Chapter 1 Introduction to Science. What is Science? Science is what scientists do Science is what scientists do Science is trying to explain the world.

Chapter 1Chapter 1

Introduction to ScienceIntroduction to Science

What is Science?What is Science? Science is what scientists doScience is what scientists do Science is trying to explain the Science is trying to explain the

world around usworld around us Science is a way of thinkingScience is a way of thinking ““Science is a system of Science is a system of

knowledge based on facts or knowledge based on facts or principlesprinciples

Book talks about “social science”Book talks about “social science” We prefer social We prefer social studiesstudies

BiologicalScience

EarthScience

PhysicalScience

Branches of ScienceBranches of Science

Science

BiologicalScience

EarthScience

PhysicalScience

Branches of ScienceBranches of Science

Science of living things

Science

Zoology

Botany

Ecology

BiologicalScience

EarthScience

PhysicalScience

Branches of ScienceBranches of Science

Science of matter and energy

Science

Chemistry

Physics

Astronomy

Meteorology

BiologicalScience

EarthScience

PhysicalScience

Branches of ScienceBranches of Science

The systems of the earth

Science

Geology

Branches of ScienceBranches of Science There are many more branches to There are many more branches to

biological and earth sciencesbiological and earth sciences The three categories overlapThe three categories overlap BiochemistryBiochemistry AstrobiologyAstrobiology GeophysicsGeophysics

Science and TechnologyScience and Technology Pure Science - search for scientific Pure Science - search for scientific

knowledgeknowledge Technology – application of Technology – application of

sciencescience Two are interrelatedTwo are interrelated Technology develops new tools Technology develops new tools

for investigating nature for investigating nature New science leads to new New science leads to new

applicationsapplications

Scientific TheoryScientific Theory A reasoned explanation tested by A reasoned explanation tested by

many observations and many observations and experimentsexperiments

Tells Tells whywhy things are things are Three thingsThree things–Must explain clearly and simplyMust explain clearly and simply–Must be repeatableMust be repeatable–Must be able to make predictionsMust be able to make predictions

Theories can be changed or Theories can be changed or modified by new evidencemodified by new evidence

Scientific LawsScientific Laws Describe Describe whatwhat happens happens Quantitative – use numbers and Quantitative – use numbers and

equations to describeequations to describe Often equations are part of the Often equations are part of the

lawlaw Mathematics is a universal Mathematics is a universal

languagelanguage

Law vs. TheoryLaw vs. Theory

Law Theory

Describes how

Explains why

Summarizes observations

Agrees with observations

Usually an equation

Predicts new discoveries

ObservationsObservations Qualitative – describe with wordsQualitative – describe with words– Hot , red, largeHot , red, large

Quantitative – describe with Quantitative – describe with numbersnumbers– 100° , 10 meters, 3.46 grams100° , 10 meters, 3.46 grams

Scientists prefer quantitativeScientists prefer quantitative Easy to agree uponEasy to agree upon No personal bias No personal bias

ModelsModels A representation of some object A representation of some object

or eventor event Made to better understand itMade to better understand it Often used if real thing is too big, Often used if real thing is too big,

small or complex.small or complex. Come in a variety of formsCome in a variety of forms– Physical modelsPhysical models– DiagramsDiagrams– Computer modelsComputer models

The Scientific MethodThe Scientific Method A way of thinking about and A way of thinking about and

solving problemssolving problems It is a logical methodIt is a logical method You do it all the timeYou do it all the time

The Scientific MethodThe Scientific Method Starts with observation- can be Starts with observation- can be

anythinganything Question – what do you want to Question – what do you want to

know?know? Gather data- what is already knownGather data- what is already known Form Form hypothesishypothesis- a possible - a possible

explanationexplanation Design experiment to test Design experiment to test

hypothesishypothesis– This is the hard partThis is the hard part

The Scientific MethodThe Scientific Method Experiments generate more Experiments generate more

observationsobservations Allow us to draw conclusions Allow us to draw conclusions

about hypothesisabout hypothesis– Support the hypothesis or notSupport the hypothesis or not– If not modify hypothesisIf not modify hypothesis

The Scientific MethodThe Scientific MethodObserv

eCollectdata

Formhypothesis

Experimenttests hypothesis

Observation

Observation

Observation

Formulatea question

DrawConclusions

The Scientific MethodThe Scientific Method Does not always work this way, Does not always work this way,

but gives a way of guiding our but gives a way of guiding our thinkingthinking

Hard part is testing only one Hard part is testing only one variable at a time.variable at a time.

