Contents:

Quick Reference Sheets:• Intro: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page2• Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page4• EquipmentList:Capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page5• Story,Part1:Evil Mister Fred's Unicycle Attack . . . . . . . . . . . . . . . .page6• Story,Ending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page7

Video Transcript:• Intro: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page8• Story,Part1:Evil Mister Fred's Unicycle Attack . . . . . . . . . . . . . .page10• Experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page13• StoryEnding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .page16

Teacher’s Guide for:

CapacitorsNote: All activities in this document should be performed with adult supervision. Likewise, common sense and care are essential to the conduct of any and all activities, whether described in this document or otherwise. Parents or guardians should supervise children. Rock-it Science assumes no responsibility for any injuries or damages arising from any activities.

Note: All activities in this document should be performed with adult supervision. Likewise, common sense and care are essential to the conduct of any and all activities, whether described in this document or otherwise. Parents or guardians should supervise children. Rock-it Science assumes no responsibility for any injuries or damages arising from any activities.

CapacitorsARock-itScienceLessonFilmedNovember,2009

Title Page of Video

NOTE: This is the transcript of a lesson that was videotaped during an actual Rock-it Science class with real students, not actors. The students’ brainstorming comments are included on the video but are not transcribed here because they’re not part of the lesson presentation.

Rock-it Science2110 Walsh Ave, Unit FSanta Clara, CA 95050www.rockitscience.org

(c) 2013 Rock-it Science Educationally Useful Programs. All Rights Reserved

Rock-it Science Teacher’s Guide Capacitors -- Page 2

Intro Quick Recap:

• There’sastaticelectricalfieldallaroundtheEarth .Itamountstoabout100voltsforevery3feetofelevation .

• PictureofBenjaminFranklinflyinghiskiteinaclearbluesky .Akeyishangingoffonanon-conductivesilkthread,hoveringnearaleydenjar .

• Ifyourkiteisup300feet,youget100x100volts,whichis10,000volts .• Ifyouuseastringmadeofcottonsoakedinsaltwater,10,000voltsofstaticelectricitycancomedownandenduponthekey .Ifyoutouchityougetaspark .

• Franklinwouldletthekeytouchtheballfromtheleydenjarafewtimes,andthevoltagewouldgetstoredupinthejar .

• Then,asajoke,Franklinwouldhandthejartosomeone,andtheelectricitywouldgothroughhisbody,makinghislegmusclescontract,sohe’djumpupandthenfalldown .

• FranklinwroteabouthisexperimentsandsentthemtoBritain,buttheywouldn’tpublishitbe-causeFranklinwasanAmerican .

• There’sastorythat,asajoke,Franklinwrotealettertosomeonesayingthathehaddonetheexperimentonacloudyday,infrontofanapproachingstorm,buttheletterhasbeenlost .

Rock-it Science Teacher’s Guide Capacitors -- Page 3

Intro Quick Recap:• SomeoneinFrancetookitseriouslyandtriedtodotheexperimentonacloudyday .Lightninghit,andhedied .ButFranklinneverdiditwithlightning,andheneverexpectedanyonetoactu-allydoitthatway .

• Hisleydenjarwasaglassjarwithfoilontheinsideandfoilontheoutside .Thetwofoilsdon’ttouch--they’reseparated .Butthere’sagoldchainthattouchesthefoil .

• Thenegativeguysgointothejar,buttheyhateeachother,sotheyspreadoutontheinside .• Whenthenegativeguysgoinside,theyattractpositiveguysontheoutside .That’scalledaca-pacitor .

• Acapacitorislikeabucketofwater .Youcanfillitupanddumpitoutreallyfast .Abatteryisdif-ferentbecauseitdoesn’tdumpoutquiteasfast .

• Ifyougoonline,youcanseevideosaboutallkindsofcapacitors,andsomeofthemholdverylargechargesandcanmeltmetalormakethingsflyacrosstheroom .

