Dr.DebbieFrench
AssistantProfessorofSTEMEducation
[email protected]
Agenda
• Powersof10,OrdersofMagnitude,Estimation
• Whatisgoingoninclassrooms?
• Possiblesolutions/Changingourcurriculum
FrustratingFermiProblems…
•Benefits
•Sowhat?
•Whatwoulda[social]constructivistsay?
Whatarewe(asteachers)reallyasking?
• Dostudentsreallyunderstandwhattheirnumericalanswer
means?
• WhydoIkeepgettinghomeworkwithanswerssuchas,
6.1790489m?
• Howcanweteachourstudentstoestimateanswers?
What’sgoingoninthelab?
• Whatstudentssay:Dotheworkà getgrade=”Science
Success!”
• Studentsaremoreconcernedaboutgettingthelabdonein
thetimeallotted.
• Studentsrushtocalculateapercenterror
• Anxiousif%Errorisnotwithin“acceptable”limits
• Studentsneedaclear“purpose”totheexperiment
Hart,C.,Mulhall,P.,Berry,A.,Loughran,J.,Gunstone,R.(2000).Whatisthepurposeofthisexperiment?
Orcanstudentslearnsomethingfromdoingexperiments?JournalofResearchinScienceTeaching,37(7),p.655-675.
AuthenticScience?
1. Worktowardssolutiontorealworldproblemoranswera
scientificquestion?
2. Researchtopic
3. Useinstruments&technology?
4. Use“grade-appropriate”math?
5. Analyzeevidence&use
evidencetosupport
conclusions?
6. Developneworrefineexisting
questions?
7. Developorrefineprocedures?
8. Provide&receivepeercritique
&feedback?
9. Collaboratewithothers?
10. Presentresults?
TheLabReport
• Typicallabreportsinclude:
• Calculating%Error
• Listpossiblesourcesoferror
• \endLabReport
• Whatifweaskedstudentsto…
• Peerreview&critiquelabs
• Reviseexperimentbasedonfeedback
• Describedpossiblesourcesoferrorandhowtomitigatethem
PracticalProblems…
• Howmanypianotunersarein
Chicago?
• HowmanycupsofDunkin’
DonutscoffeedoIdrinkayear?
Howmuchdoesthatcost?
• IfIswitchtousingareusable
waterbottle,howmanyplastic
bottleswillIkeepoutof
landfills?Whataboutreusable
grocerybags?
• HowmuchmoneycanIsave
over1yearbyswitching1IL
lightbulbwithaCFLbulb?
• AreKeurigcoffeecupsa
bargain?
• HowmanyhoursdoIhaveto
workat$10/hr tosaveupfora
$5500usedcar?Howmany
weeks(workingat20hrs/week)
willthattake?Isthisrealistic?
Whatotherfactorsgointothis
answer?
• Costofcollege?Repaymentof
studentloans?
• Sports?Howmanytennisballs
doesWimbledonuse?
CurriculumConnections
• Density:
• CokeFloats
• DensityofAlfoil
CokeFloats
Butwhatdoes40gofsugar
looklike?
Imagesource:SteveSpangler
• Amountofsugarin
varioustypesofpop:
• Coke:40g
• Mt.Dew:46g
• Sprite:38g
• Sunkist:52g
CokeFloats…
• Studentspoursugarinpapermuffin
cupstoestimate what40gofsugar
lookslike.
• ¼muffincup?
• ½muffincup?
• ¾muffincup?
• 1muffincup?
• Finally,studentsmasstheirmuffincup&
sugar,thenadd/subtracttoget40g.
ThicknessofAlfoil
• StudentshavetocalculatethethicknessofAlfoil.
• Materials:
• Rulers
• Scissors
• Markers
• Scale
• r =2.7g/cm3
𝑚𝑎𝑠𝑠
𝑚𝑎𝑠𝑠
𝐷𝑒𝑛𝑠𝑖𝑡𝑦 =
=
𝑉𝑜𝑙𝑢𝑚𝑒 𝐿𝑒𝑛𝑔𝑡ℎ𝑥𝑊𝑖𝑑𝑡ℎ𝑥𝐻𝑒𝑖𝑔ℎ𝑡
Revisedprocedure
• Studentsworkincooperativegroupstodevelopmethodtocalculate
thickness.
• Afterabitoftime,havestudentsshareideaswithanothergroupfor
peerfeedback&critique.
• Studentsrevisetechnique,ifnecessary
• Studentsshareresultswithclass
• Accurate?Precise?
• Calculate%Error
• Howcouldtheyrevisetheirproceduretomakeitmoreaccurate?
FromtheFineFolksatReynoldswrap
Standard
ReynoldsWrap
HeavyDuty
ReynoldsWrap
ExtraHeavy
DutyReynolds
Wrap
Inches
0.00064
Microns(µm)
16.256
Mils
0.64
0.0093
23.622
0.93
0.00137
34.798
1.37
FYI:1mil=0.001in
Extensions?
• Howmanyatomsthick?
• ComparetoRutherford’sGoldFoilExperiment
• IsAlfoilthicker?
RethinkingFermi?
• Whatisthepurpose?
• Connectionstostudents’interestsandexperiences?
• Practical?Relevant?Authentic?
• Howcanestimationbeincorporatedinexisting
labs/activities?
• Howcanweincorporateopportunitiesforourstudentsto
posetheirown“Fermi”questions&maketheirownOoM
estimates?
• Discipline-basedFermiquestions
• Provideconcretereferences&comparisonsforourstudents.