Standardization
Control
To have something to compare the rest of the experiment to
To be able to compare the results to something.
If you do not have a control,then you cannot compare your test results.
Having a control in an experiment allows you to see what happens when no variables are changed. If you do not have a control, you do not have anything to compare your results with after changing variables of the experiment.
Standardization
Control
A control experiment provides a benchmark against which to compare the results of the main experiment. For example, to know if heating a material changes its resistance, you must be able to compare the results of the heated experiment to a copy in which the material was left unheated.
The Control
To have something to compare the rest of the experiment to
To be able to compare the results to something.
To establish a baseline to compare your results to.
If you do not have a control,then you cannot compare your test results.
A controlled experiment compares results through various methods. Some being a graph, an average, a diagram... etc.
-- Repeat the experiment. If you have the time and money, then five or ten repetitions is an even better idea. -- Compare your results with those of other experimenters. -- Compare your results with the predictions of theory.
The purpose of a control variable in an experiment is to allow the experiment to come out with accurate results. It makes it a lot easier to measure the results when different things aren't affecting it.