Rock-it Science Teacher’s Guide Capacitors -- Page 4

Experiment Quick Recap: “Capacitors”• Studentsweargoggles .• Fortheexperiment,studentswillusea6-voltbattery,butittakes40voltstogetthroughtheskin .

• Instructordemonstratesexperimentsetupbeforegivingmaterialstostudents .

• TakeaChristmaslightanduseittotestthebatterytomakesureithascharge,andalsotomakesurethebulbisn’tburnedout .

• Usewireswithalligatorclipstoconnectthebatterytothecapacitorforseveralseconds .Thenremovethewires .Thecapacitorisnowcharged .

• Tocheckit,touchthelightbulbwirestothecapacitorandseehowlongthebulbstayson .Theclasswilluseseveraldifferentkindsofcapacitors,sosomewilllastlongerthanothers .

• Studentsworkingroupsoftwo .Aftereachgrouphashadachancetoworkwiththeircapacitorforafewminutes,theypassitontothenextgroup .Thisisrepeatedseveraltimes,soeachgrouphasachancetoworkwithseveraldifferentsizecapacitors .

• Thentheychargeupthecapacitorandshortitoutbyplacingthebladeofascrewdriveracrossthecontacts .Thiscreatessparks,whichareharmlesstotheskin .

• Instructorbringsoutagrindingwheelandmakeslargesparks .Thestudentsfilebyandholdouttheirhandtofeelthesparks .Warnstudentsnottotouchthewheelitself,becauseitwillshredtheirfingers .

• Givestudentsasquareofaluminumfoilandhavethemshortouttheircapacitorwiththefoil .Thisusuallycreateslargersparksandburnsholesthroughthefoil .

• Studentspassontheircapacitorstothenextgroupeveryfewminutesasbefore .

Charging the capacitor.

Rock-it Science Teacher’s Guide Capacitors -- Page 5

Equipment List: “Capacitors”Items needed for Instructor:

Consumables:

• SameasstudentsOther:

• GrindingWheel• Metaltomakesparkswithgrindingwheel

Items needed for Students:

Consumables (per group of 2 students):

• Christmaslight• Foil,aluminum,about12”squareOther (per group of 2 students):

• Battery,6-voltlantern• Capacitor(about10differentsizes,tobesharedamongthegroups)

• 24”insulatedConnectingWireswithAlligatorClips .(2wirespergroup)

• Screwdriver• Goggles

Prep Work:

• CutstringsofChristmaslightsintoindividuallightswithabout2-inchwiresattached .

Aluminum foil sheets, pre-cut to 12” x 10 3/4”, box of 500.

Above: 6-volt lantern battery.

Screwdriver

Assorted capacitors.

Story Recap: “Evil Mister Fred's Unicycle Attack”

Rock-it Science Teacher’s Guide Capacitors -- Page 6

Part 1:

• EvilMisterFredwantsanewcastle,andhemakestheminionsbuilditoutofchewinggumwrappers .HeorderedtenmillionpiecesofgumfromtheAcmeStoreofEverything .

• Theminionshavetochewthegum,whichkeepsthemquietsotheydon’tannoyEvilMisterFred .Andittakesalongtimetobuildthecastle,sohegetssomepeaceandquiet .

• JackandJilllivenearbyinGoodville .Theywanttogetpeopleoutoftheirhousesandgetsomeexercise,sotheyorderabunchofhamstersandunicycles .

• Theymodifythewheelontheunicyclesotheycanputahamsterinside .Theideaistomakethehamsterrunsothewheelwillturn,andtheridercansitontop .

• Butthehamstersdidn’tlikethis,soJackandJillneededtomotivatethem .Jackdiscoveredthathishamsterlikedrootbeer,sohesuspendedaglassofrootbeerinsidethewheelsothehamsterwasalwaysrunningtowardit .

• Jillmadeatwo-hamstermodel,andherhamsterslikedpizza .• Jacktriedputtingfourhamsterstogether,butwhenyougetthatmany,theytripovereachother .Buthestillwantedmorepower .

• Henoticedthatwheneverherodeunderthepowerlines,thehamsterswouldgofasterbecausetheylikedtheelectricity .

