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Scientific MethodScientific Method
Steps in the Scientific Steps in the Scientific MethodMethod
Observation/Observation/State a problemState a problem
ResearchResearch HypothesisHypothesis ExperimentExperiment Data CollectionData Collection ConclusionConclusion RetestRetest
Observations(State Observations(State the problem)the problem)
Gathered Gathered through your through your
sensessenses A scientist A scientist
notices notices something in something in their their natural natural
worldworld
ObservationsObservations
An An exampleexample of of an observationan observation
might be might be noticing that noticing that
many many salamanders salamanders near a pond near a pond
have curved, not have curved, not straight, tailsstraight, tails
Research Find out as much
information as you can on the problem
Become educated on the problem
Find other scientists who have done similar research
HypothesisHypothesis
PredictsPredicts an an outcomeoutcomeA suggested A suggested solution to the solution to the problem.problem.Must be Must be testabletestableSometimes Sometimes written as written as If…If…Then…Then… statementsstatements
HypothesisHypothesis
An An example of a example of a hypothesis:hypothesis:
If I add salt to If I add salt to water then the water then the water will boil water will boil quicker.quicker.
ExperimentExperiment
A A procedure procedure to to testtest the the hypothesishypothesis
..
ExperimentAll experiments MUST contain the
following parts: a. Variables-Independent and
Dependentb. Control Group c. Experimental Groupd. Datae. Controlled Variables (Constants)
Independent VariableIndependent Variable
Independent Independent VariableVariable – factor – factor
that is being that is being testedtested
Factor that YOU Factor that YOU change in an change in an experimentexperiment
Independent Independent VariableVariable
A good or A good or “valid” “valid”
experiment experiment will only will only
have have ONE ONE independent independent
variable!variable!
Dependent Variable Dependent
variable. The factor that is measured or observed
Results from the independent variable
Data that can be recorded
Scientific Experiments Scientific Experiments Follow RulesFollow Rules
An experimenter changes one factor (IV) and observes or measures DV) what happens.
The Controlled The Controlled Variables (Constants)Variables (Constants) The experimenter makes a The experimenter makes a
special effort to keep special effort to keep other factors constantother factors constant so so that they will not effect that they will not effect the outcome.the outcome.
Those factors are called Those factors are called control variables.control variables.
Control Group vs. Control Group vs. Experimental GroupExperimental Group
Control Group Does not contain
the variable and is NOT being tested
The Control group is used for COMPARISON only.
Experimental Group The experiment
that contains the IV variable
May have more than one exp. group
Example of Controls & Example of Controls & VariablesVariables
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?
Varying the route is the Varying the route is the independent variableindependent variable
The time it takes is the The time it takes is the dependent variabledependent variable
Keeping the same walker Keeping the same walker throughout makes the throughout makes the walker a walker a control variable.control variable.
One more thing… it is best to make several trials with each independent variable.
Valid ExperimentsValid Experiments
Remember: To be a Remember: To be a Valid Experiment:Valid Experiment:
Two groups are required --- the control & experimental groups
There should be only one IV variable
DataData Results of
the experiment
May be quantitative (numbers) or qualitative
Examples of Data
Quantitative Data using
numbers
Qualitative Describing our
observations during the experiment.
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
RetestRetest
In order to verify the results,
experiments must be retested.
ReviewReview
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