A variable is just a box you put something in. And, if later you decide you want to put something different in the box, you can.
The reason I use this analogy is quite simple. As I explained to my daughter; the box doesn't change, only the contents. Further, the contents only change if and when you decide they should. I was going to expand the idea to take in constants (i.e, a box which can never be opened) but drove myself round the twist trying to figure out how the stuff got into the box in the first place!
