presentation1

This presentation will include information about various ways

evidence is analysed.

By Sam Slack

There are four types of chromatography, these are; liquid, gas, paper and TLC, which is

also known as Thin Layer Chromatography. TLC is the main method and is where there is

a separation of coloured chemicals that have been mixed. It analyses each mixture

and separates them so it is easy for police to identify which chemical was used. E.g. urine

and blood samples. Molecules in various chemicals have different characteristics such as size and solubility so they travel at different speeds when pulled along a piece of paper;

this is that that separates them; shown by the picture to the right.

This tests any sound detected within the crime scene. An audiometer is used to perform an audiometric test which can

detect any particular noise. It also recognises different sounds like the

pitches and it can distinguish speech from any background noise. It enhances sound to make it easier to hear conversations and collect any evidence that may be

vital.

This focuses on the flight, behaviour and effects of various projectiles. This mainly involves guns and

rockets. It measures the time from the shooting to the impact made on the target. When looking into a gun

crime and analysing gun ballistics it is divided into four sections, these are:

•Internal ballistics—inside the object•Transition ballistics—as it left the object

•External ballistics—through the air•Terminal ballistics—when it hits the target

So it can look into the way the gun was used and how it was shot, so it can determine what gun it is.

It is the scientific study of various poisons, it analyses the effects and the treatment of the conditions they cause. This will help determine what is wrong

with that particular person by seeing what they have been poisoned by and what with. It may also state how much they

were poisoned with so doctors would then know how to deal with it.

This is where various instrumental techniques are used like mass

spectrometry, infra red, ultra violet and Calorimetry.

Mass Spectrometry is a technique used for measuring the molecular mass of a

sample.

This is the physiology of bone, skeleton and hard tissue. It can help answer many question like what race, sex or age is the person and it

can also show the stature of an individual.

E.g. when looking at bones we can determine the sex because males have more developed

and larger bones.

FEMALE MALE

Consists of the measurements and viewing of samples or objects through a microscope. There are three ways

microscopy can be conducted. These are through:•optical

•electron and•scanning probe microscopy.

Optical and electron Involves the diffraction, reflection or refraction of the object

being studied.

Scanning ProbeInvolves the interaction of a scanning probe with the surface or

object of interest

Electronic imaging and enhancement techniques to improve photography and video, TV

monitors, cameras, alarms.

From this by using the police force, it will then be a lot quicker to catch the criminal. As electronics are rapidly getting better and more advanced it

makes it a lot easier.

Study of weights and measurements embracing both experimental and

theoretical. It can be used by measuring

sizes of different objects that may be from a crime scene.

E.g. a bullet can be measured to determine what gun it could be or a joint of a bone can be measured to determine

what sex the bone is from.

This consists mainly the analysis of blood or anything biological, like body fluid. There are also other evidence samples

that may be analysed and they are:•Hair

•Fibres (e.g. clothing etc)

They use biological analysis because by using the fluids or fibres as evidence they can extract DNA to find out any piece of

information it is liable to give.