• 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”
• 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.
• Designing a Controlled Experiment
• In a Controlled experiment only ONE independent variable is tested at one time.
• 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
• 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.
• 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
• 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.