There can be several controlled variables. If an experiment is to be useful, only one variable at a time can be manipulated intentionally. All other variables must be controlled throughout all parts of the experiment. If more than one variable is altered, the results of an experiment cannot be interpreted with any validity.

A study was attempted to find if the length of the string in a string telephone affected its sound clarity.

I need to find the manipulated variable, responding variable, and 4 controlled variable. For the manipulated variable I got: Length of the string Is this correct?
Responding variable: Sound clarity Is this correct?
Controlled variable: String telephone Is this correct?
Another controlled variable: Audio used Is this correct?
I only have 2 controlled variables at the moment, so if you could add 2 more or 4 more if I have the 2 controlled variables wrong, then that would be wonderful. Thanks! Oh and I might ask more questions if you answer this question.

4 answers

"String telephone" not specific enough. The thickness and tension of the string and what it is made of would be controlled variables.

Audio level (db) would be more specific.
For the string telephone, doesn't controlled variable mean the variable or variables that aren't changed ? So wouldn't that be stating that the string telephone is the one that isn't being changed, like to a different model ?

tanks for the other controlled variables and fixing my audio used i appreciate !
The growth of a certain plant was measured over the period of more than a month. Which of the following correctly identifies the variables
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Help plz asap