scientific method. steps in the scientific method observation observation identify the problem...
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Scientific MethodScientific Method
Steps in the Scientific Steps in the Scientific MethodMethod
ObservationObservation Identify the Identify the
ProblemProblem HypothesisHypothesis Gather informationGather information ExperimentExperiment Organize DataOrganize Data ConclusionConclusion CommunicationCommunication
1. Observations1. Observations Gathered Gathered
through through your your sensessenses
A scientist A scientist notices notices something something in their in 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
2. Identify a Problem2. Identify a Problem Ask a Ask a
questionquestion about the about the observation observation you made.you made.
State it State it clearlyclearly and as and as a questiona question
Identify the ProblemIdentify the Problem
Example:Example: Why Why do salamanders do salamanders living near a living near a pond have pond have curved tails?curved tails?
3. Hypothesis3. Hypothesis A A suggested suggested
solutionsolution to the to the problem.problem.
State what you State what you thinkthink will will happenhappen
Must be Must be testabletestable
PredictsPredicts an an outcomeoutcome
HypothesisHypothesis
An An example of a example of a hypothesishypothesis might might be that the be that the salamanders salamanders have curved tails have curved tails due to a due to a pollutant in the pollutant in the moist soil where moist soil where they live. they live.
4. Gather information4. Gather information ResearchResearch
your topicyour topic DiscoverDiscover
what is what is already already known about known about the topicthe topic
5. Experiment5. Experiment
A A procedure procedure to to testtest the the hypothesishypothesis
..
ExperimentExperiment
VariableVariable – – factor in the factor in the experiment experiment that is being that is being testedtested
ExperimentExperiment
A good or A good or “valid” “valid” experiment experiment will only will only have have ONE ONE variable!variable!
Scientific Experiments Scientific Experiments Follow RulesFollow Rules
An experimenter changes one factor and observes or measures what happens.
VariablesVariables The factor that is The factor that is
changed is known as the changed is known as the independent variableindependent variable. .
The factor that is measured The factor that is measured or observed is called the or observed is called the dependent variable. dependent variable.
VariablesVariables Independent Variable Independent Variable – –
Pollution is added to an area Pollution is added to an area near a population of near a population of salamanders with straight salamanders with straight tailstails
Dependent Variable Dependent Variable – the tails – the tails of the salamanders are of the salamanders are observedobserved
The Control VariableThe Control Variable 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.
What is theWhat is the Purpose of a Control? Purpose of a Control? Controls are Controls are NOTNOT being tested being tested Controls are used for Controls are used for
COMPARISONCOMPARISON Compare the control group Compare the control group
with the experimental group with the experimental group (the one you are testing)(the one you are testing)
What is theWhat is the Purpose of a Control? Purpose of a Control?
Control Group Control Group – – salamanders with straight salamanders with straight tails living normallytails living normally
Experimental Group Experimental Group – – salamanders with straight salamanders with straight tails and added pollution tails and added pollution in the soilin the soil
Another ExampleAnother Example 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.
Another ExampleAnother Example
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.
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 variable you are testing
6. Organize Data6. Organize Data ResultsResults of the of the
experimentexperiment May be May be
quantitativequantitative (numbers) or (numbers) or qualitative qualitative (observations)(observations)
Organize DataOrganize Data Must beMust be
organized organized to to find out what it find out what it meansmeans
Can be Can be organized into organized into charts, tables, charts, tables, or graphsor graphs
7. Conclusion7. Conclusion Explain the data
that you collected from the experiment
Does it support your hypothesis?
Should anything else be done?
8. Communicate the 8. Communicate the resultsresults
Don’t be Don’t be greedy!greedy!
Let others Let others know what know what you learned you learned so that so that progress can progress can be madebe made
Scientific MethodScientific Method1) Make observations2) Identify a Problem3) Form a Hypothesis
about the problem 4) Research and gather
information 5) Design an Experiment
to test the hypothesis6) Organize Data7) Form a Conclusion8) Communicate the
results
Quiz!Quiz! In your In your notebooksnotebooks reflect on reflect on
the following:the following: What are the What are the 8 steps 8 steps to the to the
scientific method:scientific method: What is the scientific method What is the scientific method
used for?used for?