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©2013SuperchargedScience 2 Light
TABLEOFCONTENTS
Introduction...............................................................................................................................................................................................................3
EducationalGoalsforLight1.............................................................................................................................................................................4
MasterMaterialsListforAllLabs.....................................................................................................................................................................5
LabSafety...................................................................................................................................................................................................................6
Lesson#1:RainbowShadows...........................................................................................................................................................................7
Lesson#2:Kaleidoscopes..................................................................................................................................................................................10
Lesson#3:LiquidPrism.....................................................................................................................................................................................13
Lesson#4:LunarPhases....................................................................................................................................................................................16
Lesson#5:SkyinaJar.........................................................................................................................................................................................20
Lesson#6:LightTricks.......................................................................................................................................................................................22
Lesson#7:BlackLightTreasureHunt.........................................................................................................................................................24
Lesson#8:Benham’sDisk.................................................................................................................................................................................28
Lesson#9:EyeBalloon.......................................................................................................................................................................................31
Lesson#10:DisappearingFrog.......................................................................................................................................................................34
Lesson#11:PinholeCamera............................................................................................................................................................................36
Lesson#12:Diffraction......................................................................................................................................................................................39
Lesson#13:SpeedofLight...............................................................................................................................................................................42
Lesson#14:MixingColors................................................................................................................................................................................45
Lesson#15:MixingColdLight.........................................................................................................................................................................47
Lesson#16:RefractiveIndex...........................................................................................................................................................................50
Lesson#17:FireandOptics.............................................................................................................................................................................53
Lesson#18:SimpleMicroscopes&Telescopes.......................................................................................................................................56
Light1Evaluation.................................................................................................................................................................................................59
Light1Quiz..............................................................................................................................................................................................................60
Light1LabPractical.............................................................................................................................................................................................62
AnswerstoExercisesandQuizzes.................................................................................................................................................................63
VocabularyfortheUnit.......................................................................................................................................................................................66
©2013SuperchargedScience 3 Light
Introduction
Greetingsandwelcometothestudyoflight.Thisunitwascreatedbyamechanicalengineer,universityinstructor,airplanepilot,astronomer,robot‐builderandrealrocketscientist…me!IhavethehappyopportunitytoteachyoueverythingIknowaboutelectricityoverthenextsetoflessons.Ipromisetogiveyoumybeststuffsoyoucantakeitandrunwithit…orfly!
Togetthemostoutoftheselabs,therearereallyonlyacoupleofthingstokeepinmind.Sinceweareallheretohavefunandlearnsomethingnew,thisshouldn’tbetoohard.
Oneofthebestthingsyoucandoasthestudentistocultivateyourcuriosityaboutthings.Whydidthatmove?Howdidthatspin?What’sreallygoingonhere?
Thisunitonlightischockfullofdemonstrationsandexperimentsfortwobigreasons.First,they’refun.Butmoreimportantly,thereasonwedoexperimentsinscienceistohoneyourobservationalskills.ScienceexperimentsreallyspeakforthemselvesmuchbetterthanIcaneverputintowordsorshowyouonavideo.AndI’mgoingtohityouwithalotofthesesciencedemonstrationsandexperimentstohelpyoudevelopyourobservingtechniques.
Scientistsnotonlylearntoobservewhat’sgoingonintheexperiment,buttheyalsolearnhowtoobservewhattheirexperimentistellingthem,whichisfoundbylookingatyourdata.It’snotenoughtoinventsomenewkindofexperimentifyoudon’tknowhowitwillperformwhentheconditionschangeabit,likeonMars.We’regoingtolearnhowtopredictwhatwethinkwillhappen,designexperimentsthatwilltestthisidea,andlookovertheresultswegottofigureoutwheretogofromthere.Scienceisaprocess,it’sawayofthinking,andwe’regoingtogetplentyofpracticeatit.
Goodluckwiththisunitonthemagicoflight!
©2013SuperchargedScience 4 Light
FortheParent/Teacher:EducationalGoalsforLight1
Scientistarestilltryingtomakeheadsortailsofthisthingcalledlight,andnearastheycantell,itsometimesinteractslikeaparticle(likeamarble)andothertimeslikeawave(likeontheocean),andyoureallycan’tseparatethetwobecausetheyactuallycomplementeachother.
Energycantakeoneoftwoforms:matterandlight(calledelectromagneticradiation).Lightisenergyintheformofeitheraparticleorawavethatcantravelthroughspaceandsomekindsofmatter,likeglass.We’regoingtoinvestigatethewildworldofthephotonthathasbaffledscientistsforoveracentury.Lowelectromagneticradiation(calledradiowaves)canhavewavelengthslongerthanafootballfield,whilehigh‐energygammarayscandestroylivingtissue.
Herearethescientificconcepts:
Lighthasasourceandtravelsinadirection. Sunlightcanbeblockedtocreateshadows. Lightisreflectedfrommirrorsandothersurfaces. Thecoloroflightstrikinganobjectaffectshowoureyesseeit. Weseeobjectswhenlighttravelingfromanobjectentersoureye. Lightcantravelthroughavacuum,likespace. Lightcanchangespeeds,butthemaximumspeedisthroughavacuum(186,000milespersecond). Thethreeprimarycolorsoflightarered,blue,andgreen.Redandgreenlightmixedtogethermakeyellow
light. Prismsun‐mixlightintoitscolorsorwavelengths. Lightchangesspeedswhenitpassesthroughadifferentmaterial. Lensesworktobendlightinacertaindirection,calledrefraction. Concavelensesworktomakeobjectssmallerandconvexlensesmakethemlarger.
Bytheendofthelabsinthisunit,studentswillbeableto:
Designandbuildasimplerefractortelescopeusinglenses. Knowhowtodemonstratehowcompoundmicroscopeswork. Understandhowtodeterminehowtomeasurethespeedoflight. Differentiateobservationfrominference(interpretation)andknowscientists’explanationscomepartly
fromwhattheyobserveandpartlyfromhowtheyinterprettheirobservations. Formulateandjustifypredictionsbasedoncause‐and‐effectrelationships. Conductmultipletrialstotestapredictionanddrawconclusionsabouttherelationshipsbetween
predictionsandresults. Constructandinterpretgraphsfrommeasurements.
Followasetofwritteninstructionsforascientificinvestigation.
©2013SuperchargedScience 5 Light
MasterMaterialsListforAllLabs
Thisisabrieflistofthematerialsthatyouwillneedtodoalloftheactivities,experimentsandprojectsinthisunit.Thesetofmaterialslistedbelowisjustforonelabgroup.Ifyouhaveaclassof10labgroups,you’llneedtoget10setsofthematerialslistedbelow.Mostmaterialsarereusable.
12”fishingline 12”string 12”thread 12”yarn 8indexcards slicedcheese(individuallywrapped) babyoil ball biconvexplasticlens bookofmatches box calculator CDorDVD chocolatebar(extra‐largebarsworkbest) chocolatechips cleartape crayonsORmarkers darkeveninginsideyourhouse darkroom diffractiongrating disposablecups(6) dollarbill feather fingernailpolish(red,yellow,green,blue) fireextinguisher flashlight glassjar(2) gloves
gluestick goggles handheldmagnifyinglenses(2) indexcards laser(optional) meterstick(2) microwave(onlyoneforentireclass) milkorflour minimarshmallows nail paper paperplates paperclip pencil penny razororscissors red,green,andbluetrue‐colorlightsticks roundballoon,white,9inches rubbingalcohol scrappieceofcardboard strainer,suchasacoffeefilter tack tape tracingpaper UVblackfluorescentlight votivecandle water
©2014SuperchargedScience 6 www.SuperchargedScience.com
LabSafetyGoggles:Theseshouldbewornwhenworkingwithchemicals,heat,fire,orprojectiles.Theseprotectyoureyesfromchemicalsplatter,explosions,andtinyfast‐movingobjectsaimedattheeyes.Ifyouwearglasses,youcanfindgogglesthatfitoverthem.Don’tsubstituteeyeglassesforgoggles,becauseofthelackofsideprotection.Eyeglassesdon’tprovidethisimportantsideeyeprotection.
CleanupMesses:Yourlabareashouldbeneat,organized,andspotlessbeforeyoustart,duringyourexperiment,andwhenyouleave.Scientistswastemoretimehuntingforlostpapers,piecesofanexperiment,andtryingtorepositionsensitiveequipment…allofwhichcouldhaveeasilybeenavoidedhadtheybeentaughtorganizationalskillsfromthestart.
DisposeofPoisons:Ifapoisonoussubstancewasused,created,orproducedduringyourexperiment,youmustfollowtheproperhandlingproceduresfordisposal.You’llfinddetailsforthisintheexperimentsasneeded.
SpecialNotesonBatteries:Donotusealkalinebatterieswithyourexperiments.Findthesuper‐cheapkindofbatteries(usuallylabeled“HeavyDuty”or“SuperHeavyDuty”)becausethesetypesofbatterieshaveacarbon‐zinccore,whichdoesnotcontaintheacidthatalkalinebatterieshave.Thismeanswhenyouwireupcircuitsincorrectly(whichyoushouldexpecttodobecauseyouarelearning),thecircuitswillnotoverheatorleak.Ifyouusealkalinebatteries(likeEnergizerandDuracell)andyourstudentsshortacircuit,theirwiresandcomponentswillgetsuper‐hotandleakacid,whichisverydangerous.
NoEatingorDrinkingintheLab:Allfoodsanddrinksarebannedfromyourclassroomduringscienceexperimentation.Whenyoueatordrink,youruntheveryrealriskofingestingpartofyourexperiment.Forelectricityandmagnetismlabs,alwayswashyourhandsafterthelabisovertorinseofftheleadfromtheelectricalcomponents.
NoHorsePlay:Whenyougoofaround,accidentshappen,whichmeanschemicalsspill,circuitsshort,andallkindsofhazardscanoccurthatyouweren’texpecting.Neverthrowanythingtoanotherpersonandbecarefulwhereyouputyourhands–itcouldbeinthemiddleofasensitiveexperiment,especiallywithmagnetismandelectricity.Youdon’twanttoruntheriskofgettingshockedorelectrifiedwhenit’snotpartofyourexperiment.
Fire:Ifyouthinkthere’safireintheroom(evenifyou’renotsure),letyourteacherknowrightaway.Iftheyarenotaround(theyalwaysshouldbe),smotherthefirewithafireblanketoruseafireextinguisherandsendsomeonetofindanadult.Stop,drop,androll!
Questions:Ifyou’renotsureaboutsomethingstopandask,nomatterwhatit’sabout.Ifyoudon’tknowhowtoproperlyhandleachemical,dopartofanexperiment,ask!Ifyou’renotcomfortabledoingpartoftheexperiment,thendon’tdoit.
©2014SuperchargedScience 7 www.SuperchargedScience.com
Lesson#1:RainbowShadows
Overview:Imagineyou’reapainter.Whatthreecolorsdoyouneedtomakeupanycolorintheuniverse?(Youshouldbethinking:red,yellow,andblue…andyes,youarerightifyou’rethinkingthattherealprimarycolorsarecyan,magenta,andyellow,butsomefolksstillprefertothinkoftheprimarycolorsasred‐yellow‐blue…eitherway,it’sreallynotimportanttothisexperimentwhichprimarysetyouchoose.)
Here’satrickquestion–canyoumakethecolor“yellow”withonlyred,green,andblueasyourcolorpalette?Ifyou’reascientist,it’snotaproblem.Butifyou’reanartist,you’reintroublealready.Thekeyismixinglight,notpaint.
WhattoLearn:Thethreeprimarycolorsoflightarered,blue,andgreen.Redandgreenlightmixedtogethermakeyellowlight.Sunlightcanbeblockedtomakeshadows.
Materials
flashlights(3) fingernailpolish(red,green,andblue) cleartape(NOTtranslucent) awhitewall(oranotherlargewhitesurface)
Experiment
1. Makeyourroomasdarkaspossibleforthisexperimenttowork.2. Covereachflashlightlenscompletelywiththecleartape.Besuretogettheedgesandaroundtherim.3. Paintoneflashlight’stapelayerred,oneblue,andonegreen.Makesuretherearenounpaintedspots.4. Allowthenailpolishtodry.5. Turnoffallthelights.6. Shinetheflashlightstogetherontoawhitewall.Whatcoloristhewall?Recorditonyourchart7. Nowturnofftheredflashlight.Whatcolordoyouseenow?Recordyourobservation.8. Placeyourhand,apencil,oranotherobjectinfrontoftheflashlight.Waveitaroundabit.Whatcolor
shadowsdoyouseeonthewall?9. Experimentwiththedifferentcolorcombinationswhilefillingoutthechartwithyourobservations.
