Halfpipe
Halfpipe
Math Concept Reader
ca54os_lay_070107xad_cp.indd 3 1/8/07 11:28:02 PM
DIGITAL FINAL PROOF
Expedition:
Antarctica
by Aenea Mickelsen
ca62xs_lay_061207ad_am.indd 4 1/9/07 9:09:15 AM
DIGITAL FINAL PROOF
Halfpipe
by Ilse Ortabasi
Math Concept Reader
Copyright © Gareth Stevens, Inc. All rights reserved.
Developed for Harcourt, Inc., by Gareth Stevens, Inc.
This edition published by Harcourt, Inc., by agreement with Gareth Stevens, Inc.
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to Permissions Department, Gareth Stevens, Inc., 330 West Olive Street, Suite 100,
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HARCOURT and the Harcourt Logo are trademarks of Harcourt, Inc., registered in the
United States of America and/or other jurisdictions.
Printed in the United States of America
ISBN 13: 978-0-15-360198-9
ISBN 10: 0-15-360198-1
1 2 3 4 5 6 7 8 9 10 179 16 15 14 13 12 11 10 09 08 07
ca54os_lay_070107xad_cp.indd 1 1/8/07 11:28:04 PM
DIGITAL FINAL PROOF
Chapter 1:

Halfpipe
Dreams

 ItisearlySeptemberandMr.Dunbar’sstudentsareinscienceclass.
Outside,theweatherisstillwarm,butthepublicswimmingpoolsinBoise,
Idaho,arealreadyclosedfortheseason.Thecrowdsdisappearshortlyafterthe
LaborDayholiday.Thelifeguardsreturntoschoolortotheirwinterjobs.
 Mr.Dunbarstandsbeforetheclassasheintroducestherstscienceunit.
HesaysthattheclasswillstudyNewton’sLawsofMotion.Heasksifanyof
thestudentshaveeverheardoftheselawsofphysics.Whennobodyanswers,he
askstheclasswhetheranyofthemhavesnowboardedbefore.Onlyafewofthe
studentsraisetheirhands.Then,heaskshowmanyofthemhavewatchedthe
WinterOlympicssnowboardingcompetitions.
 Itturnsoutthatquiteafewofthestudentshavewatchedsnowboardingon
television.Thestudentsdon’thavemuchexperiencesnowboarding,buttheydo
havesomeknowledgeaboutthesportandthetricksthattheathletesdo.
 Everybodyintheclasswonderswhatsnowboardingcouldpossiblyhaveto
dowithNewton’slaws.
ca54os_lay_070107xad_cp.indd 2 1/8/07 11:28:05 PM
DIGITAL FINAL PROOF
This is a diagram of a halfpipe.

 Melanietellstheclassthatshelovestowatchsnowboardersridedownthe
halfpipeanduptheotherside.Melaniemakestheshapeofatroughwithher
handstoshowtheotherstudentswhatthehalfpipelookslike.Thehalfpipeis
dugrightintothesnowandthewallscanbeasmuchas18metersacross.
Eduardosaysthathelikestowatchsnowboardersdotrickslikearodeoip.
Heexplainsthatarodeoipisa720-degreesidewayssomersault.
 Mr.DunbarexplainsthatNewton’sLawsofMotionhelpthesnowboarder
maneuveranddotricks.HesaysthatNewton’srstlawstatesthatanobjectat

restremainsatrest.Thislawalsostatesthatanobjectinmotioncontinuesat
aconstantspeedandinastraightlineunlessactedonbyanoutsideforce.Mr.
Dunbartellstheclassthatthisisthereasonthatsnowboarderscansoarsohigh
intheair.Becausetheyareinmotionwhentheyreachthetopofthepipe,they
stayinmotion.Next,heexplainsthatNewton’ssecondlawofmotionstatesthat
theEarth’sforceofgravitypullsthesnowboarderbackdowntotheground!
10 to 18 meters
1.5 to 3
meters
Entry Ramp
Flat
Lip
Vertical
Platform
Transition
Wall
10 to 30
centimeters
50 to 100 meters
ca54os_lay_070107xad_cp.indd 3 1/8/07 11:28:08 PM
DIGITAL FINAL PROOF
When class is over, the students continue to talk about snowboarding.

