Uploaded by Monica Bhaskar

Designing a Controlled Experiment


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.