©2014SuperchargedScience 8 www.SuperchargedScience.com
RainbowShadowsDataTable
Lens#1Color Lens#2Color ShadowColor
Reading
Theuniverseismadeofmatterandenergy.Matterisanythingthathasmass,andallordinarymatterexistsinfourstates,whichwecoverinourChemistryunit.Electromagneticradiation(EM)isenergyintheformofwavesorparticlesthatareemittedfromasourceandtravelthroughspaceandeventhroughcertainkindsofmatter.
Visiblelightisaformofenergythatwecanseewithoureyes,andtheorganelles(calledconesandrods)collectlightfromimagesthatweseeandtransmitthesetothebrain.Visiblelightmakesupatinypartoftheelectromagneticspectrum.Thisenergycanbemeasuredandspecifiedbyitsintensity(howbright),frequency(wavelength),polarization(thedirectionoftheelectricfield),andphase(timeshift).
Whitelightmakesupallthecolorsoftherainbow:red,orange,yellow,green,blue,andpurple.Prismscanun‐mixlightintotheindividualcolorsbybendingthelightbydifferentamounts.Thered,green,andbluearetheprimarycolorsoflightthatmixtogethertoformeveryothercolorwesee.
Whenlightstrikesasurface,itcantravelthroughthesurfacecompletely,partially,orbeentirelyreflectedback,dependingonthesurfaceitstrikes.Lightcanalsoenteramaterialandgetcompletelytrappedinsidebyinternalreflections.Insomecases,lightcanbeabsorbed,andwhenthishappens,theabsorbingmaterialcanheatup,changecolor,changestate,orre‐transmitthelightatacompletelydifferentwavelength.
Lightcanbefilteredanddissectedintoaspecialsignaturethatallowsscientiststoidentifythepatternsandbeabletotellwhichelementgeneratedthelightinthefirstplace.Thesepatterns,orlightsignatures,areusedextensivelybyastronomersandchemiststodeterminethepropertiesofthelightandthechemicalreactionsrequiredtogeneratethelight.
©2014SuperchargedScience 9 www.SuperchargedScience.com
Mostlightisn’tdetectablebythehumaneye,whichmakesstudyinglightmorelikeinvestigatingacrimescene.You’llquicklybepuzzlingthepiecestogethertoexplainwhypencilsbreakinaglassofwater,howtofocuslightenergytofryeggs,andhowlensesbendlighttodistortandmagnifyimagesintelescopes.
Mixingthethreeprimarycolorsoflightgiveswhitelight.Ifyoutookthreelightbulbs(red,green,andblue)andshinedthemontheceiling,you’dseewhite.Andifyoucouldmagicallyun‐mixthewhitecolors,you’dgettherainbow(whichisexactlywhatprismsdo).
Ifyou’rethinkingyellowshouldbeaprimarycolor–itisaprimarycolor,butonlyintheartist’sworld.Yellowpaintisaprimarycolorforpainters,butyellowlightisactuallymadefromredandgreenlight.(Easywaytorememberthis:thinkofChristmascolors–redandgreenmergetomaketheyellowstarontopofthetree.)
Troubleshooting:Thisexperimenthasafewthingstobeawareof.Ifyou’renotgettingthecoloredshadows,checktobesurethattheflashlightisbrightenoughtoilluminateawallinthedark.Besuretoshutthedoors,shades,windows,anddrapes.Inthedark,whenyoushineyourredflashlightonthewall,thewallshouldglowred.Bewareofusingoff‐colornailpolish–makesureit’sreallyred,nothotpink.Alternately,youcouldusebrightly‐coloredcellophane.Ifyoustillneedhelpmakingthisexperimentwork,youcanvisityourlocalhardwarestoreandfindthreefloodlampholders(thecheapclamp‐styleonesmadefromaluminumworkwell–you’llneedthree)andscrewincolored“partylights”(makeonered,onegreen,andoneblue),whicharecoloredincandescentbulbs.Thesewillprovidealotmorelight!Youcanalsoaddafourthyellowlighttofurtherillustratehowyellowlightisn’taprimarycolor.Tryusingonlyred,yellow,andblue…you’llquicklyfindthatyoucan’tobtainallthecolorsasyoucouldwiththeoriginalred‐green‐bluelights.Exercises
1. Whatarethethreeprimarycolorsoflight?
2. Whatcolordoyougetwhenmixingtheprimarycolorsoflight?
3. Howdoyoumixtheprimarycolorsoflighttogetyellow?
4. Usecrayonsorcoloredpencilstodrawwhatyousawwhenallthreelightswereshiningonthewallandyouwavedyourhandinfrontofthelight.
©2014SuperchargedScience 10 www.SuperchargedScience.com
Lesson#2:Kaleidoscopes Overview: Inthesimplestsense,akaleidoscopeisatubelinedwithmirrors.Whetheryouleavetheendopenortapeonabagofbeadsisuptoyou,butthemainideaistoprovideenoughofanopticalillusiontowowyourfriends.Kaleidoscopesareanexampleofusinglightreflectors,whichdon’tgiveoffanylight,butstillbouncelightbacktoyoureyes. Thefirstkaleidoscopeswereconstructedin1816byascientistwhilestudyingpolarization(you’lllearnmoreaboutpolarizationinafuturelesson).Kaleidoscopeswerequicklypickedupasanamusementgadgetbythepublicandhavestayedwithuseversince.Todayyouwillbemakingyourveryownkaleidoscope.
WhattoLearn:Kaleidoscopesareanexampleofusinglightreflectors,whichdon’tgiveoffanylight,butstillbouncelightbacktoyoureyes. Lightisreflectedfrommirrorsandothersurfaces.
Materials
MirrorKaleidoscope
4‐5mirrors,allthesamesize tape scissors
MylarKaleidoscope
Mylar indexcardorpieceofcardboard hotgluegun scissors
Experiment
MirrorKaleidoscope
1. Layoutastripoftape,stickysideup.2. Centeronemirroronthetapewithitsreflectivesidepointingup.3. Attachthesecondandthirdmirrorsclosetothefirstat90‐degreeangles.Onewillbeontheleft;theother
willbeontheright.4. Riptheexcesstapeoffofoneendandthencarefullytapetogetherthethreeidenticalmirrors,forminga
triangularshape.Makesurethatthereflectivesurfaceisontheinside.5. Tapealltheroughedgesverywellandpeekthroughtheopeningasyouwalkaround.6. Lookattheimagesthemirrorsmakeontheinsidewhilepointingitatvariousobjects.
©2014SuperchargedScience 11 www.SuperchargedScience.com
MylarKaleidoscope
1. Foldtheindexcardintothreeequalpiecesinordertomakeitatriangulartube.2. MakesureyourMylaristhesamesizeaseachfoldofthetube.Trimasneeded.3. GluetheMylardowntothecardboard.4. Foldyourtubeagain,justmakingsurethattheedgesareascrispaspossible.5. Tapelengthwisealongthetopedgeofyourtriangulartube.6. Ifyouaremakingbothkaleidoscopes,comparethereflectionsyouseeinthislongertubewiththoseyou
sawinthemirrorkaleidoscope.
KaleidoscopeDataTable
NumberofMirrorsUsed
TypeofMirror(MylarorGlass,FlatorCurved,ShapeandSize)
HowweretheMirrorsArranged?(Triangle,Square…)
EffectonImage(Whatdiditlook
like?)
Reading
Acandleisalightsource(orsourceoflightwaves).Soareacampfire,alightbulb,andthesun.Anapple,however,reflectslight.Itdoesn’tgiveoffanylightonitsown,butyoucanseeitbecauselightbouncesofftheappleintoyoureye.Ifyoushutoffthelight,youcan’tseetheapple.Inthissameway,thesunisalightsource,andthemoonisalightreflector.
Lightcanbereflectedoffthesurfaceofdifferentmaterials.Theincidentangleofthelight(theanglethelighthitsthematerial)isalwaysthesameasthereflectedangleoflight.We’regoingtobuildakaleidoscopethatusesmirrorstoreflectlight.
©2014SuperchargedScience 12 www.SuperchargedScience.com
Kaleidoscopesuselightfromasource,suchasthelightsinyourroomorthesuninthesky,andreflectthelightbacktooureyes.ThereflectionsbouncingallaroundonthemirrorsorMylarmakeinterestingshapesforoureyestosee.
Therearemanyvariationsforthisexperiment.YoucandoboththemirrorandMylarkaleidoscopes,orsimplychooseonethatworksbestwiththematerialsyou’reabletofind.FortheMirrorKaleidoscope,you’llfindthatifyouuseonlytwomirrors,you’llgetasolidbackground.Addathirdmirrorandtilttogetherintoatriangle(asshowninthevideo)andyou’llgettheentirefieldfilledwiththepattern.Youcanplacetransparentobjectsattheend(likemarblesfloatinginwaterormineraloil)orjustleaveitopenandpointatthenightstars.Bychangingthesizeandshapeofthemirrors,youcanchangethedimensionaleffectyousee.Justbesuretolookatthemirrorsurface,nottheopening.Youcanalsomakemirrorswideratthebottomandnarroweratthetop(thisiseasiertodowiththeMylar‐cardboardmirrors).Usefourorfivemirrorsinsteadofthreeindifferentcombinationstogetdifferenteffects.YoucanalsochangethelengthofthemirrorsorusecurvedmirrorsinsteadofflatbyliningtheinsideofanoatmealboxwithMylar.
Exercises
1. Whatisalightsource?
2. Whatisalightreflector?
3. Sketchanimageofsomethinginterestingthatyouwereabletoseeasthelightreflectedfromthemultiplesurfacesofthekaleidoscopetoyoureyes:
©2014SuperchargedScience 13 www.SuperchargedScience.com
Lesson#3:LiquidPrism
Overview:Aprismun‐mixeslightbackintoitsoriginalcolorsofred,green,andblue.Inthisexperiment,waterisourprism.Youcanmakeprismsoutofglass,plastic,water,oil,oranythingelseyoucanthinkofthatallowslighttozipthrough.
WhattoLearn:Todayyou’regoingtoplaywithsplittingapartwhitelightintoitsprimarycolors.Thecoloroflightstrikinganobjectaffectshowoureyesseeit.
Materials
mirror shallowbakingdish sunlight indexcard
You’llalsohaveoneofthefollowing:
plainwater babyoilormineraloil waterwithonetablespoonofsaltmixedin distilledwhitevinegar isopropylrubbingalcohol clearliquidsoap(donotmixwithwater)
Experiment
1. Setatrayofliquidinsunlight.Ifyou’reusingwater,thenfillyourtraywithwater.Ifyou’reusingsalt,mixatablespoonofsaltintothewaterandthensetitinsunlight.Ifyou’reusinganythingelse,fillitwithyourliquidandsetitoutside.
2. Leanamirroragainsttheinsideedgeofthetrayandadjustitsothatarainbowappears.3. Usetheindexcard(oranotherwhitesurface)sothatyoucanclearlyseethereflectionfromyourprism.4. Youcanalsousealightbulbasanalternatelightsourcebyshiningitthroughaslitinaflatcardboard
surface.However,you’llfindthatsunlightismuchmoreeffectiveandwillmakeabrighter,morecompleterainbow.
5. Troubleshooting:Thisisoneoftheeasiestexperimentstodo,andthemostbeautiful.Thetroubleis,youdon’tknowwherethewatershadowwillshowup,somakesureyoupointthemirrortotheskyandplaywiththeangleofthemirroruntilyoufindthewaveringrainbow.Ifyoustillhavetrouble,usealargesheetofwhitepaperinsteadofthetinyindexcard.
©2014SuperchargedScience 14 www.SuperchargedScience.com
LiquidPrismDataTable
TypeofLiquidforthePrism
Whatdidyouobserve?
Reading
Whatisaprism?Thinkofabeamoflight.Itzoomsfastonastraightpath,untilithitssomething,likeawaterdrop.Asthelightgoesthroughthewaterdrop,itchangesspeed.Thisiscalledrefraction,whichwewilldiscussmoreinafuturelesson.Thespeedchangedependsontheangleatwhichthelighthitsthewater,andwhatthedropismadeof.Ifitwasadropofmineraloil,thelightwouldslowdownabitmorebecausethefluidhasmoreopticaldensity.Sowhenwhitelightpassesthroughaprism,likethatwaterdrop,itchangesspeed,whichwecanseewithoureyesbecauseitalsoturnscolors.
Prismsun‐mixlightintoitsdifferentwavelengths.Whenlighthitstheprism,mostofitpassesthrough,althoughasmallbitoflightdoesgetreflectedoffthesurface,butwhenitpassesthroughitchangesspeed.Sincethesunlightismadeupofmanydifferentwavelengths(colors),eachcolorgetsbentbydifferentamounts,andyouseearainbowouttheotherside.Aslongasthelighttravelsatthesamespeed(likethroughtheair),it’swhite.Butassoonasthelighthitsthewaterandbendsatdifferentangles,thewavelengthsseparateandspreadout,makingtherainbowyousee.
