Science Projects
Coins Thru a Hole

Items needed:
	1 Quarter
	1 Dime
	A Pen or Marker
	Scissors
	Paper

If you don't have U.S. coins, try this with a large coin and a small one. Cut a square of paper about 3 inches by 3 inches. Place the dime (small coin) in the center of the square and trace a circle around it. Use the scissors to carefully cut out the circle, so that you have a hole in the paper that is the same size as the dime.
Now, for the trick. I want you to put the quarter (large coin) through the hole, without tearing the paper. Simple, right? Wasn't that a fun trick? . . .

Why? Oh, is there a problem? Can't get the quarter through the hole? This is where the trick (and the science) come in. If you leave the hole as it is, you cannot get the quarter through it without tearing the paper. To succeed, we need to use the science of topology, which is the study of surfaces. We need to change the shape of the hole a bit. To do that, fold the paper in half, across the center of the hold. Crease the paper along the fold.
Hold the paper, with the fold and hole at the bottom. Place the quarter inside the folded paper, so it rests in the hole. It still won't go through, but we are not finished yet. Grasp the bottom corners of the paper between your fingers and thumbs. Bend the corners upwards and away from the hole. This will cause the paper to flex and the hole will stretch around the quarter, letting it fall through. We have not made the hole bigger, we have just changed its shape a bit. Once you have mastered this, then you are ready to use the science of topology to trick your friends.

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