just need to practiceeee

1. Chemistry of ballistics in the crime scene
Ellie Cox

2. What are they?...
• Ballistics is the science that deals with the motion and the
effects of projectiles such as bullets and also rockets.
• Ballistic body- The gun will be referred to this at a crime scene.
• Ballistic science will analyse the projectiles (bullets) that are
released from the ballistic body, the gun.

3. Internal ballistics…
• Look at things such as the passage of a bullet through the
barrel of the rifle, to see any damage of the passage from the
projectile.
Transition ballistics…
• Analysing the bullet or projectile when it leaves the barrel
and the pressure behind it.

4. External ballistics…
• Looking at the space or air that the projectile passes until it
gets to its desired target e.g. flesh/material.
Terminal ballistics…
Analysing the interaction of the bullet with its target e.g.
flesh/material.

5. Firearm ballistics
• This type of ballistics are used within a crime scene to analyse
the tool mark evidence allowing them to match guns or any
other tools to certain bullets and crimes.

6. Bullet comparisons…
Within crime scenes visual analysis is used to compare bullets
retrieved from the crime scene and link them with a suspects bullet.
To do this a bullet will be fired from the suspects gun into a water
tank, doing this they will be able to link certain bullets to certain
suspects.
They can use the lands, grooves and twists on the bullets to tell them:
• The manufacturer,
• The model
• The model
• And sometimes the year of the make.

7. Ballistics analysis…
• Bullet casing
• Evidence will be retrieved in a evidence bag and
necessary forms will be filled out before any evidence is
used and experimented on.

8. • Once this has been done, scientists are able to use a
comparison microscope that will have two separate lenses
allowing them to differentiate two different bullets using clues
like serial numbers.
•
• The comparison microscopes are also used in crime scenes to
differentiate suspects finger prints.

9. Pressed marking analysis…
• Pressed marking analysis is a vital technique within crime
scene science, using chemistry to initiate serial numbers from
bullets that have been filed off by the offender.
Serial numbers on bullets will allow us to link the bullet with
certain guns, therefore linking them with criminals with the
same gun and also the same bullets that can be linked to
other crimes.

10. • Chemistry has allowed us to be able to retrieve
the serial number if it has been filed off…
• First off all the area of the bullet will be smoothed down using
sand paper,
• Secondly it will be rinsed with acetone, which is an organic
compound used as the main ingredient within nail varnish
remover,
• Next copper on a cotton bud will be introduced and rubbed on
the area, this will then produce a chemical reaction between
the iron
• This chemical reaction will then cause the serial number to
reappear on the area.

11. References…
Bill Maher. (Aug 30th 2010). FIREARMS IDENTIFICATION AND BALLISTICS.
Available: http://www.drtomoconnor.com/3210/3210lect05a.htm. Last accessed
26th Jan 2011.
Lisa Steele. (2009). Ballistics. Available:
http://www.aware.org/arttruelaw/5450051chap1_abs.pdf. Last accessed 25th
Jan 2011
R.Conan-Davies. (2006). Crime scene investigation chemistry. Available:
http://clearlyexplained.com/answers/CSIchemistry.html. Last accessed 26th Jan
2011
http://www.forensicsciencescholars.org/resources/video/forensic-chemistry-lab-
ballistics - Video of pressed marking analysis
http://www.google.co.uk/imgres?q=bullets+serial+numbers&um=1&hl=en&tbm
=isch&tbnid=sLh2iokR9dS79M:&imgrefurl=http://www.ssaa.org.au/stories/hand
guns-the-versatile-357-magnum.html&docid=gYL5Drrl5nUlHM&imgurl=http:// -
Image of bullets