The Scientific MethodThe Scientific Method

How do scientists know so much?How do scientists know so much? How do they get to know more?How do they get to know more?

The Scientific MethodThe Scientific Method: a structured : a structured approach to problem solving and approach to problem solving and answering questions.answering questions.

Steps in Scientific MethodSteps in Scientific Method

Make Observations Make Observations Identify the Problem/QuestionIdentify the Problem/QuestionState the HypothesisState the HypothesisDesign a Controlled ExperimentDesign a Controlled ExperimentObserve and Measure Results (Collect data)Observe and Measure Results (Collect data)Analyze Results and Draw ConclusionsAnalyze Results and Draw ConclusionsReport Results to Scientific CommunityReport Results to Scientific Community

An Early Scientific TheoryAn Early Scientific Theory

Spontaneous GenerationSpontaneous Generation: a theory that : a theory that life can arise from nonlife.life can arise from nonlife.

Why did people think this was true?Why did people think this was true?

Mmmmm MaggotsMmmmm Maggots

Redi’s ExperimentRedi’s Experiment

Question: Can life arise from nonlife?Question: Can life arise from nonlife?

Set up experiment using the scientific method.Set up experiment using the scientific method.http://www.youtube.com/watch?v=WiGFoYBRYTA&feature=related&safe=activehttp://www.youtube.com/watch?v=WiGFoYBRYTA&feature=related&safe=active

http://www.youtube.com/watch?v=cQIbjhzBkU8&feature=related&safe=activehttp://www.youtube.com/watch?v=cQIbjhzBkU8&feature=related&safe=active

The Scientific MethodThe Scientific Method

My car won’t startMy car won’t start

MethodMethod Observe and Ask QuestionsObserve and Ask Questions Infer and Form a Possible Answer (Hypothesis)Infer and Form a Possible Answer (Hypothesis) Design an Experiment to test HypothesisDesign an Experiment to test Hypothesis Collect and Analyze DataCollect and Analyze Data Draw a ConclusionDraw a Conclusion Change Hypothesis if necessary and RetestChange Hypothesis if necessary and Retest

Step #1:Step #1:Make ObservationsMake Observations

Helps to define the problem for investigationHelps to define the problem for investigation

Step #2Step #2Identify the ProblemIdentify the Problem

What is the question you want to ask?What is the question you want to ask?

Step #3Step #3Form a HypothesisForm a Hypothesis

HypothesisHypothesis: :

Create a scientific explanation (answer toCreate a scientific explanation (answer to

problem) that you can then testproblem) that you can then test

Creating a HypothesisCreating a Hypothesis

““If _____ then ______” statementIf _____ then ______” statement

Ex: Ex: If you add add fertilizer to a plant, then it If you add add fertilizer to a plant, then it will will grow tallergrow taller

Step #4Step #4Create a Controlled ExperimentCreate a Controlled Experiment

Two identical groups are set up (control and Two identical groups are set up (control and experimental) experimental)

Allows you to isolate effects of one variable.Allows you to isolate effects of one variable.

Experimental GroupExperimental Group: one variable : one variable changeschanges

Control GroupControl Group: no variables change, : no variables change, (used as a basis for comparison)(used as a basis for comparison)

VariablesVariables

Variables:Variables: factors that can change factors that can change

(ex: light, time, amount of nutrients, growth)(ex: light, time, amount of nutrients, growth)

Independent VariableIndependent Variable: : isn’t influenced by other isn’t influenced by other factorsfactors

Dependant VariableDependant Variable: : “depends” on how the “depends” on how the other variable changesother variable changes

Cartoon Variables: Cartoon Variables: http://www.youtube.com/watch?http://www.youtube.com/watch?v=x2606GQmDqY&feature=relatedv=x2606GQmDqY&feature=related

Step #4Step #4Collect DataCollect Data

Collect data using various research toolsCollect data using various research tools (ex: microscope, thermometer, ruler, scale)(ex: microscope, thermometer, ruler, scale)

Follow safety proceduresFollow safety procedures

Compile data in a useful form Compile data in a useful form Ex: charts, tables and graphsEx: charts, tables and graphs

Types of Data to CollectTypes of Data to Collect

Quantitative DataQuantitative Data: measured “quantitiy” : measured “quantitiy” (ex: length, mass, speed, volume, height)(ex: length, mass, speed, volume, height)Use metric units of measurementUse metric units of measurement

Qualitative DataQualitative Data: descriptive “qualities”: descriptive “qualities” (ex: gorilla behavior, feather coloration)(ex: gorilla behavior, feather coloration)

Step #5 Step #5 Analyze DataAnalyze Data

Analyze data to look for patterns or Analyze data to look for patterns or relationshipsrelationships

Sample Size and Possible Sources Sample Size and Possible Sources of Errorof Error

Is it better to do an experiment with just a Is it better to do an experiment with just a few samples or many? Why?few samples or many? Why?

