Read the Elementary GLOBE book Discoveries atWillow Creek - either read it to the class or havestudents read it to themselves. The books can bedownloadedfromwww.globe.gov/elementaryglobe.
Teacher’s Notes
A lens is a curved shape you can see through. Amagnifying lens is a convex lens that makes closeobjectsappear larger. Bothsidesof the lenscurveoutward, and it is thicker in the middle than onthe edges. It is also called a hand lens. When amagnifyinglensisplaceddirectlyontopofanobject,theobjectappearsthesameanddoesnotlookanylarger.Ifyouraisethelens,theobjectappearslarger,ormagnified.Ifyouraisethelenstooclosetoyoureyes, the object will become blurry. Both marblesand drops of water can act like lenses; they canmagnifyobjectsbecause theyare clear andhaveacurvedsurfacethat isthickerinthemiddlethanontheedges.
Whenlookingatobjectsthroughamagnifyinglens,theobjectslooklarger.Youcandiscoverandexaminesmalldetailsthatyoumightnototherwisebeabletosee. For example, when you look at a newspaperwithamagnifying lensyouwill learnthat theblackpartsofpicturesinthenewspaperarenotsolidblack;insteadtheyaremadeoftinyblackandwhitedots.
Using magnifying glasses with children:Youngerprimarygradechildrenmay recognize thatanobjectlookslargerunderamagnifyinglens,andolder primary grade children may observe moredetails not seen with the unaided eye. Magnifiersencouragechildrenofallagestolookatobjectsalittlemore closely. A hand magnifier (magnifying glassorhand lens)withanunbreakableacrylic lensandhandle isaperfect tool tohelpchildren investigatetheenvironment.Thismagnifierhastheadvantageof being small, mobile, and inexpensive. They areavailableinseveralsizes,inavarietyofshapes,andare ideal for outdoor activities. The magnification,
or power, varies among magnifying lenses. Try tohaveseveraldifferentpowersofmagnifiersavailable.Whenyouintroducethemagnifiers,letthestudentsusethemontheirownforawhile.Letthemexploredifferent objects. Plan viewing opportunities thatpermit students to viewobjects indifferentways–withthenakedeye,magnified,andmagnifiedunderdifferentpowers.Thistoolwillcomeinhandywithalltypesofscientificinvestigations!
What To Doand How To Do It
Part 1:1.Discusswith your students howpeopleuse their
senses to discover things in their environment.Ask the students what senses they use whentheyobservethings. Discusstheadvantagesandlimitationsofeachofthefivesenses(sight,sound,touch,smell,taste).
3.Then discuss with your students why the GLOBEstudentsneededamagnifyinglensintheDiscoveriesatWillowCreekbook.Tellthemthattheyaregoingtolearnhowtouseamagnifyinglenssotheycanuseitasatoolwhenmakingobservations.
4.Passoutasheetofpaper(scrapwilldo!) toeachstudent. Showthemhowtofold it intoquarters.Ontheinsidecorner(wheretherearenoedges),havestudentsmakeamarkonecentimeteralongtheedgeineachdirection.Thenhavethestudentscutouttheareabetweenthemarks.Thiswillcreateasquareholeinthemiddleofthepaper.Noteforyoungerstudents:Haveyoungerstudentsputtheirthumb over the inner corner and trace around itwithapencil.Thentheyshouldcutthisoutanditwillmakeawindowforthemtolookthroughthatisroughlythesamesize.
6.Pass out the magnifying lenses and have thestudents repeat their observations. Explain theconceptofseeing“details”here.Askthefollowingquestions:•Whatdoyouseewith themagnifying lens that
ortextures?•Didyouknowthedetailsweretherebefore?•Describe two things that look different when
usingamagnifyinglens.
7.Give each student a leaf. Encourage them toexaminetheleafwithandwithoutthemagnifyinglens.Thenaskthemtofocustheirobservationsonthepartof the leafwhere the leafstem(petiole)enterstheleaf.Studentsshouldlookatthisspecificpartoftheleaffirstusingtheirpaperwiththeholeinitandthenusingthemagnifyinglens.HavethestudentsdrawwhattheyseeontheMagnifyThatStudentActivitySheet1andsharetheirresultswiththeclass.
Part 2:Note to teachers: this activity works better withyoungerstudentswhendoneatacentersoanadultcanworkwithafewstudentsatatime.
1.Nowhavethestudentsguesswhatcertainobjectswilllooklikewhenviewedwithamagnifyinglens.Holdupcontainersofsaltandsugarandask thestudentswhattheythinkeachsubstancewilllooklike when magnified. Have the students writedownhowtheythinkeachsubstancewilllookontheirMagnifyThatStudentActivitySheet2. Noteforyoungerstudents:Thesestudentswillprobablywrite“bigger”astheirguess,becausetheymightnotthinkaboutthepossibilityofseeingdetailsinsomethinglikesaltandsugar.
2.Pass out a piece of black construction paper toeachstudent.Havethestudentsusewhitechalkorawhitecrayon todrawa lineon thepaper todivide it inhalf. Sprinklea fewgrainsof salt ononehalfofthepaperandafewgrainsofsugarontheotherhalfof thepaper. Besure tokeep thesaltandsugarawayfromeachotheronthepaper.Havethestudents lookatthesaltandsugarwith
theirmagnifyinglenses.Havethemdescribewhatthey see, and write/draw a description on theirMagnifyThatStudentActivitySheet2.
3.The studentswill learn that salt and sugar grainslook different when magnified. Both salt andsugararecrystals.Saltcrystalsaretheshapeofacubeandhaveflatsides.Sugarcrystalsareoblongandareslantedatbothends. Haveadiscussionwiththeclassabouthowthisinformationwillhelpthemmakeobservationsofotherobjectsusingamagnifyinglens.
Adaptations for Youngerand Older Students
Younger StudentsPriortodoingthisactivitywithkindergartenstudents,itmightbehelpfultodiscussandpracticeobservationskillswithyourstudents.Onegoodwaytodothisisbyusingbooksfromthe“ISpy”series.Eitherread“ISpy”bookswiththestudentsorusean“ISpy”posterwiththeclass.Askyourstudentstopracticeobservingdetails when looking at the books. The followingWebsiteprovidesinformationonhowtobuy“ISpy”productsandalsohassomegoodactivitiesthatyoucanprintfromwww.scholastic.com/ispy.
Older StudentsDiscuss the appropriate uses of magnifying lensesversus microscopes. For example, it is possible toseedetailsonaleafwithamagnifyinglens,butnotorganisms in a drop of water – this requires morepowerfulmagnification.
Further Investigations
• Water as a Magnifier: Cut a hole the size of 3centimetersindiameteroutofapieceofcardboard.Tapeplasticwrapoverthehole,makingsure it issmooth and tight over the hole. Place this overa piece of newspaper. Squeeze a large drop ofwater from a medicine dropper onto the plastic
wrap. Look down through the water drop at thenewspaper. Then slowly raise the cardboard andwatchtheprintsizechange.Hereyouhavemadeamagnifyinglensoutofadropofwater!
• More Water Magnification:Anothersimpleactivityforusingwater as amagnifier is toput adropofwater on a coin and observe how the water dropmagnifiesthedetailsonthecoin.Thenaddanotherdropofwaterandseeiftherearemoredetails.Dothisafewtimesuntilthecoinisfullofwater.
• Other Magnification Tools: Investigate the useof digital cameras, binoculars, telescopes, andmicroscopesasmagnifiers.
