Explosives

AND THEN, IT WENT KABOOM!
By Linda Maria Frank

Every high school chemistry student, studying the incredible nature of nitrogen bonds, has heard the story of Alfred Nobel and his creation of dynamite. As the Industrial Revolution chugged along, the need for faster and more powerful methods of construction became increasingly important.

The two know explosives at the time were black power (gun powder), a relatively low grade explosive, and nitroglycerine, powerful, unstable, and deadly dangerous to use. The key ingredient in these two is the nitrogen bonds in the chemical ingredients. When the bonds between nitrogen atoms and the atoms of other elements are broken, tremendous energy is released.

Nitroglycerine contains these nitrogen bonds, but in a very unstable form. Jiggle a bottle of the oily liquid, or raise its temperature just a few degrees and Ka-Boom. In its original form, it was too dangerous to use. The potential for nitroglycerine to be used for construction purposes during the enormous building boom of the 1800’s and early 1900’s spurred the Swedish chemist, Alfred Nobel, to try to stabilize nitro, so that it could be transported, stored and used safely.

First he invented a blasting cap in 1862, in order to detonate the stuff from a distance. Previously, nitroglycerine could only be detonated with a spark or percussion at close range. A blasting cap contains a small amount of chemicals which, when stimulated with a fuse produce a shock wave of energy that sets off the nitro.

However, you were still dealing with the transport of nitro from factory to storage facility to construction site. The quest to stabilize went on. It is a little known fact that the Nobel family suffered greatly from this quest. Alfred’s brother, Emil, was killed in their factory’s explosion. Nobel, himself, suffered horrible headaches from his exposure to nitroglycerine. Those of you familiar with the nitro patch worn by folks suffering from some cardiac conditions are aware of this side effect.

Like many great discoveries an accident led to Nobel’s final safe preparation of the compound known as dynamite. As time and trials went on the transportation of nitroglycerine was done by surrounding the bottles of the liquid immersed in crates of sand. A wagon transporting the stuff had a mishap, and the nitro did not explode. A light bulb went off for Nobel. He then experimented with varying amounts of liquid nitro with sand packed in a tube. Once stabilized with the right mixture, the nitro could be detonated with a fuse or a blasting cap. Picture the Wiley J. Coyote or Yosemite Sam cartoons where someone is holding the tube of dynamite with the sparkling fuse dangling from the end. In real life the fuse is a bit longer. DYNAMITE was born! It was originally known as “Nobel’s Blasting Powder”.

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Success had been achieved in 1867 and was the tool of choice for builders of railroad tunnels, canals and other massive construction projects. When dynamite became a weapon in the attempted assassination of Tsar Alexander II in Russia, Nobel, who had become enormously wealthy as a result of dynamite, created the famous Nobel Prizes in Physics, Chemistry, Medicine, Literature, and of course, the Peace Prize.

However, explosives get most of their press, not from damn construction like the Hoover Damn, but from destruction of people and places, in acts of terrorism such as the one described above. More recently consider the tragedy of the Oklahoma City bombing in 1995, the biggest act of mass murder in U.S. history involving explosives. 168 people including 19 children died in Oklahoma City that day. The Twin Towers attack in 2001 did not involve actual explosives, but the inflammable nature of jet fuel introduced into the buildings by a plane crash.

The explosive of choice by Timothy McVeigh, the perpetrator of the crime, was ammonium nitrate, NH3NO3. Remember those energetic nitrogen bonds? Once you create the chemical reaction to release that power, you can send any material in the blast site moving out in all directions at speeds greater than 1000 meters per second. A meter is a little more than three feet. If a bomb created by a terrorist, like a pipe bomb, contains nails or tacks, think of those objects traveling at that speed and hitting soft flesh.

Nitroglycerine in explosive mixtures has been replaced with ammonium nitrate, commercially available in fertilizers. It’s mixed with fuel oil, and this mixture is referred to as ANFO. In the correct packaging ANFO can be detonated by a fuse or blasting cap, or most commonly today, a blasting cap electronically set off by a cell phone signal such as the bomb used at the Boston Marathon in 2013.

The purchase of large quantities of fertilizer and diesel fuel is a red flag for law enforcement and anti-terrorism task forces. These substances are easily available. It’s one of the tip-offs that help to prevent terrorist attacks. Tune in next time to learn how a crime scene involving the use of explosives is processed and analyzed, and how we can tell the difference between an arson scene and one involving a bomb or explosive. This was the puzzle confronting the NTSB and FBI in the crash of TWA 800.

Some notable cases to be explored are the 1993 Twin Tower bombing, the London transit system bombing in 2005, the Atocha Railroad Station bombing in Madrid, the bombing of the U.S. embassy in Nairobi, the crashes of TWA 800 and PanAm 103.

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