Imogen: Can we go to the bank today to turn my American money into Canadian money?
Me: Maybe. We'll see. We have lots to do.
Imogen, with a look of deep concentration: How do they change the money into Canadian?
Me: Well they don't actually change it; they trade us. We give them American money and they trade it for Canadian money.
Imogen, with a look of sudden understanding: Oh! So it's not magic like with a wand because that would not make any sense.
(And that's a reminder to me to be as literal as possible with her! Also, a great glimpse at how her brain attempts to make sense of the seemingly impossible.)