PARTICLE TECHNOLOGY DEMONSTRATION.pdf

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1、ChEclassroomPARTICLETECHNOLOGYDEMONSTRATIONSForTheClassroomandLaboratorySIMONM.IVESON,GEORGEV.FRANKSUniversityofNewcastle•Callaghan,NSW2308,Australianeofthejoysofteachingacourseonpowdertech-WET-POWDERSYSTEMSnologyistheabundanceofquickandsimpleexperi-Omentst

2、hatcanbeusedinlecturestodemonstrateSingle-ParticleSettling(in-classdemonstration)thefundamentalphenomenabeingdiscussed.ThesecanbeMostcoursesonfluid-particleinteractionsbeginbyexam-usedasbreakspartwaythroughalectureorasaninterest-iningthesettlingofasinglesph

3、ericalparticle.Theeffectofarousingintroductiontoanewtopic.Demonstrationscanbefluidviscositycanbedemonstratedbyusingglassmarblesusedtohighlighttheoftencounter-intuitivebehaviorofpow-intwoidenticalperspextubesabout40cmlong,onefilleddersbyaskingthestudentstobr

4、eakintogroupsandtrytowithwaterandtheotherwithglycerol(oranyothertranspar-predictapriorihowtheyexpectagivensystemtobehave.Theentviscousfluid).[9]Startbyaskingthestudentsingroupstooftenquitedifferentbehaviorthattheysubsequentlyobserveestimatethesettlingtimeof

5、eachmarble.Mostwillcorrectlywillthenchallengethemtounderstandthecausesoftheirmis-guessthatthemarblewillsettlemoreslowlyintheglycerol.conceptionsandarousetheirinterestinthelecturematerial.[1,2]Whenaskedwhy,theywillprobablyrefertoeitherglycerol’sTherearemoret

6、hanenoughsuchdemonstrationstofillagreaterdensityoritsgreaterviscositycomparedtowater.spotineverylectureofaone-semesterintroductorycourseIfstudentsthinkthatdensitydifferenceisthecause,thenaonpowdertechnology.Most,however,arereferredtoonlyinsimplebuoyantforce

7、balancecanbeusedtocalculatehowpassinginreferencesscatteredthroughouttheliterature[e.g.,3-6]longitwouldtakethemarbletofallundertheinfluenceoforarepassedonbyword-of-mouthfromonepractitionertogravityalone.For
=1g/cm3,
=1.25g/cm3andwaterglycerolanother.Klinzing

8、[7]hasprovidedapartiallistofsuchdemon-3
=2.5g/cm,theincreaseinfalltimeintheglyceroldueglassstrations,andarecentCDbyRhodesandZakhari[8]containstoitsgreaterdensitywouldbeonly10%.Thecalculatedset-videocli