 Melanieandherfriendscontinuetotalkaboutsnowboardingwhenclassis
over.Theythinkabouthowgreatitwouldbeiftheycouldgosnowboardingthis
winter.Manyofthemknowhowtorideskateboards,butMelanieandherfriends
havenevertriedsnowboarding.
 Cathypicturesherselfonasnowboard,yingdownthemountainatfull
speed.Eduardohasgonesnowboardingbefore,andhetellshisfriendsallabout
it.Heexplainsthatwhencarving,asnowboardermustturnwithoutanyskidding,

makingasingle,thinlineinthesnow.Itisaskillthatisverydifculttolearn.
Eduardopretendstocarveupthehalfpipeandperformatrickintheair.Helands
withathumponthegrassontheplayground.Hegetsup,anddeclaresthatthis
yearhewantstogosnowboardingagain.
 Michaelwalksoverandjoinsthegroupoffriends.HetellsEduardoand
theothersthattheMogulValleyResortnearbyrunssnowboardinglessonsfor
schools.Hesawanarticleabouttheresortinthesportssectionofthelocal
newspaper.
ca54os_lay_070107xad_cp.indd 4 1/8/07 11:28:12 PM
DIGITAL FINAL PROOF
This snowboarder wears the proper safety equipment as he
enjoys his run through the halfpipe.

 Melanieisexcitedabouttheideaoftakinglessons.Sheremindsherfriends
thatitwillbeexpensiveforthewholeclasstogo.Michaelsaysthecostforone
dayis$25.00aperson.Thiscostincludesthelessonaswellastheuseofa
snowboardandboots.
 “Thepriceevenincludesallthesafetyequipment,”Michaelsays.“Because
snowboardingisanextremesport,weshouldwearwristguards,kneepads,and
hippads.Hippadsareusedtocushionyourfallsandkeepyourseatwarmand
dry.Theyarestretchyandpullonlikebikeshorts.Youhavetoweara
snowboardhelmetwhilesnowboarding,too.”
 “Youalsoneedasafetyleash,”addsEduardo.“Theleashisdesignedto
keepyourboardattachedtoyourleg.Thatway,iftheboardcomesloosefrom
yourboots,theleashwillstopitfromslidingawaydownthehill.”
 Cathywondershowthestudentswouldtraveltotheslopes.Michaelexplains
thateventhebustransportationandliftticketsareincludedinthecostofthe
lesson.Now,thestudentsbelievethattheycanraisethemoneysotheycanall
gosnowboardingtogetherthiswinter.
ca54os_lay_070107xad_cp.indd 5 1/8/07 11:28:15 PM

DIGITAL FINAL PROOF
Mr. Dunbar explains how Newton’s laws affect snowboarding.

 Michaelbringsthenewspaperarticleaboutthesnowboardinglessonsto
schoolthenextday.Mr.Dunbaraskshimuptoreadthearticletotheclass.The
articlesays,“Theprogramisdesignedtoteachwintersports.Itfocusesonthe
safeenjoymentofsnowboardingasalifetimesport.Qualiedinstructorshelp
studentsdeveloptheirsnowboardingskills.Level1classesareforthosestudents
whohaveneversnowboardedbefore.”
 Theclasscriesout,“That’sus!”
 Michaellooksathisteacher.Mr.Dunbarhasalreadydecidedthatthe
experienceofsnowboardingwouldworkverywellwithhislessononNewton’s
lawsofmotion.Hecannotthinkofabetterwayforhisstudentstolearnand
understandNewton’slawsthanexperiencingthemrsthandontheslopes.Onthe
slipperysnow,hisstudentswillseeforthemselveswhatitmeansforobjectsto
stayinmotion!
 Mr.Dunbarletstheclassknowthathewillhelpthemraisethefunds.He
willalsohelporganizetheclasstriptoMogulValleyResort.Thestudentsareso
excitedaboutthetripthattheyallclapandcheer.
ca54os_lay_070107xad_cp.indd 6 1/8/07 11:28:18 PM
DIGITAL FINAL PROOF
$25.00 × 27 = $675.00
,
The students decide that the first step they need to take is to calculate how
much money they need for the trip. The class includes a total of 27 students.
Michael multiplies 27 by $25.00, which is the cost for each student. The product
is $675.00. Thatʼs how much money the class needs to pay for the trip.
Cathy suggests they raise the funds for the trip by selling popcorn. A friend
of hers in another class raised funds that way last year, and the school can
purchase cases of popcorn for students to sell. Mr. Dunbar talks to the schoolʼs

