Scientific Variables

Lesson Plan - Get It!

Audio:

Every science experiment contains variables, factors that can be altered or changed.

There are three different types of variables: independent variables, dependent variables, and controlled variables.

In the beginning of this lesson, you were told that a science teacher is performing an experiment to determine whether plants grow faster if they are watered daily.

Watch the Scientific Variables video (Alex Koning) below. While you watch the video, find the definitions for independent variable, dependent variable, and controlled variable. Also, look for an example of each variable. Write the definitions and an example of each term on a separate piece of paper. When the video is over, share your responses with a teacher or parent:

Did you determine a definition and an example for each type of variable? Let's review your responses:

• An independent variable is a thing you change in an experiment. In the experiment shown in the video, the amount of water was the independent variable because there was a different amount of water poured on each plant daily.
• A dependent variable is what you are trying to measure. The dependent variable is dependent upon on the independent variable. In the video, how much the plant grew was the dependent variable. In this experiment, plant growth was dependent upon the amount of water (independent variable) the plant was given daily.
• A controlled variable is something that stays the same in an experiment. In the video, the position of the plants was the controlled variable because the plants did not move throughout the experiment.

Variables are an important part of any science experiment. Why are variables important? Discuss your response with a teacher or parent, then move on to the Got It? section to study some experiments before trying your own!