WHY DO WE HAVE A CONTROL in an experiment? plz plz proper definition?

my exam is in 2 days and i have had so many variations of why we have a control i need the perfect definition that will gain me the full mark


PLEASEEEWHY DO WE HAVE A CONTROL in an experiment? plz plz proper definition?
You have a control in an experiment so you have a constant within the experiment, something to compare you variables against.





I hope that was good enough of an answer.WHY DO WE HAVE A CONTROL in an experiment? plz plz proper definition?
The simple definition of a control in an experiment is a trial containing specimens where the variable being tested by the hypothesis is kept constant. This allows for a comparison to the experiment where the variable is changed to see if there is a different result.





Experiments conducted with a control help reduce the incidence of skewed results that can result from human error and bias. Additionally, this methodology allows a scientist to make sure that there were no other influences on their experiment.
Easy.





Control is a method to gauge the effectiveness of an experiment. By comparing the results of your test group to the control, you can have a measure for the differences created by experimental conditions. In biology specifically, controls are useful to tell if you have some sort of contamination.





Another example. I pour tiny gels in my lab (11 uL). In order to tell if the gel polymerized, I examine the container where I mixed up my gel. (control). If that polymerized, then I know my 11uL gel did as well.
U need a control so u can compare your other results


otherwise, you have no idea what affected it.
Alex is right!