Assortments can always be selected according to your specific tastes - if you're doing a small backyard show for children and don't want much noise, you can buy a small family assortment which contains items such as fountains, sparklers, poppers, and smokes (which usually costs about $10-$30).  

Even if you're experienced with consumer fireworks and plan to do a full-scale neighborhood display, you can't go wrong with an assortment - larger ones contain a nice variety of shells, repeating aerial displays, rockets, and more.

Small, 7 shot cakes usually cost around $8, while devices like the one pictured usually sell for around $15.  In the last few years a new type of repeater has been produced, which contains 500 grams of pyrotechnic content (the legal limit).  Such devices are often over a cubic foot in volume, and cost around $40 and up.

Each cardboard tube within a cake contains clay plug in the bottom and a black powder lift charge.  The tubes contain small holes at the bottoms through which a fuse can burn through, igniting each tube sequentially.  Most devices have several parallel-fused tubes towards the end of the "fire trail", so that several tubes ignite simultaneously (or in very rapid succession) at the end of the performance in order to intensify the display.  Each tube contains a smaller "effect tube" that is usually about one-third to half the length of the main tube.  When the lift charge in the launching tube fires, it ignites a time fuse and (usually) a colored star composition in the bottom of the effect tube.  The star composition burns brightly as the tube rises, and its maximum altitude, the burst charge ignites the effects.  The diagram at the right shows stars, but there are many other types of possible effects: reports, whistles, crackles, hummers, and even parachutes.   

Larger shell assortments usually contain one or more 18" long HDPE mortars and 24+ shells that may have multiple breaks and effects.  These kits can range from $30 to nearly $200 in price, depending on what type of shells are in the assortment.  Pictured on the right is a triple-break shell assortment.  Each "shell" is actually three shells attached to each other that burst in quick succession in the sky.  Double, quadruple, and quintuple shells also exist.

If you plan on launching a lot of shells, you may want to consider buying mortar tubes and building your own mortar rack.

Shells are launched from a tube known as a mortar.  A string loop is often attached to consumer firework shells so it can lowered into the mortar by the fuse.  When the fuse enters the shell, it ignites the burst charge, creating an explosion that ignites the time fuse and shoots the shell high into the air.

As the shell ascends, the time fuse burns towards the burst charge.  At the precise altitude - usually where the shell is briefly hanging in the air - the time fuse ignites the black powder burst charge, causing the shell to explode.  The powerful explosion blasts apart the shell casing and ignites the stars, scattering them in all directions across the sky.  These stars burn brightly and give off sparks, creating a huge spherical pattern in the sky.

Display tube devices consist of little more than several aerial shells fused together to go off in sequence, with a few seconds of delay between each shell.  There are usually anywhere from 3 to 7 tubes which are glued down to a thick wooden base to stabilize the device.  Each tube contains a typical aerial shell in the bottom, protected by a cardboard disk and a cap at the top of the tube.  Holes are drilled in the bottom of each tube, and small chunks of fuse connect each shell to the tube adjacent to it.  The tube on the end has a long fuse that runs outside for a few inches.  

When that fuse is lit, the first shell fires.  The lift charge of that shell ignites the chunk of fuse leading into the next tube, which in turn ignites a shell about four seconds later, and so on.

Firecrackers are the simplest and oldest of fireworks.  A single firecracker is simply a paper tube of several layers to give it strength.  It is plugged at both ends with a dry clay-like substance, and contains a small amount of flash powder in the middle.  When the fire from the fuse ignites the flash powder, it creates a large volume of hot gas in a short period of time.  The casing of the tube contains this gas until the pressure blasts the tube open with a loud "crack".

Flying spinners are basically ground spinners with slanted wings.  As the device spins, the wings direct the air flow downward and lift it into the air, much like a helicopter.  At the end of its flight, a small burst charge ignites and ejects the colored stars inside.  Sometimes the whole thing explodes.  Helicopters can range in price from about $.50 for small ones and around $1-$2 for the device pictured at the right.

Flying spinners are another one of the most popular fireworks.  It is little more than a ground spinner with a paper or plastic wing unit attached to the tube.  When the propellant composition is ignited, it creates thrust which spins the device around.  But whereas a ground spinner would simply bump around on the ground, the spinning motion of a flying spinner causes the angled wings to direct airflow downward, lifting the device into the air exactly like a helicopter (hence the name).

Helicopters have a burst charge at the end of the propellant compound, which explodes at the end of the device's flight and ejects stars, ladyfingers, or a parachute.

Larger fountains consist of multiple tubes fused to go off in sequence.  As mentioned before, they can easily be confused with repeaters by their shape, but your clue that they are fountains is that the fuse is on the top, not the side.  Like smaller fountains, they never shoot their effects over 10 feet in the air, but they provide much longer lasting displays (from 2-3 minutes!)  and can greatly enhance your show, especially when used in combination with shells or other aerial items.  Such fountains can cost up to $20.

