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Using Physics: Bombs and Explosions
One of the most well-known criminals ever to build a bomb was
a man named Ted Kaczynski—the Unabomber. Highly intelligent,
Kaczynski earned a Ph.D. in mathematics from the University of
Michigan. He taught for a while, but eventually withdrew from so-
ciety and moved into a tiny shack in a Montana forest. There, he
started a seventeen-year career as a mail bomber, sending deadly
bombs to people around the country. His lethal packages killed
three people and wounded twenty-eight others.
The Science Behind the Blast
Everyone knows bombs are very destructive, but few people understand
how they actually accomplish the damage they do. Chemicals inside the
bomb are combined in such a way as to be very unstable, releasing huge
amounts of energy when the conditions for their reaction are met. Some-
times the only thing that is needed is a tiny spark, which can be provided
by a small battery connected to a timer. Once the reaction begins, there is
often no stopping it. As the chemicals react, the bomb explodes.
When a bomb explodes, rapid expansion of the air surrounding the
device causes a
shock wave
. Air is composed of molecules such as oxygen
and nitrogen in their gaseous state moving around in a random way. When
chemicals in the bomb react with each other, the bomb releases a great
deal of energy that moves away from the bomb very rapidly. This energy
forces the air away from the bomb, causing the shock wave. Bigger bombs
are not always more powerful, but the more powerful the bomb, the more
violent the shock wave. The shock wave gradually loses energy as it moves
