Name: ________________________________________ Date: __________________ Period: _____
Vocabulary:
Explosions Chapter 13
Define the following words as they pertain to forensic science.
1. Black powder
A mixture of potassium nitrate, carbon, and sulfur in the ration 75/15/10
2. Deflagration
A very rapid oxidation reaction accompanied by the generation of a low-intensity
pressure wave that can disrupt the surroundings
3. Detonating cord
A cordlike explosive containing a core of high-explosive material, usually PETN,
Also called a Primacord
4. Detonation
An extremely rapid oxidation reaction accompanied by a violent disruptive effect
and an intense, high-speed shock wave.
5. Explosion
A chemical or mechanical action caused by combustion, accompanied by creation
of heat and rapid expansion of gases.
6. High Explosive
Chemicals that oxidize extremely rapidly, producing heat, light, and a shock
wave; will explode even when not confined
7. Low Explosive
Chemicals that oxidize rapidly, producing heat, light, and a pressure wave; will
explode ONLY when confined.
8. Oxidizing agent
A substance that supplies oxygen to a chemical reaction (it gains electrons)
9. Primary explosive
A high explosive that is easily detonated by heat, shock, or friction
10. Safety fuse
A cord containing a core of black powder, used to carry a flame at a uniform
rate to an explosive charge
11. Secondary explosive
A high explosive that is relatively insensitivity to heat, shock, or friction
12. Smokeless powder (double-base)
An explosive consisting of a mixture of nitrocellulose and nitroglycerin
13. Smokeless powder (single-base)
An explosive consisting of nitrocellulose
14. X-ray diffraction
An analytical technique for identifying crystalline materials
Questions:
1. What is ANFO?
An explosive consisting of ammonium nitrate soaked in fuel oil.
2. What device is widely used to screen objects for the presence of explosive residues?
Ion Mobility spectrometer (IMS)
3. How are soil and other soft loose materials collected at the scene of an explosion best stored? Why?
Best stored in metal containers
4. What is the first procedure typically used to analyze bomb-scene debris that arrives in the lab?
First examined microscopically to detect particles of unconsumed explosive
5. What does the forensic scientist do to explosive debris following microscopic examination? Why?
It gets rinsed with acetone because the high solubility of most explosives in
acetone ensures their quick removal from the debris
6. What is a taggant? What purpose do taggants serve?
Tiny color-coded chips the size of sand that are added to commercial explosives
during their manufacture. The taggant chip is arranged in a color sequence that
indicates were the explosive was made and when it was produced. Taggants thus
all an explosive to be traced through its distribution chain to its final legal
possessor.
The following pieces of evidence were found at separate explosion sites. For each item, indicate
whether the explosion was more likely caused by low or high explosives, and explain your answer.
a. lead azide residues High explosives. Lead azide is a common component of
blasting caps, which are used to detonate high explosives.
b. nitrocellulose residues Low explosives.
c. ammonium nitrate residues High Explosives. Ammonium nitrate is the main
ingredient in a number of high explosives that have replaced dynamite for
industrial use.
d. scraps of primacord High Explosives.
e. potassium chlorate residues Low explosives