Wednesday, July 22, 2009

A Look at the Strange Ingredients that Make Fireworks Pop

An ancient mix of black powder, essentially gunpowder little changed from its invention in China a millennia ago, gets each rocket in the air by creating pressure in gas trapped in a tube, or mortar.
Two fuses are lit at once: one to ignite the black powder, and another that burns slower, creating a well-timed explosion high in the sky.
The shells of commercial fireworks contain a powdery concoction of chemicals that produce the bangs and the whistles, as well as the pretty effects. Tubes, hollow spheres, and paper wrappings work as barriers to compartmentalize the effects. More complicated shells are divided into even more sections to control the timing of secondary explosions.
Big booms and whistles come from flash powder. Once used for flashes in photography, it is a combination of fuel-like metal and a chemical that feeds oxygen to fire up the fuel.
Different combinations of metals and oxides produce a whole array of sounds.
While ancient Greeks and Romans used bismuth in their beauty care products and coins, chemists add bismuth trioxide to the flash powder to get that crackling sound, dubbed "dragon eggs." Ear-splitting whistles take four ingredients, including a food preservative and Vaseline.
The variety of color in a fireworks show depends on the mix of metals.
Copper produces blue sparks. A mix of strontium salts, lithium salts and other stuff makes red. Aluminum and titanium put the white stars in an aerial flag. Barium, also used in rat poison and glass making, makes green. Calcium burns orange and sodium, yellow.
In recent years, chemists have worked to develop more environmentally friendly fireworks, in part because one ingredient, perchlorate, was found in higher than normal concentrations in a lake where fireworks were shot off, and the chemical is known to cause thyroid problems in humans.
Meanwhile, to light up a red, white, and blue flag, chemists can lay out the emblem's design on wax paper. The pattern you see up in the air, whether it's a smiley face or a bow tie, mirrors the arrangement of the metals in the shell.
Because the flag, or any other pattern, shoots out from the shell as a two-dimensional image, people watching the show from different angles can't always tell what they're looking at. To make sure everyone has a good view, pyrotechnists tend to send duplicates into the sky at the same time.
You can see fireworks before you hear them because light travels faster than sound.

Fireworks factory fire kills 10 in India

July 21, 2009 - 9:54PM
At least 10 people were killed when a blaze destroyed a fireworks plant in southern India, the second such fire in two weeks, officials said on Tuesday.
Twenty-eight people were injured in the fire which erupted on Monday in the town of Sivakasi, India's leading fireworks manufacturing centre.
Thirteen of those hurt were in hospital with severe burns, Tamil Nadu Chief Minister M. Karunanidhi told the state assembly.
The chief minister said he had ordered a probe into the fire and asked experts to review safety measures in Sivakasi, 560km south of Chennai.
The blaze came after 19 people died in a similar fireworks factory fire on July 7 in Tamil Nadu.
Ninety per cent of India's pyrotechnics originate in Sivakasi.
Some 670 privately owned units in Sivakasi produce fireworks worth seven billion rupees ($A171.66 million) a year.
Fires are frequent at firecracker factories in India due to lax safety standards.

Tuesday, July 21, 2009

Jackson Board of Aldermen vote to reverse fireworks ban

JACKSON, MO (KFVS) - Just days after the 4th of July, the Jackson Board of Aldermen voted to ban fireworks.
After a lot of public outcry, the board reconsidered the measure Monday night.
The board decided to reverse the ban on fireworks by a vote of one to seven.
That means fireworks are allowed within Jackson city limits the week of Independence Day, as they were before the ban.
The lone vote in favor of the ban was Alderman Larry Cunningham who says he believes it's a safety issue.
"I think it's a safety issue and I think it needs to be addressed," Cunningham said.
"[I think it's] up to the citizens of the town to have input into it and decide what should be done on something that important," said Alderman Mark Dambach. He said he thinks fireworks should be left to parents to decide what's appropriate for their children.
Several people opposing the ban showed up to the meeting and voiced their opinions.
At least two fireworks sellers were also there, opposing the ban.
After the vote, several members in the audience applauded.
There is no ban on fireworks in Jackson and that the ordinance on the books stands as it did before.

Monday, July 13, 2009

fireworks photography tips

4th of July fireworks photography tips
Wed Jun 24, 2009 4:31PM EDT

Buzz up!36 votes The 4th of July is nearly upon us, and that means it's time to to go watch things explode violently and colorfully in the sky... and impressing your friends with the photos you take of said explosions.

Taking good fireworks pictures isn't actually all that easy, so I've cobbled together my favorite fireworks pic-taking tips -- something of an annual tradition now at Yahoo! Tech -- to help you on your way. After all, you only get one day a year (maybe two) to snap a big fireworks show.

Don't forget to charge your batteries and clear out some space on your memory card first!

4th of July Fireworks Tips

Forget the Flash
You're shooting at night or dusk, and unless you change it, your camera's auto-flash setting will want to go off with ever shutter press. Turn it off before you get started: You can no more illuminate a fireworks display with your tiny flash than you can the moon. The flash will even work against you by slowing down your camera, causing you to miss shots.

Tripods Are Your Friend
Low-light photography means keeping things as still as possible during the shot. A tripod will help immensely here. If you're comfortable with manual settings, change the aperture to f/8 or f/16 and use ISO 100, which pros say are the best settings for pyrotechnics. (Many cameras also have a special fireworks mode, obviously also worth a shot.)

Try the Rapid-Fire Mode
Most cameras have a speed mode that lets you capture 5, 10, or more shots in rapid succession with a single shutter press. Give it a try when you know a big volley is coming up. You never know what you're going to catch.

Vary Your Angles
You'll naturally feel like zooming in on the explosions in the sky, but more interesting shots often include the environment -- the crowd, surrounding buildings or landscape, clouds, and anything else nearby. Consider getting a seat further away than you might ordinarily try for so you have this option. At the same time, ultra-close zoom shots of fireworks can yield very interesting and unusual results.