Scientific MethodScientific Method

9/12/20109/12/2010 By W. RibbeckBy W. Ribbeck

Basic StepsBasic Steps(The Rattlesnake Experiment)(The Rattlesnake Experiment)

DefinitionDefinition

►►Scientific method: Scientific method: basic steps that basic steps that scientists follow in scientists follow in uncovering facts uncovering facts uncovering facts uncovering facts and solving and solving scientific problemsscientific problems

Basic Parts of Scientific MethodBasic Parts of Scientific Method

►►Stating the problemStating the problem

►►Gathering informationGathering information

►►Suggesting an answer (Hypothesis)Suggesting an answer (Hypothesis)

Performing an experiment to see whether Performing an experiment to see whether ►►Performing an experiment to see whether Performing an experiment to see whether the suggested answer makes sensethe suggested answer makes sense

►►Recording and analyzing the results of Recording and analyzing the results of experiments or other observationsexperiments or other observations

►►Stating conclusionsStating conclusions

Stating the ProblemStating the Problem

►►What invisible trail does a What invisible trail does a rattlesnake follow in tracking down rattlesnake follow in tracking down its bitten prey?its bitten prey?

(.wav)

Gathering InformationGathering Information

►► A rattlesnakes eyes are only sensitive to visible A rattlesnakes eyes are only sensitive to visible lightlight

►► A pair of organs located under the eyes detect A pair of organs located under the eyes detect invisible light in the form of heatinvisible light in the form of heatinvisible light in the form of heatinvisible light in the form of heat

►► A rattler’s tongue “smells” certain odors in the airA rattler’s tongue “smells” certain odors in the air

►► The sight or smell of an unbitten animal does not The sight or smell of an unbitten animal does not trigger the rattler’s tracking actiontrigger the rattler’s tracking action

HypothesisHypothesis

►►After the snake wounds its victim, After the snake wounds its victim, the snake follows the smell of its the snake follows the smell of its own venom to locate the animalown venom to locate the animal

Experiments Depend OnExperiments Depend On

►►ObservationsObservations

�� Using one or more Using one or more of your senses to of your senses to collect datacollect data

►►InferenceInference

�� Interpretation of Interpretation of based on evidence based on evidence or prior knowledgeor prior knowledgecollect datacollect data or prior knowledgeor prior knowledge

►►Data Data

�� Evidence gathered Evidence gathered through observationthrough observation

ExperimentExperiment

►► Drag a dead mouse that has been struck and Drag a dead mouse that has been struck and poisoned by a rattlesnake along a curved path on poisoned by a rattlesnake along a curved path on the bottom of an empty cagethe bottom of an empty cage

►► Place the snake in the cagePlace the snake in the cagePlace the snake in the cagePlace the snake in the cage

►► The snake follows the exact trail that has been The snake follows the exact trail that has been laid outlaid out

►► ControlControl

►► Drag an unbitten dead mouse along the pathDrag an unbitten dead mouse along the path

►► The snake seems disinterestedThe snake seems disinterested

Recording and Analyzing DataRecording and Analyzing Data

►►Do the Do the experiment experiment many timesmany timesmany timesmany times

►►Record the dataRecord the data

►►Make Make InferencesInferences

ConclusionConclusion

►►The scent of venom was The scent of venom was the only factor that could the only factor that could cause a rattlesnake to cause a rattlesnake to cause a rattlesnake to cause a rattlesnake to follow its bitten victim.follow its bitten victim.

Everyday ScienceEveryday Science

Scientific MethodScientific MethodScientific MethodScientific Method Car RepairCar RepairCar RepairCar Repair

ObservationObservationObservationObservation Engine won’t turn over.

Collect DataCollect DataCollect DataCollect Data Repair Manual

Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction) Predict battery is dead.Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction) Predict battery is dead.

Test/ExperimentTest/ExperimentTest/ExperimentTest/Experiment Replace battery.

Record/Analyze DataRecord/Analyze DataRecord/Analyze DataRecord/Analyze Data Engine now turns over.

New test?New test?New test?New test? Not needed.

Scientific TheoryScientific TheoryScientific TheoryScientific Theory Cars won’t work without a fully charged battery.

Design Your Own ExperimentDesign Your Own Experiment

Scientific MethodScientific MethodScientific MethodScientific Method TitleTitleTitleTitle

Problem/ObservationProblem/ObservationProblem/ObservationProblem/Observation

Gather InformationGather InformationGather InformationGather Information

Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)Hypothesis (prediction)

ExperimentExperimentExperimentExperiment

Record and Analyze Record and Analyze Record and Analyze Record and Analyze DataDataDataData

Scientific Theory?Scientific Theory?Scientific Theory?Scientific Theory?