Download - Lab 1Intro to Physics Labs and 1D Kinematics 1Intro to... · SP211 Lab: One ! Introduction to Lab and 1D Kinematics Version: August 15, 2013 Page 1 of 13 Physics Lab 1 SP211 Introduction

SP211 Lab: One ! Introduction to Lab and 1D Kinematics Version: August 15, 2013

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Physics

Lab 1

SP211

IntroductiontoPhysicsLaboratoryand1DKinematics

I. Introduction

A. SincePhysicsisthestudyofhowtheworldaroundusworks,manyScientistshaveconductedexperimentsandanalyzedthedatatodeterminethemathematicalrelationshipsthatdescribedthephenomenontheyobserved.

B. Inthedigitalage,theuseofacomputertoobtainandrecordthedataismostadvantageous.Adevicethatcommunicatesbetweenthedataacquisitionmoduleandthelaptopiscalledaninput/output(IO)interface(orinterfaceforshort).SometimesitisjustcalledanIOdevicetoo.

C. InallofthePhysicsLabsforbothSP211andSP212,theLab-ProinterfacedeviceisoftenusedtocommunicatewithvarioussensorsanddisplaytheiroutputgraphicallyintheLogger-Proprogram.

D. Graphicalanalysisisawidelyusedtechniqueinphysicstoconveyinformationvisually.Asaconsequence,itisimportantthatthestudentbecomesveryfamiliarwithgraphsingeneral;inparticularduringthelabs,howtomanipulatetheLogger-Proprogramtodisplayaccurategraphsthatconveymeaning.

E. Themainpurposeofthislaboratory,besidesfamiliarizationwithlabequipmentandprocedures,istocreateanduseagraphicalrepresentationof1Dmotiontoreinforcethe1DKinematicsconceptswithinanexperimentalstudy.

PositionGraphofaBouncingBall

Logger-Proprogram


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II. Objectives

Attheendofthisactivity,youshould:

1.HavetheLogger-Proprograminstalledonyourpersonallaptop.

2.BeabletoconnectsensorstotheLab-ProinterfaceandfindthemintheLogger-Proprogram(calibrationofadevicewillbeshowninfuturelabs.)

3.Beabletocreateandfullylabelaposition,velocity,andaccelerationgraphsintheLogger-Proprogram(ifnecessary,beabletodeleteexistingand/oraddadditionalgraphs.)

4.Beabletodiscusstherelationshipbetweentheposition,velocity,andaccelerationgraphs.

5.Beabletore-scaleagraph(bothauto-scaleandmanually.)

6.Beabletouse“LinearFit”and/or“Statistics”functionsinLoggerProandunderstandwhyandwhentouseeach(i.etohelpdescribephenomenasuchasslope.)

7.Understandwhen“CurveFit”isappropriateandfitaquadraticcurvetoyourdata.

8.(TimePermitting)BeabletodiscussuncertaintyanddiscusshowuncertaintycalculationsareconductedduringPhysicsLaboratories.BefamiliarwithUncertaintyandtheuncertaintyassociatedwithLoggerProandbeabletodiscusshowitpertainsto1DKinematics.

9.(TimePermitting)Beabletoexecuteanyotherfunctionyourparticularinstructordeemsessentialtocompletingassignedlaboratoriesthissemester.

Note:AnyoftheObjectivesnotcompletedduringthislabwillbediscussedasusedinfuturelaboratories.

III. NeededEquipment

A. Laptop,Logger-ProInstallationprocedurehandout,PrinterInstructionHandout,LabProInterface(includingUSBcable),PASCOMotionSensorII,PASCOForceSensor,Uncertainty“rulesofthumb”handout,a12inchruler,ameter-stick,a“rubberball”,andapencil/pen.

IV. TurninyourPre-lab/homeworkproblemifassigned.


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V. Procedure

A. DownloadandinstalltheLogger-Prosoftwarefollowingtheinstructionshandoutgiventoyoubyyourinstructor.

1. Note:Itisimportanttofollowtheinstructionasexplicitlywritteninordertooptimizetheinstallationprocess.

2. Note:NEVER try to run the install any software directly from the USNA Software Downloads page! It not only will bog down the network, but might also lead to unforeseen errors. Download it to your desktop first.

