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Chapter 2: Science, Matter, and Energy

CHAPTER2

SCIENCE,MATTER,ANDENERGY

Outline

2-1Whatdoscientistsdo?

  1. Scienceisasearchfororderinnature.
  2. Scientistsmakeobservationsforcollectingfactsorscientificdata.
  3. Basedonobservations,scientistsformascientifichypothesis—anunconfirmedexplanationofanobservedphenomenon.
  4. Scientiststestthesehypothesesbydesigningexperiments,makingpredictions,andcollectingdata.
  5. Scientistsuseobservations,experiments,andmodelstoanswerquestionsabouthownatureworks.
  6. Identifyaproblem.
  7. Findoutwhatisknownabouttheproblem.
  8. Askaquestiontobeinvestigated.
  9. Makeobservationsandcollectdataorpreviousresearch.
  10. Analyzedata.
  11. Proposeanhypothesistoexplaindata.
  12. Usehypothesistomaketestablepredictions.
  13. Performanexperimenttotestpredictions.
  14. Acceptorrevisehypothesisandre-test.
  15. Developascientifictheory,ifwell-testedandwidelyacceptedhypothesis.
  16. Importantfeaturesofthescientificprocessareskepticism,reproducibility,andpeerreview.
  17. Scientifictheoriesandlawsarethemostimportantandreliableresultsofscience.
  18. Scientific/naturallawdescribesevents/actionsofnaturethatreoccurinthesameway,overandoveragain.
  19. Theresultsofsciencecanbetentative,reliable,orunreliable.
  20. Resultsthathavenotbeenwidelytestedorarenotwidelyacceptedareoftencalledtentativescience.Atthisstage,disagreementamongscientistsiscommonandleadstoadvancement.
  21. Reliablescienceconsistsofwidelytestedandacceptedresultsthathavebeenscrutinizedbyexpertsinthefield.
  22. Unreliablescienceincludesresultsthathavenotbeenrigorouslypeerreviewedorthathavebeendiscardedasaresultofpeerreview.
  23. ScienceFocus:thescientificconsensusonglobalwarming.
  24. Sciencehassomelimitations.
  25. Scientistscandisprovefacts,butcanneverprovethingsabsolutelybecauseofinherentuncertaintyinmeasurements,observations,andmodels.
  26. Scientistsattempttoestablishhighprobabilityoftruthtotheirstatements.
  27. Beinghuman,scientistsarenotfreeofbias,althoughtheydoattempttominimizethiseffect.
  28. Becausethenaturalworldissocomplex,therearemanyvariablesthatcannotbecontrolled.
  29. Sciencecannotanswerquestionsthatwehavenowayoftesting.

2-2Whatismatterandhowdophysicalandchemicalchangesaffectit?

  1. Matterconsistsofelementsandcompounds.
  2. Matterisanythingthathasmassandtakesupspace,livingornot.
  3. Matterexistsinthreephysicalstates:solid,liquid,gas.
  4. Anelementisafundamentalsubstancethathasauniquesetofpropertiesandcannotbebrokendownintosimplersubstancesbychemicalmeans.
  5. Elementsarerepresentedbyaone-ortwo-lettersymbol.
  6. Compoundsarecombinationsoftwoormoredifferentelementsboundinfixedproportions.

  1. Atoms,ions,andmoleculesarethebuildingblocksofmatter.
  2. Thebuildingblocksofmatterareatoms,ions,andmolecules.
  3. Anatomisthesmallestunitofmatterthatexhibitsthecharacteristicsofanelement.
  4. Eachatomconsistsofsubatomicparticles.Theyarethepositivelychargedprotons,unchargedneutrons,andnegativelychargedelectrons.
  5. Eachatomcontainsacoreofthesubatomicparticlesprotonsandneutrons.
  6. Eachelementhasanatomicnumberthatisequaltothenumberofprotonsinthenucleusofitsatom.
  7. Themassnumberofanatomisthetotalnumberofneutronsandprotonsinitsnucleus.
  8. Isotopesareformsofanelementthathavethesameatomicnumber,butdifferentmassnumbers.
  9. Anionisanelectricallycharged(+or-)atom.
  10. pHisameasureofaciditybasedontheamountofhydrogenions(H+)andhydroxideions(OH-).
  11. Amoleculeisacombinationoftwoormoreatomsofthesameelementsheldtogetherbychemicalbonds.
  12. Chemicalformulasareatypeofshorthandtoshowthetypeandnumberofatoms/ionsinacompoundormolecule.

a.Eachelementinthecompoundisrepresentedbyasymbol(e.g.,H=hydrogen,
N=nitrogen).

b.Subscriptsshowthenumberofatoms/ionsinthecompound.