Troubleshooting:Thisisoneoftheeasiestexperimentstodo,andthemostbeautiful.Thetroubleis,youdon’tknowwherethewatershadowwillshowup,somakesureyoupointthemirrortotheskyandplaywiththeangleofthemirroruntilyoufindthewaveringrainbow.Becausetheshadowisconstantlymoving,youcansnapafewpictureswhenyou’vegotitsoyoucanlookoverthefinerdetailslater.Ifthisprojectstilleludesyou,takealargesheetanduseitinsteadofthetinyindexcard.
©2014SuperchargedScience 15 www.SuperchargedScience.com
Exercises
1. Whatservesastheprisminthisexperiment?
2. Whatpropertycanhelpmakesomethingagoodprismmaterial?
3. Whataresomeotheritemsthatcouldbeusedasprisms?
©2014SuperchargedScience 16 www.SuperchargedScience.com
Lesson#4:LunarPhases
Overview:TheMoonappearstochangeinthesky.Onemomentit’sabigwhitecircle,andnextweekit’sshapedlikeasidewaysbikehelmet.There’sevenadaywhereitdisappearsaltogether.Sowhatgives?
WhattoLearn:ThesunilluminateshalfoftheMoonallthetime.Imagineshiningaflashlightonabeachball.Thehalfthatfacesthelightislitup.There’snolightonthefarside,right?FortheMoon,whichhalfislitupdependsontherotationoftheMoon.AndwhichpartoftheilluminatedsidewecanseedependsonwherewearewhenlookingattheMoon.Soundcomplicated?Thislabwillstraighteneverythingoutsoitmakessense.
Materials
ball flashlight
Experiment
1. Assignonepersontobethesunandhandthemtheflashlight.Staystandingupaboutfourfeetawayfromthegroup.Thesundoesn’tmoveatallforthisactivity.
2. AssignonepersontobetheMoonandhandthemtheball.Staystandingup,asyou’llbecirclingtheEarth.3. TherestofthepeoplearetheEarth,andtheysitrightinthemiddle(sotheydon’tgetaflashlightintheir
eyesastheMoonorbits).4. StartwithanewMoon.ShinetheflashlightabovetheheadsoftheEarth.MovetheMoon(ball)intoposition
sothattheballblocksallthelightfromtheflashlight.AsktheEarthkidshowmuchlighttheycanseeontheirsideoftheMoon(shouldbenone).WhichphaseoftheMoonisthis?__________________________________________________________________
5. NowtheMoonmovesaroundtotheoppositesideoftheEarthsothattheEarthkidscanseetheentirehalfoftheballlitupbytheflashlight.AsktheEarthkidshowmuchlighttheycanseeontheirsideoftheMoon(shouldbehalftheball).WhichphaseoftheMoonisthis?
__________________________________________________________________
6. Nowfindthepositionsforfirstquarter.WheredoestheMoonneedtostandsothattheEarthkidscanseethefirstquarterMoon?
7. Continuearoundinacompletecircleandfilloutthediagram.ColorinthecirclestoindicatethedarkhalfoftheMoon.Forexample,thenewMoonshouldbecompletelydarkened.
©2014SuperchargedScience 17 www.SuperchargedScience.com
LunarPhasesDataObservations
1. Nowit’stimetoinvestigatewhyVenusandMercuryhavephases.PutthesuninthecenterandassignastudenttobeVenus.Venusgetstheball.
2. Venusshouldbewalkingslowlyaroundthesun.ThesunisgoingtohavetorotatetoalwaysfaceVenus,sincethesunnormallygivesofflightineverydirection.
3. TheEarthkidsneedtomovefurtheroutfromthesunthanVenus,sotheywillbewatchingVenusorbitthesunfromadistanceofacoupleoffeet.
©2014SuperchargedScience 18 www.SuperchargedScience.com
4. Earthkids:whatdoyounoticeabouthowthesunlightsupVenusfromyourpointofview?IsthereatimewhenyougettoseeVenuscompletelyilluminated,andothertimeswhenit’scompletelydark?
5. Drawadiagramofwhat’sgoingon,labelingVenus’sfullphase,newphase,halfphases,crescent,andgibbousphases.Labelthesun,Earth,andall8phasesofVenuslikewedidontheboardfortheEarthatthebeginningofthislesson:
Reading
ThesunilluminateshalfoftheMoonallthetime.Imagineshiningaflashlightonabeachball.Thehalfthatfacesthelightislitup.There’snolightonthefarside,right?SofortheMoon,whichhalfislitupdependsontherotationoftheMoon.AndwhichpartoftheilluminatedsidewecanseedependsonwherewearewhenlookingattheMoon.Soundcomplicated?Thislabwillstraighteneverythingoutsoitmakessense.
Onequestionyou’llhearis:Whydon’twehaveeclipseseverymonthwhenthere’sanewMoon?Goodquestion.TheMoon’sorbitaroundtheEarthisnotinthesameplaneastheEarth’sorbitaroundthesun(calledtheecliptic).It’sactuallyoffbyabout5°.Infact,onlytwicepermonthdoestheMoonpassthroughtheecliptic.
Thelunarcycleisapproximately28days.Tobeexact,ittakesonaverage29.53days(29days,12hours,44minutes)betweentwofullmoons.Theaveragecalendarmonthis1/12ofayear,whichis30.44days.SincetheMoon’sphasesrepeatevery29.53days,theydon’tquitematchup.That’swhyonMoonphasecalendars,you’llseeaskippeddaytoaccountforthemismatch.
AsecondfullMooninthesamemonthiscalledablueMoon.It’salsoablueMoonifit’sthethirdfullMoonoutoffourinathree‐monthseason,whichhappensonceeverytwoorthreeyears.
TheMoonisn’ttheonlyobjectthathasphases.MercuryandVenusundergophasesbecausetheyareclosertothesunthantheEarth.IfwelivedonMars,thentheEarthwouldalsohavephases.
©2014SuperchargedScience 19 www.SuperchargedScience.com
Exercises
1. DoesthesunalwayslightuphalftheMoon?
2. HowmanyphasesdoestheMoonhave?
3. WhatisitcalledwhentheMoonappearstogrow?
4. WhatisitcalledwhenyouseemorelightthandarkontheMoon?
5. Howlongdoesittakeforacompletelunarcycle?
©2014SuperchargedScience 20 www.SuperchargedScience.com
Lesson#5:SkyinaJar
Overview:Haveyoueverwonderedwhytheskyisblue?Orwhythesunsetisred?Orwhatcoloroursunsetwouldbeifwehadabluegiantinsteadofawhitestar?Thislabwillanswerthosequestionsbyshowinghowlightisscatteredbytheatmosphere.
WhattoLearn:Particlesintheatmospheredeterminethecoloroftheplanetandthecolorsweseeonitssurface.Thecolorofthestaralsoaffectsthecolorofthesunsetandoftheplanet.Thecoloroflightstrikinganobjectaffectshowoureyesseeit.
Materials
glassjar flashlight fingernailpolish(red,yellow,green,blue) cleartape water darkroom fewdropsofmilk
Experiment
1. Makeyourroomasdarkaspossibleforthisexperimenttowork.2. Makesureyourlabelisremovedfromtheglassjaroryouwon’tbeabletoseewhat’sgoingon.3. Filltheclearglassjarwithwater.4. Addateaspoonortwoofmilk(orcornstarch)andswirl.5. Shinetheflashlightdownfromthetopandlookfromtheside–thewatershouldhaveabluishhue.The
smallmilkdropletsscatterthelightthesamewayouratmosphere’sdustparticlesscattersunlight.6. Tryshiningthelightupfromthebase–wheredoyouneedtolookinordertoseeafaintred/pinktint?If
not,it’sbecauseyouarelookingforhuesthatmatchourrealatmosphere,andthejarjustisn’tthatbig,norisyourflashlightstrongenough!Instead,lookforaveryslightcolorshift.Ifyoudothisexperimentafterbeinginthedarkforabout10minutes(lettingyoureyesadjusttothelackoflight),itiseasiertoseethesubtlecolorchanges.Justbecarefulthatyoudon’tletthebrilliantflashlightruinyournewlyacquirednight‐vision,oryou’llhavetostartthe10minutesalloveragain.
7. Ifyouarestillhavingtroubleseeingthecolorchanges,shineyourlightthroughthejarandontoanindexcardontheotherside.Youshouldseeslightcolorchangesonthewhitecard.
8. Covertheflashlightlenswithcleartape.9. Paintonthetape(notthelens)thefingernailpolishyouneedtocompletethetable.10. Repeatsteps7‐9andrecordyourdata.
©2014SuperchargedScience 21 www.SuperchargedScience.com
SkyinaJarDataTable
FlashlightColor Location Color(s)
White Sideofjar
White BottomofJar
Red Sideofjar
Red BottomofJar
Yellow Sideofjar
Yellow BottomofJar
Green Sideofjar
Green BottomofJar
Blue Sideofjar
Blue BottomofJar
Reading
Whyisthesunsetred?Thecolorsyouseeintheskydependonhowlightbouncesaround.Thered/orangecolorsofsunsetandsunrisehappenbecauseofthelowanglethesunmakeswiththeatmosphere,skippingthelightoffdustanddirt(nottomentionsolidaerosols,soot,andsmog).Sunsetsareusuallymorespectacularthansunrises,asmore“stuff”floatsaroundattheendoftheday(therearelessparticlespresentinthemornings).Sometimesjustaftersunset,agreenflashcanbeseenejectingfromthesettingsun.
TheEarthappearsbluetotheastronautsinspacebecausetheshorter,fasterwavelengthsarereflectedofftheupperatmosphere.Thesunsetsappearredbecausetheslower,longerwavelengthsbounceofftheclouds.
Sunsetsonotherplanetsaredifferentbecausetheyarefarther(orcloser)tothesun,andalsobecausetheyhaveadifferentatmospherethanplanetEarth.TheimageshownhereisasunsetonMars.
Exercises
1. Whatcolorsdoesthesunsetgothrough?
2. Doesthecolorofthelightsourcematter?
©2014SuperchargedScience 22 www.SuperchargedScience.com
Lesson#6:LightTricks
Overview:Todayyougettoseethesciencebehindtheillusionbylearninghowlightstrikinganobjectaffectshowoureyesseeit.
WhattoLearn:Lightcanbebentwhenitpassesthroughmaterials.Theamountthatthelightbendsiscalledtheindexofrefraction.Howmuchlightbendsdependsonthematerialit’spassingthrough.Thisqualityismeasuredforeachindividualmaterialandiscalledtheopticaldensity.Themoredensethesubstance,theslowerthelighttravelsthroughit,andthemorethelightbends.
Materials
glassjar penny laser(optional) flashlight milkorflour
LightTricksDataTable
Whenyoudothepencilillusiontrick,recordyourobservations.
WaterLevel: WaterLevel: WaterLevel:
©2014SuperchargedScience 23 www.SuperchargedScience.com
Experiment
1. Recordyourobservationsonthedatasheetandintheexercisesasyougo.2. Tossonecoinintoawaterglassandfillwithaninchofwater.Holdtheglassupandfindwhereyouneedto
looktoseeTWOcoins.3. Lookthroughthetopoftheglass–howmanycoinsaretherenow?Whataboutwhenyoulookfromthe
side?4. Tossinasecondcoin–nowhowmanyarethere?5. Removethecoinsandturnoutthelights.Shineaflashlightbeamthroughtheglassontoanearbywall.
(Hint–ifthisdoesn’twork,tryusingasquareclearcontainer.)Stickapieceofpaperonthewallwhereyourlightbeamisandoutlinethebeamwithapencil.
6. Shinethelightatanangleupthroughthewatersothatitbouncesoffthesurfaceofthewaterfromunderneath.Traceyournewoutlineandcompare…aretheyboththesameshape?
7. Addateaspoonofmilkandstirgently.(Nomilk?Trysprinklinginabitofwhiteflour.)Nowshineyourflashlightthroughthecontainerasyoudidinsteps4and5andnoticehowthebeamlooks.
