The first firework was pretty basic. A Chinese monk named Li Tian took a piece of bamboo, stuffed it with gunpowder, and threw it into a fire, producing a bang loud enough to scare away ghosts. That was more than 1,000 years ago, but fireworks today are much the same: a shell, an explosive, and a fuse.
The early firecrackers (also known as Mandarin firecrackers) used black powder and were not very loud and produced a dull thud compared to firecrackers of today. In 1924, the black powder was replaced with flash powder which created a noticeably sharper and more brilliant bang.
In the United States, firecrackers may not exceed 50 mg of flash powder. Premium brands of firecrackers are bound more tightly in strings than generic firecrackers.