Christmas crackers are festive table decorations that make a snapping sound when pulled open, and typically contain a small gift, paper hat and a joke. They are part of Christmas celebrations in the United Kingdom, Ireland and Commonwealth countries such as Australia, Canada, New Zealand and South Africa.
A cracker consists of a segmented cardboard tube wrapped in a brightly decorated twist of paper with a prize in the centre,[1] making it resemble an oversized sweet-wrapper. The cracker is pulled apart by two people, each holding an outer chamber, causing the cracker to split unevenly and leaving one person holding the central chamber and prize.[1] The split is accompanied by a mild bang or snapping sound produced by the effect of friction on a shock-sensitive, chemically impregnated card strip (similar to that used in a cap gun).[1] One chemical used for the friction strip is silver fulminate.[2]