Step 1: Show your audience a coin. You can even let someone make a mark on it.
Step 2: Hide the coin in a handkerchief and hand it to a volunteer.
Step 3: The volunteer holds the coin in the handkerchief, feeling it with her own fingers.
Step 4: Draw the handkerchief over a clear cup full of water.
Step 5: Instruct the volunteer to let go of the money, and the coin is heard falling into the water.
Step 6: Pull the handkerchief away, and see that the coin has disappeared!
Step 7: Pour the water out of the cup, once again demonstrating that the coin is not in the cup.
Step 8: Turn the cup upside down.
Step 9: Show the bottom of the cup. The coin literally evaporated!
Step 10: Now you put your hand under another handkerchief, which has been lying the whole time to one side, and pull out a small box. “The coin might be in here?” you say. But everyone saw that you haven’t even gone near that handkerchief.
Step 11: You open the box, and to everyone’s amazement, the coin is there! The volunteer who held the coin is surprised most of all.
Step 12: The secret is in a small piece of perfectly clear glass, the same thickness and diameter as the coin. Such a piece of glass can be taken from a broken wristwatch, for example. When you demonstrate the coin, the piece of glass is already in your hand, squeezed between your palm and thumb.
Step 13: Switch the coin with the glass when hiding it under the handkerchief.
Step 14: Now holding the coin in your hand unseen, the volunteer is actually holding the piece of glass.
Step 15: The glass falls into the water, becoming practically invisible at the bottom of the cup. When you pour out the water into another cup, the glass falls into the new cup without revealing itself.
Step 16: And so, when you reach for the second handkerchief, the coin is already in your hand.
Step 17: The box should be opened in advance, carefully disguised by the handkerchief. Quickly put the coin in the box.
Step 18: Placing your thumb carefully on the edge of the box, you can close the lid without making a sound. Then, upon revealing the box’s contents, don’t forget to show your own surprise at finding the coin inside!