• SoJackputanantennaonaninsulatedhat,withawirerunningdowntothehamsters,andhe’drideunderthepowerlines .Thehamsterswouldgetenergizedandgofaster .

Story Recap (cont.):

Rock-it Science Teacher’s Guide Capacitors -- Page 7

Ending:

• EvilMisterFred’scastleismadeoutofchewinggumwrappersmadeofsilverfoil .• Thewrappersalsohavealayerofwaxedpaper,whichisaninsulator .• Whenyouhaveconductorsnexttoinsulators,theymakecapacitors .• EvilMisterFred’sarmyofminionsandthearmyfromGoodvilleclashedinthemiddleofthefieldontheirunicycles .

• EvilMisterFredwasshootinglightningboltsfromhiscloud,andhehitsomeoftheGoodvilleguys,whichmadetheirhamstersscream .

• Theirscreamsweresoloudandear-piercing,theminionshatedit,andtheystartedrunningbacktowardthecastle .

• EvilMisterFredstartedtogetoffhiscloudsohecouldmaketheminionsregroup,andhesteppedontohiscastle .

• Thecastlewasfullycharged,andEvilMisterFredwaslikethealuminumfoilintheexperiment .• Heexplodedintoagiantballoffire,withlittlepiecesofmustachedriftingdown .

• Onetimehegottooclose,andhisantennahitthepowerlines .Thismadehishamstersexplode .• EvilMisterFredsawthisthroughhistelescope,soheorderedsomeunicyclesforhimself .• Heusedminionsasriders,andotherminionsinsidethewheels .HeusedM&Mstomotivatetheminionsinthewheels .Healsoputantennasontheminionriders,andwhentheminionsinthewheelsgotazapofelectricity,theywentreallyfast .

• NowEvilMisterFredisflyingaroundonhiscloud,andhiscloudcanshootlightningboltsathisminions .

• Withminionsonunicycleswiththeirbaseballbats,hewasreadytoattackGoodville .

Rock-it Science Teacher’s Guide Capacitors -- Page 8

Transcript: Intro [The drawing on the whiteboard shows a person flying a kite with a key hanging from the string. Next to the person is writ-ten “1,000 volts” and “3 feet”. Nearby is a picture of a jar with a ball protruding from the top. IMPORTANT: The num-ber “1,000” on the video is incorrect. It should be “100.” This transcript contains the correct numbers. Use these figures, not the ones on the video.]

[NOTE: Beginning of intro is missing on the video: There’s a static electrical field all around the Earth, and it amounts to about 100 volts for every 3 feet of elevation. It’s just there. We never know about it, it just happens to be there. Here’s Benjamin Franklin flying his kite in a clear blue sky. He’s got a key hanging off a non-conductive silk thread, and it’s hovering near a leyden jar.] So if your kite happens to be up 300 feet, you get one hundredtimesahundred,whichistenthousandvolts .Sweet .Andifyouuseastringmadeofcottonsoakedinsaltwater,tenthousandvoltscancomedownandenduponthekey .It’sallstaticelectricity .

Well,Franklinwouldmaneuveroverhereandletthekeytouchtheballfromthejar .Andthenhe’dtouchitafewtimes--touch,touch,touch,touch--andsomeofthatvoltagewouldgointothejar .It’scalledaleydenjar .Itstoresitallup .Andthenhe’dfindsomebodyoutthereandsay,“Hey,I’vegotajarhere .Hereyougo .”Andtheguywouldgrabit .Andthenhewouldgobam!He’djumpupintheairbecausetheelectricitywouldgothroughhisarm,downhisbody,throughhisleg,andhislegmuscleswouldcontract,andhe’djumplikethisandthenfalldown .AndFranklinthoughtthiswasagreatjoke,andhedidthisalotoftimes .

