Which research method involves manipulating a variable in order to determine how it affects another variable (in a cause and effect relationships) ?

The research method that involves manipulating a variable in order to determine how it affects another variable (in a cause and effect relationships) is the experimental method. In this method, the experimenter would undergo several processes and along the way, he would manipulate the variables in order to see how it affects the other variable thus uncovering the cause and effect relationships of these variables.