Why do crackers go bang? © iStock

Why do Christmas crackers go bang?

Crackers: the only time you can have family fun with gunpowder in the home.

Inside a cracker there are two strips of card, attached end-to-end with a slight overlap. This overlap is treated with gunpowder – a mixture of potassium nitrate, charcoal and sulphur. When the cracker is pulled, the friction generated between the two strips causes enough heat to set the gunpowder off. The tube amplifies the sound of the tiny explosion.

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