Since their invention 25 years ago, light sticks have become a Halloween staple. They're perfect as safety lights for little trick-or-treaters because they're portable, cheap and they emit a ghostly glow. Light sticks are also extremely popular on the rave scene (as are light necklaces, light glasses and light rope), and they make an ideal lamp for SCUBA divers and campers.

While it may seem like supernatural magic to little trick-or-treaters, the technology behind light sticks is actually very simple. In this article, we'll look inside a light stick to find out how it gives off such a strong light with no bulb and no battery.