Forensics chapter 4 arson vocab

What are the motives for arson

Financial gain, revenge, excitement, vanity, crime concealment, and vandalism

Endothermic reaction

Absorbs energy from its surroundings, sometime heat

Accelerant

Any material used to start or maintain a fire

Passive or direct? Gas chromatography

Both

Passive or direct? Heat at bottom

Both

Passive or direct? Held in an air tight container such as a paint can

Both

Natural

Caused by an act of nature such as a lightening strike or intense heat

Arc damage

Caused by electricity jumping out of a circuit, there's no proof that it was arson

Oxidation

Chemical reaction that involves a loss of electrons or a gain of a oxygen molecule

Exothermic reaction

Chemical reaction that releases heat

Classic v

Common pattern of fire. Does not indicate an accelerant was used. Shaped like a V, with point of origin at bottom

Pyrolysis

Decomposition of organic matter by heat

Passive or direct? Needs a lot of debris

Direct

Passive or direct? Not very sensitive

Direct

Passive or direct? Uses syringe to draw vapors out

Direct

Passive or direct? Very fast

Direct

What makes up the fire tetrahedron

Heat Oxygen Fuel Chain reaction

Molotov cocktail

Is a homemade firebomb made with glass bottle, fuel, and a wick. Will possibly leave glass fragments

Flash point

Minimum temperature at which liquid fuel can vaporize

Does a fire investigator need a warrant why or why not

No because, by the time they got one the evidence would be gone since vapors would escape

Accidental

Not intentional for example faulty electrical wiring

Deliberate

On purpose, however, not all deliberate fires are considered arson. For example, a campfire getting out of control.

Passive or direct? Only uses a little debris

Passive

Passive or direct? Takes a long time

Passive

Passive or direct? Vapors are absorbed on a charcoal strip

Passive

Passive or direct? Very sensitive

Passive

What must a fire investigator look for first at a scene?

Point of origin

Inverted cone

Point of origin is the whole bottom of the cone good indicator that an Exceller it was use not normal fire pattern, however not absolute

Pool or plant

Puddle burn mark, someone poured an accelerant in a puddle. It was arson.

Alligatoring

Seen on wood that has burned very hot, often an indicator of an accelerant, however not absolute, can help show the point of origin

Spalling

Splatters or speckles on brick or concrete. Good indicator of accelerant and arson, fire had to be extremely hot

Explain file in reference to the fire tetrahedron

The accelerant burns first. Soon, other nearby materials, such as wood or paper, ignite and become fuel for the continuation of the fire

Describe chain reaction in reference to the fire tetrahedron

The fire itself usually releases enough heat to keep he fire burning. The fire will continue to burn until all the oxygen or fuel is used or removed

Vaporization

The process where liquid changes to gas

Streamers

Trails of burn patterns, someone poured an accelerant on the ground in a trail. it was arson.

Undetermined

Unidentifiable

Which way does a fire always burn

Up

Describe heat in reference to the fire tetrahedron

When a heat source is present, the temperature of a substance rises

Point of origin

Where the fire started

How is evidence collected at the scene

•investigators collect 3-4L of ash and debris from the point of origin •collect anything that could have traces of an accelerant (look in cracks in the floor and upholstery) •use sniffers to detect molecuales and particles in the air that hold traces of an accelerant •may use arson dogs