Scientific MethodScientific Method
StepsSteps in the in the Scientific Scientific Method (SM)Method (SM)
ObservationObservation HypothesisHypothesis ExperimentExperiment Data CollectionData Collection ConclusionConclusion PublishPublish RetestRetest
ObservationsObservations
Gathered Gathered through through using using your your sensessenses
A scientist A scientist notices notices
something something occuring in occuring in
their their natural natural worldworld
ObservationsObservations
An An exampleexample of of an observationan observation
might be might be noticing that noticing that
many deer are many deer are dying by being dying by being
hit by cars hit by cars driving toodriving too
Fast. Fast.
HypothesisHypothesis
A A suggested suggested solutionsolution to the to the problem.problem.
Must be Must be testabletestable
(Super important)(Super important) Sometimes written Sometimes written
as as If…Then…If…Then… statementsstatements
PredictsPredicts an outcome an outcome
HypothesisHypothesis
An An example of a example of a hypothesishypothesis might be that might be that more deer will more deer will live if the speed live if the speed limit was limit was lowered. lowered.
ExperimentExperiment
A A procedure procedure that that teststests
the the hypothesis.hypothesis.
ExperimentExperiment
VariableVariable – – factorfactor in the in the experiment experiment that is being that is being
testedtested
ExperimentExperiment
A goodA good or or “valid” “valid”
experiment experiment will only will only
have have ONE ONE variable variable
being tested!being tested!
Controls and VariablesControls and Variables
Scientific Scientific Experiments Experiments Follow RulesFollow Rules
An experimenter changes one factor and observes or measures what happens.
The The Control VariableControl Variable The experimenter makes a The experimenter makes a
special effort to special effort to keep 1 keep 1 factor the same or factor the same or unchangedunchanged so that they so that they will not effect the outcome.will not effect the outcome.
Those factors are called Those factors are called control variables.control variables.
What is the Purpose of What is the Purpose of a Control?a Control?
Controls are NOT being tested
Controls are used for COMPARISON
Other Variables The factor that is changed
is known as the independent variable.
The factor that is measured or observed is called the dependent variable.
You Are Already You Are Already Scientists!Scientists!
For example, suppose you want to figure out the fastest route to walk home from school.
You will try several different routes and time how long it takes you to get home by each one.
Since you are only interested in finding a route that is fastest for you, you will do the walking yourself.
What are the Variables What are the Variables in Your Experiment?in Your Experiment?
Different routes are the Different routes are the independent variable.independent variable.(changing) (changing)
The time it takes is the The time it takes is the dependent dependent variablevariable (being measured) (being measured)
Keeping the same walker Keeping the same walker (yourself) throughout makes the (yourself) throughout makes the walker a walker a control variable.control variable.(used for (used for comparison) comparison)
One more thing… it is best to make several trials with each independent variable. The more data…the better.
Valid ExperimentsValid Experiments
Mr. G example
Lochsa River Madness
Class example
Remember: To be a Remember: To be a Valid (Good) Valid (Good) Experiment:Experiment:
Two groups are required --- the control & experimental groups
There should be only one variable being tested.
DataData Is Results
(recordings) of the experiment
May be quantitative (numbers) or qualitative
DataData Must be
organized Can be
organized into charts, tables, or graphs
ConclusionConclusion
The answer to the hypothesis based on the data obtained from the experiment
Publish and RetestPublish and Retest
In order to verify the results,
experiments must be retested.
Publish in peer Publish in peer reviewed journal.reviewed journal.
Peer reviewed means that once your study is done, many other scientists with knowledge of your study go through how your experiment
was performed. If they find ANYTHING wrong or untrue, the experiment is not published.
Basically, a peer reviewed published study is very trustworthy.
Problems with studies that aren’t peer reviewed?
Hidden motives?
Solving a ProblemSolving a Problem1)Identify a Problem2) State Observations
about the problem3) Form a Hypothesis
about the problem (if…then…)
4) Design an Experiment to test the hypothesis
5) Collect Data6) Form a Conclusion7) Retest