylitthebulb,havethemmakealabeledsketchof thecircuittheybuiltintheirnotebooks.Ask:Whatwouldhappenifaswitchwere addedtothiscircuit?Provideeachgroupwithasingleknifeswitchandhavethem updatetheircircuit.Elicitanswersfromstudentsthathelpthemmakeconnections betweentheclosedcircuittheyjustbuilt,andtheearlierdemonstrationwiththe 2of13 classroomlightthatcreatesanopenandclosedcircuit.Updatethediagramyou previouslydrewontheboardtoincludeaswitchusingtheSimpleCircuitwith Switchdiagramprovided. 4.Studentsbuildseriesandparallelcircuitsinsmallgroups. Askstudentstoremovetheknifeswitchfromtheircircuit,sotheyhaveasimple circuitagain.Asktheclasstopredictwhatwillhappenifanadditionalbulbisadded tothesimplecircuit,withoutmakinganyotherchanges.(Again,theknifeswitch shouldnolongerbeincludedinthecircuit.)Havestudentsrecordtheirpredictions intheirnotebooks.Asstudentsaremakingpredictions,giveanadditionallightbulb andbulbholdertoeachgroup.Then,allowgroupstimetoexperimentwithlighting twobulbsonasinglepathway.Remindgroupsofwhatasingleclosedpathwayis bydrawingattentionbacktothediagramontheboardandthefirstcircuitthey built.Facilitateasneeded.UsetheprovidedHowtoBuildaSeriesCircuithandout thatcontainsadiagramtocheckstudentwork. Aftertheyhavesuccessfullybuilttheircircuits,tellstudentsthatthistypeofcircuit iscalledaseriescircuit.Ithasasinglepathwayfromtheenergysource(battery) throughaseriesofloads(bulbs)andbacktotheenergysource.Ask:What happenedwhenasecondlightbulbwasadded?Explainthatthebulbsaredimmer becausetheadditionalbulbslowstheflowofelectricityinthecircuit,causingthe lightstodim.Ask:Whatmighthappenwiththeadditionofathirdbulb?Explain theycouldexpectthebulbstobeevendimmerornotlightatall.Ask:Whatwould happenifacomponentinthecircuitisdisconnectedorifthereisabrokenbulbin thiscircuit?(Thecircuitwillbeopenandnoneofthebulbswillwork.)Have studentsmakealabeledsketchoftheirseriescircuitintheirnotebooksand recordtheirobservationsaboutbuildingthistypeofcircuit. Posethefollowingquestiontotheclass:Ifonebulbinyourcircuitwentout,what wouldbenecessaryinorderfortheotherbulbtoremainlit?Explainthatthe configurationofthecircuitmustchangesobulbsareonseparateclosed 3of13 pathwayswiththeenergysource.Allowtimeforgroupstoexperimentwith buildingacircuitthatlightsbothbulbs,withtheadditionalchallengethatonebulb mustremainlitwhenasinglecomponentisdisconnectedwithinthecircuit. Facilitateasneeded.UsetheprovidedHowtoBuildaParallelCircuithandoutthat containsadiagramtocheckstudentwork. Explainthatthistypeofcircuitiscalledaparallelcircuit,wherebulbsare connectedonseparatepathways.Eachbulbinaparallelcircuitwillbeequally bright,butwilldrainthebatteryatanacceleratedrate.Havestudentscompare andcontrasttheworkingmodelsofparallelcircuitscreatedbyeachgroup.Ask: Wereallthegroups’parallelcircuitsthesame?Havestudentsmakealabeled sketchoftheirparallelcircuitintheirnotebooksandrecordtheirobservations aboutbuildingthistypeofcircuit. 5.Reviewthedifferenttypesofcircuits. Reviewthesimilaritiesanddifferencesbetweenthefourdifferenttypesofcircuits thatstudentsdiscussedduringtheactivity:open,closed,series,andparallel.Have adiscussionabouttheapplicationsofeachtypeofcircuit. Givestudentstheexampleofstreetlightsbeingconfiguredinparallelcircuits. Remindthestudentsthatinaparallelcircuit,thecurrenttoeachload,likeabulb, isseparate,soifonebulbburnsout,theotherswillstillwork.Asktheclass:Why wouldthisbeuseful?(Becauseifonelightgoesout,therestwillstayon,ensuring thesafetyofpeopleonthatstreet.)Encouragestudentstoshareother applicationsineverydaylife. Modification Iftherearenotenoughmaterialsfortheseactivitiestobedoneinsmallgroups, theteachercandothemasdemonstrationsusingstudentvolunteers. 