forensics

action

the mechanical apparatus of a firearm that loads, fires, and ejects the cartridge

ballistics

the study of how projectiles move through space

barrel

the metal pipe that guides the initial flight of the bullet

bullet

projectile fired from a weapon

caliber

diameter of the gun barrel in 1/100th of a inch

cartridge

ammunition made up of casing, primer, powder, wadding, and bullet

chamber

enclosure in a gun’s design that contains the cartridge when ready to fire

drag

the force that opposes the forward motion of the bullet created by air resistance

external ballistics

study of the bullet from the time it leaves the end of the gun barrel until it reaches the target

firearm

an assembly consisting of a barrel and mechanical action that allows a projectile(s) to be propelled forward through action of an extremely fast combustion reaction

gunpowder

an explosive chemical mixture of carbon, potassium nitrate and sulfur that undergoes a rapid oxidation reaction and is used to propel projectiles in firearms

hammer

the part of the action that drives the firing pin into the primer on firing

internal ballistics

the consideration of the part of a bullet's path that occurs within the guns itself

magazine

a device for holding and delivering cartridge

magnum

a cartridge containing more than the standard amount of power which delivers more power to the bullet

muzzle

the very end of the gun barrel where the bullet exits the weapon

revolver

a firearm in which ammunition is moved into a place for firing by means of rotating a cylinder that contains a number of separate firing chambers loaded with filled cartridge

rifling

spiral grooves inside of the gun’s barrel which cause the projectile to spin about its long x-axis

semi- automatic weapon

a firearm in which the energy released from one firing mechanically ejects the spent case and reloads the next fresh round into the firing chamber; one round is fired for each pull of the trigger

shotgun

a type of long gun without rifling that uses ammunition containing either many small pellets (shot) packed into a single cartridge or a single, solid projectile (slug)

shrapnel

fragments of metal from a bomb, shell or mine

sight

the device on top of a gun that improves aim and accuracy

silencer

a device, placed over the muzzle, that reduce the noise emitted by tiring a weapon

stock

frame that hold the barrel and action together to allow aiming and firing

straiation

tiny, random imperfection marks transferred between 2 objects that pass with direct contact

arch pattern

The fingerprint pattern that has ridges beginning at one side of the fingerprint and running completely to the other side of the fingerprint without a backwards turn

loop pattern

the fingerprint pattern that contains ridge lines that enter on one side of the fingerprint, run towards the middle of the print, and then curve backwards to exit on the side that they entered the pattern

whorl pattern

the fingerprint pattern that contains ridges that complete at least one 360 degrees “circuit” in the pattern, although not always forming a regular circular pattern

bifurcation

the point in a fingerprint pattern where a single ridge splits into two new ridges

cheiloscopy

the furrows of the human lips used for individual identification

pinnascopy

the patterns of the ears used for individual identification

epidermis

the outermost layer of our skin that ranges in thickness from very thin on our eyelids (about 0.05 mm) to rather thick on the palms of our hands and the soles of our feet

dermis

the middle skin layer that is composed mostly collagen (protein) fibers, elastic tissue, and reticular fibers

hypodermis

the lowest layer of skin that is composed largely of fat and connective tissue that contains larger blood vessels and nerves

latent fingerprint

fingerprints are not observable to the naked eye but are present in oils and amino acids that have been left behind on a surface when touched by a finger. these may later be developed to become visible

patent fingerprints

a clearly seen print left on a surface when a finger coated in a liquid or powdery substance—like blood, ink, grease, or dirt—touches it, requiring no special processing to see, just simple photography for collection

sebaceous glands

glands in the skin that produce sebum, an oily material that protects, lubricates, waterproofs, and helps to inhibit the growth of microorganisms on the hair

ninhydrin

a chemical that reacts with the amino acids found in a fingerprint and, upon gentle heating, forms a typically purple/blue- coloured pattern of the fingerprint

cyanoacrylate

a technique using superglue vapors to develop invisible (latent) fingerprints on non-porous items like glass, plastic, and metal

furrows

the adjacent lower valleys next to the ridges of fingerprints

ridges

the top of the fingerprint ridge pattern on our fingers

natural Fibers

fibers come from many different naturally- occurring sources including plants animals and inorganic sources

synthetic Fibers

fibers that are prepared from chemical feedstock and are typically formed through polymerization reaction that lead to long chain molecules

anagen phase

the active growth time for hair formation

catagen phase

the transitional phase in hair growth when the hair stops growing and the portion of the follicle surrounding the hair root shrinks considerably

telogen phase

the resting period for the follicle in the hair growth cycle

keratin

a though, durable, fibrous protein composed of long chains of amino acids typically found as a structural component of hair, nails, horns, and claws

cortex

the inner potion of a hair fiber that makes up most of the bulk of the hair shaft and gives the hair it’s characteristic elasticity

medulla

the part of the hair at the center of the fiber that is characterized by either very spongy cells or no cells at all, forming a canal like structure in the center of the shaft (medullary canal)

melanin

a pigment polymer derived mostly from the amino acid called tyrosine that imparts the colour to the hair sample