The popping sound that crackers make when they are pulled is produced by a device called a “Cracker Snap.” The “snap” consists of two narrow pieces of thin cardboard that are treated with a small amount of aggregate material at one end and joined together with the treated areas overlapping. When the free ends of the “snap” are pulled, the treated areas rub across each other producing a small, friction-activated pop or crack. “Cracker snaps” are not dangerous in any way as long as they are used inside crackers as intended. They should not be used on their own as noisemakers, or employed in the construction of other craft items.