PHYSICAL SCIENCEPHYSICAL SCIENCEChapter 1: The Nature of Chapter 1: The Nature of ScienceScience

Section 1: The Methods of ScienceSection 1: The Methods of Science

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What is science?What is science?

The term science is derived from the latin word The term science is derived from the latin word scientia, meaning “knowledge.”scientia, meaning “knowledge.”

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There are 3 Major There are 3 Major Categories of ScienceCategories of Science

1. Earth science—71. Earth science—7thth grade—investigates grade—investigates Earth and spaceEarth and space

2. Life science—82. Life science—8thth grade—deals with grade—deals with living thingsliving things

3. Physical science3. Physical science—9—9thth grade—study of grade—study of matter and energymatter and energy

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The Scientific MethodThe Scientific Method

An organized set of An organized set of investigation investigation procedures is called procedures is called the the scientific scientific method.method.

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STEP 1STEP 1

STATE THE PROBLEM (after making STATE THE PROBLEM (after making observations)observations)

The problem is often stated in the form of The problem is often stated in the form of a question (Why…? How…?)a question (Why…? How…?)

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STEP 2STEP 2

RESEARCH AND GATHER RESEARCH AND GATHER INFORMATIONINFORMATION

Learn about the background of the Learn about the background of the problem.problem.

What other tests have scientists already What other tests have scientists already performed? performed?

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STEP 3STEP 3

FORM A HYPOTHESIS—A FORM A HYPOTHESIS—A hypothesis hypothesis is a possible explanation for a problem.is a possible explanation for a problem.

““Educated Guess”Educated Guess” PredictionPrediction

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STEP 4STEP 4

TESTING A HYPOTHESISTESTING A HYPOTHESIS

Make observationsMake observations Build a modelBuild a model Perform an experimentPerform an experiment

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STEP 5STEP 5

ANALYZE THE ANALYZE THE DATA—Record DATA—Record observations into observations into easy-to-read tables easy-to-read tables and graphs. and graphs.

Include Include allall results, results, even unexpected even unexpected ones. (NO BIAS)ones. (NO BIAS)

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STEP 6--DRAW A CONCLUSION—Is STEP 6--DRAW A CONCLUSION—Is your hypothesis supported or not? your hypothesis supported or not?

SUPPORTED—SUPPORTED—REPEAT steps 4-6 REPEAT steps 4-6 several timesseveral times

NOTNOT SUPPORTED— SUPPORTED—REPEAT STEPS 3-6 REPEAT STEPS 3-6 (if now supported, see (if now supported, see above)above)

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VARIABLESVARIABLES

A A variablevariable is a quantity that can have is a quantity that can have more than a single value.more than a single value.

An experiment usually contains at least 2 An experiment usually contains at least 2 variables.variables.

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EXPERIMENTEXPERIMENT

Which brand of Which brand of fertilizer helps plants fertilizer helps plants to grow the biggest?to grow the biggest?

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List variables—factors that might List variables—factors that might cause plants to grow bigger.cause plants to grow bigger.

Amount of sunlightAmount of sunlight Amount of waterAmount of water Type of fertilizerType of fertilizer Type of soilType of soil Room temperature Room temperature Plant typePlant type

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What is the What is the independent independent variable?variable?

The variable you change to see how it The variable you change to see how it will affect the will affect the dependent dependent variable.variable.

The scientist is able to choose the The scientist is able to choose the independent variable.independent variable.

Ex. The brand of fertilizerEx. The brand of fertilizer

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What is the What is the dependent dependent variable?variable?

The dependent variable changes The dependent variable changes according to the changes in the other according to the changes in the other variable. variable.

The scientist is not able to choose the The scientist is not able to choose the dependent variable.dependent variable.

Ex. The amount of plant growthEx. The amount of plant growth1515

ConstantsConstants

A A constantconstant is a factor that does is a factor that does notnot change when other variables change.change when other variables change.

Constants remain the same throughout the Constants remain the same throughout the experiment.experiment.

Examples—amount of sunlight, amount of Examples—amount of sunlight, amount of water, room temperature, type of soil, water, room temperature, type of soil, plant type plant type

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ControlControl

A A controlcontrol is the standard by which the test is the standard by which the test results can be compared.results can be compared.

One plant has no fertilizer. This plant is the One plant has no fertilizer. This plant is the controlcontrol..

Ex. Three fertilized plants grow between Ex. Three fertilized plants grow between 2-3 cms. VS. The 2-3 cms. VS. The unfertilized unfertilized plant grows plant grows 1.5 cms. 1.5 cms.

