04/10/2304/10/23 By W. RibbeckBy W. Ribbeck

Scientific MethodScientific Method

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

DefinitionDefinition

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

Basic Parts of Scientific Basic Parts of Scientific MethodMethod

►Stating the problemStating the problem►Gathering informationGathering information►Suggesting an answer for the problemSuggesting an answer for the problem►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 rattlesnake follow in tracking down its bitten prey?down its bitten prey?

Gathering InformationGathering Information

► A rattlesnakes eyes are only sensitive to A rattlesnakes eyes are only sensitive to visible lightvisible light

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

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

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

ExperimentExperiment

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

► Place the snake in the cagePlace the snake in the cage► The snake follows the exact trail that has The snake follows the exact trail that has

been laid outbeen laid out► ControlControl► Drag an unbitten dead mouse along the Drag an unbitten dead mouse along the

pathpath► The snake seems disinterestedThe snake seems disinterested

Recording and Analyzing Recording and Analyzing DataData

►Do the Do the experiment experiment many timesmany times

►Record the Record the datadata

ConclusionConclusion

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