Chapter 1Chapter 1

The Nature of ScienceThe Nature of Science

I. What is Science?I. What is Science?

A.A. Science comes from the Latin word Science comes from the Latin word scientiascientia, which means “knowledge”, which means “knowledge”1. 1. ScienceScience- process that uses - process that uses observation and investigation to gain observation and investigation to gain knowledge about events in nature.knowledge about events in nature.

B.B. Three branches of ScienceThree branches of Science1. Life Science1. Life Science

Deals with living thingsDeals with living things

2. Earth Science2. Earth Science Investigates earth and spaceInvestigates earth and space

3. Physical Science3. Physical Science Deals with matter and energyDeals with matter and energy

C.C. How do scientists learn about the How do scientists learn about the natural world?natural world?

1.1. Performing investigationsPerforming investigations ObservationObservation ExperimentsExperiments modelsmodels

II. Scientific Method- II. Scientific Method- Organized set of Organized set of investigation proceduresinvestigation procedures

A.A. Six step methodSix step method1.1. State the problemState the problem2.2. Gather informationGather information3.3. Form a hypothesisForm a hypothesis4.4. Test the hypothesisTest the hypothesis5.5. Analyze dataAnalyze data6.6. Draw conclusionsDraw conclusions

Support/Doesn’t support HypothesisSupport/Doesn’t support Hypothesis If hypothesis is supported, repeat steps 4-6 several If hypothesis is supported, repeat steps 4-6 several

timestimes If hypothesis is not supported, go back to step 3 If hypothesis is not supported, go back to step 3

and form a new hypothesisand form a new hypothesis

1. Stating the problem1. Stating the problem The problem is a question of “WHY?” The problem is a question of “WHY?”

or “WHAT?”or “WHAT?”• Example- What materials can be used to Example- What materials can be used to

create a space shuttle that will with create a space shuttle that will with stand the harsh conditions of space?stand the harsh conditions of space?

2. Researching and Gathering 2. Researching and Gathering InformationInformation

Gather information that will help Gather information that will help solve the problemsolve the problem• Example- melting points of different Example- melting points of different

materials that could be used to build a materials that could be used to build a space shuttlespace shuttle

3. Form A Hypothesis3. Form A Hypothesis HypothesisHypothesis- A possible explanation - A possible explanation

for a problem using what you know for a problem using what you know and what you observeand what you observe• In the form of an In the form of an IF/THENIF/THEN statement statement• Example- If a ceramic material is used Example- If a ceramic material is used

then the space shuttle will be able to then the space shuttle will be able to withstand the high temperatures. withstand the high temperatures.

4. Test a Hypothesis4. Test a Hypothesis Can be done by performing an Can be done by performing an

experiment, making observations or experiment, making observations or building a modelbuilding a model• An experiment uses two variables, a An experiment uses two variables, a

dependant and an independent variabledependant and an independent variable VariableVariable- quantity that can have more than - quantity that can have more than

a single valuea single value Dependant variableDependant variable- value changes - value changes

according to changes in other variablesaccording to changes in other variables Independent VariableIndependent Variable- Is independent of - Is independent of

other variablesother variables

Example 1- what factors might cause a Example 1- what factors might cause a plant to grow?plant to grow?• Independent variable- growthIndependent variable- growth• Dependent variable- water, sunlight, soilDependent variable- water, sunlight, soil

Example 2- The higher the Example 2- The higher the temperature of water, the faster an temperature of water, the faster an egg will boilegg will boil• Independent variable- water tempIndependent variable- water temp• Dependent variable- speed/ timeDependent variable- speed/ time

Example 3- An investigation was done with Example 3- An investigation was done with an electromagnetic system made from a an electromagnetic system made from a battery and wired wrapped around a nail. battery and wired wrapped around a nail. Different sizes of nails were used. The Different sizes of nails were used. The number of paperclips the electromagnet number of paperclips the electromagnet could pick up was measured. could pick up was measured.