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Are Are sciencescience and and technologytechnology the same?the same? Science Science is acquiring is acquiring

knowledge.knowledge.

Technology Technology is the is the application of science application of science to to help help people.people.

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Sweet 80’s Picture

CHAPTER 1: THE CHAPTER 1: THE NATURE OF SCIENCENATURE OF SCIENCE

Section 2: Standards of Section 2: Standards of MeasurementMeasurement

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A A standardstandard is an exact quantity is an exact quantity that people agree to use for that people agree to use for comparison.comparison.

English MeasurementEnglish Measurement

System (U.S.A.)System (U.S.A.) MilkMilkgallongallon LumberLumberfootfoot PotatoesPotatoespoundpound

Metric (Other Nations)Metric (Other Nations) Based on multiples Based on multiples

of 10 and developed of 10 and developed in the late 1700’s.in the late 1700’s.

Milk→ LiterMilk→ Liter Lumber→MeterLumber→Meter Potatoes→ KilogramPotatoes→ Kilogram

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In 1960, an improved version of the In 1960, an improved version of the metric system was devised, known as metric system was devised, known as the the International System of UnitsInternational System of Units, , abbreviated abbreviated SISI..

SI BASE UNITSSI BASE UNITS

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QUANTITY QUANTITY

MEASUREDMEASUREDUNITUNIT SYMBOLSYMBOL

LengthLength metermeter mm

MassMass kilogramkilogram kgkg

TimeTime second second ss

TemperatureTemperature kelvinkelvin KK

SI PREFIXES are easy to use, SI PREFIXES are easy to use, because they are based on because they are based on multiples of 10.multiples of 10.

The prefix The prefix kilo-kilo- means “1,000”means “1,000”

1 kilometer = 1 kilometer = 1,000 meters1,000 meters

1 kilogram = 1 kilogram = 1,000 grams1,000 grams

The prefix The prefix deci-deci- means “one-tenth”means “one-tenth”

1 decimeter = 1 decimeter = one-tenth of a meterone-tenth of a meter (0.1 m)(0.1 m) 1 decigram = 1 decigram = one-tenth of a gram one-tenth of a gram (0.1 g)(0.1 g)

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COMMON SI PREFIXESCOMMON SI PREFIXES

PREFIXPREFIX SYMBOLSYMBOL MULTIPLYING MULTIPLYING FACTORFACTOR

Kilo-Kilo- kk 1,0001,000

Hecto-Hecto- hh 100100

Deca-Deca- dada 1010

BASE UNITBASE UNIT BASE UNITBASE UNIT BASE UNITBASE UNIT

Deci-Deci- dd 0.10.1

Centi-Centi- cc 0.010.01

Milli-Milli- mm 0.0010.0012323

CONVERTING BETWEEN SI CONVERTING BETWEEN SI UNITSUNITS

Conversion factorsConversion factors are used to change are used to change one unit to another.one unit to another.

Ex. 1,000 mL = 1 LEx. 1,000 mL = 1 L

1,000 mL1,000 mL = = 1 1 LL

1 L 1 L1 L 1 L

A A conversion factorconversion factor is a ratio that is equal is a ratio that is equal to one.to one.

CFCF 1,000 mL 1,000 mL = 1 = 1

1 L1 L OROR 1L1L = 1= 1

1,000 mL1,000 mL

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To convert units, you To convert units, you multiply by the appropriate multiply by the appropriate conversion factor.conversion factor.

Ex. 1.255 L = ? mLEx. 1.255 L = ? mL

1.255 L x 1.255 L x 1,000mL1,000mL = =

1 L1 L

1,255 mL1,255 mL

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MEASURING DISTANCEMEASURING DISTANCE

The SI unit of length The SI unit of length is the meter, m.is the meter, m.

Length is measured Length is measured as the distance as the distance between 2 points. between 2 points.

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The size of the unit you measure with The size of the unit you measure with will depend on the size of the object will depend on the size of the object being measured.being measured. Distance from home Distance from home

to school to school

== kmkm

Length of your pencil Length of your pencil

= cm= cm

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MEASURING VOLUMEMEASURING VOLUME

The amount of space The amount of space occupied by an object occupied by an object is called its is called its volumevolume. . (Solids, liquids, and (Solids, liquids, and gases)gases)

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Ex. VOLUME OF A BOXEx. VOLUME OF A BOX

Measure its length, width, height Measure its length, width, height MultiplyMultiply the 3 numbers and the 3 numbers and addadd their their

units togetherunits together V = l x w x hV = l x w x h

V = 13 cm x 5 cm x 3 cmV = 13 cm x 5 cm x 3 cm V = 195 cmV = 195 cm33

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Measuring MatterMeasuring MatterMassMass is a measurement of the quantity is a measurement of the quantity of matter in an object.of matter in an object.

