Easy Magic Tricks: Liar's Lair

In this easy magic trick, you put a quarter and a paper clip on a table. You tell two people that you will leave the room, and while you're gone, for each to take one of the objects into their closed hands so you can't see them. In addition, you tell them to decide who will be the liar and who will be required to tell the truth. It's completely up to them. You then tell them that by asking one question, you'll be able to figure out who is holding the quarter and who is holding the paper clip.

You leave and come back. By asking a single question, you immediately figure out who is holding what. How is this possible? Read on.