8. Usearoundcontainerinsteadofsquare…what’sthedifference?
Reading
Haveyoueverbrokenapencilbystickingitintoaglassofwater?Thepencilisn’treallybroken,butitsurelookslikeit!What’sgoingon?Lightcanbebentwhenitpassesthroughmaterials.Theamountthatthelightbendsiscalledtheindexofrefraction.Howmuchlightbendsdependsonthematerialit’spassingthrough.Thisqualityismeasuredforeachindividualmaterialandiscalledtheopticaldensity.Themoredensethesubstance,theslowerthelighttravelsthroughit,andthemorethelightbends.Tobeexact,whenabeamoflighthitsadifferentsubstance(likemovingfromairtowater),thewavelengthchangesbecausethespeedofthelightchanges.Ifyou’rethinkingthatthespeedoflightisalwaysconstant,you’reright…inouterspace,lighttravelsat186,000milespersecond.ButtheEarthiscoveredwithanatmosphere,andassoonasthelightpassesintothisthickcloudofnitrogenandoxygengas,itslowsdownabit.Thespeedoflightchangeswheneveritpassesfromonematerialtoanother,likewhenitmovesfromwatertoice,ortosunglasses,smoke,fog,orwindows.Howmuchthelightspeedslowsdowndependsonwhatthematerialismadeof.Mineraloilandwindowglasswillslowlightdownmorethanwater,butnotasmuchasdiamondsdo.Exercises
1. Whenonecoinisinthewater,youcanactuallyseetwo:Arethecoinsboththesamesize?Whichoneistheoriginalcoin?
2. Instep2oftheexperiment:Howmanycoinsaretherewhenviewedfromthetopoftheglass?Whataboutwhenyoulookfromtheside?
3. Whathappenedwhenyoutossedinasecondcoin?
4. Howdidyouroutlinescompare?
©2014SuperchargedScience 24 www.SuperchargedScience.com
Lesson#7:BlackLightTreasureHunt
Overview:EvernoticehowBRIGHTyourwhiteT‐shirtlooksindirectsun?That’sbecausemomwashedwithfluorescentlaundrysoap(nokidding!).ThesoapmanufacturersputindyesthatglowwhiteunderaUVlight,whichmakeyourclothesappearwhiterthantheyreallyare.
WhattoLearn:Lightcanbeabsorbedandretransmittedinadifferentcolor,dependingonhowthelightstrikestheobjectandtheamountofenergythelightinitiallyhas.
Materials
UVblackfluorescentlight darkeveninginsideyourhouse
Experiment
1. TurnoffallthelightsinyourhouseandturnonyourUVblacklight.2. Findthingsthatglowbothinsideandoutsidethehouse.3. Whatfluorescesinyourhouse?Herearesomethingstotry:whitepaper(althoughpapermadepre‐1950
doesn’t,whichishowinvestigatorstellthedifferencebetweenoriginalsandfakes),clubsodaortonicwater(it’sthequininethatglowsblue),bodyfluids(yes,blood,urine,andmoreareallfluorescent),Vitamins(VitaminA,B,B‐12(crushanddissolveinvinegarfirst),thiamine,niacin,andriboflavinarestronglyfluorescent),chlorophyll(grindspinachinasmallamountofalcohol(likeethylalcohol)andpouritthroughacoffeefiltertogettheextract(keepthesolidsinthefilter,nottheliquid)),antifreeze,laundrydetergents,toothwhiteners,postagestamps,driver’slicense,jellyfish,andcertainrocks(fluorite,calcite,gypsum,ruby,talc,opal,agate,quartz,amber)andtheHopeDiamond(whichisblueinregularlight,butglowsred).
4. Completethedatatable.
©2014SuperchargedScience 25 www.SuperchargedScience.com
BlackLightTreasureHuntDataTable
Item/Object Whatcolordiditglow?
Reading
Lightbulbsuseincandescence,whichmeansthatthelittlewire(whichismadefromtheelementtungsten)getssohotwhenyouswitchitonthatitgivesoffheatandlight.Unfortunately,thesebulbsgiveoffalotofheat,whichyou’llnoticeifyoubringyourhandclosetoitafterit’sbeenonforawhile.Incandescencehappenswhenyourelectricstoveglowscherryred‐hotandyoucanvisiblyseethelightenergy.Oursungivesoffenergythroughincandescencealso–alotofit.
©2014SuperchargedScience 26 www.SuperchargedScience.com
Ontheotherendofthings,coldlightreferstothelightfromaglowstick,calledluminescence.Achemicalreaction(chemiluminescence)startsbetweentwoliquids,andtheenergyisreleasedintheformoflight.Ontheatomicscale,theenergyfromthereactionbumpstheelectrontoahighershell,andwhenitrelaxesbackdownitemitsaphotonoflight.Phosphorescenctlightistheglow‐in‐the‐darkkindoflightyouseeafteryouchargeupaglowtoywithabrightlightsource.Thisdelayedafterglowhappensbecausewhenyouchargedtheobjectwithlight,thelightactuallyhitstheatom’selectronandwhacksitintoahigherenergystate.Whentheelectronrelaxesbackdownitslowerenergystate,itemitsalightparticleof(usually)adifferentwavelength(color).That’swhyglow‐in‐the‐darktoysareoftenadifferentcolorthanthelighttheyemitafterchargedup.Sincelightisaformofenergy,theninorderforthingstoglowinthedark,youhavetoaddenergyfirst.Triboluminescenceisthesparkyouseewhenyousmacktwoquartzcrystalstogetherinthedark.Othermineralssparkwhenstrucktogether,butyoudon’thavetobearockhoundtoseethisoneinaction–justtakeaWint‐O‐GreenLifesaverinadarkclosetwithamirrorandyou’llgetyourownsparkshow.Ifyouchewthecandywithyourmouthopen,you’llbeabletoseethesparksinyourmouthwithamirror.Thesparkisbasicallylightfromfriction.Fluorescenceissimilartophosphorescence,exceptthatitrequiresacontinuallightsourceinordertoglow.Thesetypesofpaintsarepopularwithdarkamusement‐parkrides.Ifyoulookcarefully,you’llseeUVlightshiddenallaroundtomaketheimagesglowasyouspeedthroughtheride.Innature,you’llfindfluorescenceincertainrocks,plantsandanimals.FluorescentobjectsabsorbtheUVlightandremitacompletelydifferentcolor.Likewithphosphorescence,thelightstrikestheelectronandbumpsitupalevel,andwhentheelectronrelaxedbackdown,emitsaphoton(lightparticle)ofadifferentwavelength.
Fluorescentlightsgiveoutlessheat,butmorelight.Sincetheydon’tloseasmuchenergytoheat,theyaremoreenergy‐efficient.Iwillusuallyholdupanincandescentbulbandafluorescentbulbandaskthestudentshoweachmakeslight.Afluorescenttubeislinedwithwhitestuffcalledphosphor,whichgivesofflightwheneverit’sstruckbyUVrays.ThetubeisfilledwithagasthatgivesoffUVrayswhenplacedinanelectricalfield.Whenthebulbisturnedon,electronsripthroughthetubeandgoouttheotherside.Astheygothrough,theysmackintothegasvaporwhichreleaseslightrays(UVinafluorescenttube)thathitthephosphorontheinsideofthetube,whichthenemitslight.Fluorescentlights,oranytubeofgasfromthenoblegasescolumnontheperiodictable,likeneon,willalsoglowinanelectricallychargedfield.
Phosphorescenceisatypeoffluorescencelikeyoufindinglowsticksandotherglow‐in‐the‐darkitems.
Triboluminescenceisatypeoffluorescentlightthatcomesfromfriction,likewhenstrikingtwoquartzcrystalstogether.(YoucanhandoutWint‐O‐GreenLifesaversaspartoftheirhomeworkforthedayandhavethemrecordtheirresultsintheirlab.)
©2014SuperchargedScience 27 www.SuperchargedScience.com
Exercises
1. Whyareincandescentlightslessenergy‐efficientthanfluorescentlights?
2. Whatarethetwotypesoffluorescentlights?
3. Whatkindsofthingsdidyoufindthatglowonyourtreasurehunt?Giveatleastfiveexamples.
©2014SuperchargedScience 28 www.SuperchargedScience.com
Lesson#8:Benham’sDisk
Overview:CharlesBenham(1895)createdatoytoppaintedwithaspecificpattern.Whenyouspintheblackandwhitepattern,surprisingarcsofcolor(called“patterninducedflickercolors”)showup;andhere’stheoddpart:Differentpeopleseedifferentcolors!
WhattoLearn:Thecoloroflightstrikinganobjectaffectshowoureyesseeit.Theconesandrodsinsideoureyescollectimagesthataretransmittedtothebrain.
Materials
Benham’sDisksheet string(about3feet) 8indexcards gluestick
Experiment
1. CutouttheBenham’sDisks.2. Gluethediskstoindexcardsforstability.Regularpapertendstofloparoundwhenyouspinitquickly.3. Labeleachdiskwithanumberfrom1to6onthebacksidesoyoucanrecordyourobservationsinthedata
tablelater.4. Spinthedisksusingthemethodyouchoose.Playwiththisabitbeforeyoutakedatasoyoucanget
comfortablewithhowtodotheexperiment.5. Whenyouareready,recordyourobservationsinthedatatable.
Reading
Wecan’treallysaywhythiseffectwithBenham’sDiskhappens,butthereareafewinterestingtheories.Theretinaatthebackofyoureyehasabunchoflight‐sensitivecellscalledconesandrods.Youreyeballhastwodifferentwaysofseeinglight:conesandrods.Conesareusedforcolorvisionandforseeingbrightlight,andtherearethreetypesofcones(red,green,andblue).Rodsareimportantforseeinginlowlightandtheysenseblack,white,andgrayshades.Together,theyturnthelightthatentersyoureyeintoanimage.
©2014SuperchargedScience 29 www.SuperchargedScience.com
Benham’sDiskDataTable
Disk# WhatColorsDidYouSee?
1
2
3
4
5
6
YourOwnDesign#1
YourOwnDesign#2
Exercises
1. Whatcolorswereyouabletoseewhenthediskswerespinning?
2. Howdidthedifferentpatternslookwhentheywerespun?
3. Howdidspeedanddirectionaffectwhatyousaw?
©2014SuperchargedScience 30 www.SuperchargedScience.com
Benham’sDisks
©2014SuperchargedScience 31 www.SuperchargedScience.com
Lesson#9:EyeBalloon
Overview:Inthislab,wearegoingtomakeaneyeballmodelusingaballoon.Thisexperimentshouldgiveyouabetterideaofhowyoureyeswork.Thewayyourbrainactuallyseesthingsisstillamystery,butusingtheballoonwecangetagoodworkingmodelofhowlightgetstoyourbrain.
WhattoLearn:Weseeobjectswhenlighttravelingfromanobjectentersoureye.
Materials
biconvexplasticlens
roundballoon,white,9inches
assistant
votivecandle
blackmarker
bookofmatches
ruler
Experiment
1. Blowuptheballoonuntilitisaboutthesizeofagrapefruit.Ifit’sdifficulttoinflate,stretchthematerialafewtimesoraskanadulttohelpyou.
2. Youwillneedanextrasetofhandsforthisportion.Askyourpartnertoholdtheneckoftheballoonclosedtokeeptheairinwhileyouinsertthelensintotheopening.Thelenswillneedtobeinsertedperpendiculartotheballoon’sneck.Itwillpreventanyairfromescapingonceit’sinplace.Likeyoureye,lightwillenterthroughthelensandtraveltowardthebackoftheballoon.
3. Holdtheballoonsothatthelensispointingtowardyou.Takethelensbetweenyourthumbandindexfinger.Lookintothelensintotheballoon.Youshouldhaveaclearviewoftheinside.Starttotwisttheballoonalittleandnoticethattheneckgetssmallerlikeyourpupilsdowhenexposedtolight.Practiceopeningandclosingtheballoon’s“pupil.”
4. Haveanadulthelpyouputthecandleonthetableandlightit.Turnoutthelights.5. Puttheballoonabout20to30centimetersawayfromthecandlewiththelenspointedtowardit.The
balloonshouldbebetweenyouandthecandle.Youshouldseeaprojectionofthecandle’sflameonthebackoftheballoon’ssurface.Movetheballoonbackandforthinordertobetterfocustheimageonthebackoftheballoonandthenproceedwithdatacollection.
6. Describetheimageyouseeonthebackoftheballoon.Howisitdifferentfromtheflameyouseewithyoureyes?Drawapictureofhowtheflamelooks.
7. Thefocallengthisthedistancefromtheflametotheimageontheballoon.Measurethisdistanceandrecordit.
8. Whathappensifyoulightlypushdownonthetopoftheballoon?Doesthisaffecttheimage?Youareexperimentingwiththeaffectcausedbynear‐sightedness.
9. Toapproximateafarsightedeye,gentlypushinthefrontandbackoftheballoontomakeittaller.Howdoesthischangewhatyousee?
©2014SuperchargedScience 32 www.SuperchargedScience.com
EyeBalloonDataTable
Drawapictureofhowtheflamelookstoyou.
Recordthefocallengthfromflametotheimage.
Whathappenstotheimagewhenyoupushdownonthetopoftheballoon?