Single tube fountains consist of a cardboard tube (which may be inside of a cone) that stands vertically on a plastic base.  The tube is charged with a composition designed to make lots of sparks, flame, and gas.  At the end of the tube there is a clay plug with a hole drilled into it, forming what is known as a "choke".  Without a choke, the fountain would only give off a weak spray of sparks.  With a choke, however, a lot of pressure builds up inside of the tube, which forces the gas and sparks out of the fountain with a much greater velocity.  Very small fountain tubes (i.e., 1/4 in diameter) don't require chokes.

The fountain composition is often layered as to produce different effects at different stages in the burning.  For instance, one layer may burn to produce orange sparks, followed by a layer that produces white sparks and green star fragments.

Each of the individual fountain tubes has a hole near the bottom with a fuse coming out of it, which leads up to the top of the next tube.  This fuse ignites when the tube has almost finished burning, and by the time it does, the next tube has already ignited.  This sequence continues for the remainder of the tubes.  Sometimes a fuse will lead to several tubes, igniting them all at once to produce an intense spray of noise and color as a sort of 'finale'.

Another type of spinner is the circular type, where a tube of composition (or small drivers) burns to make the device spin around in a circle.

How they work

Single tube ground spinners consist of a single tube (imagine that!) that is plugged at both ends with clay and is filled with a rapidly-burning composition.  A small fuse hole has been drilled into the side of the tube, near one of the ends.  When the fuse ignites the composition, hot gases are produced and rush out of the hole, propelling the device around its central axis.  Because it is off-balance and doesn't have quite enough thrust to fly, the firework spins wildly and randomly on the ground.  The characteristic blossom shape of Ground Bloom Flowers is caused by the tube rapidly bumping up and down as it spins.

In single-shot mines, the bottom of the mine tube contains a black powder lift charge, similar to that found in a shell.  When ignited, the lift charge engulfs the stars in flame, igniting them as it propels them out of the tube in a V-shaped pattern.  The "spread" of the stars in the sky depends on both the length and the width of the mortar.  

Reloadable mines are constructed almost exactly like shells, except the burst charge/lift charge is in a single compartment of the shell.

Novelties are small fireworks that usually look like some " real life" object (tanks, ships, cars, or animals) and often scoot across the ground.  They generally don't do much and aren't that impressive, but children always get a big kick out of them.  Kids also like these because they can use what's left over as a toy (or something to stomp on).  Novelties are fairly cheap: they cost about $.75 for a simple tank to no more than $2 or so for a more "elaborate" device such as ships and monster trucks.

There are hundreds of different novelties, and they all work more or less the same way.  The example I've chosen to illustrate here is the ever-popular tank.

Tanks contain several tiny fountains that shoot multi-colored stars and often produce just enough thrust to move the device along if it's placed on a hard, level face.  A small length of gray tissue firecracker-type fuse transfers the fire from the rear fountain to the front "guns" of the tank.  These small fountains are only filled half way with composition, so the fuse can therefore enter from the side in order to ignite it.

Night parachutes are the same as daytime ones, except that the paratrooper has a strobe or colored star composition in it, which burns brightly as it slowly falls down. They cost about the same as daytime parachutes.

Aerial parachutes have a complex internal construction also similar to that of an aerial shell.  Parachutes can come in the form of single tubes with a base, or clusters of tubes that look like a tall repeater.  The launch tube is usually quite thick to withstand the forces of the powerful, noisy lift charge. When the lift charge ignites, it blasts a "parachute tube" high into the air.  Meanwhile, a time fuse is burning inside of the parachute tube, which in turn ignites a tiny burst charge when the tube reaches the highest point in its flight.

Much like a model rocket, this burst (or "ejection") charge blasts the parachutes from the parachute tube.  There is often a small piece of paper "wadding" between the burst charge and the parachutes to prevent the chutes from burning up.  The tissue parachutes are attached to small chunks of tube filled with clay to serve as weights.  They can be packed together tightly, which enables several parachutes to be put inside of one parachute tube.

Sometimes the weight tube is filled with a smoke composition.  A short piece of fuse transfers fire from the parachute tube's burst charge to the composition in the weight, which smokes as it drifts down from the sky.  Nighttime parachutes use a steady-burning star or strobe composition in place of smoke composition.

Neither snap nor party poppers are actually considered to be consumer fireworks.  Rather, they are considered "trick noisemakers" which, along with toy caps and cigarette loads, fit into the 1.4S category.  Therefore, they can be sold year-round in most toy shops and shopping centers.

Each pea-sized snap contains a few grains of sand that have been coated with a tiny amount of the friction-sensitive high explosive silver fulminate (AgONC), all twisted together in a piece of tissue paper.  When thrown on a hard surface (or squished between the fingers), the friction of the sand against the silver fulminate causes the latter to detonate with a quick, loud "pop".

