Chapter 14 - Forensic Arson & Explosives

Question 1

Accelerant

Answer 1

Compound that facilitates the initiation and/or growth of a fire

Question 2

Activation Energy

Answer 2

• The energy necessary to overcome the energetic barrier to a reaction
  - Initial heat required to get the fire started

Question 3

Backdraft

Answer 3

• A fire burns in an enclosed space and uses up most of its O2 supply
• This starves the fire of O2
• The O2 is rapidly reintroduced to the room with the accumulated unburned fuel
• Produces an explosion

Question 4

Black Powder

Answer 4

• Low explosive material comprised of potassium nitrate, sulfur, and carbon (charcoal)
• Used as propellant in fireworks

In a 75:15:10 ratio

Question 5

Chemical Explosive

Answer 5

Chemical that undergoes rapid reaction that releases kinetic and thermal energy

Question 6

Combustion

Answer 6

Chemical process in which a substance reacts rapidly with O2 and gives off heat and light

Question 7

Detonation

Answer 7

• An explosion in which the speed of burning is higher than the speed of sound in the surroundings
• Produce shock waves

Question 8

Detonator

Answer 8

A device used to detonate an explosive

Question 9

Dynamite

Answer 9

• Mixture of an adsorbent (diatomaceous earth, sawdust, clay, wood pulp)
• Has been soaked in nitroglycerin and wrapped in strong paper

Question 10

Exothermic Reaction

Answer 10

Chemical reaction that gives off heat

Question 11

Explosive

Answer 11

A solid, liquid, or combination which can produce gas at such a temp, pressure, and speed to cause damage to surroundings

Question 12

Fire

Answer 12

• The atoms in a fuel react with O2
• Reaction produces different molecules (CO2, H2O)
• Energy is released in the form of light and heat
• O2, fuel, and heat are required to start a fire

Question 13

Fire Tetrahedron

Answer 13

Four elements needed for fire to be sustained:
1. fuel
2. O2,
3. heat
4. chemical chain reaction

Question 14

Flashover

Answer 14

Event in which every combustible surface exposed to thermal radiation in a an enclosed space rapidly & simultaneously ignites

Question 15

Fuel

Answer 15

A substance that is used to begin/add to the process of combustion

Question 16

High Explosive

Answer 16

• Compound that yields rapid chemical reactions regardless of container
• Charge reacts at a speed greater than 1,000m/sec
• Detonate at a rate greater than the speed of sound
• EX: used in mining and for military purposes

Question 17

Kinetic Energy

Answer 17

The energy of motion

Question 18

Low Explosive

Answer 18

• Burn only the surface layer of a compound
• Explode when combustion reaction is contained and builds pressure
• Charge reactes at rates less than 1,000 m/sec
• EX: igniters, fireworks (black powder)

Question 19

Modus Operandi

Answer 19

The method a person uses to commit a crime

Question 20

Oxidant (Oxidizer)

Answer 20

A substance that oxidizes (to combine with O2) another substance

Question 21

PETN

Answer 21

• A nitro-containing high explosive
• Explosive used as the primary ingredient in detonating fuses

Pentaerythritol tetranitrate

Question 22

Propellant

Answer 22

A substance used as a reagent in a reaction to provide acceleration

Question 23

Secondary Explosive

Answer 23

• Explosive compound that is relatively stable to heat/ shock
• Requires more energy to be detonated

Question 24

Primary Explosive

Answer 24

Detonate by ignition from some source such as flame, spark, impact, or other means that will produce enough heat

Question 25

Shock Wave

Answer 25

Highly compressed gasses that travels radially outward from the source at supersonic velocities

Question 26

Smoldering

Answer 26

When a fire burns slowly without a flame

Question 27

Smokeless Powder

Answer 27

- A nitrocellulose-based explosive - Produces little to no smoke on explosion - Used in firearms

Question 28

TNT

Answer 28

Secondary high explosive made of trinitrotoluen