principal. She thinks the popcorn fundraiser is a good idea and agrees to help
the class.
Mr. Dunbar orders the popcorn for the fundraiser. Half of the money the
students collect will pay for the popcorn, while the other half will be the profit
for the trip. The popcorn arrives in October. Each student in Mr. Dunbarʼs class
agrees to sell at least one case of popcorn. Some students hope to sell even more
than that. Students work hard to sell popcorn right away because the date of the
December trip is not far away.

Melanie’smothervolunteerstohelpwiththefundraiser.Shecomestoschool
oftentocollectmoneyfromthepopcornsales.MelanieandMichaelhelpheradd
upthemoney.
 Theclassmeetstheirgoalforsellingpopcorn.Theymade$1,470.00!First,
thestudentsneedtopayforallofthepopcorn.Theschoolpaid$735.00forthe
popcorn.
 M
rs.Petty,theprincipal’sassistant,subtractsthisamountofmoneyfromthe
amountcollectedbythestudents.Sheusesthatmoneytopayforthepopcorn.
 $1,470.00−$735.00=$735.00
 Thestudentshave$735.00leftover.Thatamountismorethanenoughtopay
forthetrip.Thetripcosts$675.00.
 Theydidit!Thefundraiserwassuccessful.Everyoneintheclasswillgoon
thesnowboardingtrip.Mr.Dunbarandthestudentscelebratetheirsuccesswitha
fewbagsofpopcorn.
$ 1,470.00
− $ 735.00
$ 735.00
ca54os_lay_070107xad_cp.indd 8 1/8/07 11:28:25 PM
DIGITAL FINAL PROOF
Results: Men’s

and Women’s
Snowboard Halfpipe
Chapter 2:

 Mr.Dunbarprepareshismathlessonwithhisstudents’interestabout
snowboardinginmind.Healwayslikestomakeconnectionstotherealworld
inhislessons.Today’slessoniscalled“FascinatingFactsaboutSnowboarding.”
Thisisonelessonthatthestudentscan’twaittostart.
 Eduardoseemstobeveryknowledgeableaboutsnowboarding.Mr.
Dunbaraskshimtoexplaintotheclasswhatthehalfpipesnowboardingevent
isallabout.Eduardodescribesthehalfpipeasahalf-cylindricaleldabout145
meterslongthatisdugintothesnow.Snowboardersenterthehalfpipefroma
rampatthetop.
 Eduardoexplainshowthesnowboardersmustcrossthehalfpipefromsideto
sidesixtoeighttimesduringacompetition.Theymustusethefulllengthofthe
pipe.Theydothiswhileperformingacrobatics,calledmaneuversortricks.
 Fivejudgesawardpointsforthemaneuvers.Theygivepointsfortheheight
ofthesnowboarder’sjumps.Inaddition,thejudgesscoretheoveralltechnical
qualityoftheperformance.Thisportionofthescoreincludesthequalityofthe
landings.Snowboardersaresupposedtohaveclean,smoothlandings.They’re
notsupposedtofall,orusetheirhandstokeepthemfromfalling.
ca54os_lay_070107xad_cp.indd 9 1/8/07 11:28:26 PM
DIGITAL FINAL PROOF
10
 The12snowboarderswhoachievethehighestscoresinthetwo
qualifyingrunsadvancetothenalroundofcompetition.Thenalround
consistsoftworuns,eachofwhichincludesvejumps.Thesnowboardersget
ascoreforeachrun,butonlythebetterofthetwoscorescounts.Thatallows
themtotakechances.Iftheyfallontheirrstrun,theyalwayshaveanotherrun
toimpressthejudges.

