Meaning & use
controlled variable
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Meanings
nouncountabletechnical
In an experiment, a factor that is kept the same for every test so it cannot affect the result.
Grammar: Countable: use 'a controlled variable' or the plural 'controlled variables'.
Patterns
- keep something as a controlled variable
- a controlled variable in an experiment
The team kept the room temperature as a controlled variable throughout the trials.
In her report she listed light, water and soil type as controlled variables.
If you forget a controlled variable, you cannot be sure what caused the change.
nouncountablemathematicsspecialist
In mathematics, a quantity whose value is fixed while other quantities in the same problem may change.
Grammar: Countable and mainly used in technical writing about equations or models.
Patterns
- treat something as a controlled variable
In this equation, time is treated as a controlled variable.
Students plotted the controlled variable on the vertical axis.
Word forms
| plural | controlled variables |
|---|
Common combinations
- keep something as a controlled variable
- We kept the pH level as a controlled variable in every trial.
- identify the controlled variables
- Before you start, identify the controlled variables in your plan.
- a key controlled variable
- Humidity was a key controlled variable in the greenhouse study.
- list the controlled variables
- Please list the controlled variables in your lab report.
- change a controlled variable by mistake
- If you change a controlled variable by mistake, your results become unreliable.
Synonyms and how they differ
- constant
- A constant is simply something that does not change; a controlled variable is specifically one you deliberately hold steady during an experiment.
- fixed factor
- This is a looser everyday phrase for the same idea and is fine in general writing, but 'controlled variable' is the standard term in science.
Opposites
Word family
- control verb
- to keep something at a steady level or under your power
- variable noun
- a factor that can change in an experiment or equation
- control group noun
- the group in a study that receives no treatment, used for comparison
Commonly confused: controlled variable or independent variable? controlled variable or dependent variable?
controlled variable vs independent variable
The independent variable is the one you deliberately change; the controlled variable is the one you deliberately keep the same.
controlled variable vs dependent variable
The dependent variable is what you measure as a result; a controlled variable is not measured but held constant.
Practice
Which sentence uses 'controlled variable' correctly?
Choose one answer.
A controlled variable is deliberately kept the same, so 'kept the temperature as a controlled variable' fits. Option 0 describes an independent variable, and options 2 and 3 describe a dependent variable (what you measure).
Make it your own
Write a sentence using “controlled variable”, then check it and compare it with the examples above.