What possible sources of error might there What possible sources of error might there be ?be ?

Graphing ProperlyGraphing Properly

Space numbers in equal incrementsSpace numbers in equal incrementsPlot points accuratelyPlot points accuratelyConnect data pointsConnect data pointsGive title to graph and label axisGive title to graph and label axis

Graphing VariablesGraphing Variables

Independent variable: Independent variable: on “X” axison “X” axis

Dependant variable: on Dependant variable: on “Y” axis“Y” axis

Step #6Step #6Drawing ConclusionsDrawing Conclusions

Does your data provide Does your data provide evidence to support the evidence to support the hypothesis?hypothesis?

oror

Should we revise Should we revise hypothesis and test again?hypothesis and test again?

Scientific Method LoopScientific Method Loop

What happens What happens when a hypothesis when a hypothesis is not confirmed?is not confirmed?

Step #7Step #7Report ObservationsReport Observations

Scientists need to report observations, Scientists need to report observations, materials used and procedures to other materials used and procedures to other scientists.scientists.

Needs to be stated so that someone else Needs to be stated so that someone else could repeat exactly what you did.could repeat exactly what you did.

Scientific JournalsScientific Journals Different journals exist for different subfields of Different journals exist for different subfields of

science.science.

Scientists read these journals to get new Scientists read these journals to get new information on recent developments in their fieldsinformation on recent developments in their fields

Before it gets published, a research paper needs Before it gets published, a research paper needs to be reviewed by other scientists to make sure to be reviewed by other scientists to make sure that conclusions are supported by data.that conclusions are supported by data.

If your results are verified your hypothesis may If your results are verified your hypothesis may get accepted by scientific communityget accepted by scientific community

ObservationObservation::Marsh grass growsMarsh grass growstaller in some placestaller in some places

Question:Question:Why do marsh grassesWhy do marsh grassesgrow to differentgrow to differentheights in differentheights in differentplaces?places?

Experiment ExampleExperiment Example

InferenceInference: : Some environmentalSome environmentalfactor is limiting grassfactor is limiting grassgrowth in a salt marshgrowth in a salt marsh

HypothesisHypothesis: : Marsh grass growth isMarsh grass growth islimited by amount oflimited by amount ofnitrogen available in soilnitrogen available in soil

ExperimentalExperimental

& Control groups& Control groups

start out exactlystart out exactly

the samethe same

The experimental groupThe experimental groupchanges one variablechanges one variable

Independent VariableIndependent Variable::nitrogen addednitrogen added

Dependant VariableDependant Variable::growth of grassgrowth of grass

The growth of grassThe growth of grass““depends” on nitrogendepends” on nitrogenbeing addedbeing added

Data collected on heightData collected on height

of grass and size ofof grass and size of

plantsplants

Data confirmed thatData confirmed that

additional nitrogen didadditional nitrogen did

allow grass to growallow grass to grow

taller and larger thantaller and larger than

control groupcontrol group

Theories and LawsTheories and Laws

Scientific TheoriesScientific Theories: explanations that apply to a : explanations that apply to a broad range of phenomena and are supported broad range of phenomena and are supported by strong evidence and data.by strong evidence and data.

Ex: Germ Theory of Disease (Louis Pasteur)Ex: Germ Theory of Disease (Louis Pasteur) Diseases are often the effects of microscopic organisms Diseases are often the effects of microscopic organisms

living inside a person.living inside a person. Theory has lead to many effective treatments like antibioticsTheory has lead to many effective treatments like antibiotics But not all diseases are caused by germsBut not all diseases are caused by germs

Scientific LawScientific Law: Statement that is always : Statement that is always true. (Ex: Law of Gravity)true. (Ex: Law of Gravity)

Scientific Method SongScientific Method Song

http://singdancelearn.com/science-songs/scientifhttp://singdancelearn.com/science-songs/scientific-method-song/ic-method-song/

http://www.youtube.com/watch?v=eA86dYxrg4Qhttp://www.youtube.com/watch?v=eA86dYxrg4Q http://www.youtube.com/watch?http://www.youtube.com/watch?

v=k2MhMsLn9B0v=k2MhMsLn9B0 http://www.youtube.com/watch?v=JcL7det0Ogshttp://www.youtube.com/watch?v=JcL7det0Ogs

DanceDance http://www.youtube.com/watch?http://www.youtube.com/watch?

v=RmawlZCEegg&feature=relatedv=RmawlZCEegg&feature=related

The Scientific MethodThe Scientific Method

http://aspire.cosmic-ray.org/labs/http://aspire.cosmic-ray.org/labs/scientific_method/sci_method_main.htmlscientific_method/sci_method_main.html

Plant ExperimentPlant Experimenthttp://www.biologycorner.com/http://www.biologycorner.com/

worksheets/worksheets/scientific_method_plant_exp.htmlscientific_method_plant_exp.html

Why does bread turn moldy?Why does bread turn moldy?