Igniting the Sky

Fireworks have come a long way since the 12th century when the Chinese set fire to bamboo stuffed with saltpeter, sulfer and charcoal.

Today, the most advanced fireworks have entered the computer age.

Elaborate shows--including those seen at Angels and Dodgers baseball games--use a new digital firing system that allows for precision timing.

As increasing numbers of cities in recent years have outlawed backyard fireworks, people have flocked to professional holiday shows.

In Orange County, only Buena Park, Stanton, Costa Mesa, Garden Grove and Santa Ana allow sale and use of “safe and sane” fireworks. Possessing fireworks where they are banned is a misdemeanor unless they contain more than 50 grams of powder. Then it can be a felony.

A look at how fireworks operate

BEHIND THE SCENES

The appearance of the fireworks is determined by the shell used and the chemicals within. The pattern is produced by the size of the glittering “stars,” the type of packing inside a shell and the shape of the shell.

Usually, two people light the fireworks, four others reload the mortars and several others monitor the explosions.

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The Shell

1. Two to three feet of fast fuse is hand-lit using a road flare.

2. Fuse carries fire to gunpowder lift charge.

3. Charge explodes, propelling shell into the air at 300 to 400 mph.

4. A separate shell fuse ignites the burst charge about four seconds after the lift charge.

5. Chemical cubes in shell explode producing colored sparks.

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The Mortar

Cardboard or metal mortar: 3- to 6-inch diameter, buried to three quarters of its length.

The Colors

Chemicals used

Red: Strontium nitrate or carbonate

Blue: Copper salts

Yellow: Sodium salts

Green: Barium nitrate or chlorate

Orange/amber: Charcoal or iron

White: Magnesium or aluminum powder

SAFETY TIPS

* Buy only legal fireworks--marked Class C Common--that come with instructions.

* Make sure an adult is present if children are using fireworks.

* Light fireworks one at a time; move a safe distance away

* Do not light in bottles or cans.

* Light fireworks outdoors, away from structures, dry vegetation and flammable items.

* Keep used fireworks away from the launch area.

PRIME WATCHING

ANAHEIM

Disneyland’s display can be seen for miles in all directions; Anaheim Stadium show is also visible.

FULLERTON

Fullerton Union High School; also try Hillcrest Park--from a prime spot, you can see high school show as well as those at Disneyland and Knott’s Berry Farm.

BALBOA ISLAND

Displays from Laguna’s Main Beach, Emerald Bay and Big Canyon Country Club in Newport Beach are visible; likely to be crowded.

HUNTINGTON BEACH

Edwards Hill, at Elis Avenue and Edwards Street; displays at Huntington Beach High School, Disneyland, Orange Coast College and Anaheim Stadium can be seen. Beware: Parking is limited.

LAGUNA BEACH

Alta Laguna Park (Top of the World); several displays are visible, including those at Emerald Bay, Dana Point and Irvine Cove. Shows at Main Beach, Dana Point, Three-Arch Bay, Emerald Bay and Irvine Cove visible from downtown’s Heisler Park. Park away from downtown to avoid huge traffic jam.

LOS ALAMITOS

Armed Forces Reserve Center good for show there, at Old Ranch Country Club in Seal Beach and, in distance, Disneyland

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Sources: Pyro Spectaculars Inc., California state fire marshal; Researched by STEPHANIE STASSEL and APRIL JACKSON / Los Angeles Times