  1. Organiccompoundsarethechemicalsoflife.
  2. Organiccompoundscontainatleasttwocarbonatomscombinedwithvariousotheratoms,exceptmethane(CH4)whichhasonlyonecarbonatom.
  3. Hydrocarbons:compoundsofcarbonandhydrogenatoms.
  4. Chlorinatedhydrocarbons:compoundsofcarbon,hydrogen,andchlorineatoms.
  5. Simplecarbohydrates:specifictypesofcompoundsofcarbon,hydrogen,andoxygenatoms.
  6. LargerMacromoleculesoforganiccompoundsinclude:
  7. Complexcarbohydrates:twoormoremonomersofsimplesugarssuchasglucose
  8. Proteins:formedbymonomerscalledaminoacids
  9. Nucleicacids:(DNAandRNA)formedbymonomerscallednucleotides
  10. Matterbecomeslifethroughgenes,chromosomes,andcells.
  11. Cellsarethesmallestandmostfundamentalstructuralandfunctionalunitsoflife.
  12. DNAcontainssequencesofnucleotidesthatformgenesthatcodefortraits.
  13. ChromosomesarecomposedofDNAandproteins.
  14. Someformsofmatteraremoreusefulthanothers.
  15. High-qualitymatterishighlyconcentrated,istypicallyfoundneartheearth’ssurface,andhasgreatpotentialforuseasaresource.
  16. Low-qualitymatterisnothighlyconcentrated,isoftenlocateddeepundergroundordispersedintheoceanoratmosphere,andusuallyhaslittlepotentialforuseasaresource.
  17. Matterundergoesphysical,chemical,andnuclearchanges.
  18. Physicalchangeisnotchemicalcompositionchangebutachangeinstates.
  19. Chemicalchangeorchemicalreactionisachangeinthechemicalcomposition.
  20. Lawofconservationofmatterstatesthatnoatomsarecreatedordestroyed.

2-3Whatisenergyandhowdophysicalandchemicalchangesaffectit?

  1. Energycomesinmanyforms.
  2. Energyisthecapacitytodoworkortransferheat.
  3. Kineticenergyisenergyassociatedwithmotion.

a.Heatisaformofkineticenergy.Whentwoobjectsatdifferenttemperaturescontactoneanotherheatflowsfromthewarmertothecoolerobject.

b.Electromagneticradiationisaformofkineticenergyandoccurswhenenergytravelsaswavesasaresultofchangesinelectricalandmagneticfields.

  1. Potentialenergyisstoredenergy.

  1. Sometypesofenergyaremoreusefulthanothers.
  2. High-qualityenergyisconcentratedandhasahighcapacitytodousefulwork.
  3. Low-qualityenergyisdispersedandhaslittlecapacitytodousefulwork.
  4. Energychangesaregovernedbytwoscientificlaws.
  5. Thelawofconservationofenergy,orthefirstlawofthermodynamics,statesthatwhenenergyisconvertedfromoneformtoanotherinaphysicalorchemicalchange,noenergyiscreatedordestroyed.
  6. Thesecondlawofthermodynamicsstatesthatwhenenergyischangedfromoneformtoanother,energyqualityisdepleted.
  7. Threescientificlawsgovernwhatwecanandcannotdowithmatterandenergy:

a.Thereisno“away.”

b.Youcannotgetsomethingfornothing.

c.Youcannotbreakeven.

Objectives

2-1Whatdoscientistsdo?

CONCEPT2-1Scientistscollectdataanddeveloptheories,models,andlawsabouthownatureworks.

  1. Brieflydescribehowscienceworks.Statethequestionssciencetriestoanswer.Summarizescientificmethods.
  2. Statetheimportanceofcuriosity,skepticism,peerreview,andreproducibilityinthescientificprocess.

2-2Whatismatterandhowdophysicalandchemicalchangesaffectit?

CONCEPT2-2AMatterconsistsofelementsandcompounds,whichinturnaremadeupofatoms,ions,ormolecules.

CONCEPT2-2BWhenevermatterundergoesaphysicalorchemicalchange,noatomsarecreatedordestroyed(thelawofconservationofmatter).

  1. Definematter.Distinguishbetweenstatesofmatterandqualityofmatter.
  2. Distinguishamongphysical,chemical,andnuclearchanges.Distinguishbetweennuclearfissionandnuclearfusion.
  3. Statethelawofconservationofmatter.Discussthepropertiesofpollutants.

2-3Whatisenergyandhowdophysicalandchemicalchangesaffectit?

CONCEPT2-3AWheneverenergyisconvertedfromoneformtoanotherinaphysicalorchemicalchange,noenergyiscreatedordestroyed(firstlawofthermodynamics).

CONCEPT2-3BWheneverenergyisconvertedfromoneformtoanotherinaphysicalorchemicalchange,weendupwithlowerqualityorlessusableenergythanwestartedwith(secondlawofthermodynamics).

  1. Defineenergy.Distinguishbetweenformsofenergyandqualityofenergy.
  2. Distinguishbetweenthefirstandsecondlawsofenergyandgiveanexampleofeach.
  3. Describetheimplicationsofthelawsofmatterandenergyforalong-termsustainable-Earthsociety.
  4. Distinguishamonghigh-waste,matter-recycling,andlow-wastesocieties.

KeyTerms

© 2011 Brooks/Cole Publishing, a Division of Cengage Learning

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Chapter 2: Science, Matter, and Energy

acidity(p.30)

atom(p.28)

atomicnumber(p.29)

atomictheory(p.29)

cells(p.31)

chemicalchange(p.32)

chemicalformula(p.30)

chemicalreaction(p.32)

chromosomes(p.31)

compounds(p.28)

data(p.25)

electromagneticradiation(p.34)

electrons(p.29)

elements(p.28)

energy(p.34)

energyquality(p.34)

experiments(p.25)

firstlawof
thermodynamics(p.35)

frontierscience(p.26)

genes(p.31)

heat(p.34)

high-qualityenergy(p.34)

high-qualitymatter(p.32)

inorganiccompounds(p.30)

ion(p.29)

isotopes(p.29)

kineticenergy(p.34)

lawofconservationof
energy(p.35)

lawofconservationof
matter(p.32)

low-qualityenergy(p.35)

low-qualitymatter(p.32)

massnumber(p.29)

matter(p.28)

matter-recyclingeconomy(p.35)

matterquality(p.31)

model(p.25)

molecule(p.30)

neutrons(p.29)

nucleus(p.29)

organiccompounds(p.30)

peerreview(p.26)

pH(p.30)

physicalchange(p.32)

potentialenergy(p.34)

protons(p.29)

radioactivedecay(p.33)

reliablescience(p.26)

science(p.24)

scientifichypothesis(p.25)

scientificlaw(p.26)

scientifictheory(p.25)

secondlawofthermodynamics(p.35)

tentativescience(p.26)

trait(p.31)

unreliablescience(p.26)

