Kaleidoscope - Stanford University

Kaleidoscope

Materials

12cmx15cm(5"x6")Squareofmylarorthreemirrorsappx2cmx15cm (0.75"x6") Tape Scissors Smallclearcontainer(similartosmallpillboxorcosmeticcontainer) Toiletpapertube Assortedbeads Stripofcardstock,indexcardorrecycledpostcard

Instructions

1. Makethemirrorassembly. a. Formylar i. Foldthemylarintoanequilateraltriangularprismbyfolding andcreasingthesheetinhalf.Openthemylarpieceandfold andcreaseeachedgeintothecenterfoldtocreate4"panels". Overlap2panelstocreateatriangularprismshape. ii. SecuretheMylarprismintoshapewithtape. iii. Tapethetwoedgestogether.

b. Formirrors i. Tapethebackofmirror1tothebackofmirror2alongtheir longedges,leavingasmallgap(~1/8inch)betweenthem. ii. Tapethebackofmirror2tothebackofmirror3alongtheir longedges,againleavingasmallgap.

iii. Foldthemirrorssothatthefreesideofmirror3meetsthefree sideofmirror1andthemirrorsformanequilateraltriangular prism.Thereflectivesurfacesshouldbeontheinsideofthe prism.

2. Slidethemirrorassemblyintothepapertoweltubesothatitiscompletely

insidethetube.

3. Fillthesmallclearcontainerwithbeads.

4. Putthecaponthecontainerandsealtheedgeswithtape.

5. Rollthecardstockaroundthecontainersothatitformsatubewiththe

containerasanendcaponthetube.Securethetubewithtape.

6. Slipthecardstock-containertubeoverthetoiletpapertube.

ToDoandNotice

Lookthroughtheopenendofthetoiletpapertubeandrotatethecardstock tube.Notethepatternsofthebeadsinthetube. What'sHappening From"CornerReflector",TheExploratoriumSnackbook, "Whenyouputanobjectbetweenthetwohingedmirrors,lightfromthe objectbouncesbackandforthbetweenthemirrorsbeforeitreachesyour eyes.Animageisformedeachtimethelightbouncesoffamirror.The numberofimagesthatyouseeinthemirrorsdependsontheanglethatthe mirrorsform.Asyoumaketheanglebetweenthemirrorssmaller,thelight bouncesbackandforthmoretimes,andyouseemoreimages. Theillustrationbelowshowshowanimageisformedinthecorneroftwo mirrorsat90degrees.Lightraysbounceoffeachmirroratthesameangle thattheyhitthemirror:Physicistssaythattheangleofreflectionisequalto theangleofincidence.Mirrorsatotheranglesbehavesimilarly,buttheray diagramsmaygetmorecomplex.

Theinsidecornerofacornerreflector(wherethethreemirrorsmeet)sends lightbackparalleltoitsoriginalpath.Ifyoupointedathinbeamoflaserlight rightnearthecorner,thebeamwouldbouncefrommirrortomirrorand thenexitparalleltotheenteringbeam.Lightfromthecenterofyoureye bouncesstraightbacktothecenterofyoureye,sotheimageofyoureye seemstobecenteredinthecornermadebythemirrors. Inacornerreflector,multiplereflectionsreversetheimageandinvertit."

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