1835 Henry Goddard of Scotland Yard use a bullet comparison to solve a murder. He traced a flaw in the bullet’s shape to the pistol of a suspect.

1889 Alexandre Lacassagne, University of Lyon, matched individual bullets to specific gun barrels.

Comparison Microscope The comparison microscope enables two samples to be viewed side by side, so that similarities and differences are apparent. http://en.wikipedia.org/wiki/Comparison_microscope http://www.cnbftech.com/Productsshow.asp?id=529 http://www.jivepuppi.com/hairs.html http://www.trutv.com/library/crime/criminal_mind/forensics/ballistics/3.html

1974 SEM Images of GSR particles. Typically, GSR particles are very small (0.5 to 10 microns), spheroidal and contain combinations of lead, barium and/or antimony. http://www.mshp.dps.mo.gov/MSHPWeb/PatrolDivisions/CLD/TraceEvidence/gunshotResidue.html http://www.azom.com/article.aspx?ArticleID=4108 Electron microscope technique developed for the detecting of gun shot residue (GSR).

Ballistic Firearms

Ballistic Firearms Include handguns & rifles Information from the shot can be used to determine type of weapon, caliber of the weapon and distance between the shooter & weapon

Handguns Occur in two forms: Semiautomatic and Revolvers

Bullet cartridges

Speed loader for revolver

Rifles Lever Action

Shotguns Shotguns

Generic Shotgun Shell

Shotgun Cartridge

Cartridge

Semi-automatic

Rifling http://en.wikipedia.org/wiki/File:105mm_tank_gun_Rifling.jpg

Rifling http://www.google.com/imgres?hl=en&safe=off&sa=X&biw=1280&bih=907&tbm=isch&prmd=imvnsb&tbnid=cNgnkpgQUzmdYM:&imgrefurl=http://www.sott.net/article/159511-The-Assassination-of-Robert-Kennedy-Part-5-Sirhan-Sirhan&docid=TL_oHejoDBlBUM&imgurl=http://www.sott.net/image/image/9962/rifling.png&w=987&h=342&ei=Y4SGUIvDDabH0AHKjoDQBg&zoom=1&iact=rc&dur=1&sig=105852241313753638742&page=2&tbnh=92&tbnw=240&start=25&ndsp=30&ved=1t:429,r:9,s:20,i:231&tx=190&ty=58

Chambering & Firing a Round

Recoil Ouch!

Firing a Round & Ejecting the Cartridge

Build a Trajectory Device For a Class Activity

Build a Trajectory Device

Cost ~ $22 with laser ~ $5 without laser

Trajectory Angle Bang !

Angle of Entry

Check out the Lab Activities Bullet trajectory Firing pin cartridge match Building a trajectory device

The End!