4of13 Modification Toadaptthisactivityforyoungerstudents,completeactivitysteps1-3,thendo theExtendingtheLearningsectionoftheactivity. InformalAssessment Havestudentsbuildworkingmodelsofseriesandparallelcircuitswithout instruction. ExtendingtheLearning Studentsexaminetheconductivityofobjectsbytestingpredictionsabout conductorswithintheircircuits. Ask:Whyiselectricityabletoflowthroughawire?Explainthatwireismadeof metalandmetalisagoodconductorofelectricity.Asktheclasstopredictwhat kindsofmaterialstheythinkelectricitywillflowthrougheasilyandwhatmaterials electricitywillnotflowthrougheasily. Remindtheclassthatacircuitmustbeclosedforelectricitytoflowcontinuously throughit.Showtheclassitemsfromaroundtheclassroom,suchasthe following:apaperclip,apieceofstring,aneraser,arubberband,andapenny. Invitestudentstopredictwhichitemswillbegoodconductorsandwhichwillnot begoodconductors.Havestudentsrecordthesepredictionsintheirnotebooks oronaseparatesheetofpaper. Usethediagramsheetprovidedtoinstructgroupsinconstructingabrokencircuit usingthreewires,abulb,andabattery.Havestudentsintroducetheitemsfrom aroundtheclassroomintothecircuitbyattachinganalligatorclipinthecircuitto twosidesoftheobject.Ifthebulblights,thentheitemisagoodconductor;ifthe bulbdoesnotlight,theitemisnotagoodconductor. Havestudentsrecordtheirresultsintheirnotebooksorontheirpaper,nextto theiroriginalpredictions.Ask:Wereyourpredictionsaccurate?Whatobjectsmake goodconductors,andwhatobjectsmakepoorconductors?Typicallyobjects 5of13 madeofmetalaregoodconductorsandmostnon-metalmaterialsdonotconduct electricitywell. Objectives Subjects&Disciplines Science Physicalsciences Physics LearningObjectives Studentswill: Constructsimple,series,andparallelcircuits Understandandbeabletoexplainthedifferencebetweenseriesandparallel circuits Understandandbeabletoexplainthedifferencebetweenopenandclosed circuits TeachingApproach Learning-for-use TeachingMethods Discoverylearning Experientiallearning Hands-onlearning 6of13 SkillsSummary Thisactivitytargetsthefollowingskills: 21stCenturyStudentOutcomes LearningandInnovationSkills CommunicationandCollaboration CreativityandInnovation CriticalThinkingandProblemSolving CriticalThinkingSkills Analyzing Applying Creating Evaluating Remembering Understanding ScienceandEngineeringPractices Askingquestions(forscience)anddefiningproblems(forengineering) Developingandusingmodels Planningandcarryingoutinvestigations NationalStandards,Principles,andPractices NationalScienceEducationStandards •(5-8)StandardA-1: Abilitiesnecessarytodoscientificinquiry •(5-8)StandardA-2: Understandingsaboutscientificinquiry •(5-8)StandardB-3: Transferofenergy •(K-4)StandardA-1: Abilitiesnecessarytodoscientificinquiry 7of13 •(K-4)StandardA-2: Understandingsaboutscienceandtechnology •(K-4)StandardB-1: Propertiesofobjectsandmaterials •(K-4)StandardB-3: Light,heat,electricity,andmagnetism NextGenerationScienceStandards •Energy: 4-PS3-2.Makeobservationstoprovideevidencethatenergycanbetransferred fromplacetoplacebysound,light,heat,andelectriccurrents. •Energy: 4-PS3-4.Applyscientificideastodesign,test,andrefineadevicethatconverts energyfromoneformtoanother. •EngineeringDesign: 3-5-ETS1-2.Generateandcomparemultiplepossiblesolutionstoaproblembased onhowwelleachislikelytomeetthecriteriaandconstraintsoftheproblem. •EngineeringDesign: 3-5-ETS1-1.Defineasimpledesignproblemreflectinganeedorawantthat includesspecifiedcriteriaforsuccessandconstraintsonmaterials,time,orcost. •EngineeringDesign: MS-ETS1-1.Definethecriteriaandconstraintsofadesignproblemwithsufficient precisiontoensureasuccessfulsolution,takingintoaccountrelevantscientific principlesandpotentialimpactsonpeopleandthenaturalenvironmentthatmay limitpossiblesolutions. •EngineeringDesign: MS-ETS1-2.Evaluatecompetingdesignsolutionsusingasystematicprocessto determinehowwelltheymeetthecriteriaandconstraintsoftheproblem. •EngineeringDesign: MS-ETS1-3.Analyzedatafromteststodeterminesimilaritiesanddifferences amongseveraldesignsolutionstoidentifythebestcharacteristicsofeachthat canbecombinedintoanewsolutiontobettermeetthecriteriaforsuccess. •EngineeringDesign: 3-5-ETS1-3.Planandcarryoutfairtestsinwhichvariablesarecontrolledand failurepointsareconsideredtoidentifyaspectsofamodelorprototypethatcan 8of13 beimproved. Preparation WhatYou’llNeed MaterialsYouProvide 1Dcellbatteryholderpergroup 1Dcellbatterypergroup 1singleknifeswitchpergroup 2,2.5volt,0.2amp,orsmallerminibulbswithascrew-typebasepergroup 2bulbholdersforminilampbulbspergroup 3alligatorclipleadspergroup Itemstotestforconductivity:5paperclips,5piecesofstring,5erasers,5 rubberbands,5pennies(1ofeverythingpergroup) RequiredTechnology InternetAccess:Required PhysicalSpace Classroom Setup Setuproomsoitisconduciveforworkingingroupsoftwotofourstudents. Grouping