Whatdoyouseewhenyoupushonthefrontandbackoftheballoontomakeittaller?
Reading
First,we’lldiscussthepartsoftheballoonthatrelatetopartsofyoureye.Thewhiteportionoftheballoonrepresentsyoursclera,whichyoumayhavealreadyguessedisalsothewhitepartofyoureye.Itisactuallyacoatingmadeofproteinthatcoversthevariousmusclesinyoureyeandholdseverythingtogether.Ofcourse,thelensyouinsertedrepresentstheactuallensinyoureye.Themusclessurroundingthelensarecalledciliarymusclesandtheyarerepresentedbytherubberneckofyourballoon.Theciliarymuscleshelptocontroltheamountoflightenteringyoureyes.Theretinaisinthebackofyoureye,whichisrepresentedbytheinsidebackofyourballoon.Theretinasupportsyourrodsandcones.Theycollectinformationaboutlightandcolorandsendittoyourbrain.
Therearenolightreceptorsintheareaofyoureyewheretheopticnerveattachestoyoureyeball.Thisisyourblindspotandifanimageisinthisspot,thelightreflectedoffofitdoesn’tgetperceivedbyyoureye.
Thisisafunexperimenttoplaywithusingdifferentagesofpeople.Asfolksgetolder,theshapeoftheeyechangesandtheblindspotcanactuallychange.Askafewfellowadultstohelpyoudemonstratethelabandmeasurethedistancefortheblindspotbasedonhowoldtheadultsare.Youcanalsotesttoseeifdifferentpeoplewith
©2014SuperchargedScience 33 www.SuperchargedScience.com
differentvisionhavedifferentblindspots.Forexample,istheblindspotthesameforsomeonewith20/20versus20/40?Orwithorwithouteyeglasses?Havefunwiththedifferentvariations!
Exercises
1. Howdoesyoureyeworklikeacamera?
2. Howcanyoutellifalensisdoubleconvex?
3. Whatisthedifferencebetweenconvexandconcave?
4. Canyougiveanexampleofaneverydayobjectthathasbothaconvexandaconcaveside?
5. Howcanyouchangetheballoontomakeitlikeanear‐sightedeye?
6. Howcanyouchangetheballoontomakeitlikeafar‐sightedeye?
©2014SuperchargedScience 34 www.SuperchargedScience.com
Lesson#10:DisappearingFrogOverview:Youropticnervecanbethoughtofasadatacordthatispluggedintoeacheyeandconnectsthemtoyourbrain.Theareawherethenerveconnectstothebackofyoureyecreatesablindspot.Therearenoreceptorsinthisareaatallandifsomethingisinthatarea,youwon’tbeabletoseeit.Thisexperimentlocatesyourblindspot.WhattoLearn:Conesandrodsturnthelightthatenterstheeyeintoimagesthataretransmittedtothebrain.Oureyeshaveablindspotwheretheopticnerveconnectstothebackoftheeyebecausetherearenolightreceptorsthere.
Materials
froganddotprintout meterstick scrappieceofcardboard
Experiment
1. Printoutthefroganddotandremovethedottedportion.Attachittothepieceofcardboard,whichshouldhaveamatchingportionremoved.Youcanplacethepaperandcardboardonthemeterstickatthenotchedarea.
2. Nowtolocateblindspots.First,closeyourlefteye.Lookatthefrogwithyourrighteye.Canyouseethedotandthefrog?Youshouldbeabletoseebothatthispoint,butconcentrateonthefrog.Nowslowlymovethesticktowardyousothatthefrogiscomingtowardyoureye.Payattentionandstopwhenthedotdisappearsfromyourperipheralvision.Atthispoint,thelighthittingthedotandreflectingbacktowardyoureyeishittingtheblindspotatthebackofyourrighteyeball,soyoucan’tseeit.Recordhowfaryoureyeisfromthecardforyourrighteye.
3. Continuetomovethesticktowardyourface,andatsomepointyouwillnoticethatyouareabletoseethedotagain.Keepmovingthestickforwardandback.Whathappenstothedot?
4. Repeatsteps2and3withyourlefteye,keepingyourrighteyeclosed.Thistime,stareatthedotandwatchforthefrogtodisappear.Movethepaperonthestickbackandforthslowlyuntilyounoticethefrogdisappears.Youhavefoundtheblindspotforyourlefteye.Besuretonotethedistancethepaperisfromyoureye.
©2014SuperchargedScience 35 www.SuperchargedScience.com
DisappearingFrogDataTable
StudentName RightorLeftEye? DistancefromEyetoFrog
Exercises
1. Whatdidyounoticeaboutthevisionofthestudentandtheblindspotthatyoumeasured?
2. Whydoyouthinkit’simportanttoknowwhereyourblindspotis?
©2014SuperchargedScience 36 www.SuperchargedScience.com
Lesson#11:PinholeCamera
Overview:Todayyougettolearnhowtomakeasimplecamerausingequallysimplematerials.It’ssurprisinghowsharptheimagesappearwhenyoudothisexperiment!
WhattoLearn:Althoughthismightseemobvious,weseeobjectswhenlighttravelingfromanobjectentersoureye.Wecandetectlightinotherways(asyou’llfindoutinalaterlesson),buttheeyesdetectonlyvisiblelight.
Materials
box tracingpaper razororscissors tape tack meterstick
Experiment
1. Useacardboardboxthatislight‐proof(noleaksoflightanywhere).2. Seallightleakswithtapeifyouhaveto.Cutoffonesideofthebox(Note–there’snoneedtodothisif
you’reusingashoebox.)3. Tapeapieceoftracingpaperoverthecutoutside,keepingittautandsmooth.4. Makeapinholeintheboxsideoppositeofthetracingpaper.5. Pointthepinholeatasunnywindowandmovetowardorawayfromthewindowuntilyouseeitsimagein
clearfocusonthetracingpaper.6. Ifyouhaveamagnifyingglass,placeitinfrontofthepinholetohelpsharpentheimage.7. Completethedatatablebymeasuringyourcamerawiththemeterstick.
©2014SuperchargedScience 37 www.SuperchargedScience.com
PinholeCameraDataTable
Measure: Length(inches,feet,cm,or…?)
Boxlength(thisisonedimensionofthescreen)
Boxwidth(thisistheotherscreendimension)
Boxheight(thisisthedistancefromtheholetothescreen)
Distancefromholetothewindow(orcandle)whenfocused
Drawadiagramofyourexperiment,labelingthedifferentpartsanddistancesmeasuredfromabove:
Reading
Lighttravelsinastraightline;itcomesthroughthewindowandintotheholeinyourcamera.Theraysoflightcrossastheyenterthetinyhole,creatinganinvertedimagethatyouseeprojectedonthescreen.Thebiggestproblemwiththiscameraisthattheinletholeissotinythatitletsinsuchasmallamountoflightandmakesafaintimage.Ifyoumaketheholelarger,yougetabrighterimage,butit’smuchlessfocused.Themorelightrayscomingthrough,themoretheyspreadouttheimageandcreateafuzzierpicture.You’llneedtoplaywiththesizeoftheholetogetthebestimage.Youcanalsolightasinglecandleinthemiddleoftheroom(insteadofusingabrightwindow)forthekidstousetheircamera.Justbecarefultheydon’tgettooclose–thecamerasareflammable!Youcanletyourstudentsgocrazytakingactualphotoswiththiscamerabystickingonapieceofundevelopedblackandwhitefilm(useamoderatelyfastASAratingifyoucanstillfindit),butIrecommendusingtracingpaperandasetofeyeballstoviewyourimages.OPTIONAL:Youcanholdupamagnifyingglassinfrontofthepinholetosharpentheimage.
©2014SuperchargedScience 38 www.SuperchargedScience.com
Exercises
1. Howdotheimagesappearwhenthey’reprojectedontothepaperinsideyourcamera?
2. Whydoyouthinkit’simportanttomaketheboxaslight‐proofaspossible?
3. Isthereapartofyourbodythatworkssimilarlytothepinhole?
4. Sketchapictureofsomethingyousawthroughyourpinholecamera.
©2014SuperchargedScience 39 www.SuperchargedScience.com
Lesson#12:Diffraction
Overview:Whenlightpassesthroughdiffractiongratings,itsplits(diffracts)thelightintoseveralbeamstravelingatdifferentdirections.Ifyou'veeverseenthe“iridescence”ofasoapbubble,aninsectshell,oronapearl,you'veseennature'sdiffractiongratings.
WhattoLearn:Everplaywithaprism?Whensunlightstrikestheprism,itgetssplitintoarainbowofcolors.Prismsun‐mixthelightintoitsdifferentwavelengths(whichyouseeasdifferentcolors).Diffractiongratingsaretinyprismsstackedtogether.Thedirectionthatthebeamgetssplitanddiffracteddependsonthespacingofthediffractiongratingandalsothewavelengthoftheincominglight.
Materials
feather CDorDVD diffractiongrating
Experiment
1. Takeafeatherandputitoveraneye.2. Stareatalightsourcethroughthefeather,likeanincandescentlight.3. YoushouldseetwoorthreelightsandarainbowX.4. AimtheCDsothelighthitstheCDandmakesrainbows.5. Lookatthelightsourcethroughthediffractiongrating.6. Drawwhatyouseeforallthree.Weretheythesame?7. Takethisona“lighttreasurehunt”tofinddifferentlightsources.Goodchoicesarecandles,incandescent
bulbs,fluorescentbulbs,nonsigns,halogenlamps,streetlights,stoplights,andanythingelseyoucanthinkofthatgivesofflight(exceptthesun).
8. Completethetableasyouviewthedifferentlightsourcesthroughyourdiffractiongratings.
©2014SuperchargedScience 40 www.SuperchargedScience.com
DiffractionDataTable
LightSource DiffractiveObject(Feather,CD,orGrating?)
DrawWhatYouSee:
©2014SuperchargedScience 41 www.SuperchargedScience.com
Reading
Everplaywithaprism?Whensunlightstrikestheprism,itgetssplitintoarainbowofcolors.Prismsun‐mixthelightintoitsdifferentwavelengths(whichyouseeasdifferentcolors).Diffractiongratingsaretinyprismsstackedtogether.Thedirectionthatthebeamgetssplitanddiffracteddependsonthespacingofthediffractiongratingandalsothewavelengthoftheincominglight.
Thefeatherworksbecausetherearetiny“hairs”onthefeatherthatareactingliketinyprisms.
DiffractiongratingswerefirstdiscoveredbyJamesGregory,rightaroundthetimeNewtonperformedhisfamousprismexperimentswithbirdfeathers.Thefirstdiffractiongratingstookalongtimetoconstruct,astheywereindividualhairsstrungbetweenscrews.
Adiffractiongratingbendsthelightandsplitsitintodifferentbeams.Youcanseethisverywellwhenyouuseamonochromaticlightsource,likealaser,insteadofamulti‐wavelengthlightsource.
Exercises
1. Whichlightsourcegavethemostinterestingresults?
2. Whathappenswhenyouaimalaserbeamthroughthediffractiongrating?
3. HowisaCDdifferentandthesameasadiffractiongrating?
4. Whydoesthefeatherwork?
©2014SuperchargedScience 42 www.SuperchargedScience.com
Lesson#13:SpeedofLight
Overview:Oneofthebiggestchallengeswithmeasuringthespeedoflightisthatthephotonsmovefast,toofasttowatchwithoureyeballs.Soinstead,we’regoingtowatchtheeffectsofmicrowavelightandbaseourmeasurementsontheeffectsthelighthasondifferentkindsoffood.
WhattoLearn:Todayyougettothinkandactlikearealscientistbydoinganexperiment,takingmeasurements,usingmathtofigureoutananswer,andtestdifferentmaterialstoseewhichgivesyouthebestresult.
Materials
chocolatebar(extra‐largebarsworkbest) minimarshmallows chocolatechips Americanslicedcheese(thekindthatcomesindividuallywrapped) paperplates ruler calculator pencilandpaper microwave(You’llonlyneedoneofthesefortheentiregroup.)
Experiment
1. First,you’llneedtofindthe“hotspots”inyourmicrowave.Thevideowilldemonstratethisforyou,butherearethesteps:
2. Removetheturntablefromyourmicrowaveandplaceanakedbarofchocolateonaplateinsidethemicrowave.(MakesurethechocolatebaristheBIGsize–you’llneedatleast7inchesofchocolateforthistowork.)
3. Turnthemicrowaveonandwaitafewminutesuntilyouseesmallpartsofthechocolatebarstarttobubbleup,andthenquicklyopenthedoor(itwillstarttosmokeifyouleaveitintoolong).
4. Lookcarefullyatthechocolatebarwithouttouchingthesurface…youarelookingforTWOhotspots,notjustone–theywilllooklikesmallvolcanoeruptionsonthesurfaceofthebar.
