1. Characteristics
Of an Explosion

2. X Not like a fire – does not need oxygen
Energy and gases released as products of rxn
Expanding gases produce a pressure wave (= longitudinal wave) X

3. Compressions = where coils are close together
Rarefactions = where coils are far apart
Wave transfers energy from one end to other
Explosion energy forces particles in air to move back and forth
If in container, stretches until bursts sending flying debris ( = shrapnel) all over

4. Explosives
= chemicals that react under certain conditions to cause explosions
Most are solids
2 categories – based on rate of reaction
1. low – slower, can burn rather than explode
2. high – faster, violent

5. Low Explosives Burn rapidly, but explode only when confined
Produce combustion rxn = deflagration
= rapid, intense burning
- produces pressure wave w/ a speed of less than 340 m/s (speed of sound)
Used as propellants
- produces enough gas and energy to push objects away from original explosion

6. Need a small amount of energy to ignite low explosive
Examples:
Black powder used to make safety fuses – carries spark to another explosive
Smokeless gunpowder – safest and most powerful

7. Fireworks = black powder or smokeless gunpowder and a fuse
- rxn produces gases putting pressure on paper surrounding firework -> explosion
- elements added to firework give off the colors

8. Natural gas – when mixes w/ oxygen can explode if ignited
- smell added to it to detect it

9. High Explosives Materials that detonate
= results in violent disruption to the surrounding area
Do not need to be confined to explode
Many decompose upon detonation
Example – TNT (C7H5N3O6)
2 C7H5N3O6  3N2 + 5H2O + 7CO + 7C
(Carbon will leave black soot)

10. Detonate easily producing pressure wave that moves as fast as 8,500 m/s
= shock wave
Widespread damage
Used to blast or shatter a target
2 categories – primary and secondary

11. Primary – dangerous
- sensitive to heat, pressure, and movement
- used to detonate other explosives or in shotgun shells
Examples – lead styphnate, mercury fulminate, nitroglycerin

12. Secondary – relatively safe
- not as sensitive, but can cause very violent explosions
- used for military or commercial purposes
Examples – TNT and dynamite (= nitroglycerin and silica mixture)

13. Categories based on usage
1. commercial – mining, road construction, demolition
2. military – ex. RDX (form of C-4), PETN, TNT
3. improvised explosive – illegal; low explosives in a container
- used for terrorism & guerrilla warfare