A sparkler is a firework that glows and sparks as you hold in you hand. A sparkler burns very slowly, giving you time to wave it around and make patterns in the dark before its flame goes out.
Most sparklers are thin pieces of flexible metal that are partly coated with chemicals that burn and sparkle. Though sparklers are often thought of as a fireworks for kids, they burn at a very high temperature and can cause serious burns if they're not used carefully. Sparklers are particularly beautiful when they're lit outside in the dark. While the sparkler's invention is a bit of a mystery, the word sparkler came into use around 1879, from the verb sparkle.