AndhehadaproblemwiththeBritish .HewasanAmericancolonial,andhewrotescientificpapers,andhestudiedthingsverycarefully .Andhe’dsendhispaperstopeopleinBritain,andthey’dsay,“Oh,thatrube,hedoesn’tknowanything .”Andtheywouldn’tpublishhispapers .Soonce,apparently,hewrotealettertosomeonethatunfortunatelyhasbeenlost,tellingthemaboutthisexperiment .Buthesaidhediditonacloudyday,infrontofanapproachingstorm .Andtheyallsaid,“Oh,thatstupidFranklin .Hedoesn’tknowanything .Hecouldn’tdothatright .We’llshowhimhowtodoit .”

AndaguyinFrancedecidedhewasanexpertonelectricityandstuff .Hereproducedtheexperimenttodoitright .Sohewentoutwithakiteonacloudyday .Lightninghit,andhedied .SoFranklinintendedittobeajoke,thatsomebodywouldtryitonacleardaylikehedidandgetabigzapoutofit .Hedidn’teverthinkthatsomebodywouldgoanddoitonadaywhenthere’dbelightning .Butsomehowtheword

Key on string and leyden jar.

Ben Franklin flying his kite in a clear sky.

Rock-it Science Teacher’s Guide Capacitors -- Page 9

Transcript: Intro (cont.) gotoutthathediditwithlightning .AndIthinkit’sScientificAmericanthattriedtofindtheletter .AndMythBustersalsotriedtofindtheactualletter,andtherewasnorecordofhimactuallydoingthisonarainyday,becausehewasn’tthatdumb .

Andthejarthatheused,thisthingcalledaleydenjar,issome-thingthatwe’regoingtousetoday .Inittherewasaglassjar .Andtherewasfoilontheoutsideandfoilontheinside .Thetwofoilsdon’ttouch--they’reseparated .Andifyouletelec-tricitygoin,andthere’sagoldchainthattouchesthefoil . . .Supposeit’sallnegativeguys .Thenegativeguysgointhere,andtheyhateeachother .Theyallspreadoutontheinside .Andwhennegativeguysgoontheinside,itattractspositiveguysontheoutside .Andtheycallthatthingacapacitor .Any-timeyoucangetonechargetoattractanother,youhaveasortofacapacitor .

Areallygoodexampleofacapacitorisjustabucketofwater .Ifyouhaveabucketofwater,it’slikeacapacitorfullofelec-trons .Youcanfillitup,andyoucandumpitoutreallyfast .Abatteryisalittlebitdifferent,becausewithabatteryyoucan’tdumpthingsoutquiteasfast .Todaywe’regoingtobedoingsomeexperimentswithcapacitorsandseewhathappens .

Doyouguysevergoonlineandlookatvideos?[Students: Yes.]Oh,okay .Theyhavesomereallygoodvideosaboutcapacitors,super-capacitors,andultra-ca-pacitors .Andsomeofthemarejustfantastic .Ifyougetacapacitorthatislikethatsize[holds up a small capacitor],it’snottoolarge .Buttheseguysareusingcapacitorsthatarelikethissize[large].Andtheyputthreethousandvolts,tenthousandvoltsinthemandseewhathappens .Maybesometimelaterwe’llgetsomeofthosevideosandshowyou,becauseyoucanmeltmetalwiththem,youcanmakethingsflyacrosstheroom,getdestroyed .

Butfirst,weneedacrazystory .

Cross-section of leyden jar.

Bucket of water.

Rock-it Science Teacher’s Guide Capacitors -- Page 10

Story: “Evil Mister Fred's Unicycle Attack”Let’ssupposethatEvilMisterFredwantsanewcastle .Andusuallyheletstheminonsbuildthecastleoutofstone .They’reprettygoodwiththat .Theyusetheirbaseballbatsandbreakthestone .Butthey’vebeenreallyobnoxiouslately,andhewantsthemtotakesometimetobuildthecastle .Plustheminionsareallrunningaroundmakingminionsoundsandbotheringhim .Hewantstofocusondoingwhateverbadhe’sgoingtodo,sohesays,“Minions,you’vegottobuildmeanewcastle,andyou’vegottomakeitoutofgumwrappers .”Andtheminionssaid,“Gumwrappers?Oh,boy!Whogetstochewthegum?”Hesays,“Youchewthegum .”

