The chemistry behind it
what is the fundamental chemical reaction of fire
oxidation
What is the energy barrier for fire, and why
high energy barrier as a lot of heat is needed to start a fire
why is it important to be timely in fire investigations
accelerant residue may evaporate within a few days or even hours
the transfer of heat through direct contact of solids
conduction
explosives that are slower than the speed of sound and are food propellants for ammunitions
low explosives/ deflagration
what is the simple equation of fire
CH4 + 2O2 -> CO2 + 2H2O
what are three things needed for combustion
heat
oxygen
fuel
what is the most valuable thing to search for in a fire scene
the fires origin
(burn marks, fuel container,...)
the transfer of heat that occurs in fluids
convection
__________ are high explosives, characterized by supersonic shockwaves, breakage of chemical bonds, and new instantaneous buildup of heat and gases
detonation
where does heat come from in a chemical reaction
the breaking and formation of chemical bonds
while gasoline is flammable, simply mixing with oxygen does not produce fire. what is missing
energy/heat/spark
what are some tell tale signs that a fire was arson and not accidental
separate/ unconnected fires
a burn path
oxidation of iron produces what (not fire)
rust
explosives that are faster than the speed of sound and produce shattering effects on their targets
high explosives/detonation
an exothermic reaction ______ energy, as heat or light. what does this do to the surrounding temperature
releases, raises surrounding temperature
only when fuel is in a ___________-- state can it support a fire. Why?
gaseous
as a gas, molecules can collide frequently enough to support
samples collected from the scene are placed in airtight containers to trap volatiles. where the volatiles are trapped is called the _________
headspace
the transfer of heat through electromagnetic waves
radiation
________ are low explosives , characterized by very rapid oxidation, production of heat and light, and subsonic pressure waves
deflagration
an explosion is the product of combustion accompanied by what
creation of gases and heat
the lowest temperature at which a liquid gives off sufficient vapor to form a mixture with air that will support combustion
flashpoint
what is the portable tool used to search for accelerants
hydrocarbon detector
In dr. gilberts arson story, what method of heat transfer was most prevalent in the destruction of neighboring properties
radiation
______explosives will burn only the surface layer of compound while ________ explosives will detonate the entire mass simultaneously
low
high