3. Notifyyourinstructorifyoureceiveanyerrorsduringtheinstallationprocess.

4. Donotproceedtothenextstepuntilallerrorsareresolved.

B. Ifnoerrorswerereceivedduringtheinstallationprocess,startthelogger-proprogrambydoubleclickingontheLogger-Pro3.8.5.1icon.

1. Whatyoushouldseeisagenericxvs.ygraphandcolumnsfordatasetslabeledxandy.Directlyabovethedatasetcolumnsyoushouldnoticeitsays“Nodeviceconnected.”Thisisbecausewehavenotyetconnectedtheinterface.

2. NowconnecttheLabProinterfaceasshownbelow.

a. UsetheUSBconnectionnexttotheEthernetport.ThisconnectionoptimizesthecommunicationbetweentheLabProinterfaceandtheLogger-Proprogram.

USBconnectionnearEthernetPort

PlugintoOutlet


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b. Aniconoftheinterfacedeviceshouldappearwherebeforeitsaid“Nodeviceconnected.”MostinterfaceswillnowhaveaflashinggreenLEDtosignifythatthedeviceisworkinganditisactivelysearchingforasensortocommunicatewith.

3. Connectingasensor:

a. NextwewillconnectthePASCOMotionSensorII.

1) ConnectthemotionsensortotheLabProdeviceasshownbelow.UseDig/Sonic2port.(Wearepurposelyinstallingthedeviceintothenon-defaultportsothatyouwillbeforcedtotelltheinterfacewhichportyouarepluggedinto.)Forfuturelabs,youmaychoosetoplugintothedefaultportunlessyourinstructororthelabinstructionstellyoudifferently.

2) Notice:ThegreenLEDonthemotionsensorisnotyetlit.Thisisbecausethesensorandtheinterfacearenotyetcommunicating.WemustnowsetupthesensorinLogger-Prosothattheinterfacedeviceknowswhatsensorisconnectedandwheretolookforit.

4. “SetUpSensors”

a. NowmoveyourcursoroverandclickonthewordExperimentinthetopleftcornerofthescreen.Youshouldseeatableexpand.Nowslidedownto“SetUpSensors.”Anotherexpandedtableshouldappear.Select“ShowAllInterfaces.”

b. YoushouldnowseeapictureoftheLabProdevice(mostlikelyoppositelyorientedfromyours).Itisspecificallyshowingyoualltheports.Thereare4analogconnectionportslabeledCH-1throughCH-4.InadditiontherearetwodigitalconnectionportslabeledDig/Sonic1andDig/Sonic2.ItalsoshowsyoutheOperatingSystem(OS)versionandtellsyouthestatusofyourbatteryintheinterface.Onthefarleftandrightitshowsyouthemanydifferentsensorsofeachtypethatyoucouldpossiblyconnect.

Dig/Sonic2


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c. Toconnectourmotiondetector,leftclickonthearrownexttoDig/Sonic2.Anexpandedtableshouldpopupwith“ChooseSensor”displayed.Slidethemouseoveranddownandselectbyleftclickingon“MotionDetector.”

d. ThegreenLEDonthemotiondetectorshouldstartflashingimmediatelyandyoumighthearanaudibleclickingsound.Thisdevicedetectspositionthroughanovelapplicationofthesametechnologyfoundonourmostsophisticatedsubmarines:soundrangingorSONAR.(Ofcourse,inthecaseofsubmarines,thesoundtravelsthroughwaternotair.)Soundpulsesareemittedthroughthegold-coloredmembraneonthefrontofthesensor.Thesepulsestravelthroughtheairuntiltheycomeintocontactwithanobject.Whenasoundpulsebouncesofftheobjectandreturnstothemotionsensor(MS),thesystem(computer/LoggerPro,LabPro,andMS)comparestheemittedandreceivedpulsesandcalculatesthepositionoftheobjectrelativetothesensor(theorigin).