SohecalledtheAcmeStoreofEverythingandorderedtenmillionpiecesofgum .Andtheminionswouldtakethegumout,chewthegum,andthey’dhavethewrapperleftover .AndthentheyhadtostickthewrapperstogethertomakeacastleforEvilMisterFred .Andheendedupwitharegularcastle,butitwasmadeoutofgumwrappers .Theydidagoodjob .AndEvilMisterFredcouldstandonitanditdidn’tfalldown .Hewaskindofsurprised .Itprobablydidn’tfalldownbecausethey’dleftgumalloverit .

Anditkepttheminionsbusy .Theywerechewingthegumandworking,andtheycouldn’tmakenoisebecausetheywerechewingthegum .Andminionscan’tmulti-tasktoowell .Whenthey’rechewinggum,theycan’tdootherthings .Buttheycanstickwrapperstogether .It’shardforaminiontochewgumandwalkatthesametime .Andwhenhegothiscastlealldone,EvilMisterFredwaslookingaroundforevilthingstodo .

Andofcourse,nearbyisGoodville .AndJackandJillarethere .AndJackandJillwanttogetthepeopleoutoftheirhouses,havethemdoalittlebitofexercise,havesomefun .Sotheyorderedabunchofhamstersandunicycles .Andtheymodi-fiedthewheelontheunicyclesothatyoucouldputahamsterinside .Itwouldbeaone-hamster-poweredunicycle .Andyou’dsitontop,oryoucouldstandontop .Andyou’dtellthehamstertogo,andyou’dbalanceyourselfupthereandrideonthisunicycle .

Well,thehamstersdidn’tlikethis .Theydon’twanttogo .Soyouneedsomemo-tivationforthehamsters .Atfirsttheythought,“Well,wecouldplaysomeinspi-

Evil Mister Fred on his castle, with minions carrying baseball bats.

Jack and Jill live in Goodville.

Jack’s hamster- powered unicycle.

Rock-it Science Teacher’s Guide Capacitors -- Page 11

rationalmusic .”Butthehamstersdidn’tliketheirinspirationalmusic .Thentheythought,“Food!We’llgivethemthefoodthattheylike .AndsoJackwasexperimentingwithhishamsteranddiscoveredthehamsterlovedrootbeer .Heputaglassofrootbeersus-pendedlikethatinsidethewheel,sothehamsterwasalwaysrunning,tryingtogettherootbeer .Andashe’druntogettherootbeer,thewheelwouldturn,andJackcouldrideallaroundthecountrysideonthisthing .

AndJillthoughtthatwasprettygood,soshemadeoneforherself .Butshemadehersatwo-hamster-poweredmodel .Andherhamsterslikedpizza .AndshecouldgotwiceasfastasJack .

AndJacksaid,“Well,that’snogood .Iwantmorehamsters .”Sohetriedputtingfourhamstersinhis,butwhenyouputfourhamstersinthere,theytripovereachother .Nextthingyouknow,there’srootbeercoveredhamsters,andit’sgoingthunk-a,thunk-a,thunk-a,likethat .AndJacksaid,“Well,Ineedmorepower .Gottogetthesehamsterstoworkharder .”

Sohenoticedthatnottoofarawaythereweresometelephonepolesandpowerlines,likethat .Andhenoticedthatearlyinthemorningthe

powerlineswouldhissandhumm--ssszzzzz,likethat .Andhetookhishamstersoutearlyonemorning,andhewasridingunderthepowerlines,andhe’dgofasterwhentheyweregoingbythepowerlines .Sohesaid,“Oh,that’sprettycool!Theyliketheelectricity .Iwonderhowmuchisgoodandhowmuchisbad .”

Soheputanantennaonhishead,likethat .Andheputonahatthatwasinsulated .Andhetookawirefromtheantennaandputitdownonthehamsters .Thenhe’drideunderthepowerlines .Theantennawouldpickupsomeoftheelectricityfromthepowerlines,andthehamsterswouldgetenergizedandgofaster .AndhecouldbeatJillinraceswithhishamstersgoingthatway .AndJillsaid,“Wow,that’sre-allygood!”