 Mr.Dunbarbroughttheresultsfromamen’sandwomen’shalfpipe
competitiontosharewiththeclass.Hewantstheclasstodeterminethewinner
ofeachnalevent,aswellashowtherstfourcompetitorsranked.Mr.Dunbar
saysrankingmeansputtingthecompetitorsinrst,second,third,andfourth
positions,accordingtotheirscores.Thenheadds,“Thiscanbedonebyadding
andsubtractingdecimals.”
 Mr.Dunbarprojectsatableonthescreenoftheclassroom’scomputer.The
tableshowsthepointsthevejudgesgavethemalesnowboarders.Theclasswill
computethescoresforeachsnowboarderinthecompetition,andrankthetop
four.Tondthescoreforeachathleteinbothruns,theyneedtoaddupthepoints
foralljumps.

Athlete’s
Bib Number Jump 1 Jump 2 Jump 3 Jump 4 Jump 5
31 8.58 8.03 8.1 8.5 8.48
25 8.1 7.6
8.47 8.4 7.8
 19 4.4 4.06
4.23 4.04 4.2
 8 9.56 9.4
9.6 9.02 9.5
 31 7.8 6.7
7.67 7.01 8.03
25 6.95 5.2
6.82 5.7 6.8
 19 9.03 8.63
8.7 8.6 9.1
 8 5.5 5.5 6.5 4.5 4.62
1
st

Final Run2
nd
Final Run
Results from Final Men’s Halfpipe Competition
ca54os_lay_070107xad_cp.indd 10 1/8/07 11:28:27 PM
DIGITAL FINAL PROOF
A snowboarder completes a maneuver on the
halfpipe.
11
 “Youknowhowtoaddwholenumbers,soyoualreadyknowhowtoadd
numberswithdecimals,”Mr.Dunbarsays.“Youjustneedtolineupthedecimal
points.Youcangiveyourdecimalsthesamenumberofplacesbyaddingon
zeros.Thatmakesiteasiertokeeptrackofplacesasyoudoyouraddition.”
 Asanexample,Mr.Dunbarstandsinfrontoftheclassandcomputesthe
rstnalrunscoreforthesnowboarderwithbibnumber31.Hetakesthe
snowboarder’svejumpscoresandaddsthemtogetherbyliningupthe
decimalpointsandaddingzeroessothatallofthescoreshavethesame
numberofplacesafterthedecimal.
 Soonthewholeclassisbusyguringoutwhowonthemen’shalfpipe
competition.Eduardoremindstheclassthattherunwiththehighestscoreisthe
onethatcountsforeachsnowboarder.Hedoesn’tknowifthatscoringruleis
thesameforallOlympicwintersports,though.Eduardo,Roy,andAngelawork
together.Theynishaddingthescoresforthemen’shalfpipesnowboarding
competition.
ca54os_lay_070107xad_cp.indd 11 1/8/07 11:28:30 PM
DIGITAL FINAL PROOF
1
 Thesnowboarderwhowaswearingbibnumber8rankednumber1.Hehad
thehighestscoreonhisrstrun!Thesecondhighestrankedsnowboarder
receivedhisbestscoreonthesecondrun.Thethirdandfourthhighestranked

snowboardersreceivedtheirbestscoreontheirrstruns.
 Mr.DunbartellstheclassthatnotallofthesportsintheWinterOlympicsare
scoredthesamewayassnowboarding.Inskijumping,thewinneristheathlete
whoreceivesthehighesttotalscorefromtwojumps.Unlikeinsnowboarding,the
worstscoreisn’tthrownout.
 Eduardowonderswhetherthatdifferentmethodofscoringwouldhave
changedtheresultsofthesnowboardinghalfpipecompetition.Melanieraises
herhandandtellstheclassthatshehasalreadydonethecomputationsinher
notebook.Sheaddedupscoresfromtherstandsecondnalrunsforeach
snowboarder,andrankedthembasedontotalscore.IftheOlympicjudgeshad
computedthepointsaccordingtotheskijumpingrules,thenalrankingofthe
snowboarderswouldhavebeendifferent!

