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Transcript of The Scientific Method How do scientists know so much? How do scientists know so much? How do they...
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?
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