Independent variable- nail sizeIndependent variable- nail size Dependent variable- how many paperclips were Dependent variable- how many paperclips were

picked up picked up

Experiments also have CONSTANTS Experiments also have CONSTANTS and CONTROLSand CONTROLS• Constant- Constant- A factor that does not change A factor that does not change

when other variables dowhen other variables do• Controls-Controls- Standard by which the test Standard by which the test

results can be compared.results can be compared. Example- Have 4 plants with the same soil Example- Have 4 plants with the same soil

and amount of fertilizer. Three of the plants and amount of fertilizer. Three of the plants get different types of fertilizer and the fourth get different types of fertilizer and the fourth gets none.gets none.

• Constant- soil and sunlightConstant- soil and sunlight• Control- plant that does not receive fertilizerControl- plant that does not receive fertilizer

5. Analyzing Data5. Analyzing Data This is done by recording This is done by recording

observations making charts and observations making charts and graphsgraphs

6. Drawing Conclusions6. Drawing Conclusions Based on data analysis, is your Based on data analysis, is your

hypothesis supported or not?hypothesis supported or not?• You must be objectiveYou must be objective

BiasBias- When the scientists expectations - When the scientists expectations changes how the results are viewedchanges how the results are viewed

Scientific Theories and LawsScientific Theories and Laws TheoryTheory- explanation of things or - explanation of things or

events based on knowledge gained events based on knowledge gained from many observations and from many observations and investigationsinvestigations

Scientific LawScientific Law- A statements about - A statements about what happens in nature and seems what happens in nature and seems to be true all the time.to be true all the time.

Standards of Standards of MeasurementMeasurement

Chapter 1Chapter 1Section 2Section 2

Units and StandardsUnits and Standards StandardStandard- an exact quantity that - an exact quantity that

people agree to use for comparisonpeople agree to use for comparison• Examples- ???Examples- ???

International System of UnitsInternational System of Units• SI standard- universally excepted units SI standard- universally excepted units

of measurement used by scientistsof measurement used by scientists• Measured in the Power of 10Measured in the Power of 10

Different MeasurementsDifferent Measurements Mass- amount of matter in an objectMass- amount of matter in an object

• Measured in gramsMeasured in grams Volume- The amount of space Volume- The amount of space

occupied by an objectoccupied by an object• Measured in liters or gramsMeasured in liters or grams• Volume = length X width X heightVolume = length X width X height

Length- distance between two pointsLength- distance between two points• Measured in metersMeasured in meters

SI Units

Quantity Measured

Unit and Symbol Examples

Length Meter (m)Mass gram (g)Time Second (s)Volume Liter (L)Temperature Celsius ( C )

SI prefixesUnit Symbol Value

Mega M 1,000,000Kilo k 1,000Hecto h 100Deca da 10

Basic Unit (gram, meter, liter, etc.)

Deci d 0.1Centi c 0.01Milli m 0.001Micro m 0.000001

L

R

Conversion examples!Conversion examples!

Communicating with Communicating with GraphsGraphs

Chapter 1Chapter 1Section 3Section 3

GraphsGraphs GraphGraph- visual display of information - visual display of information

or dataor data• X-axis- horizontal axisX-axis- horizontal axis

Independent variableIndependent variable• Y-axis- vertical axisY-axis- vertical axis

Dependant variableDependant variable• Three types of graphsThree types of graphs

1.1. LineLine2.2. BarBar3.3. piepie

Y-axisdep. variable

X-axisind. variable

Line GraphsLine Graphs Often used to show change over timeOften used to show change over time

Bar GraphsBar Graphs Used for comparing information Used for comparing information

collected by countingcollected by counting

Pie ChartsPie Charts Used to show how a fixed quantity is Used to show how a fixed quantity is

broken down into partsbroken down into parts• Usually represented in percentsUsually represented in percents

Career ChoicesCareer Choices