Large-groupinstruction 9of13 ResourcesProvided:Handouts&Worksheets SimpleCircuitDiagram HowtoBuildaSimpleCircuit SimpleCircuitwithSwitchDiagram HowtoBuildaSeriesCircuit HowtoBuildaParallelCircuit ExtendingtheLearning:BrokenCircuitSetup Background&Vocabulary BackgroundInformation Electricityisusedtolighthousesandruntelevisions,computersandother electronicdevices.Electricitycanpowervariousrobotcomponents,suchas mechanicalplatforms,sensorsystems,controllers,andjoints. Electricityisprovidedbyenergysourcessuchasgeneratorsorbatteries. Generatorsconvertmechanicalenergyintoelectricity,andbatteriesconvert chemicalenergyintoelectricity. Electriccurrentistheflowormovementofelectrons(negativelycharged particles).Highercurrentmeansmoreelectronsareflowingthroughacircuit. Resistanceisameasureofhowdifficultitisforelectricitytoflow.Voltageishow muchenergytheelectronshaveandissometimesdescribedashowhardtheyare being“pushed.”Current,resistance,andvoltagearerelated:Thecurrent(in amperes)inasimplecircuitisequaltothevoltage(involts)dividedbythe resistance(inohms). 10of13 Electricalconductorslikecopper,othermetals,andionicsolutions(likesaltwater) arematerialsthatallowelectronstomovefreelythroughthem.Electricalinsulators aredifficultforelectronstomovethrough.Aresistorreducesorlimitstheflowof electrons(dimmerswitchesonlampscontainresistors).Acapacitorcontains conductorsseparatedbyinsulators,andcanstoreelectriccharge,evenout current,orreleasethechargeveryrapidly(asforacameraflash). Aconductingloopiscalledacircuit.Circuitshavethreeessentialcomponents;a conductivepathway(suchasacopperwire),anenergysource(suchasabattery orgenerator),andaload(suchasalightbulboraheatingelementinatoaster). Aclosedcircuitisanunbrokenpathwayandallowscurrenttoflow.Acircuitmust beclosedinordertopoweralightbulborotherload.Anopencircuitisabroken pathwaythatdoesnotallowcurrenttoflow.Anopencircuitcannotprovide electricitytotheload.Aswitchisawaytoopenandcloseacircuit,byeither allowingorstoppingtheflowofelectrons.Thewallswitchinmanyclassroomsand homescontainsastripofmetalthatcontactsthecircuitinthe“on”position, causingthelighttocomeon;whentheswitchisinthe“off”position,thecircuitis broken,turningthelightoff. Inaseriescircuit,aseriesofbulbsorotherloadsareconnectedinasingle pathwaysoelectricityflowsthrougheachone.Withasinglepathway,ifawireis cut,aswitchisopened,oraloadceasestowork,allloadswithinthecircuitwill ceasetoworkbecausethepathhasbeeninterrupted. Inaparallelcircuit,therearetwoormorepathwaysthroughwhichelectricitycan flow.Thebulbsorotherloadsondifferentpathwaysinthiscircuitaresaidtobe paralleltooneanother.Ifabulbinaparallelcircuitburnsout,electricitywillstill flowtootherbulbsonotherpathways,allowingthebulbstocontinuetolight. 11of13 PriorKnowledge [] RecommendedPriorActivities None Vocabulary Term battery circuit closed circuit Partof Definition Speech devicecontainingoneormoreelectriccellswhichstore noun chemicalenergythatcanbeconvertedintoelectricalpower. noun noun completepathwaythroughwhichelectricityflows. continuouspathwaythroughwhichelectricitycanflow. conductive pathway noun courseofanelectricalcircuit. electric current flowofelectricity,orchargedparticles,throughaconductor. electricity electron noun noun noun setofphysicalphenomenaassociatedwiththepresenceand flowofelectriccharge. negativelychargedsubatomicparticle. 12of13 Term energy source load open circuit parallel circuit Partof Definition Speech locationinwhichtheenergyresource(oil,coal,gas,wind,etc.) noun isconvertedintoelectricalenergy. noun noun noun componentwithinacircuitthattransformselectricityintoa differentformofenergysuchaslight,heat,orsound. incompletepathwaythatprohibitsthefreeflowofelectricity. pathway(closedcircuit)inwhichtheelectricalcurrentisdivided intotwoormoreparallelpathsandreturnsthroughonepath. Iftheloadsinthiscircuitarebulbsandoneblowsout,thereis stillelectricityflowingtotheotherloads. series circuit switch noun noun electricalpathwaywherealltheloadsareconnectedin sequence,formingasinglepathwaythroughwhichelectricity canflow. devicethatallowsanelectricalcircuittobeopenedorclosed. ForFurtherExploration Video TechTopics:Electricity Funder ©1996–2016NationalGeographicSociety.Allrightsreserved. 13of13