5. Ifyoudon’thavetwo,grabafreshplate(youcanreusethechocolatebar)andtryagain,changingthelocationoftheplateinsidethemicrowave.You’relookingfortheplacewherethemicrowavelighthitsthechocolatebarintwospotssoyoucanmeasurethedistancebetweenthespots.
6. Openupthedoororlookonthebackofyourmicrowaveforthetechnicalspecifications.You’relookingforafrequencyinthe2,000‐3,000MHzrange,usuallyabout2450MHz.Writethisnumberdownonasheetofpaper–thistellsyouthemicrowaveradiationfrequencythattheovenproduces,andwillbeusedforcalculatingthespeedoflight.
7. Whenyou’rereadytotakeameasurement,popinthefirstfoodtypeonaplate(withouttheturntable!)intothebestspotinthemicrowave,andturniton.Removewhenbothhotspotsform,andbeingcarefulnottotouchthesurfaceofthefood,measurethecenter‐to‐centerdistanceusingyourrulerincentimeters.TIP:Ifyou’reusingmini‐marshmallowsorchocolatechips(orothersmallerfoods),you’llneedtospreadthemoutinanevenlayeronyourplatesoyoudon’tmissaspotthatcouldbeyourhotspot!
8. Notethatwhenyoumeasurethedistancebetweenthehotspots,youareonlymeasuringthepeak‐to‐peakdistanceofthewave…whichmeansyou’reonlymeasuringhalfofthewave.We’llmultiplythisnumberby
©2014SuperchargedScience 43 www.SuperchargedScience.com
twotogettheactuallengthofthewave(wavelength).Ifyou’reusingcentimeters,you’llalsoneedtoconvertthosetometersbydividingby100.
9. So,ifyoumeasure6.2cmbetweenyourhotspots,andyouwanttocalculatethespeedoflightandcomparetothepublishedvaluewhichisinmeterspersecond,here’swhatyoudo:2,450MHzisreally2,450,000,000Hzor2,450,000,000cyclesper1second
10. Findthelengthofthewave(incm):2*6.2cm=(12.4cm)/(100cm/m)=0.124meters11. Multiplythewavelengthbythemicrowaveovenfrequency:
0.124m*2,450,000,000Hz=303,800,000m/s12. Thepublishedvalueforlightspeedis299,792,458m/s=186,000miles/second=671,000,000mph13. Calculate%Differencebyusingthissimpleformula:
%Diff=|MeasuredValue–PublishedValue|÷PublishedValuex100
SpeedofLightDataTable
FoodType HotspotDistance(cm)
CalculatedSpeedofLight(m/s)
%Difference
Graphing:Usethedatafromyourtabletomakeagraphofyourresults,puttingthedifferenttypesoffoodontheverticalaxisandthemeasured(calculated)speedoflightvalueonthehorizontalaxis.Refertothesamplewhileyoucreateyourown.Inthegraphsample,notethat“3.00E+08”means3witheightzerosafterit,or300,000,000meterspersecond.
©2014SuperchargedScience 44 www.SuperchargedScience.com
Reading
Whenyouwarmupleftovers,haveyoueverwonderedwhythemicrowaveheatsthefoodandnottheplate?(Well,someplates,anyway).Ithastodowiththewaymicrowaveovenswork.
Microwaveovensusedielectricheating(orhighfrequencyheating)toheatyourfood.Basically,themicrowaveovenshootslightbeamsthataretunedtoexcitethewatermolecule.Foodsthatcontainwaterwillstepupanotchinenergylevelsasheat.(Themicrowaveradiationcanalsoexciteotherpolarizedmoleculesinadditiontothewatermolecule,whichiswhysomeplatesalsogethot.)
Oneofthebiggestchallengeswithmeasuringthespeedoflightisthatthephotonsmovefast,toofasttowatchwithoureyeballs.Soinstead,we’regoingtowatchtheeffectsofmicrowavelightandbaseourmeasurementsontheeffectsthelighthasondifferentkindsoffood.Microwavesuselightwithawavelengthof0.01to10cm(that’sthe”microwave”partoftheelectromagneticspectrum).Whendesigningyourexperiment,you’llneedtopaycloseattentiontothefinerdetailssuchasthefrequencyofyourmicrowaveoven(foundinsidethedoor),whereyouplaceyourfoodinsidetheoven,andhowlongyouleaveitinfor.
0.00E+00 1.00E+08 2.00E+08 3.00E+08 4.00E+08
Hershey's milk chocolate
Two raw eggs, beaten
Marshmallows (big)
Chocolate chips
Buttered bread
Cheese on crackers
Hershey's dark chocolate
Hershey's white chocolate
Mini‐marshmallows
Published Value: Speed of Light
Speed of Light (m/s)
Material Typ
eSAMPLE GRAPH: Measuring the Speed of Light
©2014SuperchargedScience 45 www.SuperchargedScience.com
Lesson#14:MixingColors
Overview:Therearetwodifferentsetsofprimarycolors.Thethreeprimarycolorsoflightarered,green,andblue.However,thethreecolorsthatartistsusearered,yellow,andblue.Whathappensifyoumixred,green,andbluepaint?
WhattoLearn:Thethreeprimarycolorsoflightarered,blue,andgreen.Redandgreenlightmixedtogethermakeyellowlight.
Materials
scissors crayonsORmarkers sharpenedwoodpencilORskewer indexcards cup drill(optional)
Experiment
1. Stacktheindexcards2. Usethecuptotraceacircleonthetopcard.3. Keepthecardsstackedwhileyoucutoutthecircles.Theydon’thavetobeperfect,butmakesureallthe
sharpcornersarecutoff.4. Usingdifferentcolormarkers,makedifferentcoloredslices(orpiepieces)oneachcircle.Thesearethe
colorsthatwillblurtogetherinyourexperiment.5. Pokeaholethroughthecenterofthenow‐colorfulcirclewithyourpencilorskewer.Makesurethecolored
sideisfacinguptowardyou,notdowntowardthetable.6. Tospinthislikeatop,makethe“okay”symbolwithyourindexfingerandthumb.Puttheskewerinside
thecircleyourfingersmakeandspinit.Yourhandwillhelptokeepthetopuprightsothatyouareabletoseehowthecolorsblendtogether.
7. Optionally,anadultcanhelpyouuseadrill,handheldmixer,orelectricscrewdrivertospinthecirclemuchfasterforamorenoticeableeffect.
©2014SuperchargedScience 46 www.SuperchargedScience.com
MixingColorsDataTable
ColorandPercentage
ColorandPercentage
ColorandPercentage
Result
Example:blue50%
Example:red50%
Example:(nothinghere‐somecellsmaybeblank)
Example:purple
Reading
Mostkidsunderstandhowyellowpaintandbluepaintmakegreenpaint,butaretotallystumpedwhenredlightandgreenlightmixtomakeyellowlight.Thedifferenceisthatwe’remixinglight,notpaint.Lotsofsciencetextbooksstillhavethisexperimentlistedunderhowtomixlight:“Stirtogetheroneofredwaterandoneglassofgreenwater(dyedwithfoodcoloring)togetaglassofyellowwater.”Hmmm…theresultIgetisayuckygreenish‐browncolor.Whathappened?Thereasonyoucan’tmixgreenandredwatertogetyellowisthatyou’reessentiallystillmixingpaint,notlight.Butdon’ttakeourwordforit–testitoutforyourselfwiththissuper‐fastlightexperimentonmixingcolors.Exercises
1. Whathappenswhenblueandredaremixedonthespinner?
2. Whathappenswhenredandgreenaremixedonthespinner?
3. Whatcolorswouldyoumixtogetorange?
4. Whataretheprimarycolorsoflight,andhowdotheydifferfromtheprimarycolorswelearninartclass?
©2014SuperchargedScience 47 www.SuperchargedScience.com
Lesson#15:MixingColdLight
Overview:Youcandemonstratehowtheprimarycolorsoflightmixtogetherusingglowsticks.Theglowstickgivesoffitsownlightthroughachemicalreactioncalledchemiluminescence,whichisn’tthesameasmixingpainttogether,sincecupsofpaintarereflectinglight,notgeneratingit.It’slikethedifferencebetweenthesun(whichgivesoffitsownlight)andthemoon(whichyouseeonlywhensunlightbouncesoffittoyoureyeballs).
WhattoLearnThis
Materials
disposabletesttubes red,green,andbluetrue‐colorlightsticks(oneofeach) scissors(withadulthelp) gloves goggles strainer,suchasacoffeefilterorbitofcheesecloth
Experiment
1. Bendthelightstickstobreaktheglassinsidethecontainer(you’llhearalittle“crack”).Dothisforallthreelightsticks.Thiswillactivatethesticks.
2. Slapyourglovesonyourhandsandgogglesonyoureyes.Noexceptions.3. Standoverasinkandcarefullycutoneendoffofthelightsticks.Getanadulttohelp,astheplasticcanbe
stifftocutthrough.4. Carefullypouratinyamountofoneofthecolorsintoyourtesttube.Ifbitsofglasscomeoutalso,usethe
cheeseclothasastrainertocatchthepiecesofglassfrominsidethetube.5. Nowaddasecondcolorandswirlgentlytomix.Recordyourobservationsinthedatatable.6. Repeatsteps4and5foryourdatatable.7. Note:Youmaynotneedallofthered,duetoitslevelofcolorconcentration.Onlyaddabouthalfofthered
andswirluntilthecolorsarecompletelymixed.Addmoreredifneededtoadjustthecolor.8. Whenyouaredonewiththislab,discardthebitsofglassinthetrashandflushtheliquiddownthesink
withplentyofwater.
©2014SuperchargedScience 48 www.SuperchargedScience.com
MixingColdLightDataTable
Color#1 Color#2 Color#3(optional) ResultingColor
Reading
Whenwetalkaboutlight,itsthreeprimarycolorsareactuallyred,green,andblue.Asapainter,youalreadyknowthatmixingthesethreecolorstogetherwouldgetamuddybrown.Butasascientist,whenyoumixtogetherthreecupsofcoldlight,youwillgetsomethingdifferent.You’dgetwhitelight.Thekeyisthatwewouldbemixinglight,notpaint.Mixingthethreeprimarycolorsoflightgiveswhitelight.Ifyoutookthreelightbulbs(red,green,andblue)andshinedthemontheceilingsotheyoverlap,you’dseeawhitespotwherethethreeconverge.Andifyoucouldmagicallyun‐mixthewhitecolors,you’dgettherainbow(whichisexactlywhatprismsdo).Ifyou’rethinkingyellowshouldbeaprimarycolor–itisaprimarycolor,butonlyintheartist’sworld.Yellowpaintisaprimarycolorforpainters,butyellowlightisactuallymadefromredandgreenlight.There’saneasywaytorememberthis:thinkofChristmascolors–redandgreenmergetomaketheyellowstarontopofthetree.Thecoldlightisgivingoffitsownlightthroughachemicalreactioncalledchemiluminescence,whereasthecupsofpaintareonlyreflectingnearbylight.It’slikethedifferencebetweenthesun(whichgivesoffitsownlight)andthemoon(whichyouseeonlywhensunlightbouncesoffittoyoureyeballs).
Note:Ifyou’rewonderingiftherealprimarycolorsforpaintersarecyan,magenta,andyellow,you’reright…butsomefolksstillprefertothinkoftheprimarycolorsasred‐yellow‐blue…eitherway,it’sreallynotimportanttothisexperimentwhichprimarysetyouchoose,sincetheexperimentdealswithlight,notpaint.
©2014SuperchargedScience 49 www.SuperchargedScience.com
Exercises1.Whatcolordoyougetwhenyoumixblueandgreenliquidlights?
2.Whathappenswhenyoustarttoaddtheredlight?
3.Whatisyourfinalcolorresultwhenmixingred,blue,andgreenlights?
4.Howwouldyourresultdifferifyouinsteadmixedred,blueandgreenpaints?
©2014SuperchargedScience 50 www.SuperchargedScience.com
Lesson#16:RefractiveIndexOverview:We’regoingtobendlighttoshowthemagicbehindapopularopticalillusionbyusingacupofliquidasalens.WhattoLearn:Whenabeamoflighthitsadifferentsubstance,itbendsasittravelsthroughthenewsubstance.Thespeedatwhichthelighttravelsandthewavelength(color)alsochanges.Theamountofchangedependsontheindexofrefractionofthematerial.
