Variables

Definition INDEPENDENT VARIABLE-
a variable (often denoted by x ) whose variation does not depend on that of another.

Definition DEPENDENT VARIABLE-
a variable (often denoted by y ) whose value depends on that of another.

Definition CONTROL VARIABLE-
The control variable is something that is constant and unchanged in an experiment. Further, a control variable strongly influences values; it is held constant to test the relative impact of independent variables.

They are important to the experiment because without your variables you wouldn't know really anything about your experiment. You also have to have the independent variable to get the dependent variable, so if you didn't have that you wouldn't get a result.

You should do multiple trials in your experiment so it is, accurate, reliable, and redouble.