An experimental variable is a variable that is being tested to answer a scientific question; while a control variable is a variable that is not being altered or changed during the experiement to serve as a constant. An example of an experimental variable is plant food solution A and whether it makes a kidney bean sprout faster than plant food solution B. An example of a control variable is water, because there is no plant food mixed in to create a solution; so it will serve as a natural constant.
