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Lesson 3How Should We Care for Our Bones?

ObjectivesStudents will

• identifycalciumasthemineralthatstrengthensbones

• identifyexerciseandadietrichincalciumasfactorsthatsupportgoodbonehealth

Vocabularycalcium(KAL-see-uhm)—themineralfromwhichbonesaremade

fracture(FRAK-cher)—abreakinabone

Structuring the CurriculumHavestudentssetupLet’s Find Out: What Happens to Bone When It Is Placed in Vinegar?atleast

twoweeksaheadoftime.

Preparation/MaterialsDemonstration: Bone Properties

√ cleanbone(suchasachickenorturkeydrumstickorahambone)

Let’s Find Out: What Happens to Bone When the Calcium is Removed?

√ cleanchickenbones,oneperteam

√ protectivegloves,onepairperstudent

√ glassjarswithlids,oneperteam

√ vinegar,enoughtocovereachbone

Demonstration: Fracture

√ cleanchickenorturkeydrumstickbone,brokentodemonstrateafracture

Discussion: Calcium

√ milkcontainer

√ samplesofsesameseeds,almonds,freshbroccoli,salmon,and/ormolasses

Activity: Bone Mobile

√ craftsticks,twoperstudent

√ glue

√ constructionpapercutintoeighths,atleastfoureighthsperstudent

√ crayonsormarkers

√ scissors,oneperstudent

√ yarn

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BackgroundBonesarecomposedofmineralsandprotein.Theinnerboneisaproteinmatrixonwhichthemin-

erallayer(primarilycalciumphosphate)isdepositedtoformastrongbone.Collagen,aprotein,isthe

maincomponentincartilage.Aschildrengrow,thecartilageossifies(becomesbone)asmoremineral

isincorporatedintothecartilage.

Dietandexercisearethemainfactorsthatdetermineskeletalhealth.Adietrichincalciumespe-

ciallyfavorsstrongbonedevelopment.VitaminDisessentialforcalciumtobeabsorbedfromfood.

ThebodyproducesvitaminDwhensunshinesontheskin,andmostfluidmilkhasbeenfortifiedwith

vitaminD.Foodshighincalciumincludenotonlydairyproductsbutalsosesameseeds,almonds,

salmon,sardines,oysters,andmanydarkgreenleafyvegetablessuchaskale.Softdrinksaren’t

advisableforgrowingchildren’sdiets—notonlydotheyoftensubstituteformilk,butphosphoricacid

alsocompetesdirectlywithdietarycalciumandinhibitsstrongbonemineraldevelopment.

Maximumskeletalstrengthisreachedduringadolescence.Thereafter,apersoncanmaintainskel-

etalstrength,butit’sgenerallynotpossibletoexceedthestrengththathasbeengainedatthatpoint.

Therefore,it’simportantforchildrentohavewell-balanceddietsandalifestylethatincorporatesregu-

larweight-bearingexercise.

Bonesbecomemorebrittlewithage.Olderpeoples’bonesbreakmoreeasily.Osteoporosisisa

conditionthatdevelopsinolderpeople,especiallypost-menopausalwomen.Thespongybonetissue

becomeslessdenseandmorebrittle.Weight-bearingexercise,inwhichskeletalmusclepullsagainst

thebone,strengthensandincreasesbonedensity.

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Discover1. Demonstration: Bone Properties.Holdupacleanbone,suchasaturkeyorchickendrum-

stickboneorahambone.BrainstormalistofpropertiesthatGodgivesbonesthatmakethem

functionalinourbodies.(Answerswillvarybutmayincludetheirhardness,length,howtheyfit

together,thefactthattheycontainmarrowtomakebloodcells,andsoon.)

2. Holduponeofthejarswithavinegar-coveredbonefromLet’s Find Out: What Happens to

Bone When the Calcium Is Removed?Havestudentspredicthowthebonewillbechanged.

(Makesurethatstudentswearglovesduringthisactivity.)Discussthepropertiesofthebone

thattheyputinthere(hard,white,etc.).Havestudentsfinishtheactivity.Discusshowthe

hardnesshaschanged.Explainthatthevinegarisamildacidthatdissolvedthehardlayerof

calcium.

8. What does it feel like? (It’s soft and rubbery.)

10. What would happen if all the bones in your body were like the bones in the vinegar? (We

couldn’t stand up straight, we couldn’t lift heavy things, and we couldn’t support ourselves.)

Havestudentswashtheirhandsthoroughlyafterthisactivity.

3. Havestudentsdemonstrate(mime)whattheirmovementswouldbelikeiftheirboneswere

rubbery.Discusswhatwouldbeharder(walking,sitting,chewingfood,etc.),andwhatwould

beeasierormoreadvantageous(fewerbonebreaks,curlingintosmallerspaces)iftheirbones

weren’thard.

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Develop1. Demonstration: Fracture.Holdupabrokenchickenorturkeybone.Discusswhathappens

whenabonebreaks.Introducethewordfracturetomeanabreakinabone.Havestudents

sharetheirexperienceswithbrokenbones.

2. Discussthedifferencebetweenacompoundfractureandasimplefracture.(Inasimplefrac-

tureabreakinthebonedoesn’tbreaktheskin;inacompoundfracturethebrokenbone

breaksthroughtheskin.)Discusstheimportanceofkeepingthebreakareastillandseeing

adoctorpromptly.Askwhatmighthappenifboneisn’tsetbyadoctor.(Althoughthebone

willhealandgrowbacktogether,itmightnotgrowbacktogetherasitshould.Itmightstay

crooked.)MarveltogetherthatGodgivesbonestheabilitytomendtogether.

