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control variable
Definition
A control variable is something that you keep the same in an experiment so that you can see what the other things are doing.
For example, if you are testing how much water a plant needs to grow, you might keep the amount of sunlight the plant gets the same in both groups. This would let you know that the only thing that is different between the two groups is the amount of water they get, so you can be sure that the difference in growth is caused by the water.
How can the word be used?
The control variable was the amount of sunlight that the plants received.
Different forms of the word
Noun:
Control variable: A variable that is held constant in an experiment in order to isolate the effects of the independent variable.
Adjective:
Control variable: Relating to a control variable.
Verb:
To control variable: To hold a variable constant in an experiment.
Etymology
The etymology of the word "control variable":
Control: This comes from the Latin word "controllare", which means "to check" or "to restrain".
Variable: This comes from the Latin word "variabilis", which means "changeable".
The word "control variable" is made up of these two parts:
Control: This refers to the act of holding a variable constant in an experiment.
Variable: This refers to a factor that can change in an experiment.
Question
What is a control variable in an experiment?