Rockets are the second oldest type of firework that were originally discovered by mistake - the Chinese discovered that an open-ended firecracker propelled itself along the ground, rather than exploding.  Since then, their construction has become much more complex.  Rockets and missiles operate the same way; the only difference being in the method of stabilization (either fins or a stick).  When the burning fuse enters the end, the cone-shaped chamber ignites within a fraction of a second.  The shape of this chamber provides a very large surface area for burning to take place, creating a large volume of gas which is forced out of the back to create thrust.  As a result, the rocket/missile travels in the opposite direction.  Because of the rapid burning, the fuel is exhausted in a matter of seconds.  The casing of the rocket is usually fairly thick so it can withstand the high pressures of the burning fuel.  The internal time fuse then transmits fire to the burst charge, which explodes to break open the rocket casing and ignite the stars or reports inside.

Standard, star-shooting roman candles cost about $0.75-$1.00; those with more elaborate effects cost $1.50-$2.00, and the thicker "shell" type candles cost about $5.

Though roman candles seem like a simple firework, the construction process is quite complex and difficult.  After a clay plug at the bottom, the roman candle tube consists of alternating layers of lift charge, stars, and delay compositions.  When the fuse enters the tube, it activates a slow-burning delay composition that makes its way down.  Within seconds, the delay charge reaches the first star, simultaneously igniting both it and the lift charge below it, which blows the star out of the tube.  This ignites another layer of delay composition, which will light a star and the lift charge to blow it out a few seconds later.  This continues until every star has been blown out of the tube.  

Cylindrical "smoke grenades" are also available, which create thick clouds of smoke for up to 2 minutes.  They cost about $1-$2

The most famous consumer smoke device is probably the "smoke ball" or "smoke bomb", a large ball of clay with a hollow center.  Inside the center is a composition that usually consists of potassium chlorate, lactose, and a powdered dye.  When ignited, this composition burns at a relatively low temperature, which evaporates the dye into fine particles and disperses them into the air (so the colored "smoke" isn't actually smoke at all).  

The smoke composition must be "cooled off" fairly quickly after ignition, or else the dye particles will react with oxygen to burn up.  This is why smoke is always observed rapidly exiting the burning chamber.  If you hold a smoke device too close to a solid object, the burning particles can't get away fast enough to cool down.  At this point, the device will begin emitting a flame rather than smoke.

Most strobe devices (pictured at left) come in boxes of a half dozen, and they emit bright, disorienting flashing of light.  A box of strobes typically costs about $1.00  Snakes come in the form of small black pellets.  When they burn, they emit a long, brittle carbon ash, which looks like a snake coming out of the ground.  A box of 6 snake pellets costs about $.25-$.50.  

Consumer strobes are usually small paper cups filled with a damp composition that is allowed to dry.  Strobe composition is a mixture that consists of two main parts: a composition that reacts easily, and one that doesn't.  When the fuse ignites the composition, the more reactive compound burns to create a large amount of heat.  This heats up the the more difficult to ignite portion of the mixture, which goes off with a sudden flash once it reaches ignition temperature.  This process repeats itself over and over, gradually increasing in frequency and producing hundreds of flashes.

In display fireworks, strobe composition is made into stars and put into either aerial shells or mines.

Sparklers are tiny hand held fountains that give off colored sparks from the burning tip.  They are the only firework meant to be held.  There are two types - metal rod (pictured at left), and "Morning Glory".  Metal rod sparklers are typically single-color (usually gold or silver).  They are fairly difficult to ignite, and cost around $.75  for a box of 6.  Morning Glories are attached to wooden rods and have 3 distinct burning phases - usually a red flame for about 20 seconds, then a crackle/snapping phase for 20 seconds, and finishing off with 20 seconds of a green/white flame.  They cost a bit extra ($1 per pack of 6), but are much safer than metal sparklers because they don't leave a hot wire behind.  Some companies manufacture very large sparklers known as "California Candles", which are basically a roman-candle sized fountain.

Wheels consist of a cardboard frame to which are attached several small rockets, or "drivers".  The device is usually attached by a nail to a wooden post.  When the burning fuse enters each driver, the propellant burns rapidly to give off gas, which is forced out of the small nozzle to create thrust.  This thrust spins the device around its axis.  Unlike most rocket propellants (which are designed to lift the rocket up into the air and not give color), the propellant used in wheel drivers burns to produce rich colors, sparks, crackle, etc.  Because the wheel spins so fast, it appears that there are "rings" of fire.  When each driver is exhausted, the fire is transferred by another fuse to the next driver, which starts up again and continues the process (usually with a different effect).  This usually happens so fast that the wheel doesn't have time to stop spinning.