science spectrum科学谱

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1、ScienceSpectrumPhysicalScience–Grade9IntroductiontoScience–Chapter1Science-asystemofknowledgebasedonfactsorprinciples-observing,studying,&experimentingtofindthenatureofthingsTechnology-theapplicationofsciencetomeethumanneedsscienceandtechnologyrelyoneachother–theadvancementofonepro

2、motestheadvancementoftheother–example:microscopesScientificTheory-atestedpossibleexplanationofanaturaleventScientificLaw-asummaryofanobservednaturaleventGiveanexampleofatheory?alaw?theoriesarenotabsolute–theyarechangedorreplacedasnewdiscoveriesaremadethatdonotagreewiththemModel-avi

3、sualrepresentationofanobjectoreventthatcanbestudied&allowpredictionstobemadeabouttherealobjectoreventScientificMethod-aseriesoflogicalstepstofollowinordertosolveaproblemthereisnoone“scientificmethod”–scientistsemploymanydifferentmethods,butthisisthebasicideaofthethoughtprocessuseda

4、stheyproceedExperiment-controlledobservationofevents–withasfewvariablesaspossibleVariable-anythingthatcanchangeinanexperimentWhyisonly1variablethemostdesirable?UnitsofMeasurement–standardunitsallowquantitiestobeunderstoodanywhereintheworld–thesystemofunitsused–leSystemeInternationa

5、leorSISIUnits   Length metermMassgramgTimesecondsTemperaturekelvinKElectricCurrentampereAAmountofSubstancemolemolLuminousIntensitycandelacdBase10Prefixes mega1000000000109giga1000000106kilo1000103hecta100102deca10101 deci0.110-1centi0.0110-2milli0.00110-3micro0.00000110-6nano0.0000

6、0000110-9practiceconversionsfromoneprefixtoanotherexample–265centimeterstokilometers265cm1m1km=0.00265ORcm= 10-210(-2-3)=265x10-5100cm1000mkm=103ScientificNotation–avaluewrittenasasimplenumbermultipliedbyavalueof10scientificnotationisimpliedinbase10prefixesSignificantFigures-thedig

7、itsinameasurementthatareknownforsurePrecision–thedegreeofexactnessofameasurement-arethevaluesrepeatable?Accuracy-theextenttowhichameasurementapproachesthetruevalue-howmanydecimalplacescanitbemeasuredto?Namesomesituationsthatshowpooraccuracyand/orprecisionChapter8–MotionandForceSpee

8、d-distancehowfastanobjectm