• Note:WhentheMSsuccessfullylocksontarget,thetinygreenlightonthefrontoftheMSilluminates.

e. Positiondeterminationiscarriedoutfrequently(20times/secondbydefault)sothatthepositioncanbemeasuredatcloselyspacedtimeintervals.Consequently,displacement,velocity,andaccelerationcanbecalculatedfromthechangeinposition,changeinpositionvstime,andchangeinvelocityvstime,respectively.Wewillstudythesequantitiesinlaterlabs.

f. OnthetopoftheMSisasmall,blackswitchthatenablesyoutochoosebetweenanarroworwidesonarbeam.ThesesettingsaredescribedonthebackoftheMS.Useofthenarrowbeamreducesclutterbuthasashortrangeofabout2meters.Thewide(orstandard)settinggiveslong-rangedetectionouttoabout8metersbutis,ofcourse,moresusceptibletounwantedsignals(reflections).Thedialonthesideofthedeviceallowsonetorotatethedetectorupanddown.

• Note:TheMSwilldetectanythinginitsrange.Itisimportanttokeepthepathtotheobjectofinterestclear,i.e.,keepbooks,otherpeople,etcoutofthepathofthebeamoftheMS.


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5. Addinganadditionalsensor:

a. Althoughwearenotgoingtospecificallyusetheforcesensorintoday’slabweneedtobeabletoconnectadditionalsensorsfromtimetotimeinourphysicslabs.Todaywewilladdtheforcesensorsothatweknowhowtoaddadditionalsensors.

b. AddtheforcesensorbyfirstconnectingitintoCH-3port(Again,wearepurposelyinstallingthedeviceintothenon-defaultportsothatyouwillbeforcedtotelltheinterfacewhichportyouarepluggedinto.)Forfuturelabs,youmaychoosetoplugintothedefaultport(unlessyourinstructororthelabinstructionstellyoudifferently.)

c. Ifthe“ShowAllInterfaces”screenisnolongeronthescreen,moveyourcursoroverthewordExperimentinthetopleftcornerofthescreen.Youshouldseeatableexpand.Nowslidedownto“SetUpSensors.”Anotherexpandedtableshouldappear.Select“ShowAllInterfaces.”

d. Toconnectourforcesensor,leftclickonthearrownexttoCH-3.Anexpandedtableshouldpopupwith“ChooseSensor”displayed.Slidethemouseovertwiceanddownovertheword“Force”thenoveranddownandselectbyleftclickingon“DuelRangeForce.”

e. Closethe“ShowAllInterfaces”screenbyclickingonthe“RedX”.

6. Youshouldnoticethatyouhave3graphsonyourscreen:Position,Velocity,andForce.SincewearenotgoingtobeusingtheforcesensortherestofthislabdisconnectthesensoratthistimebyremovingtheplugfromCH-3.

a. Thenrightclickontheforcegraphandselectdelete.

b. Asyoucanseeyoucandeletegraphsthatyoudonotdesire.


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7. Nowwewanttoverifythatweunderstandalltheprocessesdiscussedabove.Sogouptothelefthandportionofthescreenandselect“File”thenslidedownandselect“New.”DONOTSAVEanything.

a. Addthemotionsensoraspreviouslydiscussedinsection4.Closethe“ShowAllInterfaces”screenbyclickingonthe“RedX”.

b. Oneshortcuttogettothe“ShowallInterfaces”screenistoclickontheiconoftheLabProabovethe“LatestData”columns.

c. Sothatwecanlearnhowtoinstalladditionalgraphs,manuallydeletethevelocitygraphbyrightclickingonitandselectingdelete.

8. InsertingAdditionalGraphs:

a. Toaddadditionalgraphsclickon“Insert”intheupperleftofthescreen.Slidedownto“Graph”andselect.

b. Thegraphthatappearsonthescreenisanaccelerationgraph,butwewantavelocitygraph.Tochangethetypeofgraph,placeyourcursoroverthewordAccelerationandthenleftclick.Selectthetypeofgraphyouwant.InthiscasewewantaVelocitygraph.Toarrangethegraphsnicely,goupto“Page”nearthetopmiddleofthescreen.Select“Page”thenslidedownandselect“AutoArrange.”

9. Sometimes,yourinstructormightchoosetousepre-loadedtemplatesinwhichallthesetupworkisalreadycompletedsothatstudentscanjumprightintotakingdata.

Ifinstructedbyyourinstructor,downloadthetemplatesfromtheIRC’sUSNASoftwareDownload’spagewhereyoudownloadedtheLoggerProprogram.PlacetheminafolderlabeledSP211Labsonyourdesktop.

ExtensionCMBLisafilethatcanbedoubleclickedontoopenLoggerProandthetemplateatthesametime.

