EXPERIMENTAL VARIABLES: What in the World Are Variables?

In science a variable can be anything. More specifically, in an experiment or test, a variable can cause something to change, be the result of something that changed, or be controlled so it has no effect on anything.

Variables that cause something to change are called independent variable or manipulated variables. Whether you choose to call it an independent variable or a manipulated variable depends on the term you pair it with. The acronym MIX DRY can help you keep these paired terms straight.

Manipulated Independent X-axis

Dependent Respodning Y-axis

Variables that are the result of something that changed are called dependent variable or responding variables. Again, the term you choose to use depends on how you pair the words.

Variables can sometimes affect an experiment when you do not want them to. In order for you to conduct a proper investigation, you have to set up the right environment that is as controlled as possible. You need to make sure that you control the effects of as many factors, or variables, as you can so that you can prove your hypothesis. Some of these variables will stay the same throughout the whole investigation. These are the controlled or constant variables. They do not get to play along in the experiment, even though they may be indirectly part of it.

Since variables are necessary for an experiment, you need to make sure they are properly identified. By the time you have arrived at your hypothesis, you have a pretty good idea of what you are trying to prove. Hypotheses are usually written in "if-then" format or “what is the effect of X on Y” because these are a great way to make sure your "Hypothesis" is specific to what you are going to test.

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