There are many parts in a firework. There's the launching tube, which is three times as long as the firework shells, but its diameter is the same size. It is important that the firework fits snugly into the launching tube or the pressure from the lift charge will escape and the firework will not be able to launch into the air. When gunpowder burns, and it is confined at the bottom of the launching tube, the heat and gas are trapped and therefore force their way to the surface until an explosion happens. This is called the lift charge. When exploded the heat and gas then become free from the launch tube, and the firework becomes airborne. Then there is the fuse, a fast-acting fuse, and a timidly fuse. Another part is black powder which has the same formula as it always did, which is seventy-five percent saltpeter, fifteen percent charcoal, and ten percent sulfur. Black powder explodes at a relatively slow rate of 1/10 of a second per foot, that makes it a " low explosive. " Stars are an important part of a firework. They are hand made and have to be handled with care. They can be detonated by a static shock. Last, but not least there is the break.