Independent Variable- Effects the dependent variable and is what you are changing and finding what kind of effect it has.
Dependent Variable- Is what you are measuring in order to find if your independent variable has an effect and what kind of an effect that is.
Extraneous Variable- Is a variable that can effect the Dependent variable but is not the independent variable e.g. it could be the tempurature.
Control Variable- Are the variable that you purposely keep the same so that the experiment is fair.