50 Fabulous 4th of July Facts: Fiery Fireworks

Sky Lights

fireworks show in Indiana

Fireworks on the Fourth of July in Indianapolis, Ind.
(Image credit: © Alexey Stiop | Dreamstime.com )

Each day through July Fourth, LiveScience brings you some of the most fascinating, little-known facts about America's celebration of independence.

[Read: 50 Fabulous 4th of July Facts: \The 13 Original Colonies, Come Celebrate! and All About Patriotism]

Static Cling

seaport village fireworks

New years 2002 at Seaport Village in San Diego, Calif.
(Image credit: Public Domain.)

The static electricity in synthetic clothing can unleash sparks that could detonate fireworks, those who make the shells must wear cotton clothing (all the way down to their underwear!), according to Wichita State University.

Cool Colors

July fourth fireworks

Fourth of July fireworks in Davis, Calif.
(Image credit: © Venkatramanan Krishnamani | Dreamstime.com)

The dazzling colors that light up Fourth of July skies depend on the mix of metals inside the fireworks:

  • Copper produces blue sparks;
  • A mix of strontium salts, lithium salts and other substances makes red;
  • Aluminum and titanium put the white stars in an aerial flag;
  • Barium makes green;
  • Calcium burns orange and sodium, yellow.

Big Business

fireworks stand

It is is common for buildings, by the side of a highway, to sell fireworks in rural America.
(Image credit: Skubasteve834)

Fireworks are big business. According to the U.S. Census Bureau, America imports $190.3 million worth of fireworks each year, almost all from China. The U.S. itself makes $231.8 million of fireworks and pyrotechnics each year.

Top This!

Portugal fireworks show

The largest fireworks display on record took place in Madeira, Portugal in December 2006. During the show, 66,326 fireworks went off.

(Image credit: ; See YouTube video)

The largest fireworks display on record took place in Madeira, Portugal in December 2006. During the show, 66,326 fireworks went off.

Lights ... Boom!

fireworks show in Indiana

Fireworks on the Fourth of July in Indianapolis, Ind.
(Image credit: © Alexey Stiop | Dreamstime.com )

You brain isn't playing tricks on you. … You really do see the sky light up before you hear the “boom.” That's because light travels about a million times faster than sound. While light trucks along at a whopping 300,000,000 meters per second, sound chugs at 340 meters per second. To figure out how far away the fireworks are, start counting seconds as soon as you see them light up the sky and stop counting once you've heard the explosion. Divide by 3 and that’s the distance in kilometers.

Hot Stuff

sparklers

People moving sparklers around.
(Image credit: Wikimedia Commons / Public Domain)

Sparklers, which are commonly used by children, burn at temperatures upward of 2,000 degrees Fahrenheit (1,093 degrees Celsius). In 2003, sparklers caused 700 injuries, according to the Consumer Product Safety Commission (CPSC). More than half of injuries of children under 5 were caused by sparklers.

Caution, Please

July fourth fireworks

Fourth of July fireworks in Davis, Calif.
(Image credit: © Venkatramanan Krishnamani | Dreamstime.com)

Between June 18 and July 18, 2010, there were about 6,300 fireworks-related injuries in the U.S., according to the U.S. Consumer Product Safety Commission (CPSC). An estimated 1,200 injuries were associated with sparklers and 400 with bottle rockets.

Boo-Boos

kid with boo-boo

A kid getting a band-aid on for a boo-boo.
(Image credit: © Richard Nelson | Dreamstime.com)

The parts of the body most often injured from fireworks, based on the 2010 CPSC study, were hands and fingers (estimated 30 percent); legs (estimated 22 percent); eyes (estimated 21 percent); and head, face and ears (estimated 16 percent).

Leave it to the Professionals

NYC fireworks

What better symbol of our independence?
(Image credit: CREDIT: © Warren Rosenberg | Dreamstime.com)

But despite the dangers of fireworks, the injury rate has actually gone down 37 percent since 1991, the CPSC found. These days, about 3 out of every 100,000 people gets injured by a firework. The decreased injury rate may be due to people's preference for large, professional fireworks displays rather than backyard pyrotechnics.

Falling from the Sky

Fireworks over Georgia beach

A collection of palm-shell fireworks illuminating the beach of Tybee Island, Georgia.
(Image credit: Steevven1)

All of the propellants, oxidizers and coloring agents that go into dazzling light shows on July Fourth leave a smoky skeleton in the sky that ends up in the area’s soils and waterways.