Independent variables answer the question "What do I change?" Dependent variables answer the question "What do I observe?" Controlled variables answer the question "What do I keep the same?"
dependent variable is the thing you measure in an experiment and a independent is the one you change.
The Independent Variable, in an experiment, is the variable that is being manipulated and the Dependent Variable is what will be affected.
well they both need to be changed in order to have done the experiment right if it is nott right then do it again