Object: Bring a pen, the kind that can be taken apart and has a small spring in it. Before you come to the children, take your pen apart, put the spring in your pocket and then put it back together without the spring. As an option, bring a pen for each child present.

(Begin by trying to write something with your pen.) Say: My pen doesn't seem to be working properly. It looks all right. I don't see anything missing. Does anyone know what is wrong with it? (If no one suggests the spring is missing, take the pen apart to investigate.)

Oh, the spring is missing. Surely that can't mess up the whole pen! It is just a tiny little spring. Oh, you think that c…