Variable (adjective, noun, “VAIR-ee-uh-bull”)
The word “variable” can be an adjective or a noun. As an adjective, it means able to vary or change. As a noun, a word refers to something that can change. That thing can be a quantity that can take on different values. Or, it could be a factor in an experiment that someone is changing.
In mathematics, a variable is a symbol that represents an unknown value. It is usually a letter, such as x or y. The value of the variable varies depending on the context. Solving the equation x + 1 = 3, for example, finds that x = 2. In the equation x + 2 = 5, meanwhile, x = 3. And in the equation x + 1 = y, adding different values for x results in different values for y.
Scientific experiments also include variables. In an experiment, a person can change one thing and see how it can affect another thing. The factor that a person changes is independent variable. What can change in response to that is dependent variable. But the dependent variable can be affected by other things as well. So the scientist is trying to keep those external factors – or controlled variables – constantly. This will not affect the outcome of the experiment.
In a sentence
In the five-second rule study, the independent variable is how long the food lies on the floor.
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