© 2011 Brooks/Cole Publishing, a Division of Cengage Learning

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Chapter 2: Science, Matter, and Energy

© 2011 Brooks/Cole Publishing, a Division of Cengage Learning

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Chapter 2: Science, Matter, and Energy

TeachingTips

Askthestudentstodescribewhatscientists“do,”orhowscientistsexpandourknowledgebase.Leadthediscussiontocontrolledexperiments,namelyhowtheydevelopexperimentsandtesthypotheses.Usethediscussionofcontrolledexperimentstointroducethecorecasestudy,HubbardBrook.

  • Usethecorestudytosolidifythestudents’understandingofcontrolgroup,experimentalgroup,andbaselinedata.Here,BormanandLikensperformthedauntingtaskofconductingacontrolledexperimentinthefield.Therefore,laboratoryandfieldexperimentscanbecompared.
  • Manystudentshavelittlenotionofhowscienceis“done.”Considerabletimeshouldbespentdiscussingwhatscienceis,includingthescientificmethod,itsuses,andlimitations.
  • Astheunderpinningofalltopicsdiscussedinthecourse/book,thetopicsofmatter,energy,andenergyuseshouldbeemphasized.

Askthestudentstoselectascientist(youcanhaveindexcardswithscientists(name,dates,location,scientificachievements)ortheycanresearchthescientistontheirown.Askthestudentstopretendtheyarethatscientist,andhavetheclasstrytoguesswhoeachstudentrepresents.

Bringinproductsmadeofmaterialsfoundontheperiodictable(jewelryworkswell).Foodorplantsworkwellfororganic(carbon-containing)examples,whileseasaltworkswellforinorganicexamples.

Inclearglassesplacesugarincoldwaterandhotwater(heatenergy)toshowdifferentratesofdissolving,thenstir(mechanicalenergy).

DiscussionTopics

  1. Howmuchareyouwillingtopayintheshorttermtoreceiveeconomicandenvironmentalbenefitsinthelongterm?Explorecostsandpaybacktimesofenergy-efficientappliances,energy-savinglightbulbs,andweatherstripping.
  1. Canwegetsomethingfornothing?Exploretheattemptsofadvertisingtoconvincethepublicthatwecanindeedgetsomethingfornothing.Exploreattemptstocreateperpetualmotionmachines.Explorethehistoryofthefreelunchconcept.
  1. Isconveniencemoreimportantthansustainability?ExploretheinfluenceofU.S.frontieroriginsonthethrowawaymentality.
  1. Whatactionscanyoutaketoimproveyourhome’senergyefficiencyandreduceconsumptionofmaterials? Doyoubelievethesereductionswillincreaseordecreaseyourqualityoflife?
  1. Whatisournationalenergypolicy?Howhasitchangedoverthepast20years?Isourcurrentpolicysupportedbythescienceinthischapterregardingthelawsofenergy?Whataretheshort-andlong-termeconomic,environmental,andnational-securityimplications?
  1. HowdoesthetotalamountofmatterandenergyintheuniverserelatetotheBigBangTheoryoftheoriginoftheuniverseandtheroleofentropyinthedestinyoftheuniverse?
  1. Whatwoulditbeliketoleadalow-energylifestyle?Arepeoplealreadysuccessfullyusinglessenergywhilemaintainingahighqualityoflife?Whataresomeofthechallengesinconvincingmorepeopletoembracealow-energylifestyle?

ActivitiesandProjects

  1. Ahumanbodyatrestyieldsheatataboutthesamerateasa100-wattincandescentlightbulb.Asaclassexercise,calculatetheheatproductionofthestudentbodyofyourschool,theU.S.population,andtheglobalpopulation.Wheredoestheheatcomefrom?Wheredoesitgo?
  1. Asaclassexercise,conductasurveyofthestudentsatyourschooltodeterminetheirdegreeofawarenessandunderstandingofthethreebasicmatterandenergylaws.Discusstheresultsinthecontextoftheneedforlow-entropylifestylesandsustainable-Earthsocieties.
  1. Askaphysics/chemistryprofessor(s)orphysics/chemistrylabinstructor(s)tovisityourclassand,byusingsimpleexperiments,demonstratethematterandenergylaws.
  1. Asaclassexercise,trytoinventorythetypesofappliancesthatareusedtomaintainaclassroomenvironment—thelighting;spaceheatingandcooling;electricityforprojectors;andotherfacilities,equipment,andservices.Listthematterfromwhichtheyaremadeandtheirapproximatemassandenergyconsumption,ifapplicable.
  1. Inviteamedicaltechniciantospeaktoyourclassonthebeneficialusesofionizingradiation.Whatcontrolsareemployedtolimittherisksassociatedwiththeuseofradioisotopesfordiagnosticandtreatmentprocedures?