Changing only one thing at a timeChanging only one thing at a time If you change more than one, you If you change more than one, you

don’t know which one is the don’t know which one is the causecause

MeasurementMeasurement A number without a unit is A number without a unit is

meaninglessmeaningless It is 4 longIt is 4 long 4 what?4 what? Scientists use the metric system or Scientists use the metric system or

SI for SI for le System Internationale le System Internationale d’Unitsd’Units

Makes sharing data easierMakes sharing data easier

Metric SystemMetric System Measurements have two partsMeasurements have two parts Base unit and prefixBase unit and prefix Prefixes multiply or divide the Prefixes multiply or divide the

base units by multiples 10base units by multiples 10 Prefixes are the same for all unitsPrefixes are the same for all units

Base UnitsBase UnitsQuantity Unit Abbreviatio

nLength meter m

Mass gram g

Temperature

kelvin K

Electric current

ampere A

Amount of substance

mole mol

Luminous intensity candela

cd

PrefixesPrefixesPrefix Symbol Meanin

gAs a numberkilo- k thousan

d1,000

mega-

M million 1,000,000

giga- G billion 1,000,000,000deci- d tenth 0.1

centi- c hundredth

0.01

milli- m thousandth 0.001

micro-

millionth 0.000 001

TablesTables Organizing data into groups Organizing data into groups Putting those groups into rows Putting those groups into rows

and columnsand columns Gives us an easy way to compare Gives us an easy way to compare

datadata

GraphsGraphs Give a visual representation of dataGive a visual representation of data Summarizes data.Summarizes data. Two types of variablesTwo types of variables– Independent variableIndependent variable the thing the thing

you have control over you have control over – Dependent variableDependent variable the thing that the thing that

you don’t have control over.you don’t have control over. Three types of graphs line, bar, and Three types of graphs line, bar, and

circlecircle

33%

25%

42%

Buildings

Transportation

Industrial

Circle GraphsCircle Graphs Often called a pie Often called a pie

chartchart divided into partsdivided into parts easy to compare easy to compare

to whole amountto whole amount.. Use several to Use several to

show changes show changes over timeover time

0

2

4

6

8

10

12

Production of Energy pergram

CarbohydratesProteinsFats

Bar GraphsBar Graphs Bar Graphs- Bar Graphs-

wide columns wide columns used things like used things like weight, height , weight, height , and length. and length.

Compare Compare quantitiesquantities

Line GraphsLine Graphs Line Graphs- compares sets of Line Graphs- compares sets of

data, show change and patterns data, show change and patterns over time.over time.

0

5

10

15

20

25

30

35

J F M A M J J A S O N D

New YorkSan DiegoSalina Cruz

Graphs includeGraphs include A titleA title Labeled axesLabeled axes A consistent scale.A consistent scale.

Metric conversionsMetric conversions Changing the unitChanging the unit Does not change the size of the Does not change the size of the

measurementmeasurement If the unit gets bigger the number gets If the unit gets bigger the number gets

smallersmaller If the unit gets smaller the number If the unit gets smaller the number

gets biggergets bigger Math with multiples of 10Math with multiples of 10 We will cancel out units to make sure We will cancel out units to make sure

we set the problem up rightwe set the problem up right

Metric conversionsMetric conversions A common race is the 5 K, which is 5 A common race is the 5 K, which is 5

km. How many meters is this?km. How many meters is this? Given unit -kmGiven unit -km Unit wanted –mUnit wanted –m The unit gets smaller, so the number The unit gets smaller, so the number

must get biggermust get bigger 1000 m = 1 km1000 m = 1 km

Metric conversionsMetric conversions

Distance in m = 5 km

Distance in m = 5000 m

1000 m

1 km x

Metric conversionsMetric conversions The recommended daily The recommended daily

requirement of vitamin C is 500 requirement of vitamin C is 500 mg. How many grams is this?mg. How many grams is this?

mass in g = 500 mg

mass in g = 0.5 m

1 g

1000 mg

x

Measuring lengthMeasuring length Use a rulerUse a ruler Line up from zero not the end of the rulerLine up from zero not the end of the ruler Small divisions are millimetersSmall divisions are millimeters

0 1 2 3 4

VolumeVolume Liter a common unitLiter a common unit 1 L about 1/4 of a gallon - a quart1 L about 1/4 of a gallon - a quart 1 mL is about 20 drops of water 1 mL is about 20 drops of water

or 1 sugar cubeor 1 sugar cube

Measuring VolumeMeasuring Volume Use a graduated Use a graduated

cylinder.cylinder. The water will The water will

curve in the curve in the cylinder.cylinder.

Hold it level with Hold it level with your eye.your eye.

Read the bottom Read the bottom of the curve.of the curve.

Measures in Measures in milliliters mL.milliliters mL.

10

20

30

MassMass weight is a force, is the amount of weight is a force, is the amount of

matter. matter. 1gram is defined as the mass of 1 1gram is defined as the mass of 1

cmcm33 of water at 4 ºC. of water at 4 ºC. 1 kg = 1 L of water1 kg = 1 L of water 1 kg = 2.5 lbs1 kg = 2.5 lbs 1 g = 1 paper clip1 g = 1 paper clip 1 mg = 10 grains of salt or 2 1 mg = 10 grains of salt or 2

drops of water.drops of water.

Measuring MassMeasuring Mass Use a triple beam balanceUse a triple beam balance First balance it at zero.First balance it at zero. Then put item onThen put item on Then move one weight at a timeThen move one weight at a time When balanced, add up the When balanced, add up the

weightsweights

0 1 2 3 4 5 6 7 8 9 10

0 10 20 30 40 50 60 70 80 90 1000 10 20 30 40 50 60 70 80 90 100

0 100 200 300 400 500