FSC239Y5 Lecture Notes - Lecture 6: Statistical Hypothesis Testing, Gunshot Residue, Sodium Carbonate
Document Summary
What do guns fire? cartridges, not bullets cartridges contain bullets, gunpowder, primer primer is shock-sensitive, explodes on physical impact burns gunpowder and fires bullet, expels cartridge. What is gunshot residue? gunshot residue not visible to the naked eye- only unburnt gunpowder to be considered gunshot residue, must contain lead, barium, antimony typically particles are spherical, usually about 1-10um. Gsr is a misnomer- actually looking for residues of primer. Was near a gun when it fired touched a surface with gsr on it. Negative result means didn"t fire a gun gun didn"t deposit residue. Gsr lost due to activity sampling was ineffective. Limitations of gsr analysis can"t determine firing angle, distance, gun, ammunition total number of gsr particles found can vary greatly victims are not sampled. Metals/metal compounds added to produce effects display-grade (professional) can produce gsr-like particles, but contains magnesium too. Airbags some use a primer similar to those in ammunition these do produce gsr except with cobalt as well.
