A Bigger Bang in your future

Future Tense for Jul. 02, 2007

By Steve Welker

Growing up, I wanted to be a chemist. Other kids wanted to be cowboys, firemen, cops or robbers. But I had discovered the secrets of chemistry:

• Chemists make stinks worse a skunk’s sweatsocks.

• Chemists make dyes so permanent that jeans fall apart before the stains fade.

• Chemists make stuff that goes “Bang!”

I my youth, the homemade explosive of choice was black powder. The Chinese invented it around 1042 A.D. All you need is potassium nitrate, sulfur and charcoal (connoisseurs say willow wood produces the best charcoal). Combine the ingredients by weight in a specific ratio, add a little water to prevent sparks and carefully grind the powders together. After the paste dries, a spark will set it ablaze. Wrap it up in paper or cardboard, add a fuse, light it and bang! — you have a cherry bomb.

Substitute sugar for charcoal, alter the proportions slightly and you make a nice rocket fuel.

By the way, I’m certainly not the only person whose childhood hobbies included making his own fireworks. Robert Merritt and I ran into each other at a party and happily compared notes on my Midwest vs. his East Coast mixtures.

I’m not going to share the details with you. Let me state clearly, (a) all of these formulas are on the Internet and (b) I’m not going to tell you where to look and (c) even if the Internet didn’t exist, all of this data is in books, pamphlets (many produced by the U.S. armed forces) and magazines. Friar Roger Bacon first published the gunpowder recipe in 1242 A.D.

And, yes, the usual warning applies: Don’t try this at home.

The 19th century was the golden age for new explosives. No, I’m not old enough to remember it, but one of my other hobbies is the history of science.

Italian chemist Ascanio Sobrero invented nitroglycerin as a medicine in 1846. I’ve never met anyone crazy enough to make it at home or in a school lab. One look at Sobrero’s mangled face, horribly rearranged in a lab explosion, should be enough to convince anyone not to mess with it. But nitroglycerin remained in use for years up until the 1930s because it was five times more powerful than black powder.

Alfred Nobel designed a safe detonator for “blasting oil” in 1865 and invented dynamite — a stable mixture of nitroglycerin and clay — in 1867. Dynamite helped build the railroads and opened vast mines, such as the one operated in Mount Airy by N.C. Granite Corp.

TNT’s discovery preceded dynamite’s. In 1863, Joseph Wilbrand created trinitrotoluene, the first of a long line of explosive substances with a “high” overabundance of nitrogen and oxygen atoms. Gelignite followed in 1878; Lyddite in 1882; cordite in 1888; TATP in 1895; RDX (cyclonite) and HMX (octogen, today’s most widely used military explosive) in 1899; and PETN, a key ingredient of Semtex (plastique), in 1901.

DuPont introduced ammonium nitrate as a fertilizer and explosive in 1935; ANFO, a combination of ammonium nitrate and fuel oil, has been used for blasting since 1955. Timothy McVeigh’s homemade ANFO — ammonium nitrate and nitromethane racing fuel — blew up the Murrah Building in Oklahoma City in 1995.

TATP is what al-Qaida’s Richard Reid had in his shoes when he tried to blow up American Airlines Flight 63 in 2001. When people talk about a high explosive “that can be mixed from three common household chemicals,” this is probably what they mean. It’s highly unstable, friction sensitive and Reid is lucky he didn’t blow off his legs. On second thought, it would have served him right. When terrorist bomb makers have fatal lab accidents — not often enough, in my opinion — it’s often TATP they’re concocting.

Anyway, politics aside, most high-explosive formulas have been known for years. Weapons experts, demolition teams, fireworks’ makers and miners simply use more of what they have.

Grucci, one of America’s premier pyrotechnics companies, built two of the biggest fireworks, Fat Man I and Fat Man II, in 1976. Each was 40 inches wide and weighed 720 pounds. Fat Man I blew up in its mortar, throwing a heavy chunk of steel a quarter-mile. Fat Man II exploded just 100 feet off the ground, scaring some sense into everyone around. Most lately, Grucci has used wireless detonators to set off its shells at the proper height.

In 2003, MOAB (“Mother of All Bombs”) was the biggest conventional bomb in the U.S. military inventory. Thirty feet long and 40 inches wide, its 21,500 pounds included 9 tons of high explosive. Too bad it’s a ground penetrator. Exploded at altitude, you could probably hear and see it for 20 miles around.

Since then, the Air Force has been developing Big BLU, also known as “MOP,” that reportedly tips the scale at 13 tons. MOP stands for Massive Ordnance Penetrator, not for the distinctly low-tech device you would need to clean up what remains after it breaks up a fortified bunker. Technology marches on.

In 1999, chemists Phillip Eaton and Mao-Xi Zhang at University of Chicago synthesized octanitrocubane. It’s a cube of carbon atoms studded with nitrogen and oxygen molecules. Almost no one thought it could be made and its creation certainly was a milestone in chemical synthesis. Theorists predicted it would be 20-25 percent more powerful than HMX or twice as powerful as TNT, but it hasn’t lived up to their expectations. Other polynitrocubanes, may be even more destructive. Fortunately, no kid is likely to cook up this stuff with a home chemistry set.

In 2002, a chunk of porous silicon doped with gadolinium nitrate blew up unexpectedly in a lab at University of California-San Diego. Pound for pound, it may be the most-powerful explosive yet.

I don’t want to worry anyone, but there’s some gadolinium nitrate in the silicon chips on your computer. You might want to clear the room and cover your ears if your PC suddenly blurts out, “Good morning, Mr. Phelps.... This device will self-destruct in 10 seconds....”

You might hear a very large bang ... in the future.

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