A table-tennis (ping pong) ball and a golf A table-tennis (ping pong) ball and a golf ball have about the same ball have about the same

volumevolume..

The golf ball has more The golf ball has more

massmass..

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The mass of a golf ball is The mass of a golf ball is almost 18 times the mass of a almost 18 times the mass of a ping pong ball.ping pong ball.

GOLF BALL GOLF BALL

= 45 g= 45 g

PING PONG BALLPING PONG BALL

= 2.5 g= 2.5 g

DENSITYDENSITYCubeCube of Aluminum vs. of Aluminum vs. CubeCube of of CopperCopper

Same Same

SIZESIZE

SameSame

VOLUMEVOLUME

Different Different

MASSMASS

DifferentDifferent

DENSITYDENSITY

WHAT IS DENSITY?WHAT IS DENSITY?

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DensityDensity is the mass per unit is the mass per unit volume of a material.volume of a material. Density (D) = Density (D) = mass (m)mass (m)

volume volume (v)(v)

D = D = 10 10 gg 2 cm2 cm33

D = 5 g/cmD = 5 g/cm33

The measurement The measurement unit for density, g/cmunit for density, g/cm33, , is a combination of SI is a combination of SI units.units.

A unit obtained by A unit obtained by combining different SI combining different SI units is called a units is called a derived unitderived unit..

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TIMETIME

TimeTime is the interval is the interval between 2 events.between 2 events.

The The SISI unit for time unit for time is the second. is the second.

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TEMPERATURETEMPERATURE

For most scientific For most scientific work, temperature is work, temperature is measured on the measured on the Celsius Celsius (C)(C) scale. scale.

The The SISI unit of unit of temperature is the temperature is the kelvinkelvin (K)(K)..

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THE 3 TEMPERATURE SCALESTHE 3 TEMPERATURE SCALES

FREEZING POINT FREEZING POINT OF WATEROF WATER00°C, 32°F, or 273K°C, 32°F, or 273K

BOILING POINT BOILING POINT

OF WATEROF WATER100°C, 212°F, or 100°C, 212°F, or

373K373K

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Converting Fahrenheit (F) to Converting Fahrenheit (F) to Celsius (C)Celsius (C)

Ex. 70Ex. 70°F = ? °C°F = ? °C

C = C = 5(F-32)5(F-32)

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C = C = 5(5(7070-32)-32)

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C = C = 5(38)5(38)

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C = C = 190190

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C = 21.1 or 21C = 21.1 or 21°C°C

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CONVERTING CELSIUS (C) TO CONVERTING CELSIUS (C) TO FAHRENHEIT (F)FAHRENHEIT (F)

Ex. 21Ex. 21°C = ? °F°C = ? °F

°F = 32 + °F = 32 + (9x°C)(9x°C)

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°F = 32 + °F = 32 + (9x21)(9x21)

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°F = 32 + °F = 32 + 189189

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°F = 32 + 37.8°F = 32 + 37.8

°F = 69.8 or 70°F°F = 69.8 or 70°F

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CHAPTER 1: THE CHAPTER 1: THE NATURE OF SCIENCENATURE OF SCIENCE

Section 3—Communicating with Section 3—Communicating with GraphsGraphs

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A VISUAL DISPLAYA VISUAL DISPLAY

Scientists often graph Scientists often graph the results of their the results of their experiments because experiments because they can detect they can detect patternspatterns in the data in the data easier in a graph than easier in a graph than in a table.in a table.

A A graphgraph is a visual is a visual display of information display of information or data.or data.

Why are graphs Why are graphs important?important?

Graphs are a quick Graphs are a quick way to communicate way to communicate a lot of information in a lot of information in a small amount of a small amount of space.space.

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There are 3 types of There are 3 types of graphs---line, bar, and circle graphs---line, bar, and circle (pie).(pie).

LineLine graphs graphs show show how a relationship how a relationship between variables between variables changes over changes over time.time.

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Bar GraphsBar Graphs

A A barbar graph is useful for graph is useful for comparing comparing information information collected by collected by counting.counting.

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Circle GraphsCircle Graphs

A A circlecircle graph or pie graph or pie graph is used to show graph is used to show how some fixed how some fixed quantity is broken quantity is broken down into parts. down into parts.

The circular pie The circular pie represents the represents the totaltotal. .

The slices represent The slices represent the the parts parts (percentages of the (percentages of the total).total).

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