ExtensionXMBLisafileformatthatcanonlybeopenedfromtheLoggerProprogram.

Note:WhenusingLoggerPro,pleasedonotsaveoveranyofthepreprogrammedexperimentfiles.Ifitwouldbeusefultosavethedata,choosetheSAVEASoptionundertheFilemenuandsavethedataunderanewfilename.(Forexample,useyourlastnameandthedate.)Whenclosingexperimentfiles,youwillbeaskedifyouwouldliketosavethechangestothefile.AlwaysclickonNO.


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C. Recurringsteps:UsingLoggerProtoprogramtheLabPro:Knownasthe“ThreeSteps”

!Experiment->SetUpSensors->ShowallInterfaces:Makesurealltherightsensorsshowupinalltherightholes.

!Experiment->DataCollection:Setthelengthoftimedataistobetakenandtherateatwhichdataistobetaken.

!File->Settingsfor...:CheckthecheckboxtoShowZeroonToolbar,andmakesurenumberofpointsforDerivativeandSmoothingareboth7.

D. Askyourinstructorwhichexperimentsheorshewouldlikeyoutoconducttodayandthenproceedtothoseapplicablestepsasappropriate.

E. Experiment1:WalkingToandFro:PositionandVelocity

1. FollowtheThreeStepsinLoggerProtoprogramtheLabPrototakedataforpositionandvelocityasfunctionsoftimeappropriatelyforthisexperiment.

Note:TheMSwilldetectanythinginitsrange.Itisimportanttokeepthepathtotheobjectofinterestclear,i.e.,keepbooks,otherpeople,etcoutofthepathofthebeamoftheMS.

2. Takedataforthepositionofyourownbodyasyou:

a. PlacetheMSontheedgeofthelabtableandsettheselectorswitchtoStandard(thewidebeam).PointtheMSintoanaisleorsomeareathatwillgiveyouoryourlabpartnerroomtowalk.

b. Thepersonbeingtheexperimentwillstandabout12inchesfromthedetectorandwhentoldbythedatacollector(afterthedatacollectorclicksonthegreen“Collect”buttonnearthetopmiddleofthepage)she/hewillwalkawayfromthedetectorandbacktowardthedetector.Tryfortoday’slabtowalkatasteadypace.

c.Standmotionlesslyforasecondortwo,then

d.WalkslowlyawayfromtheMotionDetectoratasteadyspeed,then

e.Standmotionlessforasecondortwo,then

f.WalkrapidlytowardtheMDatasteadyspeed,andthen

g.Finallystandmotionlesslyforasecondortwo.

Ifyouarenotsatisfiedwithyourgraphyoumightchoosetotakeafewpracticetries.


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3. Scalingaplot:

a. Therearetwowaystoscaleaplot,automaticallyandmanually.

b. Toscaleautomatically,rightclickontheaxisofyourchoiceandthenslidedownto“Autoscale,”youwillbegiventhechoiceof“Autoscale”or“AutoscaleFrom0.”Autoscalefromzeroisfrequentlythecorrectchoice,butclearlynotalways;whichyouchoosedependsontheexperimentyouareconductingorthemeaningyouaretryingtocommunicatetoyourreader.Tryeachandseetheireffectonyourgraph.

c. Toscale“Manually,”rightclickonanaxisandselect“GraphOptions”thenselectthe“AxesOptions”tab.Makechangestoitemsonthistabandseetheiraffectstoo.

d. Itisimportanttolabelthegraphwiththeinformationthatitrepresents.Thebestwaytolabelthegraphistomodifyitstitle.Thiscanbedonemanydifferentways,buttheeasiestistorightclickonthegraph,andselect“GraphOptions”thenselectthe“GraphOptions”tab.Youwilleasilyfindthetitlearea.Titleyourgraphappropriately.

3. InthePositionvsTimegraph,findtheaveragevelocityforeachofthetimeperiodsa-eabove.UseAnalyze->LinearFittodothis.

4. IntheVelocityvsTimegraph,findtheaveragevelocityineachofthesameregions.UseAnalyze->Statistics.

5. Annotate,print,and,inashortparagraph,comparethetwodifferentmethodsofmeasuringtheaveragevelocityinthisexperiment.Dotheyagree?Explain.