AttitudesandValuesAssessment

  1. Wheredoyoufitintotheflowofenergyfromthesun?
  1. Doyoufeelyouplayaroleinnature’scyclesofmatterandenergy?
  2. Whatisyourbodytemperature?Howdoesyourbodystayatthattemperatureeveninthecoldweather?Howdoyoufeelwhenyouareinair-conditionedorheatedrooms?
  1. Doyouusealotofenergy(e.g.,lights,television,CDplayer,car,orheatedwater)?Wheredoestheenergycomefrom?Whywouldyouincreaseordecreaseyourusage?
  1. Howdoyoufeelonasunnyday?Acloudyday?Whatisthewinddoingwiththeatmosphericenergythosedays?
  1. WhatrightdoyouhavetouseEarth’smaterialresources?Arethereanylimitstoyourrights?Whatarethey?
  1. WhatrightsdoyouhavetoEarth’senergyresources?Arethereanylimitstoyourrights?Whatarethey?
  1. Doyoubelievethatcyclesofmatterandenergyflowingfromthesunhaveanythingtodowithyourlifestyle?Withyourcountry’spolicies?

LaboratorySkills

Wells,Edward.LabManualforEnvironmentalScience.2009.Lab#1:IntroductiontoExperimentalDesign.

NewsVideos

StuffThatWeLeaveBehind;EnvironmentalScienceintheHeadlines,2007;DVD;ISBN:0495385433

AdditionalVideos

AcidRainTheInvisibleThreat(VideoplusLab)
Hands-onlabactivitiesplusvideo.

The Scientific Method Song

A musical explanation of the scientific method

The Scientific Method

An explanation of the history behind the method

WebResources

TheParticleAdventure

AnexplorationofthefundamentalsofmatterfromtheLawrenceBerkeleyLabs.

SuggestedAnswerstoEndofChapterQuestions

Answerswillvarybuttheserepresentphrasesfromthischapter.Thefollowingareexamplesofthematerialthatshouldbecontainedinpossiblestudentanswerstotheendofchapterquestions.Theyrepresentonlyasummaryoverviewandservetohighlightthecoreconceptsthatareaddressedinthetext.Itshouldbeanticipatedthatthestudentswillprovidemorein-depthanddetailedresponsestothequestionsdependingonanindividualinstructor’sstatedexpectations.

Review

1.ReviewtheKeyQuestionsandConceptsforthischapteronp.24.DescribethecontrolledscientificexperimentcarriedoutintheHubbardBrookExperimentalForest.

Seepages23–24.

2.Whatisscience?Describethestepsinvolvedinascientificprocess.Whatisdata?Whatisamodel?Distinguishamongascientifichypothesis,scientifictheory,andscientificlaw(lawofnature).Whatispeerreviewandwhyisitimportant?Explainwhyscientifictheoriesarenottobetakenlightlyandwhypeopleoftenusethetermtheoryincorrectly.

  • Scienceisanattempttodiscoverhownatureworksandtousethatknowledgetomakepredictionsaboutwhatislikelytohappeninnature.
  • Dataistheinformationneededtoanswerscientificquestionsusuallyobtainedbymakingobservationsandmeasurements.
  • Modelisanapproximaterepresentationorsimulationofasystembeingstudied.
  • Scientifichypothesisisapossibleandtestableexplanationofwhatisobserveinnatureorintheresultsofexperiments.
  • Awell-testedandwidelyacceptedscientifichypothesisoragroupofrelatedhypothesesiscalledascientifictheory.
  • Ascientificlaw,orlawofnatureisawell-testedandwidelyaccepteddescriptionofwhatwefindhappeninginnature.
  • Animportantpartofthescientificprocessispeerreview,inwhichscientistsopenlypublishdetailsofthemethodsandmodelstheyused,theresultsoftheirexperiments,andthereasoningbehindtheirhypothesesforotherscientistsworkinginthesamefield(theirpeers)toevaluate.Andanyevidencegatheredtoverifyahypothesismustbereproducible.Thatis,scientistsshouldrepeatandanalyzetheworktoseeifthedatacanbereproducedandwhethertheproposedhypothesisisreasonableanduseful.
  • Ascientifictheoryshouldbetakenveryseriously.Ithasbeentestedwidely,supportedbyextensiveevidence,andacceptedbymostscientistsinaparticularfieldorrelatedfieldsofstudy.Nonscientistsoftenusethewordtheoryincorrectlywhentheyactuallymeanscientifichypothesis,atentativeexplanationthatneedsfurtherevaluation.Thestatement,“Oh,that’sjustatheory,”madeineverydayconversation,impliesthatthetheorywasstatedwithoutproperinvestigationandcarefultesting—theoppositeofthescientificmeaningoftheword.

3.Explainwhyscientifictheoriesandlawsarethemostimportantresultsofscience.

Sincethegoalofscienceistocomeupwiththeoriesandlawsbasedonfactstoexplainhowtheworldworks,thesetheoriesandlawsaretheculminationofthescientificprocess,especiallysinceascientificlawcannotbebrokenaslongasthedatausedtoformulateitisaccurate.

4.Distinguishamongtentativescience(frontierscience),reliablescience,andunreliablescience.Describethescientificconsensusoverprojectedclimatechange.Whatarethreelimitationsofscienceandenvironmentalscience?