Materials
paper indexcard pencil scissors ruler disposablecups(4) flashlight rubbingalcohol water babyoil
Experiment
1. Turnoffthelightsandmaketheroomverydark.Ifyoudon’thaveadarkenoughroom,youcandothisexperimentinsideashoebox.
2. Cuttwosmallparallelslitsintheindexcardaboutaninchapart,nothickerthanadime.3. Placeyoursheetofpaperonthetable(seesampleonnextpage).4. Placeanemptycupontopofthepaperandtracearoundthecupsoyouhaveasmallcircleonthepaper.5. Holdtheindexcardupabout4‐6inchesfromthecup.6. Shineyourflashlightthroughtheindexcard,about4moreinchesaway.Youshouldseetwobeamsoflight
hittingthecup.7. Usingyourruler,tracethebeamsoflightfromtheflashlightalongthepaperbeforeandafterthecupand
labelthelines“air.”8. Repeatsteps7‐9byfillingthecupwithadifferentliquideachtimeandtraceeachline.
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Cup(ofliquidorgas)
Indexcard
Slits
LightfromFlashlight
©2014SuperchargedScience 52 www.SuperchargedScience.com
Reading
Whenabeamoflighthitsadifferentsubstance(likeglass),thelightbendsandthespeedoflightchanges,whichmeansitslowsdownorspeedsupasittravelsthroughthenewsubstance.Thecolorofthelight(calledthewavelength)canalsochange,whichiswhatprismsdotowhitelight:Prismsbendthewhitelightbydifferentamountstogetarainbow.Howmuchthelightbendsdependsontheopticaldensityofthesubstance.Moredensematerialsbendthelightmore.Glassisopticallydenserthanwater,whichisdenserthanair. OpticalDensitiesforSelectMaterials:Vacuum(Space) 1.0000Air 1.0003Ice 1.3100Water 1.3333Pyrex 1.4740Cookingoil 1.4740Diamond 2.4170DidyounoticehowPyrexandcookingoilhavethesameopticaldensity?ThismeansifyouplaceaPyrexcontainerinsideabeakerofvegetableoil,itwilldisappearbecausethelightwillnotbend,soyouwillnotbeabletodetectonefromtheother.ThistrickalsoworksforsomemineraloilsandKarosyrup.(Notehoweverthattheopticaldensitiesofliquidsvarywithtemperatureandconcentration,andmanufacturersarenotperfectlyconsistentwhentheywhipupabatchofthisstuff,sosomeadjustmentsareneeded.)Magnifyinglenses,telescopes,andmicroscopesusethisideaofbendinglighttodistortimagestomakeobjectsappeardifferentsizes.Thelightdoesn’talwaysappeartobend.Forexample,whenlightentersanewsubstance(likegoingfromairtowater)perpendiculartothesurface(lookingstraighton),refractiondoesnotoccur.Whereyouareobservingfromwillaffecthowthelightappearstobend.Exercises
1.Whichsubstancebentthelightthemost?
2.Whatotherkindsofmaterialsdoyouthinkmightworkinthecup?
3.Canweseelightwaves?
©2014SuperchargedScience 53 www.SuperchargedScience.com
Lesson#17:FireandOptics
Becausethisactivityinvolvesfire,makesureyoudothisonaflame‐proofsurfaceandnotyourdiningroomtable!Goodchoicesareyourdriveway,cementparkinglot,theconcretesidewalk,oralargepieceofceramictile.Don’tdothisexperimentinyourhand,oryou’reinforahot,nastysurprise.
Overview:Todayyougettoconcentratelight,specificallytheheat,fromthesunintoaverysmallarea.Normally,thesunlightwouldhavefilleduptheentireareaofthelens,butyou’reshrinkingthisdowntothesizeofthedot.
WhattoLearn:Magnifyinglenses,telescopes,andmicroscopesusethisideatomakeobjectsappeardifferentsizesbybendingthelight.Whenlightpassesthroughadifferentmedium(fromairtoglass,water,alens…)itchangesspeedandusuallytheangleatwhichit’straveling.Aprismsplitsincominglightintoarainbowbecausethelightbendsasitmovesthroughtheprism.Apairofeyeglasseswillbendthelighttomagnifytheimage.
Materials
sunlight glassjar nailthatfitsinthejar 12”thread hairfromyourhead 12”string 12”fishingline 12”yarn paperclip magnifyingglass fireextinguisher adulthelp
ExperimentPleasedothisonafireproofsurface!Thisexperimentwilldamagetables,counters,carpets,andfloors.Dothisexperimentonsurfacelikeconcreteorblacktop.
1. Haveyouradultdothesestepsforyou:a. Holdthemagnifierabovetheleafandbringitdowntowardtheleafuntilyouseeabrightspotform
onitssurface.Adjustituntilyouseethelightasbrightandasconcentratedaspossible.Firstyou’llnoticesmoke,thenatinyflameastheleafburns.
b. Youareconcentratingthelight,specificallytheheat,fromthesunintoaverysmallarea.Normally,thesunlightwouldhavefilleduptheentireareaofthelens,butyou’reshrinkingthisdowntothesizeofthedotthat’sburningtheleaf.
2. Screwthelidonthejar.3. Tieoneendofthethreadtothepaperclip.4. Poketheotherendofthethreadinsidetheholeonthelid.5. Unscrewthelidandtieanailtotheotherendofthethread.Youwantthenailtobehangingabovethe
bottomofthejarbyaninchortwo,soadjusttheheightasneeded.
©2014SuperchargedScience 54 www.SuperchargedScience.com
6. Bringyourjaroutside.7. Question:Withoutbreakingtheglassorremovingthelid,howcanyougetthenailtodroptothebottomof
thejar?
Fire&Optics&EyesDataTable
MaterialforSuspendingNail HowLongDidItTaketoDrop?(measureinseconds)
Reading
Magnifyinglenses,telescopes,andmicroscopesusethisideatomakeobjectsappeardifferentsizesbybendinglight.Whenlightpassesthroughadifferentmedium(fromairtoglass,water,alens…)itchangesspeedandusuallytheangleatwhichit’straveling.Aprismsplitsincominglightintoarainbowbecausethelightbendsasitmovesthroughtheprism.Apairofeyeglasseswillbendthelighttomagnifytheimage.
Thislabisintwoparts.Thedemonstrationyoudowiththekidsisnottheonetheydofortheiractivity.You’regoingtoconcentratethepowerofthesunonaflammablesurface.
Pleasedothisonafireproofsurface!Thisexperimentwilldamagetables,counters,carpets,andfloors.Dothisexperimentonsurfacelikeconcreteorblacktop.
Thermoelectricpowerplantsusethisprincipletopowerentirecitiesbyusingthisprincipleofconcentratingtheheatfromthesun.
Neverlookthroughanythingthathaslensesinitatthesun,includingbinocularsortelescopes,otherwisewhat’shappeningtotheleafrightnowisgoingtohappentoyoureyeball.
©2014SuperchargedScience 55 www.SuperchargedScience.com
Exercises
1. Whathappenedtotheleaf?Why?
2. Howdidyougetthenailtodrop?
3. Whichmaterialignitedthequickest?
©2014SuperchargedScience 56 www.SuperchargedScience.com
Lesson#18:SimpleMicroscopes&Telescopes
Overview:Didyouknowyoucancreateacompoundmicroscopeandarefractortelescopeusingthesamematerials?It'sallinhowyouusethemtobendthelight.Thesetwoexperimentscoverthefundamentalbasicsofhowtwodouble‐convexlensescanbeusedtomakeobjectsappearlargerwhenrightupcloseorfartheraway.
WhattoLearn:Thingslikelensesandmirrorscanbendandbouncelighttomakeinterestingthings,likecompoundmicroscopesandreflectortelescopes.Telescopesmagnifytheappearanceofsomedistantobjectsinthesky,includingthemoonandtheplanets.Thenumberofstarsthatcanbeseenthroughtelescopesisdramaticallygreaterthancanbeseenbytheunaidedeye.
Materials
window dollarbill penny handheldmagnifyinglenses(2) ruler
Experiment
1. Placeapennyonthetable.2. Holdonemagnifierabovethepennyandlookthroughit.3. Bringthesecondmagnifyinglensabovethefirstsonowyou’relookingthroughboth.Movethesecondlens
closerand/orfurtherfromthepennyuntilthepennycomesintosharpfocus.You’vejustmadeacompoundmicroscope.
4. Who’sinsidethebuildingonanolderpenny?5. Tryfindingthespider/owlonthedollarbill.(Hint:it’sinacornernexttothe“1”.)6. Keepingthedistancebetweenthemagnifiersaboutthesame,slowlyliftupthemagnifiersuntilyou’renow
lookingthroughbothtoawindow.7. Adjustthedistanceuntilyourimagecomesintosharp(andupside‐down)focus.You’vejustmadea
refractortelescope,justlikeGalileoused400yearsago.8. Findeightdifferentitemstolookatthroughyourmagnifiers.Makefourofthemup‐closesoyouusethe
magnifiersasamicroscope,andfourofthemfar‐awayobjectssoyouusethemagnifierslikeatelescope.Completethetable.
©2014SuperchargedScience 57 www.SuperchargedScience.com
SimpleMicroscope&TelescopeDataTable
Forthelasttwocolumns,measurewithyourrulercarefully.Don’tforgettolabelyourunits!
MagnificationUsed:______________________________________________(multiplythemagnificationofbothlensestogether)
ObjectLookedAt
DidyouusetheMagnifiersasaMicroscopeor
Telescope?
HowFarApartaretheLenses?
HowFarisyourEyefromtheEyepiece?
Reading
WhatIlikebestaboutthisactivityishoweasilywecanbreakdownthebasicideasofsomethingthatseemsmuchmorecomplexandintimidating,likeatelescopeormicroscopeinawaythatkidsreallyunderstand.
Imaginetossingarockintoastillpondandwatchingthecirclesofripplesformandspreadoutintorings.Nowlookattheripplesinthewater‐noticehowtheyspreadout.Whatmakestheripplesmoveoutwardisenergy.
Theripplesarelikelight.Noticethewavesarenotreallymovingthewaterfromonesideofthepondtotheother,butrathermovingenergyacrossthesurfaceofthewater.
©2014SuperchargedScience 58 www.SuperchargedScience.com
Toputitanotherway,energytravelsacrossthepondinawave.Lightworksthesameway–lighttravelsasenergywaves.Onlylightdoesn'tneedwatertotravelthroughthewaythewaterwavesdo‐itcantravelthroughavacuum(likeouterspace).
Lightcanchangespeedthesamewaysoundvibrationschangespeed.(Thinkofhowyourvoicechangeswhenyouinhaleheliumandthentrytotalk.)
Thefastestlightcangois186,000milespersecond–that'sfastenoughtocircletheEarthseventimeseverysecond,butthat'salsoinsideavacuum.Youcangetlightgoingslowerbyaimingitthroughdifferentgases.Inourownatmosphere,lighttravelsslowerthanitdoesinouterspace.
Exercises
1. Canlightchangespeeds?
2. CanyouseeALLlightwithyoureyes?
3. Givethreeexamplesofalightsource.
4. What'sthedifferencebetweenamicroscopeandatelescope?
5. Whyisthetelescopeimageupside‐down?
©2014SuperchargedScience 59 www.SuperchargedScience.com
Light1Evaluation
StudentWorksheet
Overview:Todayyou’regoingtotaketwodifferenttests:thequizandthelabpractical.You’regoingtotakethewrittenquizfirst,andthelabpracticalattheendofthislab.Thelabpracticalisn’tapapertest–it’siswhereyougettoshowyourteacherthatyouknowhowtodosomething.
LabTest&Homework
1. Yourteacherwillcallyouupsoyoucansharehowmuchyouunderstandaboutthebasicsoflightandhowitworks.Sincescienceissomuchmorethanjustreadingabookorcirclingtherightanswer,thisisanimportantpartofthetesttofindoutwhatyoureallyunderstand.
2. Whileyouarewaitingforyourturntoshowyourteacherhowmuchofthisstuffyoualreadyknow,yougettochoosewhichhomeworkassignmentyouwanttocomplete.Theassignmentisduetomorrow,andhalfthecreditisforcreativityandtheotherhalfisforcontent,soreallyletyourimaginationflyasyouworkthroughit.Chooseone:a. Writeashortstoryorskitaboutlightfromtheperspectiveofthephotonorthewave.You’llreadthis
aloudtoyourclass.b. Makeaposterthatteachesthemainconceptsaboutlightwaves.Whenyou’refinished,you’lluseitto
teachtoaclassintheyoungergradesanddemonstrateeachoftheprinciplesthatyou’velearned.c. Writeandperformapoemorsongaboutlight.Thiswillbeperformedtoyourclass.
©2014SuperchargedScience 60 www.SuperchargedScience.com
Light1Quiz
Name__________________________________________________________1. Whatarethethreeprimarycolorsoflight?
