Biology 11A Lab #1
The Scientific Method - Finding
the Best Paper Towel
Pre-lab. (Monday lab will do this in lab) Read your text pages 10-15. Answer the
following questions and bring to your lab, TYPED. Copy the question, and answer in
complete sentences. The answer needs to make sense on its own even if the question
were not there.
1. Look at figure 1.14 of the text (or see last page of this handout). What argument
would you make for or against the high, versus medium, versus low virus concentration
in the rotavirus vaccine ? Which is best?
2. Which is the dependent variable in this experiment?
3. Which is the independent variable in this experiment?
4. What do you have to say about the ethics of this study?
5. What is a theory? (Do not Google this from a non-scientific source, you’ll get goofy
answers). See text.
Today’sObjectives
1.Usescientificinquirymethodstoansweraspecificquestion.
2.Performthescientificmethodbydesigningandrunninganexperiment.
3.Perfectyouroralskillsbypresentingyourexperimentclearlysothatitmaybe
understoodbyothers.
Introduction
Inthislabyouwillbeabletodesignsomeexperimentsin
ordertotestdifferentbrandsofpapertowelsanddecide
whichisbest.Yourjobistoscientificallytestthesebrandsand
comeupwithsomeevidencethatdeterminestheefficacyof
thesepapertowels.Rememberwearelookingfor“evidence
based”conclusions.Inordertoachievethatyouwillneedtofollowthescientific
method.Toreviewthesteps,checkyourtextpages10-13.
TheChallenge:
Wewillbecomparingtheefficacyofpapertowels,andinvestigatingthisingroups
of3-4.(No,notfive).Yourjobistodecidehowyouwilltestdifferentbrandsof
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papertowelsanddecidewhichthe“best”brand.Thinkofthematerialsthatyou
wouldneedinordertoconducttheexperimentandrequestthemfromme.Design
anexperimentthatcanbeperformedinthethree-hourperiodthatwehaveinlab.
Thechallengeison!Yoursamplesizeshouldbethelargestitcanpossiblybeinthe
timeassignedtoyou.Oneortwotrialsarenotgoodenough.Thebigger,thebetter.
Youwouldnotbelieveastudydonewithtoofewrepetitions,wouldyou?Youwill
presentyourresultstotherestoftheclassattheendofthelabperiod.
Procedure:
a.Learnthenameofthepeopleinyourgroup.
b.Discussthequestionsyouarereallyaskingasagroup.Thisiseasiersaidthan
done.Thinkofthemethodsthatwouldbeneededtoconductanexperimenttoget
resultsthatmayanswerthosequestions.
Comparing4brandsofpapertowels.Herearesomeexamplesofspecific
questionsrelatingto“whichbrandisbest”.Perhapswhatwereallymeanis:
• Whichbrandismoreabsorbent?
• Howdothebrandsrankastotheirresistancetotearingwhilebeenusedto
mopupspills?Howmuch“spill”canonesquaremopup?
• Isitsofttothetouch?Whichissoftest?Whichisroughest?
• DoesBountyreallyabsorb“twiceasmuchasthebargainbrand”asthey
claim?
• IsBounty“moredurable”thanotherbrands?
Feelfreetoaddyourownquestionsinstead.
c.GeneratealistofmaterialsthatyouthinkyouwillneedandaskmeortheTAfor
them.ImaynothaveALLthematerialsthatyourequest.You’llhavetoadapt.Not
allscientistshaveinfinite$$$$.CheckwithmeandI’llseewhatIcando.
d.Collectyourdataasagroup.Remembertorepeattrialsasmuchasyoucan!
Thingstothinkabout:
•
•
•
•
•
Whatsortofdatawillyoucollect?
Willthosedataansweryourquestion?
Howmuchdatawillyoucollect?(Themorethebetter!)
Whatwillyoudowiththedataonceyoucollectit?(Thepublicdoesnotlike
tobeshownlistsofnumbers)
Howcouldyousummarizethedataattheendofyourtrialsinorderto
presenttotherestoftheclass?Tryandvisualizehowyouwouldplotit.
e.Whatconclusionscanyoudrawfromyourdataifany?Evidence-basedclaimsare
allweareinterestedin.Canyoumakeanyclaims?Really?Areyousure?
f.OralPresentation:Waituntiltheothergroupsarefinishedinordertopresent
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yourworktotheclass.Whenpresenting,youwillneedtoshowus:
• Titleofyourwork(bedetailedhere)
• Specificquestionthatyouasked(Majorwork)
• Methods-Howyouwentabouttestingyourquestion.(Rationale)
• Results-GRAPH!Notableswithnumbersplease!ONEGRAPH(ormore?)
• Discussion-thisiswhereyoutelluswhatyoucouldconclude(ornot).Be
honest,wewillclapregardlessoffailurestogetperfectdata.Wedon’twant
ittosoundgood,wewantittosoundhonest.Soundinghonestalsoincludes
suchconclusionsas“wehavenoevidencetoshowthatBrawnypapertowels
aremoreabsorbentthanBountypapertowelswhenusedinasinglelayer”.
THEEND
WrittenPresentation:HomeworktobehandedinindividuallynextFriday,typed,
double-spaced.
Lab#1WhattohandinnextLab(10points)
1. Usingagraph,(andgraphpaper!!!),presenttheresultsofyourexperiment.Usearuler
whendrawingyourgraph(Iamreallygrumpyaboutthis).Labeltheaxesandusethe
correctunits.Giveitaspecificcaption.AnExcelgraphisfinetooifyouknowhowtousethe
program.Don’tforgettolabelthexaxis(horizontalaxis),andy-axis(verticalaxis)when
plottingthedata.Giveitalegend.
2.FindonecommercialforanotherproductyouseeonTVorelsewhere(notforpaper
towels)thatmaynotbebackedupbydata.Somearequitecomical.Findmeagoodone
anddescribewhatitclaims!Whatisnotbelievable?
Rubric-
2points
2points
2points
2points
2 points
Usedgraphpaper
Usedrulers
Labeledaxes
Hascaptionthatexplainstheresultsinthreesentences
Submittedcommercialthatclaimssomethingunbelievable
_______________________________________________________________________________________________________
NEXTWEEK
Onmostweeksyouwillhandinsomewrittenupsectionofthelabfromtheweek
before,andthepre-labforthelabyouareabouttodo.
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Graphingyourdata(Eachmemberofthegroupneedstheirowngraph)
Whenitcomestographingyourresultsforyourreport,thereare5majorpartsto
yourgraph.
1.TheIndependentVariable:thisisthevariable(partoftheexperimentthat
changes)thatcanbecontrolledormanipulatedbytheexperimenter.Thevariable
shouldbeplacedonthehorizontalorx-axis.
2.TheDependentVariable:thisisthevariabledirectlyaffectedbythe
independentvariable.Itistheresultofwhathappensbecauseoftheindependent
variable.Thevariableisplacedontheyorverticalaxis.
3.TheAxes:Yourscaleontheaxesmustincludeallthedatapoints.Theincrements
shouldallbethesameonaparticularaxis.Multiplesof5,10aregood,while
multiplesof1.22arenot!Ifyournumbersareallbig,itisNOTnecessarytostart
youraxisatzero.Across-hatchedlineindicatesthattheyaxisdoesnotstartat
zero.Yourscalemustbeplottedontheamountofgraphspaceavailable,andwillbe
dictatedbyyourdatapoints.
4.TheLegend:Thisisashortdescriptivenarrativedescribingthedata.Itshould
betothepointandplacedunderthegraph.
Excelisfineifyouwouldratherusethat.
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Weight,
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