Firework

A firework is a colorful explosion created by the detonation of a pyrotechnic device. They are often used as decoration or entertainment at celebrations and festivals. A very popular light show in the World of Avatar, fireworks add an aesthetic touch to wherever they are used. Although sometimes seen during the day, fireworks are typically used at nighttime, when they are most visible and spectacular.

History
Little is known about the invention or development of fireworks, but they were in wide use at several locations across the Earth Kingdom, Fire Nation, and Fire Nation colonies by 100 ASC. Fireworks were first seen at a nighttime Fire Days Festival being held in a Fire Nation colony. Chey, while assisting Team Avatar by helping them avoid capture from Fire Nation soldiers, set off a firework starter by bombing it. Later on their journey, when Team Avatar arrived at General Fong 's outpost in the Earth Kingdom, they were greeted with a daytime fireworks show. It was held in honor of Avatar Aang 's successful task of defending the Northern Water Tribe from a Fire Nation invasion. This is the first time fireworks were seen in the Earth Kingdom. A similar celebration was held later that year in Ba Sing Se, when Team Avatar attended a fireworks show to commemorate their success in defeating the Fire Nation and ending the Hundred Year War. Here, Toph admitted she hated fireworks because she could not see them, so all she could make of them were the fact that they were loud explosions in the sky.

In 170 ASC, during the Pro-Bending Tournament finale in Republic City, a brief indoor fireworks show was conducted inside the arena as the opening act for the White Falls Wolfbats team. This is the first time fireworks have been seen indoors.

Description
The primary reason why fireworks are so popular is because they are quite colorful and explosive. Red, pink, white, and green fireworks have been seen in the past.

In the Fire Nation, firework starters have two different designs. One design is made to resemble red dynamite. They have a cone-shaped top with rounded edges and peak that rests on a long cylinder. It is most likely filled with explosive material. The alternate design looks like a sausage on a stake. There is some wrapping around the starter, which is probably used to contain flammable substance. The starters can be detonated either by fire or explosion. After the starters fire, they fly upward with rapid speed, leaving a trail of blazing yellow fire behind them. Eventually, they explode in mid-air, sending out streaks of multi-colored light in every direction. The explosions themselves last just one second, but are very bright. These fireworks create very loud noises.

Earth Kingdom firework starters are more simplistic. They are round, earthen spheres that earthbenders can fire into the sky. Like Fire Nation starters, the spheres are filled with highly explosive material that combusts in the sky. Earth Kingdom fireworks are identical to Fire Nation fireworks.