  • Tentativescienceorfrontierscienceisthepreliminaryresultsthatcapturenewsheadlinesandmaybecontroversialbecausetheyhavenotbeenwidelytestedandacceptedbypeerreviewyet.
  • Reliablescienceconsistsofdata,hypotheses,theories,andlawsthatarewidelyacceptedbyallormostofthescientistswhoareconsideredexpertsinthefieldunderstudy,inwhatisreferredtoasascientificconsensus.Theresultsofreliablesciencearebasedontheself-correctingprocessoftesting,peerreview,reproducibility,anddebate.Newevidenceandbetterhypothesesmaydiscreditoralteracceptedviews.
  • Scientifichypothesesandresultsthatarepresentedasreliablewithouthavingundergonetherigorsofpeerreview,orthathavebeendiscardedasaresultofpeerreview,areconsideredtobeunreliablescience.
  • Since1990,theIPCChaspublishedfourmajorreportssummarizingthescientificconsensusamongtheseclimateexperts.Inits2007report,theIPCCcametothreemajorconclusions:
  • Itisverylikely(atleast90%certainty)thattheloweratmospherewarmedbyabout0.74C°(1.3F°)between1906and2005.
  • Basedonanalysisofpastclimatedataanduseof19climatemodels,itisverylikely(atleast90%certainty)thathumanactivities,ledbyemissionsofcarbondioxidefromburningfossilfuels,havebeenthemaincauseoftheobservedatmosphericwarmingbetween1957and2007.
  • Itislikely(66–89%certainty)thattheearth’smeansurfacetemperaturewillincreasebyabout3Co(5.4Fo)between2005and2100,unlesstheworldmakesdrasticcutsingreenhousegasemissionsfrompowerplants,factories,andvehiclesthatburnfossilfuels.
  • Environmentalscienceandscienceingeneralhavethreeimportantlimitations:
  • Scientistscannotproveordisproveanythingabsolutely,becausethereisalwayssomedegreeofuncertaintyinscientificmeasurements,observations,andmodels.
  • Alimitationofscienceisthatscientistsarehumanandthusarenottotallyfreeofbiasabouttheirownresultsandhypotheses.
  • Alimitation—especiallyimportanttoenvironmentalscience—isthatmanyenvironmentalphenomenainvolveahugenumberofinteractingvariablesandcomplexinteractions.

5.Whatismatter?Distinguishbetweenanelementandacompoundandgiveanexampleofeach.Distinguishamongatoms,ions,andmoleculesandgiveanexampleofeach.Whatistheatomictheory?Distinguishamongprotons,neutrons,andelectrons.Whatisthenucleusofanatom?Distinguishbetweentheatomicnumberandthemassnumberofanelement.Whatisanisotope?Whatisacidity?WhatispH?

  • Matterisanythingthathasmassandtakesupspace.Itcanexistinthreephysicalstates—solid,liquid,andgas,andtwochemicalforms—elementsandcompounds.
  • Achemicalelementisafundamentalsubstancethathasauniquesetofpropertiesandcannotbebrokendownintosimplersubstancesbychemicalmeans.Compoundsareacombinationsoftwoormoredifferentelementsheldtogetherinfixedproportions.
  • Themostbasicbuildingblockofmatterisanatom—thesmallestunitofmatterintowhichanelementcanbedividedandstillhaveitscharacteristicchemicalproperties,suchasasinglehydrogenatom.Asecondbuildingblockofsometypesofmatterisanion—anatomorgroupofatomswithoneormorenetpositive(+)ornegative(–)electricalcharges,suchasH+.Amoleculeisacombinationoftwoormoreatomsofthesameelementsheldtogetherbyforcescalledchemicalbonds,suchasO2,oxygen.
  • Theatomictheoryistheideathatallelementsaremadeupofatoms.
  • Threedifferenttypesofsubatomicparticles:positivelychargedprotons(p),neutrons(n)withnoelectricalcharge,andnegativelychargedelectrons(e).
  • Eachatomconsistsofanextremelysmallanddensecentercalleditsnucleus—whichcontainsoneormoreprotonsand,inmostcases,oneormoreneutrons—andoneormoreelectronsmovingrapidlysomewherearoundthenucleus.
  • Eachatomhasequalnumbersofpositivelychargedprotonsandnegativelychargedelectrons.Becausetheseelectricalchargescanceloneanother,atomsasawholehavenonetelectricalcharge.Eachelementhasauniqueatomicnumber,equaltothenumberofprotonsinthenucleusofitsatom.Themassofanatomisdescribedbyitsmassnumber:thetotalnumberofneutronsandprotonsinitsnucleus.
  • Formsofanelementhavingthesameatomicnumberbutdifferentmassnumbersarecalledisotopesofthatelement.
  • Ionsarealsoimportantformeasuringasubstance’sacidityinawatersolution,achemicalcharacteristicthathelpsdeterminehowasubstancedissolvedinwaterwillinteractwithandaffectitsenvironment.
  • ScientistsusepHasameasureofacidity,basedontheamountofhydrogenions(H+)andhydroxideions(OH–)containedinaparticularvolumeofasolution.

6.Whatisachemicalformula?Distinguishbetweenorganiccompoundsandinorganiccompoundsandgiveanexampleofeach.Distinguishamongcomplexcarbohydrates,proteins,nucleicacids,andlipids.Definecellandbrieflydescribecelltheory.Distinguishamonggenes,traits,andchromosomes.Whatismatterquality?Distinguishbetweenhigh-qualitymatterandlow-qualitymatterandgiveanexampleofeach.

Seepages28–32.Studentanswerswillvaryslightly.

