Now there is a special card detector in your iPhone that can find the card that someone has picked, like magic. After your volunteer picks a card out of a real deck, and puts it back in the deck, you fan out the cards in a wide line. Then, run your iPhone over the deck slowly. The Geiger Counter uses the radioactive heat from the person\’s hand to find the card. The clicking will become more intense as you get closer to the chosen card, then fade a bit as you go past it. Coming back again, it will click like crazy when it\’s over the exact card. You never touch the card. You don\’t need to. Just lift up the screen and the card is magically on the screen. This is one cool and amazing trick that your friends will want to see over and over!