How can fireworks hold their shape when they explode?

Question

When something explodes, pieces go in many different directions and keep traveling in different directions. However when fireworks explode in the night sky, the pieces hold their shape in a near perfect circle until they fall to the earth...how is this possible? It seems to defy the laws of physics. I have never taken a physics class, by the way. Serious answers only, please.

Answer 1

For aerial fireworks:

Simple shells consist of a paper tube filled with stars and black powder. Stars come in all shapes and sizes, but you can imagine a simple star as something like sparkler compound formed into a ball the size of a pea or a dime. The stars are poured into the tube and then surrounded by black powder. When the fuse burns into the shell, it ignites the bursting charge, causing the shell to explode. The explosion ignites the outside of the stars, which begin to burn with bright showers of sparks. Since the explosion throws the stars in all directions, you get the huge sphere of sparkling light that is so familiar at fireworks displays.

More complicated shells burst in two or three phases. Shells like this are called multibreak shells. They may contain stars of different colors and compositions to create softer or brighter light, more or less sparks, etc. Some shells contain explosives designed to crackle in the sky, or whistles that explode outward with the stars.

Multibreak shells may consist of a shell filled with other shells, or they may have multiple sections without using additional shells. The sections of a multibreak shell are ignited by different fuses. The bursting of one section ignites the next. The shells must be assembled in such a way that each section explodes in sequence to produce a distinct separate effect. The explosives that break the sections apart are called break charges.

The pattern that an aerial shell paints in the sky depends on the arrangement of star pellets inside the shell. For example, if the pellets are equally spaced in a circle, with black powder inside the circle, you will see an aerial display of smaller star explosions equally spaced in a circle. To create a specific figure in the sky, you create an outline of the figure in star pellets, surround them as a group with a layer of break charge to separate them simultaneously from the rest of the contents of the shell, and place explosive charges inside those pellets to blow them outward into a large figure. Each charge has to be ignited at exactly the right time or the whole thing is spoiled.



Shell Name Descriptions

Palm Contains large comets, or charges in the shape of a solid cylinder, that travel outward, explode and then curve downward like the limbs of a palm tree
Round shell Explodes in a spherical shape, usually of colored stars
Ring shell Explodes to produce a symmetrical ring of stars
Willow Contains stars (high charcoal composition makes them long-burning) that fall in the shape of willow branches and may even stay visible until they hit the ground
Roundel Bursts into a circle of maroon shells that explode in sequence
Chrysanthemum Bursts into a spherical pattern of stars that leave a visible trail, with an effect somewhat suggestive of the flower
Pistil Like a chrysanthemum shell, but has a core that is a different color from the outer stars
Maroon shell Makes a loud bang
Serpentine Bursts to send small tubes of incendiaries skittering outward in random paths, which may culminate in exploding stars



Dr. H

Answer 2

The physics of explosions has become well known over these last few decades. With the advent of super computers, explosions can be simulated down to almost the molecular level. At a well known national laboratory in the 1970's, we used Cray computers that ran literally for days while they crunched the numbers for shaped explosions tracked at close to the molecular level of the explosives. Today, the super computers are faster and bigger; so they can do in hours what it once took days to do.

In addition to the super computers, the chemistry of explosions has also become better known. Thus, for example, we can rather precisely calculate how fast and what directions given mixes of explosives will go when they explode. Some explosive mixes can burn at a rate near the speed of sound; while others might just creep along at a snail's pace. By packing the fireworks with different explosive mixes, the net result of the explosions can be made into a variety of shapes and colors.

Packing is key to the shapes, colors, and sequencing of fireworks. But underlying that are the super computers and better understanding of the chemistry of explosives; so we know what to pack and where to give us what we want.

Answer 3

Firecrackers do their "special effects" either by the use of multibreak shells or multi sections. Multibreak shells are actually shells within the main shell, which is the main body cylinder of fireworks. Multi sections, on the other hand, are the sections that divide the main cylinder body. These multibreak shells / multi sections are arranged in such a way that their ignitions follow a sequence.

To get a specific pattern, the star pellets (kind of like a sub-firework) inside the cylinder are first arranged as a group according to the desired pattern's outline. Then they are simultaneously separated from the rest of the fireworks by a layer of break charge. Break charges are basically explosives that break the sections apart. Finally these sections are thrust outward by another ignition, thus creating those fancy shapes we see in the sky.

To get more useful info, please follow the link below. It will take you HowStuffWorks/Fireworks. This site contains lots and lots of useful information. Happy surfing.

Answer 4

The only way something would explode and the pieces continue to travel in the direction they started, is in a vacuum (no wind resistance) and in space (no gravity). The particles go outward because of the explosion, they stop moving because of wind resistance which affects all particles equally. They start falling down because of gravity, which affects all equally.

Answer 5

in "Italian" aerial shells, the stars are poured into the container, and when they burst, a random pattern emerges.

On the other hand, in "Japanese" shells, the stars are carefully arranged around the circumference of the shell so that they produce circles and globes.

I have seen special shells with hearts and other simple shapes also.

explosions are not random, but follow rules, for example the EFP (explosively formed penetrator) used in roadside bombs is a specially shaped charge.

Answer 6

It is because of the laws of physics that fireworks act the way they do.

The science of pyrotechnics
http://library.thinkquest.org/15384/physics/index.htm

Answer 7

I wanned to exercising consultation max. 2 sentences as instantly as I clicked in this question. it somewhat is the incorrect section. no man or woman will research each and each of the sources you wrote reason we are too damn lazy. staggering, have a good day sir.