F. Experiment2.WalkingToandFro:VelocityandAcceleration

1. UsethesamedatafromExperiment1,above.ClosealltheStatisticsandLinearFitboxes.ChangetheverticalaxesfromPositionandVelocitytoVelocityandAcceleration.

2. IntheVelocityvsTimegraph,findtheaverageaccelerationforeachofthefivetimeperiodsinPartsB.2.c-g.UseAnalyze->LinearFit.

3. IntheAccelerationvsTimegraph,findtheaverageaccelerationineachofthesameregions.UseAnalyze->Statistics.

4. Annotate,print,and,inashortparagraph,comparethetwodifferentmethodsofmeasuringtheaverageaccelerationinthisexperiment.Dotheyagree?Explain.

5. Whendoweuse"LinearFit"tofindtheaverageofanobservable,andwhendoweuse"Statistics?"


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G. Experiment3.UniformlyAcceleratedMotion

1. Raiseoneendofthetracksothatyouhavearamp.MakesureyouhaveLoggerProsettoshowgraphsfortheposition,velocityandaccelerationofthecart.

2. Holdthecartstill.Starttakingdata.Waitasecond;thenlaunchthecartuptherampasyourinstructordemonstrates.Takedatawhilethecartstartsuptheramp,slowstoastop,thanacceleratesbackdowntheramp.Becareful!Thesecartscost$80!!

3. In the Position vs Time graph, use Analyze -> Curve Fit to fit a quadratic to your data, and find the cart's average acceleration.

4. IntheVelocityvsTimegraph,useAnalyze->...whichoneshoulditbe?...tofindthecart'saverageacceleration.

5. IntheAccelerationvsTimegraph,use...whichone????...tofindthecart'saverageacceleration.

6. Annotate,print,and,inashortparagraph,comparethethreemethodsoffindingaverageaccelerationinthisexperiment.Dotheyagree?Explain.

H. Experiment4.Position,velocity,andaccelerationforaBouncingBall

1. EitheryouoryourlabpartnerholdstheMSaboutchestheightandensuretosettheselectorswitchtoStandard(thewidebeam).PointtheMSdowntowardtheground.

2. Withyourotherhand,afteryoucoordinatewithyourlabpartnertostartcollectingdatainLogger-Pro(Labpartnerpressescollectandgivesyouthegosignal),releasetherubberballandallowittogentlyfalltotheground.Trytomaintainthemotionsensorovertheball,butyouDONOThavetotracktheballintheupanddowndirection,onlyiftheballmovesleftorright.

3. In the Position vs Time graph, use Analyze -> Curve Fit to fit a quadratic to your data, and find the ball's average acceleration. Remember your position graph will have opposite coordinates than the graph on the first page of this procedure due to how you are holding the motion sensor.

4. IntheVelocityvsTimegraph,useAnalyze->...whichoneshoulditbe?...tofindtheballs'saverageacceleration.

5. IntheAccelerationvsTimegraph,use...whichone????...tofindtheball'saverageacceleration.

6. Annotate,print,and,inashortparagraph,comparethethreemethodsoffindingaverageaccelerationinthisexperiment.Dotheyagree?Explain.


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4. Printingaplot(ifdirectedtobyyourinstructor,manyinstructorspreferthatyouprintyourlabreportsinyourBarrackssothatyoucantaketimetoproperlylabeltheaxis,etc.):

a. Followtheinstructionsontheprinterinstructionshandouttomaptheprinterforthelabroom.

b. Ifyoureceiveanyerrors,immediatelynotifyyourinstructorsothattheymayberesolved.

c. Ifnoerrors,thenprintyourgraphtoensurethatyouwillbeabletoprintforfuturelabs.Saveyourgraphasitmightbeausefulreferencenextweek.

Askyouinstructorifshe/hewantsyoutocontinuewiththeLABorproceedtosectionVIII(cleanup).

VI. (TimePermitting)UncertaintyandRegressionLines

A. ReadtheHandoutfromyourinstructoraboutuncertaintyandanswerthefollowingquestions:

1. Measurethedeskusinga12inchruler.Recordthemeasurementincludingtheuncertainty.

2. Nowmakethesamemeasurementusingameterstick.Recordthemeasurementincludingitsuncertainty.

3. Nowdeterminetheareaofthetable.Recordeachmeasurementandshowthecalculationforareaincludingitsuncertainty.Hint:Howdoestheuncertaintyofeachmeasurementaffecttheareauncertainty?