2. Whatcolordoyougetwhenmixingtheprimarycolorsoflight?
3. Whatisalightsource?Pleasegiveanexample.
4. Whatpropertycanhelpmakesomethingagoodprismmaterial?
5. Whatisalightreflector?Pleasegiveanexample.
6. DoesthesunalwayslightuphalftheMoon?
7. HowmanyphasesdoestheMoonhave?
8. Howdoesyoureyeworklikeacamera?
9. Whatisthedifferencebetweenconvexandconcave?
©2014SuperchargedScience 61 www.SuperchargedScience.com
10. CanyouseeALLlightwithyoureyes?
11. Givethreeexamplesofalightsource.
12. What'sthedifferencebetweenamicroscopeandatelescope?
©2014SuperchargedScience 62 www.SuperchargedScience.com
Light1LabPracticalStudentWorksheet
Thisisyourchancetoshowhowmuchyouhavepickeduponimportantkeyconcepts,andifthereareanyholes.Youalsowillbeworkingonahomeworkassignmentasyoudothistestindividuallywithateacher.
Materials:
Twomagnifyinglenses Glassofwater Pencil
LabPractical:
Designandbuildanexperimentthatshowshowtochangethespeedoflight.
Designasimplemicroscopetolookatoneofyourhairsfromyourhead.
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AnswerstoExercisesandQuizzes
Lesson #1: Rainbow Shadows 1.Whatarethethreeprimarycolorsoflight?(red,blue,andgreen)2.Whatcolordoyougetwhenmixingtheprimarycolorsoflight?(white)3.Howdoyoumixtheprimarycolorsoflighttogetyellow?(greenandredlightmakeyellowlight)4.Usecrayonsorcoloredpencilstodrawwhatyousawwhenallthreelightswereshiningonthewallandyouwavedyourhandinfrontofthelight.Lesson #2: Kaleidoscopes 1.Whatisalightsource?Pleasegiveanexample.(asourceoflightwaves–thesun,lightbulbs,fire,etc.areallexamples)2.Whatisalightreflector?Pleasegiveanexample.(Areflectordoesnotemitlight.Insteaditbounceslightoffofitandreflectsthelightbacktooureyes.Water,mirrors,themoonareallexamples.)3.Sketchanimageofsomethinginterestingthatyouwereabletoseeasthelightreflectedfromthemultiplesurfacesofthekaleidoscopetoyoureyes.Lesson #3: Liquid Prism 1.Whatservesastheprisminthisexperiment?(waterorotherclearliquid)2.Whatpropertycanhelpmakesomethingagoodprismmaterial?(transparency:amaterialthatallowslighttopassthroughit)3.Whataresomeotheritemsthatcouldbeusedasprisms?(glass,oil,clearplastic)Lesson #4: Lunar Phases 1.DoesthesunalwayslightuphalftheMoon?(Yes.Wedon’talwaysgettoseeit,whichisbecausetheMoonhasphases.)2.HowmanyphasesdoestheMoonhave?(eight)3.WhatisitcalledwhentheMoonappearstogrow?(waxing)4.WhatisitcalledwhenyouseemorelightthandarkontheMoon?(gibbous)5.Howlongdoesittakeforacompletelunarcycle?(about29½days)Lesson #5: Sky in a Jar 1.Whatcolorsdoesthesunsetgothrough?(Thesunsetgoesthroughthecolorsoftherainbowasthesunsetslowerinthesky,startingwithyellow,thenorange,andthenredasitsets.)2.Doesthecolorofthelightsourcematter?(Yes.Whitelightgivesthebestresults.)Lesson #6: Light Tricks 1.Whenonecoinisinthewater,youcanactuallyseetwo:Arethecoinsboththesamesize?Whichoneistheoriginalcoin?(thesmallercoinisthereflection)2.Instep2oftheexperiment:Howmanycoinsaretherewhenviewedfromthetopoftheglass?Whataboutwhenyoulookfromtheside?(onecoinwhenlookingfromabove,twowhenlookingthroughtheside)3.Whathappenedwhenyoutossedinasecondcoin?(Therewerefour.)4.Howdidyouroutlinescompare?(Thefirstwasacircle,thesecondwasanoval.)
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Lesson #7: Black Light Treasure Hunt 1.Whyareincandescentlightslessenergy‐efficientthanfluorescentlights?(Incandescentlightgiveoffmoreheatandlesslight–theyloseenergytoheatandfluorescentlightsdonot.)2.Whatarethetwotypesoffluorescentlight?(Phosphorescenceandtriboluminescience)3.Whatkindsofthingsdidyoufindthatglowonyourtreasurehunt?Giveatleastfiveexamples.(answersvary)Lesson #8: Benham’s Disk 1.Whatcolorswereyouabletoseewhenthediskswerespinning?(answersvary)2.Howdidthedifferentpatternslookwhentheywerespun?(answersvary)3.Howdidspeedanddirectionaffectwhatyousaw?(answersvary)Lesson #9: Eye Balloon 1.Howdoesyoureyeworklikeacamera?(Bothhavelenses,bothproduceimageswithlotsofcomponentsworkingtogether.)2.Howcanyoutellifalensisdoubleconvex?(Whenyourunyourfingersacrossit,youfeeltwobumpsoneachside.)3.Whatisthedifferencebetweenconvexandconcave?(Aconcavesurfacecurvesinward,whileaconvexsurfacebulgesout.)4.Canyougiveanexampleofaneverydayobjectthathasbothaconvexandaconcaveside?(spoon)5.Howcanyouchangetheballoontomakeitnear‐sighted?(lightlypushdownonthetop)6.Howcanyouchangetheballoontomakeitfar‐sighted?(gentlypushinfrontandbackoftheballoontomakeittaller)Lesson #10: Disappearing Frog 1.Whatdidyounoticeaboutthevisionofthestudentandtheblindspotthatyoumeasured?(answersvary)2.Whydoyouthinkit’simportanttoknowwhereyourblindspotis?(soyoucanexpectitandworkarounditifyouneedto)Lesson #11: Pinhole Camera 1.Howdotheimagesappearwhenthey’reprojectedontothepaperinsideyourcamera?(upside‐down)2.Whydoyouthinkit’simportanttomaketheboxaslight‐proofaspossible?(itallowsonlyasmallamountoflighttopassthroughsothatwecanseethereflectionbetter)3.Isthereapartofyourbodythatworkssimilarlytothepinhole?(oureyes)4.Sketchapictureofsomethingyousawthroughyourpinholecamera.Lesson #12: Diffraction 1.Whichlightsourcegavethemostinterestingresults?(Thisvarieswithdata.)2.Whathappenswhenyouaimalaserbeamthroughthediffractiongrating?(Itsplitsintothreebeamsoflight,asshowninthesecondvideo.)3.HowisaCDdifferentandthesameasadiffractiongrating?(ACDhasaspiraloffinely‐spaceddatatrackswhilethediffractiongratinghasaseriesofparallellines.TheCDsplitsthelightthesamewayasthediffractiongrating.TheCDsplitsthebeamintomorethanthreebeams.)4.Whydoesthefeatherwork?(Therearetiny“hairs”onthefeatherthatareactingliketinyprisms.)Lesson #14: Mixing Colors 1.Whatdoyouseewhenblueandredaremixedonthespinner?(purple)2.Whatdoyouseeredandgreenaremixedonthespinner?(yellow)
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3.Whatcolorswouldyoumixtogetorange?(redandyellow)4.Whataretheprimarycolorsoflight,andhowdotheydifferfromtheprimarycolorswelearninartclass?(Red,blue,andgreenaretheprimarycolorsoflight–inart,theprimarycolorsarered,yellow,andblue.)Lesson #15: Mixing Cold Light 1.Whatcolordoyougetwhenyoumixblueandgreenliquidlights?(answersvary–greentoblue)2.Whathappenswhenyoustarttoaddtheredlight?(thecolorstartstopale)3.Whatisyoufinalcolorresultwhenmixingred,blue,andgreenlights?(white)4.Howwouldyourresultdifferifyouinsteadmixedred,blueandgreenpaints?(itwouldbeabrowncolor)Lesson #16: Refractive Index 1.Whichsubstancebentthelightthemost?(oil)2.Whatotherkindsofmaterialsdoyouthinkmightworkinthecup?(answersvary)3.Canweseelightwaves?(yes)Lesson #17: Fire and Optics 1.Whathappenedtotheleaf?Why?(Youareconcentratingthelight,specificallytheheat,fromthesunintoaverysmallarea.Normally,thesunlightwouldhavefilleduptheentireareaofthelens,butyou’reshrinkingthisdowntothesizeofthedotthat’sburningtheleaf.)2.Howdidyougetthenailtodrop?(Byconcentratingtheenergyfromthesunusingthemagnifier.)3.Whichmaterialignitedthequickest?(Refertodatatable.)Lesson #18: Simple Microscopes & Telescopes 1.Canlightchangespeeds?(Yes,whenittravelsthroughdifferentmediums.)2.CanyouseeALLlightwithyoureyes?(No,onlyvisiblelight,likearainbow.)3.Givethreeexamplesofalightsource.(Answerwillvary,butherearemine:sun,acandle,andaglowstick.)4.What'sthedifferencebetweenamicroscopeandatelescope?(Amicroscopemagnifiesanimagebeforethefocalpoint;atelescopemagnifiesanimageafterthefocalpoint.Bothareusedtomakeimagesappearcloserandlarger.Amicroscopeisusedwhenobjectsarenear;atelescopeisusedforfarawayobjects.)5.Whyisthetelescopeimageupside‐down?(Becauseyou’vefocusedtheimagebeyondthefocalpoint.)
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VocabularyfortheUnitThethreeprimarycolorsoflightarered,blue,andgreen.Redandgreenlightmixedtogethermakeyellowlight.Prismsunmixlightintoitscolors(wavelengths).
Concavelensesworktomakeobjectssmaller(doorpeephole),andarecurvedinwardlikeacave.
Convexlensesmakethemlarger(magnifyinglenses),andhavea”bump”inthemiddleyoucanfeelwithyourfingers.
Theamountofenergyaphotonhasdetermineswhetherit’saparticleorawave.Photonswiththelowestamountsofenergyandlongestwavelengths(somearethesizeoffootballfields)areradiowaves.Thenextstepuparemicrowaves,whichhavemoreenergythanradiowaves.IRhasslightlymoreenergy,andvisiblelight(therainbowyoucanseewithyoureyes)hasmoreenergyandshorterwavelengths.Ultraviolet(UV)lighthasmoreenergythanvisible,andX‐rayshaveevenmoreenergythanUV,andfinallythedeadlygammarayshavethemostamountofenergy.
Filterscanbeusedtoblockcertainwavelengths.
Intensity,orbrightness,istheamountofphotons(packetsoflight)youhaveinacertainamountofspace.Aflashlighthaslessintensitythanacarheadlight.
LASERstandsforLightAmplificationbyStimulatedEmissionofRadiation.Mostlasersaremonochromatic(onecolor).Lasersareconcentratedbeamsoflight,andareilluminatedbysmallparticles(likesmokeanddust).
Lensesworktobendlightinacertaindirection(refraction).Alensisacurvedpieceofglassorplasticthatchangesthespeedofthelight.Lenseshavethesameeffectonlasersasonlightbeams.
Lightcanbedefinedbyfourthings:intensity(howbright),frequency(orwavelength),polarization(thedirectionoftheelectricfield),andphase(timeshift).
Objectscaneitherbealightsource(likethesun)orreflectlight(likethemoon).
Lightcanchangespeeds,butthemaximumlightspeedisthroughavacuum(186,000milespersecond).Lightchangesspeedswhenitpassesthroughadifferentmaterial(likewater,glass,orfog).
Dependingontheopticaldensityofthematerial,lightwillbendbydifferentamounts.Glassisopticallydenserthanwater.Waterismoreopticallydensethanair.
Whentwobeamsoflightareoutofphasewitheachother,it’slikeplayingaGandAonthepiano.Thisiscalledphaseshift.
BlueandUVlightejectelectronsfrommetalplates,butredlightdoesnot(photoelectriceffect).
Polarizationhastodowiththedirectionoftheelectricfield.Yoursunglassesarepolarizingfilters,meaningthattheyonlyletlightofacertaindirectionin.
Whenabeamoflighthitsawindow,itbendsandchangesspeed(refraction).Technically,thewavelength(color)changesbutthefrequencystaysthesame.Inorderforthistohappen,thespeedoflightmustalsochange.
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Razor‐edgeslitscreateinterferencepatterns.Slitsareskinnyholesthatallowlighttopassthrough.Scientistsuseslitstofilteroutallotherlightsourcesexcepttheonetheywanttouseintheirexperiment.
Whenyouchangethewavelength,youchangethecolorofthelight.Thewavelength()equalsthespeedoflight(c)dividedbythefrequency(),or=c/.