Well,onetimeJackwasridingunderthepowerlinesoverthehillhere,andhecameupoverarise,andhisantennahitthepowerlines .Andhishamstersex-ploded .Hesays,“Oh,man!Tooclose .Bad .”Sohehadtomakehisantennalower .Andherealizedtoomuchelectricitywasbad .

Glass of root beer in the wheel.

Jill’s two hamsters with pizza.

Four hamsters -- too many.

Power lines.

Jack’s antenna hat.

Rock-it Science Teacher’s Guide Capacitors -- Page 12

Imagination and Brainstorming Time[Students make suggestions](THEREARENOWRONGANSWERS!Whatevertheysay,youshouldreply:“That’sagoodidea,”“Theymightdothat,”etc .Afterbrainstorming,proceedwiththeexperi-ments,thenfinishthestory .)

We’llleavethis“TobeContinued . . .”

Now,whilethiswasgoingon,EvilMisterFredhappenedtonotice,beingthathehadatelescope .AndhesawwhatJackdid .Andhesaid,“Thatfool!Thatidiot!Lookwhathedid .Hejustblewuphishamsters!That’sgreat!”

SoEvilMisterFredgothimselfsomeunicyclesforhisminions .Buthedidn’tputhamstersinthere .Knowwhatheput

inthere?Minions .Sonowthere’sminionsridingontop,there’sminionsontheinside,andminionslikeM&Ms .SoheputM&Msinthere .Andheputantennasonhisminions,andhetrieditout .Andsureenough,ifyougiveaminionmotiva-tionwithM&Ms,givehimalittlebitofazapofelectricity--zzzoom!Hegoesreallyfast .

Now,EvilMisterFredboughthimself . . .what’sagoodwaytouseelectricity?He’sflyingaroundonhiscloud,andhe’smadeitsohiscloudcanshootlightningboltsdownathisminions .Hesays,“Nowwe’vegotit .We’vegottheelec-tricity .We’vegottheminionsonwheels,they’vegottheirbaseballbats .I’mreadytoattack .”

SoJackandJillseethatEvilMisterFredhascopiedtheirfool-ishdesign,andhe’sgoingtoattackthecitywithminionsonunicycles .IfyouwereJackandJill,whatwouldyoudo?

Evil Mister Fred’s Telescope.

Minion unicycle.

Evil Mister Fred on his cloud.

Rock-it Science Teacher’s Guide Capacitors -- Page 13

Experiment: “Capacitors”Now,electricityisprettygoodstuff .Luckily,youguyshaveskin .Ifyoudidn’thaveskin,we’dhaveaproblemwiththisexperiment .You’regoingtousea6-voltbattery .Ittakes40voltstogetthroughyourfingers .Andwe’regoingtohookthemuptosomeofthecapacitorsandseewhattheydo .Usu-ally,ifyouputabatterylikethisonalight,thelightwilllightup .[Takes out a bag of Christmas lights.]You’regoingtohavetofindalightthatworks .Theseweretestedbyotherkidsyesterday,sotheymayhavegottenburntout .

Soyouhavealightandabatteryandoneofthesethings[holds up a capacitor].Soifyouwanttochargeoneup,youneedtogetsomevoltageonthetwoscrewsthatareonthetop .Andtheseguyshavealittleplussignonthem,andaminussign .Thebatteryhasaplussignandaminussign .Ifyougetclosetotheratedvoltageofit,itmakesadifference,butforusitprobablydoesn’t .Thisguysaysit’smadeforfifteenvolts,andwe’reonlyusingsix .

Andwe’llhookourwiresontoit .Youcanjusttouchthemwithyourfingers .Negativegoestonegative,andthepositivegoestopositive[connects battery to capacitor with wires and alligator clips for several seconds].Andnowyoucantakethewiresoff[disconnects wires from capacitor].Theelectricitywentintothecapacitor .Andyoucantouchthelightbulbtoitandsee[bulb lights up]thatitlightsup .Sothisca-pacitorcanmakethelightgo . . .[bulb goes out]thatlong .

