What are variables? How do scientists use variables within scientific experiments?

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A scientific variable is a factor that can be controlled or that is changed within an experiment. There are three main types of variables within a scientific experiment, which are identified and explained below.

Independent variable

In a scientific experiment, the independent variable is the variable that is changed by the scientist. For this reason, the independent variable is sometimes referred to as the manipulated variable. In order for a scientist to accurately determine what causes a change to occur within his or her lab, scientific experiments should contain only one independent variable.

Dependent variable

The dependent variable of a scientific experiment is the variable that is measured. It is the variable that is affected by the independent variable. For this reason, dependent variables are sometimes referred to as “responding variables”.

Controlled (constant) variable

This is the variable that is left at normal conditions. A controlled variable is important in a scientific experiment because it enables a scientist to determine if the independent variable caused the change in the dependent variable.

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