3. Students’experienceswithbrokenbonesmaybelimitedtosituationscausedbyfallsoracci-

dents.Discussthatwhiletheimpactofafallcanbreakeventhestrongestofbones,notall

boneshavethesamestrength;weakerbonesbreakmoreeasily.

4. Askthefollowingquestions.

• Whatcouldmakesomebonesstrongerorweakerthanothers?(Answerswillvarybutmay

includebonesize,boneage,andhowthickthe“hard”bonelayeris.)

• HoldupandbendarubberybonefromtheLet’sFindOutactivity.Doyouthinkthatit’s

importanttohaveasolidlayerofmineralinyourbones?(Yes.)

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5. Discussion: Calcium.Askthefollowingquestions.

• Wheredoyouthinkyourbodygetsthemineralstomakeyourboneshard?(Wegetthese

mineralsfromfood.)Tellstudentsthatmostofthehardlayeroftheboneisamineralcalled

calcium.Eatingfoodswithlotsofcalciumhelpsyourbodymakestrongbones.

• Whichfoodsdoyouthinkhavelotsofcalcium?(Milkandfoodsmadefrommilkhavelots

ofcalcium.)Holdupamilkcontainer.

• Whatfoodsaremadefrommilk?(Yogurt,cheese,andicecreamaremadefrommilk.)

• Doyouthinkotherfoodshavecalcium,too?(Answerswillvary.)Holdupsamplesofses-

ameseeds,almonds,broccoli,salmon,and/ormolassesasexamplesoffoodsthathave

calcium.

6. Toestablishtheimportanceofexerciseindevelopingandmaintainingstrongbones,leadstu-

dentsthroughtheseinstructions.

• There’ssomethingelseyoucandotomakeandkeepyourbonesstrong.Thinkaboutwhat

thatmightbe.

• Standupanddotenjumpingjacks.

• That’sexercise!Exercisehelpsyourbonesstaystrongandhealthy.

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Reinforce/Assess1. Asaclass,readBone Care(page42)inthestudenttext,andanswertheThink Backques-

tions(page46).

1. What mineral makes bones strong and hard? (Calcium makes bones strong and hard.)

2. What can you do to keep your bones strong? (We can exercise and eat foods high in cal-

cium.)

3. Why are strong bones important? (Strong bones don’t fracture easily.)

2. Askstudentswhywekeepourboneshealthy.Studentsshouldunderstandtheimportanceof

bonestodailyactivities.TheyshouldalsounderstandthatbonesareagiftfromGodthatwe

havearesponsibilitytocarefor.

3. Activity: Bone Mobile.HavestudentsgluetwocraftstickstogetherintheshapeofanX.Have

themdraworwriteonconstructionpaperpieceswaystokeepboneshealthy.Havethemuse

yarntohangthesepiecesfromthesticks.(Savethemobilesforstudentstoaddtoduring

Lesson7.)

Extend Havestudentsresearchtheuseofseatbeltsinpreventingbrokenbones.Startaclassscrap-

bookofnewspaperclippingsaboutcaraccidents,notingwhetherthevictimswerewearing

seatbelts.Assignonestudenttobethe“accidentclerk.”Thatstudentshouldkeepthescrap-

bookandreportadditionstotheclass.

Haveinterestedstudentsfindoutaboutx-rays.Howdox-rayswork?Whatdotheyshow?

Howaretheyhelpful?Cantheybeharmful?

Havestudentsmakeamealplanforadaythatincludesfoodshighincalcium.

Havestudentsdevelopanexerciseprogramforthemselves.Evenmoderateexercisecanben-

efitbones.Havethemplantowalk,run,jumprope,ordosomeotherweight-bearingactivity

twoorthreetimesaweek.

Havestudentslistsafetyrulesforexercising.Discusstheserulesandtheimportanceofexer-

cisesafety.

Demonstratetheneedforwearingbicyclehelmets.Dropaveryripemelononafloorcovered

withprotectiveplasticornewspaper.Themelonwillshatterlikeanunprotectedskull.Repeat

theactivitywithanothermelonprotectedinsideabicyclehelmet.

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Your bones are very important. They are part of God’s plan for your body. You can take care of your bones by eating the right foods and exer-cising.

Minerals in the bone make the bones strong. The mineral from which bones are made is called calcium (KAL-see-uhm). Milk and foods made from milk have lots of calcium.

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Bone Care

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You can also get calcium by eat-ing some kinds of fish. Broccoli has a lot of

calcium. So do sesame seeds and

almonds.

Exercise also makes bones strong. When you walk, run, and jump, your bones get stronger.

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What Happens to Bone When the Calcium is Removed?

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You will need√ clean chicken bone√ protective gloves, one pair per student√ glass jar with a lid√ vinegar

Do this1. Put on the gloves.2. Feel the bone. What does it feel like? 3. Try to bend it. 4. Write down what the bone is like.5. Put the bone in the jar. Pour vinegar over it. Put the lid on the jar.6. Guess what the bone will be like in two weeks.7. Write your ideas down in your science journal.8. After two weeks, take the bone out of the jar. 9. What does it feel like? Try to bend it. 10. Write your observations in your science journal. 11. What would happen if all the bones in your body were like the bone in the vinegar?

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Exercise that puts weight on your bones makes them stronger, too.

Old people’s bones can get weak. Weak bones break more easily. Even bones that aren’t weak can break, though. A break in a bone is called a fracture (FRAK-cher).

Do you know someone who has had a fracture?

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Think Back1. What mineral makes bones strong and

hard?2. What can you do to keep your bones

strong?3. Why are strong bones important?

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FractureA bone with a fracture can heal

itself. But it must stay still a long time.

To make sure it heals right, a doctor sets the bone in position. Then you get a cast or splint on it.

In simple fractures the broken bone stays inside the skin. In compound fractures the broken bone pokes through the skin.