Ifyouuseadifferentcapacitor[brings out a small one],we’llseehowitgoes .[Charges capacitor, then tests light. The bulb only lasts a few sec-onds.]Anditgoesthatlong .Now,thethingshavewrittenonthesidenumbers .Thisone [reads info on side of large capacitor]says“SpraguePow-

erlitic36DX .300,000-15DC .8621L1901 .MadeinUSA .85degreesC .”Well,that’salotofinformationthatmeansnothingtous .TheonlythingIrecognizeisthe15DC .FifteenvoltsDC .Beforethatthere’sabignumber,300,000 .Thisone[reads from small capacitor]hasanumber24,000 .Butitsays“MFDs” .Hmm .MiniatureFlowerDevelopers .No .Or,MicroFarads .It’ssupposedtobemicro-farads .Afaradisameasureofhowmuchchargeitwillhold .Thisone’sgotthreehundredthousand,thisone’sgottwenty-fourthousand .Andifyoulookinthebox,therearevariouskinds .Thisone’sgotonehundredandfortythousand .Thisoneissixtythousand .Thisguyisforty-seventhousand .Theyallhavetheirownvalues .Thepreviousclassmayhaveleftsomeelectricityinthemstill,sowhenyoufirstgetthem,touchyourlightsonthereandseeiftheylightup .

Checking the capacitor’s charge with a Christmas light.

6-volt lantern battery hooked up to a capacitor with alligator clips.

Small capacitor.

Rock-it Science Teacher’s Guide Capacitors -- Page 14

Andafteryoufigureouthowtomakethelightslightupandseehowlongtheygo,we’regoingtodosomethingyou’renotsupposedtodo .Thethingyou’renotsupposedtodoisshortoutacapacitorbyputtingsomethingconductivebetweenthetwoscrews .Andyoucantouchthemtodothat .I’llmakeitsoIcanturnoutthelights .It’smorefunthatway .

WhatI’lldoischargeitupandturnoffthelightsandshortitout .Ihavetofirstreleasethebatterysoit’llgooff .Sowhenyougetyours,you’llchargeupyourcapacitor .Giveitabouttensecondsforthebigones .Andthenyouchooseaweaponofyourchoice,eitherafatoneoraskinnyone[picks up a screw-driver].Youcangosidewaysacrossit .[Turns off lights and places screwdriver across the screws to create sparks.]Andjustkindofusethescrewdriveruntilitstops .Seehowlongitgoes .

[Student: What happens if the spark makes contact with your skin?]Thenyouwouldexplodeintoflames,dotheooh-ah-ooh-ahdance,anddie .No,theydon’tdoanything .Theyjustbounceoff .Haveyoueverusedagrindertogrindmetalandseensparksgoflyingoff?[Some of the students say no.]

Soyouneedapartner,andyou’llneedabatteryandalligatorclips .Sochoosesomeonetoworkwith .Sendoneofyourpartnerstogogetabattery .Sendtheotheronetogetwires .Andwhenyoutakethewires,trynottocreateanincredibletangledmess .Thensendsomebodyoverheretopickeitherafatscrewdriveroraskinnyscrewdriver .[Student: Do we take a capacitor?]Notyet .

[After students have their other materials, the Instructor pass-es out a capacitor to each group so there are several different sizes being used.]Ifyouhaveonethathasametalplateonthetop,thereisathinpieceofplasticbetweenthetwosides .Youwanttoshortbetweenthose .

Nowyouneedalightbulb [passes out bulbs]. Testoneonyourbatteryandseeifitworks .Ifitdoesn’twork,I’lltossyouanotherone .Doeseveryonehavealightbulbthatworks?

Okay,nowchargeupyourcapacitor .Whenit’scharged,thenyoutakethewiresoff .Everybodybesuretoputongoggles .

