Forensic Chemistry: Explosives

Flashcards on key terms and concepts from the Forensic Chemistry lecture on explosives.

Explosion

Rapid release of pressure and gas, which may or may not involve detonation.

Combustion

Self-sustaining oxidation that proceeds by heat transfer, characterized by visible flame.

Deflagration

Subsonic flame front driven by thermal conductivity, with speeds less than 1 km/s.

Detonation

Supersonic reaction front that compresses unreacted explosive materials through shock waves.

Brisance

The ability to shatter materials, which is proportional to detonation pressure.

Fragmentation

The breaking of the casing into high-velocity projectiles that can cause secondary injuries.

ANFO

Ammonium Nitrate Fuel Oil, a commonly used commercial explosive.

Primary Explosive

An explosive that is very sensitive and can detonate with minimal stimulus, such as Lead Azide.

Secondary Explosive

Requires a booster or shaped detonation wave to initiate, examples include TNT and RDX.

Improvised Explosive Devices (IEDs)

Devices made from dual-use chemicals outside of military supply chains.

Oxygen Balance (OB)

A measure of the relative excess or deficit of oxygen available for combustion in an explosive.

Ion Mobility Spectrometry (IMS)

A technique that separates ions in a gas phase based on their mobility, used for detecting explosives.

Heat of Explosion

The energy released during a complete detonation, typically given in kJ/kg.

Overpressure Thresholds

Pressure levels that indicate potential for injury or fatality, such as 5 psi for eardrum rupture.

Thermal Effects

Heat generated from an explosive that ignites surrounding materials.