There are many different classes of fireworks from the ones that you see on the fourth of july to sparklers. Even though these two fireworks are completely different they are very close to the same on a chemical level.
The chemistry behind fireworks is a series of oxidation and reduction reactions which result in the desired sound and light. This happens as propellants push the firework into the sky. Oxidation reactions ensure that the oxygen needed to burn the mixture of reducing agents and excite the atoms in the light-emitting compounds is produced. Oxidizers used such as chlorates and nitrates and reducing agents such as carbon and sulfur are available off the shelf for people who make their own. Black powder, which mainly contains nitrates, is the most commonly used oxidizer. A look at an explosion under the use of potassium nitrate to provide nitrate ions (NO3-) after decomposition can be represented as, Potassium nitrate potassium oxide + nitrogen gas + oxygen gas. The reaction is more controlled since when reacting, nitrates only release two in every three oxygen atoms, the reaction is not vigorous since not all the oxygen atoms are actively used up. But the nitrates do not provide enough power to propel the firework into the sky and also ignite the package. So they cannot be used in star explosions since they cannot produce temperatures high enough to energize most color metal salts.
Star reactions need a temperature ranging from 1700 to 2000°C. This was found by the Italians in the 1830’s where they came across more explosive oxidizers, chlorates (ClO3-), which give up all their oxygen atoms when they react. But chlorates have been known to be highly unstable, so they can be very dangerous to handle. But on the good side, chlorate can be easily ignited. For example, dropping them on the ground can lead to a major explosion. This happens because chlorates