How are independent and dependent variables used in an experiment?
An independent variable is the variable that was changed. The dependant is what was measured.
Eg. If you filled 3 cups of water - one with 1/4 of a cup, one with half a cup and one with 3/4 of a cup. Then you grab a spoon to find the highest note, then the amount of water is the independent variable and the sound is the dependant.