Athlete’s 1
st
Final Run 2
nd
Final Run
Bib Number
Total Score Total Score

31 41.69 37.21
25 40.37 31.47

19 20.93 44.06

8 47.08 26.62
Results from Final Men’s Halfpipe Competition

Athlete’s

Rank Bib Number
Score

1 8 47.08
2 19 44.06
 3 31 41.69
 4 25 40.37
Final Rankings
ca54os_lay_070107xad_cp.indd 12 1/8/07 11:28:31 PM
DIGITAL FINAL PROOF
1
 Melanietellstheclassthatifthescoresfromthetworunshadbeenadded
together,rstplacewouldhavegonetothesnowboarderwearingbibnumber
31.Snowboardernumber8wouldhavenishedinsecondplaceinsteadofrst
place.Thethirdrankingathletewouldbenumber25andthefourthranking
athletewouldbenumber19.
 Theclassconcludesthatthescoringrulescanmakeabigdifferenceon
whereeachsnowboardernishesinthenalrankings.Theyalsoagreethatfor
snowboarding,keepingjustonescoreisagoodidea.Otherwise,theathletes
mightnottryasmanyriskytricks,anditmightnotbeasexcitingtowatch.
 Astheschoolbellrings,Mr.Dunbarpassesoutthedatafromthewomen’s
naleventandtellstheclassthatthecomputationsoftheresultsofthewomen’s
naleventwillbetheirhomeworkassignment.
 Thenextday,Mr.Dunbargoesoverthehomeworkwithhisstudents.The
classmeetsingroupstoreviewtheircomputations.Angelaandtheother
studentsinhergroupmadeatableoftheresultsforthesecondnalruninthe
women’shalfpipesnowboardingcompetition.

Athlete’s
Bib Number Jump 1 Jump 2 Jump 3 Jump 4 Jump 5

1 8.0 8.5 8.0 8.4 8.2
3 8.2 8.7 8.3 8.7 7.6

4 8.9 9.0 8.9 8.9 8.9
22 7.7 8.3 7.9 8.6
8.4
Results from 2
nd
Final Run Women’s Halfpipe Competition

Athlete’s
Bib Number
Score

1 41.1
3 41.5
4 44.6
22 40.9
2
nd
Final Run
ca54os_lay_070107xad_cp.indd 13 1/8/07 11:28:32 PM
DIGITAL FINAL PROOF
Chapter 3:
Off to the
Slopes
It’s time to try snowboarding!
1
 Atlast,thebigdayofthesnowboardinglessonishere.Thebusarrivesearly
inthemorning.Thegroupcan’twaittogetstartedontheday.Mr.Dunbarand