Dideverybody’scapacitorlightupthelightbulb?[Students: Yes.]Okay,nowthatyouknowhowtochargeitanddischargeitwithalightbulb,thenyouchargeitbackupagainandtryit

withascrewdriver .[Instructor turns out lights to make the sparks easier to see.]

[After students have worked with their capacitors for a few minutes, Instructor turns on lights.]Okay,noweveryone’sgoingtomovetheircapacitoronegrouptoyourleft .[Students pass on their capacitors and repeat the experiment. After a few minutes, they pass them on again. They do this five or six times so everyone has a chance to work with several different sizes of capacitors.]

Charging the capacitor.

Using screwdriver to short out capacitor.

Rock-it Science Teacher’s Guide Capacitors -- Page 15

[After turning on the lights again, Instructor brings out a grinding wheel and points to the outer edge of the wheel.]Thispartofthewheelyoudon’twanttotouch .It’sagrinder .Itwillgiveyouhamburgerfingers .Whatwe’regoingtodois,I’mgoingtotouchthistomakesparks .Ifyouwantto,youcancomebytofeelthesparkswithyourfingerstoshowyouwhatsparksfeellike . [Instructor turns off lights, then holds a piece of metal against the grinding wheel to make sparks. Students file by and hold out their hand to feel the sparks.]

[Lights on.]Nowwe’renotgoingtousescrewdrivers .Whatwe’regoingtodois,you’regoingtochargeupyourcapaci-torandputaluminumfoilbetweenthemandseewhatitdoestothealuminumfoil .It’sbetterifyouleaveitthinthanmakeitthick,butyoucantryiteitherway .[Instructor hands out a square about 12” x 12” of aluminum foil to each team, then turns out the lights. Students try shorting out the capacitors with the foil and pass them on every few minutes as before.]

Above: Grinder wheel. Below: Sparks.

At Left and Above: Shorting out the capacitor with foil.

Rock-it Science Teacher’s Guide Capacitors -- Page 16

End of Story * DO NOT * present this part of the lesson until after the experiments!Sonowweneedanendingforourstory .Haveyouevereatengum?Haveyoueverhadthegumthatwhenyoutakethecoveroffthegumit’slikeasilverfoil?Well,EvilMisterFred’scastlewasmadeoutofpiecesofsilverfoil .Andthegumhas,insidethesilverfoil,alittlebitofwaxedpaper,whichisaninsulator .Sowhenyouhaveconductorsnexttoinsulators,theymakecapacitors .Now,EvilMisterFred’supinhiscloud,andhe’sbeenbusyzappinghisminions,tryingtogetthemtogooverandattackGoodville .JackandJillarecomingoutwitheverybodyinGoodvilleandtheirhamster-powereduni-cycles,tryingtofightofftheminions .Andwhenthetwoarmiesclashedinthemiddleofthefield,EvilMisterFredisshootinglightningboltseverywhere .Andheaccidentallyshotsomeofthegoodguys .Andhamstersturnouttohavesuperpowerswhenyouhitthemwithjustthatkindofelectricity .Andthehamstersdon’tjustrunfast,theyscream .Haveyoueverheardahamsterscream?Oh,it’sareallyloudear-piercingsound .Theminionshateit .Theminionswent,“Aaaaaaahh!”andtheyturnedaroundandran .

EvilMisterFredsaid,“No,no,stop!Turnaround,youcowards!”Theminionskeptrunning .AndEvilMisterFredsaid,“Arrrgh!We’llregroupandwe’llattack .”Sohegotoffhiscloud .Hewasgoingtostepfromhiscloudontohiscastle .Thecastlewasfullycharged .EvilMisterFredwaslikethealuminumfoil .Hejustkindofexplodedintoagiantballoffireandflame .Andlittlepiecesofmustachefellthiswayandfellthatway .Andeverybodylivedhappilyeverafter,exceptEvilMisterFred .

End of LessonIf y0u have questions about this lesson, please ask them through the online Teacher Support Forum on our web site.

Evil Mister Fred in a ball of fire.