  • Chemistsuseachemicalformulatoshowthenumberofeachtypeofatomorioninacompound.
  • Organiccompoundscontainatleasttwocarbonatomscombinedwithatomsofoneormoreotherelement,suchastablesugarandmethane.Allothercompounds,exceptmethane(CH4),arecalledinorganiccompounds,suchwater.
  • Complexcarbohydrates,suchascelluloseandstarch,consistoftwoormoremonomersofsimplesugars,suchasglucose.
  • Proteinsareformedbymonomerscalledaminoacids.
  • Nucleicacids(DNAandRNA)areformedbymonomerscallednucleotides.
  • Lipids,whichincludefatsandwaxes,arenotallmadeofmonomers,butareafourthtypeofmacromoleculeessentialforlife.
  • Cellsarethesmallestandmostfundamentalstructuralandfunctionalunitsoflife.
  • Theideathatalllivingthingsarecomposedofcellsispartofthecelltheory,themostwidelyacceptedscientifictheoryinbiology.
  • WithinsomeDNAmoleculesarecertainsequencesofnucleotidescalledgenes.EachofthesedistinctpiecesofDNAcontainsinstructions,calledgeneticinformation,formakingspecificproteins.Eachofthesecodedunitsofgeneticinformationconcernsaspecifictrait,orcharacteristic,passedonfromparentstooffspringduringreproductioninmostanimalsorplants.Thousandsofgenes,inturn,makeupasinglechromosome,aspecialDNAmoleculetogetherwithanumberofproteins.
  • Matterisanythingthathasmassandtakesupspace.Itcanexistinthreephysicalstates:solid,liquid,andgasandtwochemicalforms:elementsandcompounds.
  • High-qualitymatterishighlyconcentrated,istypicallyfoundneartheearth’ssurface,andhasgreatpotentialforuseasaresource,coalforexample.Low-qualitymatterisnothighlyconcentrated,isoftenlocateddeepundergroundordispersedintheoceanoratmosphere,andusuallyhaslittlepotentialforuseasaresource,asaltsolutionforexample.

7.Distinguishbetweenaphysicalchangeandachemicalchange(chemicalreaction)andgiveanexampleofeach.Explainthedifferencesamongradioactivedecay,nuclearfission,andnuclearfusion.Whatisthelawofconservationofmatterandwhyisitimportant?

Seepages32–33forthesequotes.Studentanswerswillvaryslightly.

  • Whenasampleofmatterundergoesaphysicalchange,thereisnochangeinitschemicalcomposition.Apieceofaluminumfoilcutintosmallpiecesisstillaluminumfoil.
  • Whenachemicalchange,orchemicalreaction,takesplacethereisachangeinchemicalcompositionofthesubstancesinvolved.Chemistsuseachemicalequationtoshowwhathappensinachemicalreaction.Forexample,whencoalburnscompletely,thesolidcarbon(C)inthecoalcombineswithoxygengas(O2)fromtheatmospheretoformthegaseouscompoundcarbondioxide(CO2).
  • Radioactivedecayoccurswhennucleiofunstableisotopesspontaneouslyemitfast-movingchunksofmatter(alphaparticlesorbetaparticles),high-energyradiation(gammarays),orbothatafixedrate.
  • Nuclearfissionoccurswhenthenucleiofcertainisotopeswithlargemassnumbers(suchasuranium-235)aresplitapartintolighternucleiwhenstruckbyaneutronandreleaseenergyplustwoorthreemoreneutrons.
  • Nuclearfusionoccurswhentwoisotopesoflightelements,suchashydrogen,areforcedtogetheratextremelyhightemperaturesuntiltheyfusetoformaheaviernucleusandreleaseatremendousamountofenergy.
  • Thelawofconservationofmatterstateswhenevermatterundergoesaphysicalorchemicalchange,noatomsarecreatedordestroyed.Thislawhelpsusunderstandthatweneedtoletourwastecyclebacktoitsoriginalnutrients/productsinorderforourresourcestobesustainable.

8.Whatisenergy?Distinguishbetweenkineticenergyandpotentialenergyandgiveanexampleofeach.Whatisheat?Defineandgivetwoexamplesofelectromagneticradiation.Whatisenergyquality?Distinguishbetweenhigh-qualityenergyandlow-qualityenergyandgiveanexampleofeach.

Seepages34–35forthesequotes.Studentanswerswillvaryslightly.

  • Energyisthecapacitytodoworkortransferheat.
  • Therearetwomajortypesofenergy:movingenergy(calledkineticenergy)andstoredenergy(calledpotentialenergy).Examplesofkineticenergyincludewind(amovingmassofair),flowingwater,andelectricity(flowingelectrons).Anexampleofpotentialenergyisgasoline.
  • Heatisaformofkineticenergy,thetotalkineticenergyofallmovingatoms,ions,ormoleculeswithinagivensubstance.Whentwoobjectsatdifferenttemperaturescontactoneanother,heatflowsfromthewarmerobjecttothecoolerobject.
  • Electromagneticradiationisenergythattravelsintheformofawaveasaresultofchangesinelectricalandmagneticfields.FormsofelectromagneticradiationareshortwavelengthssuchasgammaraysandXrays.
  • Energyqualityisameasureofanenergysource’scapacitytodousefulwork.
  • High-qualityenergyisconcentratedandhasahighcapacitytodousefulwork.Examplesareveryhigh-temperatureheat,nuclearfission,concentratedsunlight,high-velocitywind,andenergyreleasedbyburningnaturalgas,gasoline,orcoal.
  • Low-qualityenergyisdispersedandhaslittlecapacitytodousefulwork.Anexampleisheatdispersedinthemovingmoleculesofalargeamountofmatter(suchastheatmosphereoranocean)sothatitstemperatureislow.

