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Identify independent and dependent variables

In an experiment, the independent variable is the one you change, and the dependent variable is the one you measure. Think of it as 'I' change the Independent variable, and the Dependent variable 'Depends' on that change.

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Lesson 2 of 51
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Concept

Independent Variable: The variable that is changed or manipulated by the researcher. It is the variable whose effect is being studied.

Dependent Variable: The variable that is observed and measured in response to the independent variable. Its value depends on the independent variable.

Mnemonic:
*   Independent = The variable that I change.
*   Dependent = The Data you collect.
Example: Testing Fertilizer
In an experiment testing the effect of fertilizer on plant growth:
*   Independent Variable: The amount of fertilizer given to the plants. The scientist directly controls this.
*   Dependent Variable: The growth of the plants (e.g., height, weight, number of leaves). This is what is measured to see the effect of the fertilizer.

Try it

Practice: Identify independent and dependent variables.