4. Asyoucanimagine,calculationscangetmorecomplicatedthansimplemultiplication.Readthehandoutandthendiscusshowyouwouldusetheuncertaintiesofeachmeasurementtodeterminethedensityofabrasscylinder.Discussnowhowyouwouldcompareyourcalculatedanswertothatoftheactualknowndensityofbrasstoseeifyouwereaccurateand/orpreciseorneither.

5. Askyourinstructorifshe/hewantsyoutocontinuewiththeLABorproceedtosectionVIII(cleanup).


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B. CalculatetheslopeofyourpositiongraphbyhandandthenhaveLoggerProdoitforyou.Inordertohavethecomputercalculatetheslope,youfirstselecttheportionofthecurvetobeanalyzedbyclickinganddraggingthemousefromlefttorightsothatthecursorintheLoggerProwindowtraversesthedatatobefit.Ifyouaresuccessful,ashadedareawillcoverthedatatobeanalyzedonthecomputerscreen.Afterselectingtheportionofthedatatobefit,clickonAnalyzeinthemenuoftheLoggerProwindow.Fromthemenuthatappears,chooseLinearfitandthe“leastsquares,”best-fitstraightlineshouldappearontheLoggerProwindowalongwiththeslopeandintercept.

1. Theuncertaintyintheslopeisnotquiteaseasytoestimateastheuncertaintyinasinglemeasurement.Oneapproachistoestimatewhatthelargestandsmallestpossibleslopesarebyeye.Alternatively,thecomputercangiveanestimateoftheuncertainty.Itcancalculatethestandarddeviationoftheslopeandtheintercept,andforthepurposeofthiscourse,onecanusetheseastheuncertainties.Tohavethecomputerdisplaytheuncertainties,double-clickontheboxshowingthefitparametersforthegraphintheLoggerProwindow.LinearFitOptionswillappear.Selecting"ShowUncertainty"forboththe"Slope"and"Y-Intercept,"andthenclickingtheOKbuttonwilldisplaytheseparameters.

2. Askyourinstructorifshe/hewantsyoutocontinuewiththeLABorproceedtosectionVIII(cleanup).

C. Atthistime,yourparticularinstructormightpresenttoyouotherfunctionsinLogger-Prothatareessentialtocompletingfuturelabsinyourclass.Seekguidancefromyourinstructoronwhichprocessestocompleteatthistime.IftherearenootherprocessestobediscussedproceedtosectionVIII(cleanup).

VII. LabReporttoHandIn(onlygraphsasassignedbasedonyourinstructor’sinput)

A. GraphfromPartE,Experiment1,annotatedandwithdiscussion.

B. GraphfromPartF,Experiment2,annotatedandwithdiscussion.

C. GraphfromPartG,Experiment3,annotatedandwithdiscussion.

D. GraphfromPartH,Experiment4,annotatedandwithdiscussion.


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VIII. Clean-Up

A. GoldenRule:“Dountoothersasyoudesirethemtodountoyou.”

ThisappliesasmuchhereinthelabasitdoesintheFleet.AsfutureNavalOfficers,howcanyouexpectyourenlistedsailorstomaintainacleanworkareaifyourstateroom,workareas,messarea,etcisa“pigsty?”SoasofficersitisimperativethatwecleanupafterourselvesnotonlytofollowtheGoldenRule,butalsotoleadbyexamplefortheenlistedpersonnelunderourcharge.

1. EndofLabCheckout:Beforeleavingthelaboratory,pleasetidyuptheequipmentattheworkstationandquitallrunningsoftware.

2. Thelabstationshouldbeinbetterconditionthanwhenyouarrivedandmoreimportantly,shouldbeofanappearancethatyouwouldbePROUDtoshowtoyourlegalguardiansduringa“ParentsWeekend.”

3. HaveyourinstructorinspectyourlabstationandreceivetheirpermissiontoleavetheLabRoom.

YouSHALLfollowthisprocedureduringeverylabforSP211andSP212

ManythankstoDr.Huddle,Dr.Ertel,Dr.Mikulski,andDr.FontanellafortheirassistanceinproducingthisLaboratoryprocedure;specificreferencescanbesuppliedonrequest.LCDRTimothyShivok