9.Whatisthefirstlawofthermodynamics(lawofconservationofenergy)andwhyisitimportant?Whatisthesecondlawofthermodynamicsandwhyisitimportant?Explainwhythesecondlawmeansthatwecanneverrecycleorreusehigh-qualityenergy.

Seepage35forthesequotes.Studentanswerswillvaryslightly.

  • Thefirstlawofthermodynamics,alsoknownasthelawofconservationofenergy,statesthatwheneverenergyisconvertedfromoneformtoanotherinaphysicalorchemicalchange,noenergyiscreatedordestroyed.Thisscientificlawtellsusthatnomatterhowhardwetryorhowcleverweare,wecannotgetmoreenergyoutofaphysicalorchemicalchangethanweputinbecauseenergyinputalwaysequalsenergyoutput.
  • Thesecondlawofthermodynamicsstatesthatwhenenergyischangedfromoneformtoanother,italwaysgoesfromamoreusefultoalessusefulform.
  • Wecanneverrecycleorreusehigh-qualityenergybecausewheneverenergyisconvertedfromoneformtoanother,wealwaysendupwithalowerqualityorless“usable”energythanwestartedwith.

10.Whatarethischapter’sthreebigideas?RelatethethreeprinciplesofsustainabilitytotheHubbardBrookExperimentalForestcontrolledexperiment.

Seepage36forthesequotesandtheHubbardBrookExperiment.Studentanswersshouldslightlyvary.

  • Thethreebigideasofthischapter:
  • Thereisnoaway.Accordingtothelawofconservationofmatter,noatomsarecreatedordestroyedwhenevermatterundergoesaphysicalorchemicalchange.Thus,wecannotdoawaywithchemicals;wecanonlychangethemfromonephysicalstateorchemicalformtoanother.
  • Youcannotgetsomethingfornothing.Accordingtothefirstlawofthermodynamics,orlawofconservationofenergy,noenergyiscreatedordestroyedwheneverenergyundergoesaphysicalorchemicalchange.Thismeansthatinsuchchangeswecannotgetmoreenergyoutthanweputin.
  • Youcannotbreakeven.Accordingtothesecondlawofthermodynamics,wheneverenergyisconvertedfromoneformtoanotherinaphysicalorchemicalchange,wealwaysendupwithlowerqualityorlessusableenergythanwestartedwith.

CriticalThinking

  1. WhatecologicallessoncanwelearnfromthecontrolledexperimentontheclearingofforestdescribedintheCoreCaseStudythatopenedthischapter?

Vegetationcontrolswaterandnutrientlossfromecosystems.Lossofvegetationdiminishesthesystems’abilitytoretainnutrientsandwater.

  1. Youobservethatallofthefishinapondhavedisappeared.DescribehowyoumightusethescientificprocessdescribedintheCoreCaseStudyandonpp.24–25todeterminethecauseofthisfishkill.

AnswerswillvarybutthestepsinFigure2.2forthescientificprocessshouldbefollowed.Observation:thefishkill;Question:Whatcausedthefishtodie?Hypothesis:Maybethedissolvedoxygenwastoolow;Testthehypothesiswithanexperiment:Measurethedissolvedoxygenlevel;Result:Dissolvedoxygenlevelistoolow;Conclusion:Hypothesisisverified.

  1. Thinkofanareayouhaveseenwheresomesignificantchangehasoccurredtoanaturalsystem.Whatisaquestionyoumightaskinordertostartascientificprocesstoevaluatetheeffectsofthischange,similartotheprocessdescribedintheCoreCaseStudy?

Theanswershouldbeginwithsomeobservationthatcanleadtoahypothesis.Anobservationcouldbesomethinglikeincreasedrunoff,increasedpollutants,decreaseinvegetationorbiodiversity,etc.

  1. Describeawayinwhichyouhaveappliedthescientificprocessdescribedinthechapter(Figure2-2)inyourownlife,andstatetheconclusionyoudrewfromtheprocess.Describeanewproblemthatyouwouldliketosolveusingthisprocess.

Onemorningasyoupreparetodepartforyourcollege,youfindthatyourcarwillnotstart.Youobservethatthereisnosoundoftheengineturningover.Youhypothesizethatyouhaveadeadbattery.Youthendeviseanexperimenttotestthishypothesis.Youreasonthatyoucanchargethebatteryorjumpstartthecartotestwhetherornotthebatteryistrulythecause.Uponcharging,yourcarwillstart,soyouconcludethatyourbatterymusthavedied.Otherproblemsthestudentscouldsolverangefromissuesthataffectthemdirectlytothoseaffectingthecommunityortheworld.

  1. Respondtothefollowingstatements:a.Scientistshavenotabsolutelyproventhatanyonehaseverdiedfromsmokingcigarettes.b.Thegreenhousetheory—thatcertaingases(suchaswatervaporandcarbondioxide)warmtheatmosphere—isnotareliableideabecauseitisjustascientifictheory.

