ReadingExplorerFoundations:Unit7LessonB

DIRECTIONS:Choosethebestanswerforeachquestion.

SeeingtheImpossible

[A]Canyoubelieveeverythingyousee?Notalways!Sometimesourmindsandoureyesmakemistakesandgetconfused.1Thismaybebecausewearelookingatanopticalillusion.

[B]Thewordopticalmeansrelatedtosight-thewayweseethings.Anillusionissomethingthatlooksdifferentfromthewayitreallyis.Inshort,anopticalillusionisatrickthatoureyesplayonus.

[C]Lookattheseopticalillusionsandcomparewhatyouseewithwhatyourclassmatessee.Thewayweseethingsisoftenpersonal,sonoteveryonewillseethingsthesameway.

1.Arethelinesstraight?

[D]Atafirstlook,mostpeoplesayNo.Butifyoucomparethelinesagainstanobjectwithastraightedge,youllseeotherwise.Thesmallcirclesinthesquareshelpcreatetheillusion.

2.Whatcolorarethesquares?

[E]Square1isclearlygray.Butwhataboutsquare2?Isitwhite?Isitlightgray?Youmaynotbelieveit,butsquares1and2areexactlythesamecolor.Youreyesseethecolors,butyourbrainnoticestheshadowmadebytheapple.Itthereforedecidesthatthesquareintheshadowisalightercolorthanitreallyis.

3.Arethecirclesmoving?

[F]Ifyoulookcloselyatthispicture,thecirclesmayappeartomove.Ofcourse,thisisimpossible.Howcanapicturemove?Whenweseecircle-in-circleshapes,likeincarwheels,theyareusuallymoving.Ourbrainsareusedtoseeingtheseshapesmove.Whenoureyesseethisshape,ourminddecidesthattheimageismoving.Otherscientistsbelievetheillusionofmovementiscausedbythemovementsofoureyesaswelookatthedifferentcolorsandpatternsofthepicture.

1Ifyouareconfused,youdontunderstandsomethingcorrectly.

____ 1. Whatcouldbeanothertitleforthispassage?

a.

WhenYouHavetoLookTwice

b.

OpticalIllusionsinNature

c.

ThePartsoftheBrain

d.

HowWeSeeint