11.3 Notes

Explosions Product of combustion accompanied by creation of gases and heat and occurring at a rapid rate Most bombings are perpetrated by individuals Most bombs are homemade Criminalist must detect and identify the chemicals recovered from the crime scene –Identify the detonating device Product of combustion accompanied by creation of gases and heat and occurring at a rapid rate Most bombings are perpetrated by individuals Most bombs are homemade Criminalist must detect and identify the chemicals recovered from the crime scene –Identify the detonating device

Gas pressures expand and compress layers of surrounding air moving out in all directions –Causes violent physical disruption of surrounding environment –Can create artificial gale as high as 7000 miles per hour May be classified as a high explosion or a low explosion Gas pressures expand and compress layers of surrounding air moving out in all directions –Causes violent physical disruption of surrounding environment –Can create artificial gale as high as 7000 miles per hour May be classified as a high explosion or a low explosion

Speed of deflagration Burning Characterized by rapid oxidation that produces heat, light, and subsonic pressure waves –Low Explosives –Include Black and smokeless powders Burning Characterized by rapid oxidation that produces heat, light, and subsonic pressure waves –Low Explosives –Include Black and smokeless powders

Speed of denotation Creation of a supersonic shock wave within the explosive charge –Shock wave causes the chemical bonds of the explosive charge to break apart, leading to new instantaneous buildup of heat and gas –High explosives Include dynamite, TNT, PETN, RDX –Detonate almost instantaneously at 1,000 to 8,500 m/s Creation of a supersonic shock wave within the explosive charge –Shock wave causes the chemical bonds of the explosive charge to break apart, leading to new instantaneous buildup of heat and gas –High explosives Include dynamite, TNT, PETN, RDX –Detonate almost instantaneously at 1,000 to 8,500 m/s

Low Explosives Used as a medium to carry a flame Only ingredients required = fuel and oxidizing agent –Oxidizing agent = Potassium chlorate KClO 3 When mixed with sugar produces a popular and accessible explosive mix Chlorate can also be combined with carbon, sulfur, starch, phosphorus and magnesium Suitable as propellants for ammunition or skyrockets but dangerous Used as a medium to carry a flame Only ingredients required = fuel and oxidizing agent –Oxidizing agent = Potassium chlorate KClO 3 When mixed with sugar produces a popular and accessible explosive mix Chlorate can also be combined with carbon, sulfur, starch, phosphorus and magnesium Suitable as propellants for ammunition or skyrockets but dangerous

Black Powder Stable mix of KNO 3 /NaNO 3, charcoal and sulfur Unconfined if just burns Used as a medium for carrying a flame Safety Fuse – black powder wrapped in fabric or plastic casting Becomes explosive and lethal when contained Stable mix of KNO 3 /NaNO 3, charcoal and sulfur Unconfined if just burns Used as a medium for carrying a flame Safety Fuse – black powder wrapped in fabric or plastic casting Becomes explosive and lethal when contained

Smokeless powder Safest and most powerful Consists of nitrated cotton, single-base powder, or double-base powder Natural Gas Escapes from confided area and mixes with sufficient amount of air Simultaneous combustion Will only explode or burn in limited concentration range ( %) –Too high = not enough oxygen for combustion –Too low = not concentrated enough for combustion Safest and most powerful Consists of nitrated cotton, single-base powder, or double-base powder Natural Gas Escapes from confided area and mixes with sufficient amount of air Simultaneous combustion Will only explode or burn in limited concentration range ( %) –Too high = not enough oxygen for combustion –Too low = not concentrated enough for combustion

11.3 Questions 1.What produces the violent physical disruption associated with an explosion? 2.What is the difference between deflagration and detonation? 3.What ingredients are required to create a low explosive? 4.What types of explosives largely have replaced dynamite for industrial uses? What are the advantages of these types of explosives? 5.What is a detonator? What is the composition of most detonators? 1.What produces the violent physical disruption associated with an explosion? 2.What is the difference between deflagration and detonation? 3.What ingredients are required to create a low explosive? 4.What types of explosives largely have replaced dynamite for industrial uses? What are the advantages of these types of explosives? 5.What is a detonator? What is the composition of most detonators?