(a)Themedicalandscientificevidencethatlinkssmokingtoprematuredeathcausedbyanumberofpathologicalconditionsisoverwhelming.Asweareexposedtomanychemicalhazardsinourenvironmentitisoftendifficulttospecificallylinkthecauseandeffect.Thechancesofanindividualdyingfromsmokingonecigaretteisstatisticallynegligibleandhighlyunlikely,butmanyyearsofheavysmokinghasamuchhigherprobabilitythatadiseaseleadingtodeathcouldresult.

(b)Sometimespeoplewithalimitedknowledgeofthescientificmethodoftenconfuseatheorywithahypothesis.Atheoryhasbeenwidelytestedandisendorsedbyawidegroupofscientistsworkinginthatparticularfieldofstudy.Manyscientistsconcurwiththescientificevidence,obtainedthroughconductingcontrolledexperiments,thatwaterandcarbondioxidearegreenhousegases.

  1. Atreegrowsandincreasesitsmass.Explainwhythisphenomenonisnotaviolationofthelawofconservationofmatter.

Thegrowthofatreeisanexampleofachemicalchangeorchemicalreaction.Smallinorganicelementsandcompoundsarecombinedtoformmorecomplexmoleculesthatmakeupthematerialfoundinthetree.Thecomponentsthatwerepresentinthesoilandairhavebeenrearrangedtoformothertypesofchemicalcomponents.Theamountofmaterialthatwaspresentbeforethisrearrangementorchemicalchangetookplaceisthesameastheamountafterwards.Astudentmaydiscussphotosynthesistosupportandexplaintheiranswer.

  1. Ifthereisno“away,”whyistheworldnotfilledwithwastematter?

Justlikewhensmallmoleculesarecombinedtoformlargercompounds,asinthecaseofthegrowthofatree,whenlargercompoundsarebrokendowntheyreleasesmallermoleculesbackintotheenvironment.Anexampleisthatofarottinglog.Atreelimbmaybreakoffandfalltotheforestfloor.Overaperiodoftimeitisdecomposedbyavarietyoforganismsandthematerialscontainedinthelogreturnonceagainintotheenvironment.Inthiswaynaturerecyclesallmatterthatexistsintheenvironment.Thestudentmaydiscusscellrespirationtosupportorexplaintheiranswer.

  1. Someonewantsyoutoinvestmoneyinanautomobileenginethatwillproducemoreenergythantheenergyinthefuel(suchasgasolineorelectricity)usedtorunthemotor.Whatisyourresponse?Explain.

Thatisnotagoodinvestment!Thefirstlawofthermodynamicsstatesthatenergycanbechangedfromoneformtoanother(suchaschemicalenergyintomechanicalenergy),butenergycannotbecreatedordestroyed.Anenginethatproducesmoreenergythanitconsumesissimplynotafeasiblescientificallysoundprospect.

  1. Usethesecondlawofthermodynamicstoexplainwhyabarrelofoilcanbeusedonlyonceasafuel.

Thesecondlawofthermodynamicsstatesthatwhenenergychangesfromoneformtoanother,someoftheusefulenergyisalwaysdegradedtolower-quality,moredispersed,lessusefulenergy.Whenabarrelofoilthatcontainshigh-qualitychemicalenergyisusedasafuelinordertodousefulwork,itistransformedorchangedintolow-qualityenergysuchasheat,whichhaslittleabilitytodousefulwork.Thereforethebarrelofoilcanonlybeusedonceasafuel.

  1. Imagineyouhavethepowertorevokethelawofconservationofmatterforoneday.Whatarethethreemostimportantthingsyouwoulddowiththispower?b.Imagineyouhavethepowertoviolatethefirstlawofthermodynamicsforoneday.Whatarethethreemostimportantthingsyouwoulddowiththispower?

(a)Studentanswerswillvarybutcouldinclude:makemoreoiltooffsettheworldshortage;producemorewatertosupplyareasthatdesperatelyneedit;transformallchemicalpollutantsintousefulmaterialsthatarenotharmful.

(b)Studentanswerswillvarybutcouldinclude:growmorecropstoprovidefood;produceelectricitythatcanbestoredinbatteriesforlateruse;physicallychangemoreofthewaterintheArcticOceanintoseaicetooffsetthelossesthathaveoccurredinthepastfewdecades.

  1. Listtwoquestionsthatyouwouldliketohaveansweredasaresultofreadingthischapter.

Studentanswerswillvarybutcouldinclude:

Whatotherexamplesarethere,apartfromEasterIsland,thatshowcivilizationsthathavefallenasaresultofdegradingtheirresourcebase?

Howclosearescientiststobeingabletomimicphotosynthesisandusesunlighttosplitwaterintohydrogenandoxygen,similartotheprocessofelectrolysisofwater,andprovidetheworldwithhydrogenasamajorenergysource?

Data Analysis

  1. Which years confirm their hypothesis?
    The years 1991-1992, 1993-1995, 1996-1997 and 2000-2001 support the hypothesis that as the striped bass population rises, the population of blue crabs decreases. In these years, the population of striped bass increased and the population of blue crabs decreased.
  1. Which years do not support their hypothesis?
    The years 1990-1991, 1992-1993, 1995-1996 and 2001-2003 do not support the hypothesis that that as the striped bass population rises, the population of blue crabs decreases. In these years, populations of blue crab increased even though the striped bass population also increased.
  1. If the crab population reaches 100% of its goal, what percentage of its goal would the striped bass population achieve, by your projection?
    If the blue crab population reaches 100% of its goal, the striped bass population will also be near 100% of its goal. In 1996, both populations were near 100% of their goal. This would be the ideal situation for marine scientists.

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