Any one know how to teach variables and control variables to a 5th grader?

having trouble getting the point across any suggestions?


she knows the definition but the understanding the meaning is not going so well.


Just need a basic way to get her to understand.Any one know how to teach variables and control variables to a 5th grader?
it's like when you eat peanut butter sandwhiches every day for lunch. One day you mom says the hypothesis ';if you add jelly to you sandwhich, then you will like it better'; So you test the experiment. You bring a sandwhich with just peanute butter, the control group, and one with peanut butter and jelly, the jelly is the thing added, or changed, so it is a variable

beauty