theotheradults,whowillridealongtohelpstudents,noticethestudents’laughter
andchatter.Thestudentsareexcitedabouttheirtrip.
 Aninstructormeetstheclasswhenthebusarrives.Shehasalreadysetoutall
thesnowboards,boots,helmets,andtheothergearthestudentsneedfortheirrst
lesson.Theinstructorexplainshowtheequipmentworksandshowsthegroup
howtoproperlyusethesafetygear.
 Thestudentswatchasanadvancedsnowboarderdoestricksinthehalfpipe.
Ridingthehalfpipeisdenitelynotfornewsnowboarders!Eduardoremarks,
“NowIcanseeNewton’sLawsofMotionatwork.That’samazing!”
 Theinstructortakestheclasstothebeginner’s
area.Shetellsthestudentsthatittakesyearsof
practicetobeagoodhalfpiperider.New
snowboardersneedtostartonthebeginner’sslope,
wheretheycanlearnhowtoproperlycontroltheir
boards.Thestudentssoonrealizethat
snowboardingisalotharderthanitlooks!
ca54os_lay_070107xad_cp.indd 14 1/8/07 11:28:34 PM
DIGITAL FINAL PROOF
This student slides down the beginner’s slope.
1
 Bytheendoftheday,allofthestudentsareabletoslidedownthe
beginner’sslope.Johnevenmanagestoride“fakie.”Ridingfakie,oraswitch
stance,meansthatyourfrontfootisatthebackoftheboard,andyourbackfoot
isatthefrontoftheboard.Itsoundslikeitshouldbeeasy,butit’snot!Someof
thestudentsintheclasstryit,butJohnistheonlyonewhodoesnotendupwith
hisnoseinthesnow.
 Theinstructorexplainsthatridingfakieonasnowboardisimportantto
learnifyouwanttodoothermoredifculttricks.Manytricksbeginorendwith
aswitchstance.
 Beforelong,itistimetogohome.Itisnearlydarkandeveryoneis

exhausted.Whenthebusreturnstotheschoolparkinglot,manyofthestudents
areasleep.Someoftheadultsareasleep,too.Thedaywasahugesuccess,and
everyonehadagreattimeontheslopes.Thestudentsareeagertotelltheir
familiesallabouttheirexperiences.Nodoubt,therewillbesomegreatstories
abouttheirsnowboardingadventures!
ca54os_lay_070107xad_cp.indd 15 1/8/07 11:28:39 PM
DIGITAL FINAL PROOF
1
Glossary
acrobaticscontrolledbodymovementsinthesportofgymnastics
bib numberi
nsportsevents,aracenumberthatiswornbycompetitorsandis
attachedtotheirouterwear
cylindricals
hapedlikeacylinder
decimalan
umberwithoneormoredigitstotherightofthedecimalpoint
fakier
idingbackwardsonthesnowboard
nalf
ormingoroccurringattheend
halfpipe as
mooth-surfacedstructureshapedlikeatroughandusedforstuntsin
sportssuchasin-lineskatingandsnowboarding
lifetime sport s
portsperformedbypeopleonaregularbasisevenaftertheyare
nolongeryoung
maneuver am
ovementthatrequiresskillandability
NewtonE

nglishmathematicianandphysicist.SirIsaacNewton,wholivedfrom
1642-1727.Newtondevelopedthelawsofgravityandmotion.
Olympicst
hemodernrevivaloftheancientGreeksportsgamesheldonceevery
4yearsinaselectedcountry
qualify m
eetingtheproperstandards,requirements,andtrainingforanofceor
positionortask
rank apo
sitioninagroup
PhotoCredits:cover,titlepage,pp.5.6©Corbis;p.4©MaryKateDenny/PhotoEdit;p.11©Jeff
Curtes/Corbis;pp.14.15©CindyCharles/PhotoEdit.
ca54os_lay_070107xad_cp.indd 16 1/8/07 11:28:40 PM
DIGITAL FINAL PROOF
Think and Respond
1. Five judges give a snowboard competitor scores of 5.6, 6.7, 8.9, 5.8, and 8.4 for
her first jump. What is the mean score for this jump?
2. The popcorn for the fundraiser that Mr. Dunbarʼs class sold cost $7.30 for each
package. There are three bags of popcorn in each package. How much would
three packages of popcorn cost?
3. This table shows the scores of the four women snowboarders from a recent
competition. Find the range, which is the difference between the greatest
number and the least number, for this set of data.
4. Is it possible for a competitor in the snowboarding halfpipe event to win the
event if his or her first run gets a low score? Explain your answer.
Results from Women’s Halfpipe Competition
Athlete’s
Bib Number 14 38 58 67 70 89
Score 50.12 52.09 52.93 55.29 51.02 53.91