Uploaded by Monica Bhaskar

Designing a Controlled Experiment

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Designing a Controlled Experiment
In experiments, to show the cause and effect relationship, scientists study factors called
a) Independent Variable: This is the experimental variable, the factor that is changed in the
experiment. The “CAUSE”
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Designing a Controlled Experiment
a) Dependent Variable: This variable changes in response to the independent variable. This is
measured during an experiment; they are experimental data- the “EFFECT”
b) Control Factors: Also called constants these are conditions that remain the same during an
experiment.
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Designing a Controlled Experiment
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In a Controlled experiment only ONE independent variable is tested at one time.
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We setup 2 groups in a controlled experiment:
a) Control group: The control group is the part of the experiment that
 Does not receive the independent variable,
 Receives all the control factors
 Is used as the point of comparison
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Designing a Controlled Experiment
b) Experimental Group: This group is the part that

receives the independent variable

receives the control factors
In the controlled experiment both the groups are treated exactly the same except the experimental
group gets the factor (independent variable) that you are testing.
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Scientific Process
 What is a hypothesis?
A proposed answer to a scientific question
 What is a theory?
A proposed explanation for a wide range of observations and experimental results that is also
supported by a wide range of evidence
 Why are theories never proven?
Because new scientific evidence can lead to a theory being changed or discarded
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Scientific process
 What is the difference between a theory and a hypothesis?
A theory explains a wide range of observations; a hypothesis is a proposed answer to one scientific
question.
 How can you remember the difference between an independent variable and a dependent
variable?
Think about what the words independent and dependent mean.
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